SEARCH RESULTS FOR: shock

Cardiogenic Shock

Distributive Shock

Obstructive Shock

Drugs used to treat shock

Pediatric Uncompensated Shock: pathogenesis and clinical findings

Tonsillitis: Pathogenesis and clinical findings

Tonsillitis: Pathogenesis and clinical findings
Group A Streptococci (GAS) infection1,2
Authors:
Amanda Marchak
Reviewers:
Nicola Adderley Jim Rogers Danielle Nelson* * MD at time of publication
   Viral pathogen1
5-15 years3
     Pathogen colonizes the nasopharynx
Pathogen colonizes oropharynx4 **
             ↑ vascular permeability Leakage of protein and fluid
into surrounding tissue
Inflammatory cytokine release
Inadvertent cellular injury and hemolysis
Tonsillar petechiae and erythema
Systemic inflammatory cytokines disrupt hypothalamic regulation
Fever
White blood cell (WBC) activation WBCs infiltrate site of infection
WBCs kill pathogen
Accumulation and deposition of cellular debris and products of inflammatory response
Tonsillar exudate
Note:
*When GAS is the pathogen, cytokine release and WBC activation is secondary to the release of exotoxins by GAS.
               Swelling and irritation
↑ lymph drainage to regional nodes
Enlarged anterior cervical nodes
Cough
Note:
It is extremely important to distinguish between viral tonsillitis and bacterial tonsillitis. Viral tonsillitis is usually self-limited while GAS tonsillitis can be associated with a number of complications.
Notes:
       Tonsillar tissue
Tonsillar edema
Nasal tissue6
Nasal congestion
Coryza
Nasal discharge irritates back of throat
Complications5:
            Peritonsillar abscess, neck abscess, otitis media, sinusitis, pneumonia, scarlet fever, bacteremia, osteomyelitis, meningitis, arthritis, erythema nodosum, hepatitis, acute poststreptococcal glomerulonephritis, acute rheumatic fever, and toxic shock syndrome
1. In general, viral tonsillitis is more common than GAS infection. However, in the absence of cough and coryza (acute, isolated tonsillitis), GAS is more common.
2. While GAS is the most bacterial cause of tonsillitis, it can be caused by other pathogens.
3. GAS tonsillitis is most common in patients of this age group although, rarely, it can occur in adults.
4. When GAS colonizes the oropharynx, the primary location of infection determines how it’s identified.
• tonsils primarily effected = tonsillitis
• pharynx (throat) primarily effected = pharyngitis (See slide on Group A Streptococci
Pharyngitis: Pathogenesis and Clinical Findings) • both = pharyngotonsillitis
5. The listed complications are the result of exotoxins entering systemic circulation or the bacterial infection extending beyond the tonsils.
6. While viral tonsillitis tends to be associated with more upper respiratory tract symptoms, clinical signs and symptoms are NOT reliable for diagnosing GAS tonsillitis. Throat swab or rapid antigen detection test are the standards for diagnosis.
 Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
  Complications
Published November 5, 2018 on www.thecalgaryguide.com

Hypernatremia Physiology

Hypernatremia: Physiology Unreplaced H2O loss
Hypodipsia
H2O shift into cells
Severe exercise, electroshock induced seizures
Transient ↑ cell osmolality
Na+ overload
Inappropriate IV hypertonic solution, salt poisoning
Abbreviations:
H2O: Water
GI: Gastrointestinal
DM: Diabetes Mellitus
DI: Diabetes Insipidus
Na+: Sodium ion
IV: Intravenous
ADH: Antidiuretic Hormone LOC: Level of Consciousness
               Skin
Sweat, burns
GI
Vomiting, bleeding, osmotic diarrhea
Fluid [Na+] < serum [Na+]
↑ H2O loss compared to Na+ loss
Renal
DM, Mannitol, Diuretics
Absent thirst mechanism
Hypothalamic lesion impairs normal drive for H2O intake
Nephrogenic
↑ renal resistance to ADH
H2O Deprivation Test + no AVP response
↓ access to H2O
            DI
Central
↓ ADH secretion
H2O Deprivation Test + AVP response
↑ [Na+] 10- 15 mEq/L within a few minutes
Weakness, irritability, seizures, coma
↑ thirst, ↓ urinary frequency and volume
                      Note:
Hypernatremia
Serum [Na+] > 145 mmol/L
Intracranial hemorrhage
Headache, vomiting, ↓ LOC
 • Plasma [Na+] is regulated by water intake/excretion, not by changes in [Na+].
• Effects on plasma [Na+] of IV fluids or loss of bodily fluids is determined by the tonicity of the fluid, not the osmolality.
Authors: Mannat Dhillon Reviewers: Andrea Kuczynski Kevin McLaughlin* * MD at time of publication
     Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
  Complications
Published January 11, 2019 on www.thecalgaryguide.com

Takotsubo Cardiomyopathy- Pathogenesis and clinical findings

Takotsubo Cardiomyopathy- Pathogenesis and clinical findings emotional physical stresses other neurologic endocrine drug brain natriuretic peptide coronary artery disease takotsubo catecholamine release stimulation Beta receptors ionotropic effect alpha receptors coronary vessels metabolic contraction band necrosis edema inflammatory cell infiltration localized fibrosis coronary vasospasm microvascular dysfunction decrease oxygen supply relative to demand hypo-contraction ballooning left ventricular apex chest pain troponin BNP elevation ST ECG changes absence of obstructive CAD transient left ventricle systolic dysfunction dyskinetic apex Mitral regurgitation ventricular thrombus cardiac output  low dyspnea syncope heart failure cardiogenic shock echocardiogram apex Gu gagnon Ryznar Waechter

Sepsis, and Septic Shock- Pathogenesis and Clinical Findings

Sepsis, and Septic Shock: Pathogenesis and Clinical Findings
Authors: Daniel J. Lane Simonne Horwitz Reviewers: James Rogers Emily Ryznar Braedon McDonald* Christopher Doig* *MD at time of publication
Sepsis
     Pathogen (Bacteria, Fungi, Virus, or Parasite)
Comorbidities
Immunosuppression or ↑ susceptibility (e.g. splenectomy)
Pathogen virulence
Invasion and host immune avoidance
Vulnerable infection site
↑ likelihood of spread of infection & mortality
Genetics
↑ Sensitivity of innate immune response
            Community acquired
Hospital acquired
      Infection of host
Innate immune response
Fever, Leukocytosis/ Leukopenia, Left Shift/ Bandemia
Compensatory response
Tachypnea, Altered Level of Consciousness, Hypotension
↓ perfusion and oxygen delivery to organs
Dysregulated Host Response
Pro- and anti-inflammatory response
           Life-threatening organ dysfunction caused by a dysregulated host response to infection
The Sequential Organ Failure Assessment (SOFA) or quick
SOFA (qSOFA) Scores may be used to assess mortality risk
                 Respiratory
↓ PaO2 / FiO2 (mmHg)
Nervous
↓ Level of consciousness
Septic Shock
Cardiovascular
↓ Mean Arterial Pressure
Organ Dysfunction
Liver
↑ Bilirubin
Kidney
↑ Creatinine, Acute oliguria
Coagulation
Thrombocytopenia, ↑ INR or aPTT
Require vasopressors to ↑ mean arterial pressure
                          Persistent hypotension despite adequate fluid resuscitation
↓ Mean Arterial Pressure (< 65 mmHg), ↑ Lactate (> 2 mmol/L)
  Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
  Complications
Published February 12, 2019 on www.thecalgaryguide.com

Ischemic Colitis

Ischemic Colitis: Pathogenesis and clinical findings
    Superior and inferior mesenteric arteries (SMA and IMA) supply blood to colon
Surgical repair of aorta
Borders of SMA and IMA collaterals at the splenic flexure and rectosigmoid junction are vulnerable to ischemia (“watershed” areas)
Atherosclerosis and narrowing of mesenteric arteries
Low flow state
(e.g., CHF, hypotension, arrhythmia)
Underlying CAD/PVD
Atrial fibrillation, endocarditis
Embolic arterial occlusion of SMA and/or IMA
Trauma, infection, clotting abnormalities
Mesenteric vein thrombosis
Vascular risk factors (e.g., smoking, hypertension)
Thrombotic arterial occlusion of SMA and/or IMA
               Endograft coverage of IMA
Nonocclusive hypoperfusion
      Inadequate blood flow to meet the cellular metabolic needs in the colon
Ischemic Colitis
Tachypnea Tachycardia Hyperthermia Hypotension
         Ischemic period
Loss of oxygen and nutrients to bowel
Reperfusion period
Influx of O2àreacts to produce more oxygen free radicals
Lipid peroxidation
Systemic inflammatory response syndrome*
Nausea and vomiting
Abdominal pain (generally left sided)
Peritonitis
Leukocytosis
Systemic shock
(inadequate perfusion to tissue)
Author: Audrey Caron Michael Blomfield Reviewers: Tony Gu Yan Yu* Edwin Cheng* * MD at time of publication
                Systemic shock
(inadequate perfusion to body tissue)
Hematochezia (Bloody stool)
Gangrene (tissue death)
Hemorrhage
Tissue damage/cell death (starting from mucosa and submucosa going outwards to serosa)
          Mucosal ulceration
Colonic inflammation
    Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
Published November 10, 2019 on www.thecalgaryguide.com

Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu disease)

Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu disease):
Pathogenesis and Clinical Findings
Inherited or de novo mutation in the ACVRL1, ENG, or Smad4 genes
Abnormal signalling within the transforming growth factor ß (TGF-ß) pathway
Unclear mechanismsàInability of vascular mural cells to stabilize and remodel newly formed blood vessels
Excessive proliferation of endothelial cells and ensuing overgrowth of blood vessels
Authors: Tony Gu Reviewers: Brian Rankin Yan Yu* Laurie Parsons* * MD at time of publication
          Formation of friable telangiectasias
(small dilated vessels apparent near the surface of skin or mucous membranes)
Formation of Arteriovenous malformations (AVMs):
Direct connection between arteries and veins without intervening capillary bed
        Nasal telangiectasias
Epistaxis (nosebleeds)
Gastrointestinal telangiectasias
Gastrointestinal bleeding
Mucocutaneous telangiectasias
Cerebral AVMs
Hepatic AVMs
Left to right shunting of blood
Heart works harder to perfuse tissues
Heart failure
Pulmonary AVMs
              Rupture
High flow left to right shunting of blood (the steal effect)
Cerebral ischemia
No oxygenation at capillaries
Hypoxemia
↑ erythropoietin production
Secondary polycythemia
No filtering from capillaries
      Hemorrhage, shock, death
Venous emboli enter arteries (paradoxical embolism)
Stroke
Venous bacteria enter arteries
Cerebral abscess
       Iron deficiency anemia
↓ serum iron is associated with ↑ coagulation factor VIII levels (mechanism unclear)
Venous thromboembolism
               Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
Published July 28, 2020 on www.thecalgaryguide.com

acute-pancreatitis-complications

Acute pancreatitis:
Complications
Inflammation causes vasodilation and vasculature leakage
Mild, (85%):
Interstitial edematous pancreatitis
Local accumulation of fluid in the pancreas
<2 weeks after onset
Acute peripancreatic fluid collection (not encapsulated)
Walled off by fibrous & granulation tissue
>2 weeks after onset
Pancreatic pseudocyst
(completely encapsulated)
Peritoneal irritation à pain
Large cyst can (very rarely) compress surrounding bowel
Acute Pancreatitis
Inflammatory cytokines are released from damaged pancreas
If recurrentàchronic pancreatitis (see relevant slide)
Inflammation damages pancreatic exocrine
cellsàInappropriate release of pancreatic enzymes into surrounding tissue & vasculature àdigesting pancreatic parenchyma
Authors: Nissi Wei, *Yan Yu Reviewers: Dean Percy, Miles Mannas, Varun Suresh, Brandon Hisey, *Kerri Novak, *Sylvain Coderre * MD at time of publication
                     complete resolution (most cases)
Necrotic tissue is vulnerable to
infection (esp. Gram neg GI bacteria)
inflammation & necrosis activate cytokine cascade
Severe, necrosis (15%): Necrotizing pancreatitis
Local infection
Severe pancreatic inflammation shifts body fluid into retroperitoneal spaceàintravascular volume depletion
                 Systemic Inflammatory Response Syndrome (SIRS) (see relevant slide)
Organ failure (may be sole feature on presentation)
Stagnant fluid can more easily become infected
Infection spreads to bloodstream
Cardiac failure Hypovolemic shock Renal failure
Local accumulation of fluid & necrosis in the pancreas
< 4 weeks after onset:
Acute necrotic collection (not encapsulated)
Walled off by fibrous & granulation tissue
> 4 weeks after onset
walled-off necrosis
(completely encapsulated)
When treated with excess fluid resuscitation:
Intra- abdominal hypertension
                Respiratory failure (ARDS)
Disseminated intravascular coagulation (DIC)
          Bowel obstruction Gastric outlet (see relevant slide) obstruction
Infected pancreatic necrosis
  Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
Published September 20, 2016, updated September 7, 2020 on www.thecalgaryguide.com

Beta-Blockers-Mechanism-of-Action-and-Side-Effects

Beta-Blockers: Mechanism of Action and Side Effects Two classes of “Beta-Blockers” are used clinically:
Non-cardio-selective: binds Cardio-selective: binds largely beta-1 and beta-2 receptors to beta-1 receptors
Authors: Tegan Evans, Davis Maclean, Yan Yu* Reviewers:, Amanda Nguyen, P. Timothy Pollak*, Sean Spence* * MD at time of publication
        Beta blockers bind to beta 1 and/or beta 2-receptors of various tissues throughout body, and thus competitively inhibit binding of sympathetic adrenergic molecules (such as catecholamines from the adrenal medulla, e.g. epinephrine) to these receptors, ↓ their normal adrenergic tone
Beta-2 receptor antagonism Beta-1 receptor antagonism
      Lungs Eyes Central nervous system Heart Kidneys ↓ cAMP (intracellular messenger) productionàcomplex, tissue-specific intracellular mechanisms resulting in a variety of effects in different tissues:
Throughout body tissue
             Epinephrine (via cAMP) indirectly ↑ the activity of the Na+/K+ pump on cell membranes (a pump that moves 3 Na+ out of cells per 2 K+ moved into cells)
Blocking epinephrine from binding
the beta-2 receptor and producing cAMPà↓ activity of Na+/K+ pump à↓K+ moved into cells
↑ proportion of K+ now resides in extracellular fluid, detectable in serum (total body K+ remains the same)
Hyperkalemia (see Calgary Guide: Hyperkalemia – Clinical findings)
Blocking sympathetic hormonesà↓ relaxation of smooth muscle circumferentially wrapped around airways
↑ resting airway muscle toneà bronchoconstriction
↑ resistance to airflow
Wheezing, dyspnea, chest tightness
Exacerbation of underlying airway disease (e.g. asthma)
↓ ciliary epithelium’s production of aqueous humor (fluid that fills anterior chamber of the eye)
Reduced intraocular pressure
Blocking adrenergic response mediated by epinephrine and norepinephrine (e.g. the physiologic “fight- or-flight” response to stress)
↓ tremor, irritability, anxiety
↓ ability to produce adrenergic symptoms in response to hypoglycemia
Hypoglycemia unawareness
Coronary perfusion pressure = diastolic blood pressure in aorta – LV end diastolic pressure
↓ inotropy (contractility of cardiac muscle)
  ↓ chronotropy (heart rate and conduction velocity)
↓ renin releaseà↓ creation of angiotensin II & aldosterone
+ ↓ reabsorption of Na
and H2O in nephron
↑ urinary Na+ & H2O loss
↓ total blood volume
Decompensation of acute heart failure
Dizziness and fatigue Hypotension (Blood pressure = cardiac
output x systemic vascular resistance)
        ↓ O2 demand of myocardial tissue
             Bradycardia
Inability to ↑ heart rate in response to stress (e.g. shock, sepsis)
↓ stroke volume
            ↓ cardiac output
               Beta blockers ↓ diastolic blood pressure, & thus may ↓ coronary perfusion pressure
Before giving beta blockers, ensure blood pressure isn’t too low
Otherwise, may worsen acute myocardial ischemia
      Legend:
 Pathophysiology
Mechanism
 Sign/Symptom/Lab Finding
  Complications
 Published Jan 14, 2021, updated Feb 7, 2021 on www.thecalgaryguide.com

AAA-Clinical-Findings-and-Complications

Abdominal Aortic Aneurysm (AAA): Clinical Findings and Complications AAA = Abnormal, irreversible dilation of a focal area of abdominal aorta (area of aorta between
diaphragm & aortic bifurcation) to twice the diameter of adjacent normal artery segments
     Asymptomatic, non-ruptured aneurysm:
Most AAAs are asymptomatic until rupture or days before impending rupture
Asymptomatic AAAs are only detectable on imaging or by palpation
Given their structural weakness, AAAs are at risk of rupture (risk ↑ with ↑ size of aneurysm)
Ruptured AAA: a medical emergency
Aorta lies in between the peritoneal and retroperitoneal space
Symptomatic, non-ruptured aneurysm: rarely, an unruptured AAA can cause symptoms or complications (0.1%-1% of AAAs)
                   Authors: Olivia Genereux, Davis Maclean, Yan Yu* Reviewers: Jason Waechter*, Amy Bromley*, Sandeep Aggarwal*, Gregory Samis* *MD at time of publication
Posterior aortic wall rupture
Retroperitoneal hemorrhage
Sudden and severe abdominal and/or back pain
Anterior aortic wall rupture
Peritoneal hemorrhage
Peritoneal space is larger and holds larger volumes of blood
Peritoneal hemorrhages are large (entire blood volume can pool in the peritoneal space in minutes)
Prior to rupture, the adventitia (thin outermost collagenous layer of the aorta) may dilate significantly
Adventitia is the only layer of the aorta that contains sensory innervation à nociceptors there can be activated by adventitia dilation
Very rarely (0.1%), areas of stagnant blood flow within the AAA allow for blood & clotting factors to accumulate
Thrombi (blood clots) develop in these aneurysms
Thrombi may dislodge and travel (embolize) to distal vasculature, cutting off blood- flow to these areas
                              This process (referred to as tamponade) is crucial in preventing catastrophic blood loss, allowing for a window of opportunity for treatment
Compensated Hypovolemic Shock: Low blood pressure &
poor organ perfusion, but blood loss has temporarily stopped. This state of shock is compatible with life if patient is otherwise healthy (e.g. no coronary artery disease)
↓ space for blood to accumulate in the retroperitoneal space (compared to the peritoneal space)
Rapid pressure ↑ in retroperitoneal space overcomes the pressure in aorta
Since blood will only travel from areas of ↑ pressure to areas of ↓ pressure, this pressure gradient prevents further blood loss from ruptured aorta
Massive hemorrhage due to high blood flow volume through aorta
Hypotension and rapid progression to hypovolemic shock
Abdominal and/or àorgan ischemia
back pain
The most common symptom of a symptomatic non- ruptured aneurysm, and may be the first sign of an impending aneurysm rupture
     Death within minutes
(rare)
      If low blood pressure is now (inappropriately) treated with fluid resuscitation, the blood pressure will ↑
Differential pressure gradient is reversed (aortic blood pressure > pressure in retroperitoneal space)
Bleeding into retroperitoneal space resumes
Decompensation of hypovolemic shock Possible death
Kidney ischemia
Lower limb ischemia
            Time exists to transfer patient to tertiary care center for surgical treatment
  Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
Re-Published February 28, 2021 on www.thecalgaryguide.com

Fat-Embolism-Syndrome

Fat Embolism Syndrome: Pathogenesis and clinical findings
Panniculitis (conditions causing
inflammation of subcutaneous fat)
Non-trauma related (rare)
        Long bone fracture
Pelvic fracture
Orthopedic Trauma
Intraosseous access
Soft tissue injuries
Chest compressions
Bone marrow transplant
Pancreatitis
Diabetes mellitus
                   Fat from bone marrow is disrupted and leaks into bloodstream via damaged blood vessels
Fat globules obstruct dermal capillaries
Capillaries rupture
Blood leaks into the skin
Petechial rash
Non-Orthopedic Trauma (less common)
Fat from injured adipose tissue is released from adipocytes into bloodstream
Metabolic disturbance mobilizes stored fat and moves it into circulation
     Fat Embolism Syndrome
the presence of fat globules in circulation
Fat globules damage blood vessel walls
Platelets stick to damaged areas Platelet aggregation
↑ circulating free fatty acids
↑ inflammatory cytokines (TNF, IL1, IL6)
↑ serum C Reactive Protein (an acute phase reactant)
C reactive protein binds to lipid vesicles in circulation
↑ formation of lipid complexes in the blood
                      Obstruction of cerebral vasculature
↓ blood flow and oxygen delivery to brain tissue
Neurological findings: ranging from ↓ level of consciousness to seizures
Notes:
Large quantities of fat globules can obstruct pulmonary vasculature
           Blood clots form throughout the body
Disseminated intravascular coagulopathy
Back up of blood into right heart àRight ventricular dysfunction
   ↓ pulmonary arterial blood flow à↓ gas exchange in the lungs
Higher CO2 & lower O2 levels in blood àdetected by chemoreceptors
Chemoreceptors stimulate respiratory centre in the brain to ↑ rate of respiration
Dyspnea / Tachypnea
Authors: Tabitha Hawes Reviewers: Hannah Koury, Alyssa Federico, Davis MacLean, Mehul Gupta, Yan Yu*, Jeremy Lamothe* * MD at time of publication
              • Underlined findings indicate classic triad of symptoms (petechial rash, neurologic findings, dyspnea/tachypnea)
• Clinical presentation of fat embolism syndrome is variable and may present with any or all of these findings
↓ pumping of blood into systemic circulation
Hypotension Obstructive shock
      Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
Published July 19, 2021 on www.thecalgaryguide.com

covid-19-pathophysiology-and-clinical-findings

COVID-19 (Corona Virus Disease 2019): Pathophysiology and Clinical Findings
Authors: Ryan Brenneis, Yan Yu* Reviewers: Ciara Hanly, Yonglin Mai (􏰄􏰁􏰃)*, Stephen Vaughan* * MD at time of publication
-Respiratory failure -Septic shock -Multiple organ dysfunction
Critical
      Respiratory droplet production (cough, sneeze, talking, breathing) by human host or animal vector infected with SARS-CoV-2
Note: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the name of the betacoronavirus (a positive sense, single stranded RNA virus). COVID-19 is the name of the disease caused by this virus.
rate, ↓ oxygen saturation -Bilateral interstitial infiltrates on Chest X-ray, progressively worsening
     Small droplets (<5μm in diameter) are aerosolized and become airborne
Inhalation of aerosolized particles that are suspended in air
Patient exposed to the virus (SARS-CoV-2)
Droplet contacts the mucus membranes (eyes, nose, mouth) of recipient
Live viral particles can adhere to inanimate objects called fomites (e.g. doorknobs)
Symptoms are on a continuum -Worsening dyspnea: ↑ respiratory
    -Fever
-Cough
-Myalgia, fatigue -Nausea/vomiting -Diarrhea
-Loss of taste/smell
            Recipient touching infected fomite subsequently touches any of their mucus membranes
Mild
Moderate
Severe
      Virus spreads in the body via 1) mucus membrane spread to surrounding cells and 2) entering the blood
Virus adheres to angiotensin-converting enzyme 2 (ACE-2) receptor on body cells, mimics ACE-2, & gains access into cell
COVID-19
Symptomatic infection with SARS-CoV-2
Viral proliferation in cells of tissues with more ACE-2 receptors: lungs (type II pneumocytes); vasculature (endothelial cells), kidneys (proximal tubular epithelium), heart (myocardium), GI tract (enterocytes)
Cell death and ↑ in inflammatory cytokines triggers immune response
           Neutrophils move to lungs, release reactive oxygen species and cytokines
Alveolar/capillary damage
Fluid accumulates in interstitium and alveoli
↑ Distance for O2 to diffuse from alveoli to capillaryà ↓ blood O2 saturation
Cytokines induce the hypothalamus to release prostaglandins
↑ body temperature set point to fight infection
     Virus disassembles, releasing viral RNA, which uses host cell’s ribosomes to make new viral proteins like RNA-polymerases
Newly made viral RNA-polymerases use cell’s own nucleotides to synthesize new viral RNA
Bilateral ground-glass opacities (CT lung) & interstitial infiltrates on Chest X-ray
Dyspnea
Airway irritation
Cough
Myocardial cell damage
↑ Troponin
↑ skeletal muscle cell damage
                  Viral RNA & proteins packaged into new viral particles
New virus assembled and released from cell, killing the cell and contributing to disease symptoms
Average incubation period (time from initial infection to symptom onset) is 4-5 days; can be up to 14 days
Heart tries to compensate for
Fever Myalgia
              hypoxemiaà↑ cardiac output   Arrhythmogenic
  and strain on myocardium
state
 Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
  Complications
 Published March 22, 2020, updated Aug 18, 2021 on www.thecalgaryguide.com

Ectopic Pregnancy

Ectopic Pregnancy: Pathogenesis and Clinical Findings
In vitro fertilization
Tubal disorders leading to infertility and unknown procedural causes
      Previous ectopic pregnancy
Underlying tubal disorder leading to previous ectopic
Pelvic inflammatory disease (PID)
Endometriosis
Tubal surgery or disorders
Age >35
Risk factor accumulation over time
Smoking
Impairment in tubal motility; impaired immunity (risk factor for PID)
        Tubal scarring leading to adhesions, obstruction, and alteration of tubal function
   Ectopic Pregnancy:
Implantation of developing blastocyst outside the uterine cavity, most commonly in fallopian tube (other locations: interstitial > cornual > cervical > ovarian > abdominal)
Embryo releases human chorionic gonadotropin (β-hCG), which supports corpus luteum to continue producing progesterone
On transvaginal ultrasound: Extrauterine gestational sac with a yolk sac or embryo
Embryo & trophoblast deathàloss of hormone support for the decidua (modified endometrial lining)
Progesterone maintains the endometrial lining, preventing it from shedding
Missed period
       Penetration of ovum into muscular wall of fallopian tube
Tubal distention àTubal rupture
Intra-abdominal hemorrhage
Pregnancy cannot survive without the uterine endometrium
Maternal blood extrudes through fimbriae of fallopian tubes and into peritoneal cavity
Lower abdominal pain (including peritonitis in cases of hemoperitoneum)
Hemoperitoneum
(blood in the peritoneal cavity)
Sloughing of decidua out of the uterus through the vagina
Vaginal bleeding (usually in first trimester)
Cessation of human chorionic gonadotropin (β-hCG) release from embryo
β-hCG plateaus or decreases
Authors: Jemimah Raffé-Devine Tahsin Khan Yan Yu* Reviewers: Brianna Ghali Bishwas Paudel Mackenzie Grisdale Christina Schweitzer Ron Cusano* Jadine Paw* * MD at time of publication
                     Syncope
↓ Level of consciousness
Positive β-hCG, but rising <35% over 2 days
Discriminatory zone: β-hCG >2000 + absence of intrauterine pregnancy
 Hypotension
   Shock
 Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published Oct 1, 2017, updated Oct 19, 2021 on www.thecalgaryguide.com

necrotizing fasciitis

Necrotizing Fasciitis: Pathogenesis and Clinical Findings
Authors: Alyssa Federico, Amanda Eslinger, Matthew Harding, Mehul Gupta Reviewers: Heena Singh, Yan Yu*, Donald Graham*, Duncan Nickerson* * MD at time of publication
       Diabetes
Loss of protective sensation in lower extremities
Peripheral vascular disease
Poor arterial perfusion causes necrosis of tissue
Immune compromised host
Increased susceptibility to infection
Bacteria introduced to tissue
Pharyngitis
Blood carries bacteria from throat to other tissue (hematogenous spread)
Laceration
Recent surgery
Injection
Burn
Blunt force trauma
Childbirth
            Lower extremity wounds
Bacteria enters tissue through open wound
Infection of muscle fascia Local immune response
Production of exotoxins by bacteria
Disruptions of protective skin barrier
Bacteria introduced into tissue during injury
     Necrotizing Fasciitis
Type I infection: mixed aerobic and anaerobic bacteria Type II infection: group A streptococcus
Type III infection: marine organisms, clostridial infections Type IV infection: fungal organisms
Poor blood supply of muscle fascia allows for progressive spread of infection
Systemic immune response
Pyrogens produced by immune system
Pyrogens travel through
the bloodstream to the hypothalamus and alters the body’s thermal setpoint
Transmission of bacteria from infected tissue to blood
Sepsis
                                 Streptolysin (exotoxin) causes blood clot formation
Blood clots in vessels
Tissue ischemia in epidermis, dermis, subcutaneous fat, muscle fascia, and/or muscle
Stimulation of programmed cell death
Tissue destruction
Pain more severe than clinical findings
↓ blood flow fails to meet tissue’s needs
Tissue death
Build up of gas in subcutaneous
tissue from bacteria metabolism
Crepitus
↑ serum creatinine
kinase from protein breakdown
↑ blood flow to infected tissue
Warmth Erythema
Immune cells release vasoactive cytokines into the blood
Capillary vasodilation
Fluid and proteins shift from cells and capillaries to interstitial space
Blood
vessel dilation
↓ perfusion of vital organs
Organ failure
Hypotension
↑ heart rate to perfuse vital organs
Tachycardia
Bacteria releases toxins which are taken up into the bloodstream
Immune cells produce inflammatory cytokines
Circulating toxins activate T cells, over- activating the systemic immune response
Toxic Shock syndrome
Infection ↑ white blood cell production in bone marrow
↑ white blood cells
                         Destructionof peripheral nerve endings
Insensitivity to pain
Tissue hypoxia à anaerobic metabolism
Poor perfusion of lungs impairs gas exchange
Tachypnea
Cytokines affect dopamine production in the basal ganglia
Acute malaise
Production of non-specific acute phase reactants
↑ C reactive protein and erythrocyte sedimentation rate
 Fluid-filled blisters
Edema
Fever Compartment syndrome (see relevant Calgary Guide slide)
  Amputation ↑ serum
lactate
    Legend:
 Pathophysiology
 Mechanism
 Sign/Symptom/Lab Finding
 Complications
First published Nov 20, 2013, updated Dec 19, 2021 on www.thecalgaryguide.com

sepsis-y-shock-septico-patogenesis-y-hallazgos-clinicos

sepsis-y-shock-septico-patogenesis-y-hallazgos-clinicos

Vitiligo Pathogenesis and Clinical Findings

Vitiligo: Pathogenesis and clinical findings
Authors: Wisoo Shin Reviewers: Lauren Lee
Stephen Williams Ben Campbell Laurie Parsons* Yan Yu* * MD at time of publication
  Genetic predisposition
Variants in over 30 susceptibility loci
Environmental exposure
UV light, monobenzone, phenol, catechol
      Production of IgG auto- antibodies to melanocyte-specific proteins
Auto-antibodies bind to melanocytes and trigger antibody-dependent cellular cytotoxicity: marking melanocytes for destruction by Fc- receptor bearing immune cells such as neutrophils
Impaired mitochondrial function in melanocytes
↑ Susceptibility of melanocytes to oxidative stress
↓ E-cadherin or ↑ anti- adhesion molecule expression in melanocytes
↓ Adhesion of melanocytes to keratinocytes
↑ Clearance of melanocytes from epidermis
    ↑ Reactive oxygen species production within melanocytes Activation of apoptosis and senescence signaling pathways
Pressure or friction
          Melanocytes excrete exosomes (melanocyte- specific antigens, microRNA, heat shock proteins) that, through complex mechanisms, stimulate the immune system’s CD8+ T-cells to destroy melanocytes
Melanocytes enter apoptotic or senescent state
↓ Functional melanocytes
↓ Melanin production
Overall loss of functional melanocytes
Vitiligo
Normal Skin
Pigmented Epidermis Dermal- Epidermal Junction
Dermis
Autoimmune destruction of melanocytes
Depigmented Epidermis
      Melanocytes
   Immune-mediated destruction of melanocytes (by both neutrophils and CD8+ T cells)
   A depigmenting skin disorder characterized by selective loss of melanocytes
    Depigmentation in areas of
↑ pressure, friction and/or trauma
Nonsegmental vitiligo
Smooth unpigmented macules or patches in bilateral, often symmetric pattern
Somatic mosaicism (mutation limited to a subset of cells) in zygote during development
Segmental vitiligo
Smooth unpigmented macules or patches in unilateral pattern not crossing midline
Vitiligo
     Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
Published February 15, 2022 on www.thecalgaryguide.com

Hypovolämischer Schock: Pathogenese, Komplikationen und klinische Befunde

Hypovolämischer Schock: Pathogenese, Komplikationen und klinische Befunde

complications-of-pulmonary-embolism

Complications of Pulmonary Embolism
Authors:
Sravya Kakumanu, Dean Percy, Yan Yu
Reviewers:
Tristan Jones, Ciara Hanly, Jieling Ma (马杰羚), Ben Campbell, Dr. Man-Chiu Poon*, Dr. Lynn Savoie*, Dr. Tara Lohmann * * MD at time of publication
IF CHRONIC:
Unresolved clot after 2 years leading to fibrosis of pulmonary vasculature
Chronic Thromboembolic Pulmonary Hypertension (CTEPH)
(<5% of PE cases)
     Venous Stasis Hypercoagulable state
Vessel Injury
Virchow’s Triad (*See Suspected Deep Vein Thrombosis slide)
Deep Vein Thrombosis
Clot migrates from deep limb veins à femoral àiliac veins
ACUTE/MASSIVE PE:
Clot obstructs pulmonary arterial or arteriolar flow
Lung infarction (tissue death) from ischemia
Inflammatory cells migrate to site and release cytokines
↑ Permeability of blood vessels
Permeability-driven (exudate) fluid leakage into pleural space
Pleural Effusion
Clot migratesàinferior vena cava àright atrium (RA) of heartà right ventricle (RV) à gets lodged in pulmonary arteries/arterioles
Pulmonary Embolism (PE)
           ↑ RV afterload
↑ RV pressure and expansion
Well-ventilated (V) areas of lung do not receive adequate blood supply (Q)
V/Q Mismatch
           Leftward shift of ventricular septum
↓ Left ventricle filling in diastole
↓ Cardiac output
Obstructive Shock
Impaired heart filling
Pulseless Electrical Activity
(ECG activity in absence of palpable pulse)
Back up of pressure in systemic venous system
↑ Pressure in capillaries draining parietal pleura
Pressure-driven (transudate) fluid leakage into pleural space
For signs and symptoms, see the Obstructive Shock slide
For signs and symptoms refer to CTEPH slide
Chronic ↑ RV afterload
↑ Stretching of myocytes causing RV hypertrophy and dilation
↓ RV ejection fraction
Right Heart Failure
“Cor Pulmonale”
For signs and symptoms, see the Right Heart Failure slide
               Failure to oxygenate blood
Type I Respiratory Failure
Hypoxemic: patient has ↓ blood [O2]
IF MASSIVE PE (less common):
↑ Alveolar dead space
Failure to ventilate
Type II Respiratory Failure Hypercapnic: patient has ↑ blood [CO2]
             Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published August 7, 2012, updated Mar 31, 2022 on www.thecalgaryguide.com

burn-shock-pathogenesis-complications-and-clinical-findings

Burn Shock: Pathogenesis, Complications, and Clinical Findings Thermal burn injury > 20% Total Body
Surface Area
Authors: Shayan Hemmati Reviewers: Christy Chong Ben Campbell Donald McPhalen* * MD at time of publication
     ↑ Production of local inflammatory markers (ex. histamine, bradykinin, and prostaglandins)
Endothelial cell lining in blood vessel walls is compromised
↑ Local vessel permeability
Shift of plasma + proteins from vessel into interstitial space
Direct vascular thermal injury (within burn wound)
↑ Production of circulating inflammatory mediators (ex. IL-1, IL-6, TNF-!)
↑ Systemic vessel permeability
↑ Circulating reactive oxygen species
Damage to DNA, proteins, and lipids throughout body, including myocardium (muscle cells of the heart)
↑ Myocardial stress
Myocardial dysfunction
↓ Cardiac contractility ↓ Stroke volume ↓ Cardiac output Cardiogenic
Shock
Refer to Cardiogenic Shock:
Pathogenesis, Complications and Clinical Findings
              ↓ Protein concentration in vessels causes ↓ intravascular oncotic pressure
Further shift of plasma from vessel into interstitial space (↑ interstitial proteins pull plasma into interstitium)
↓ Intravascular plasma
↑ RBCs per unit volume of plasma
↑ Systemic vasoconstriction to maintain blood pressure (↑ Afterload)
↓ Circulating blood volume leads to less venous return (↓ Preload)
↑ Hematocrit
    Pitting edema (burned & unburned tissue)
↓ Circulating blood volume
Hypovolemic Shock
Refer to Hypovolemic Shock: Pathogenesis, Complications and Clinical Findings
Burn Shock: A complication of large burns causing end-organ hypoperfusion with resultant organ dysfunction
                   Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published August 15, 2022 on www.thecalgaryguide.com

ascending-cholangitis-pathogenesis-clinical-findings

Ascending Cholangitis: Pathogenesis and clinical findings
Authors: Brandon Hisey, Neel Mistry Reviewers: Alec Campbell, Vina Fan, Ben Campbell, Kelly Burak*, Eldon Shaffer* * MD at time of publication
Reflux of biliary contents into the vascular system (cholangiovenous reflux)
Bacteria ascends into biliary tract from duodenum via Sphincter of Oddi
     Gallstone in the common bile duct
Stricture of biliary/hepatic ducts
Biliary / pancreatic duct malignancy
Biliary obstruction (partial bile duct obstruction)
↓ Excretion of bilirubin into
bileà ↑ bilirubin in blood
↑ Serum bilirubin
Deposition of bilirubin in the skin and mucous membranes
Jaundice*†
Parasites in bile duct
(E.g. Clonorchis)
Complication of endoscopic retrograde cholangiopancreatography (ERCP)
        Bile accumulates in biliary tract
Bile duct dilation on ultrasound
Sludge (bile precipitants) impact bile ducts worsening obstruction
Obstruction & detergents in bile inflame ductal mucosa. Inflammation then spreads to adjacent structures
Stimulates phrenic (C3-C5) and foregut autonomic nerves (T5-T8)
Dull right upper quadrant pain*† radiating to back and right shoulder
↑ Intra-biliary pressure
Impaired forward flowà
↑ backflow of bile
Impaired bile secretion damages ductal epithelium of the biliary tract
Damaged ductal epithelium leaks ALP and GGT (enzymes) into blood
↑ Serum ALP and GGT
↑ Permeability of bile ductules
Reduced flushing of bile out to duodenum
               Inflammatory response triggered
Fever*† ↑ WBCs
Tachycardia Hypotension† Confusion† Oliguria
Bacterial translocation from biliary tract into blood
Bacteremia
Massive systemic inflammatory response
Septic Shock
(see Distributive Shock slide)
                   * Charcot’s triad ~20% of cases | † Reynolds’ pentad ~7% of cases
 Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
First published November 18, 2015; Updated August 31, 2022 on www.thecalgaryguide.com

acute-lower-gi-bleeds-pathogenesis-and-clinical-findings

Acute Lower GI Bleeds: Pathogenesis and Clinical Findings
      Diverticulosis
Formation of diverticula (outpouchings of the bowel wall)
Intestinal vessels are stretched over the domes of the diverticula
Angiodysplasia
Formation of
dilated, thin- walled vessels in GI tract mucosa/ submucosa
Colorectal Cancer
Infectious Colitis
Invasion of bacteria and/or bacterial toxins into intestinal wall
Cell damage and cell death
Sloughing off of intestinal epithelial cells
Ischemic Colitis
↓ Blood flow to a portion of the colon
Lack of oxygen delivery to colon wall
Necrosis (cell death) in the colon wall
Inflammatory Bowel Diseases (Note: these are chronic diseases and rarely present with acute lower GI bleed)
                    New, extremely friable blood vessels develop within the tumor
Malignant tissue invades the colon wall and disrupts colonic blood vessels
Crohn Disease
Immune- mediated full thickness inflammation of bowel wall
Ulcer formation and disruption of intestinal vessels
Ulcerative Colitis
Recurrent immune- mediated inflammation of colon mucosa
    Authors:
Miranda Schmidt Illustrator:
Mizuki Lopez Reviewers:
Vina Fan,
Ben Campbell, Kerri Novak*
* MD at initial time of publication
Acute Lower GI Bleed
↑ Risk for vessel damage and rupture
       Blood travels rapidly through GI tract
Hematochezia
(bright red blood per rectum)
May result in significant blood loss
Blood from the small intestine or right colon travels a longer distance through the GI tract
Bacteria in the GI tract has time to oxidize hemoglobin in the blood
Oxidization makes blood a darker color
Melena (rare in a lower GI bleed) (tarry black stool)
      Inferior Vena Cava
Diaphragm
Esophagus
Loss of red
blood cells results in a loss of hemoglobin (a component of red blood cells)
Fluid from the extravascular space moves into the blood vessels to maintain vascular volume
Fluid is administered in a healthcare setting to compensate for blood loss
Hypovolemic Shock (rare in a lower GI bleed) (↓ Oxygen delivery to tissues due to low blood volume)
See “Hypovolemic Shock” slide for signs and symptoms
       Lower GI Bleeds
are intra-luminal GI tract bleeds that occur anywhere distal to the ligament of Treitz (transition between duodenum and jejunum)
After 24 hours, the addition of fluid to the intravascular space dilutes hemoglobin in the blood
Normocytic Anemia
       Duodenum
Ligament of Treitz
 Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published August 31, 2022 on www.thecalgaryguide.com

ventilator-associated-pneumonia-pathogenesis-and-clinical-findings

Ventilator-Associated Pneumonia: Pathogenesis and Clinical Findings
Respiratory failure or inability Risk factors: e.g. immunocompromised, poor swallowing
   to maintain airway ability, weakened respiratory muscles, chronic disease Insertion of endotracheal tube (ETT) for invasive mechanical ventilation to maintain respiration
          Paralytics and
sedatives lead to inhibition of cough reflex
Damage to cilia on epithelial cells of trachea during insertion of ETT
↓ Mucociliary clearance
Insertion of nasogastric (NG) tube for feeding
Constant opening by NG tube ↓ esophageal sphincter function
Introduction of oropharyngeal microbes during intubation
Severe acute illness impairs phagocytosis and dysregulates T- cells (mechanism unclear)
Medications, chronic disease, or severe acute illness can weaken immune system
             Desensitization of
pharyngoglottal
adduction reflex (PAR) (PAR normally induces closure of epiglottis to protect the airway when swallowing)
↑ Reflux of gastric contents
Accumulation of subglottic secretions containing microbes
Microbial colonization on inside of ETT
Development of biofilm on inside of ETT
Dislodgement of biofilm into lower airway
↑ Age or chronic disease can weaken respiratory function
       Micro aspirations of subglottic and gastric contents
      Impaired mechanisms to remove microbes from airway Positive pressure pushes microbes down
Fever/rigors ↑ White blood cell count
Introduction of pathogenic microbes to airway Susceptible patient (not required for infection)
         Septic shock
See Distributive Shock slide
Sepsis
Microbes descend airway and infect lungs
Ventilator-Associated Pneumonia (VAP)
Occurs > 48-72 hours after intubation
↑ Inflammatory response at infection site promoting immune cell extravasation and cytokine release
Cytokine signalling ↑ permeability of capillaries leading to ↑ fluid leakage into interstitium and alveoli
Authors: Sravya Kakumanu Reviewers: Ben Campbell *Tara Lohmann *Bryan Yipp * MD at time of publication
Acute respiratory distress syndrome
See ARDS pathogenesis slide
         Pleural effusion Lung consolidation on chest x-ray (CXR) ↑ Sputum production to clear fluid on CXR (Note: In patients with Acute Respiratory Distress Syndrome (ARDS), look for VAP consolidation in non- within alveoli/airways (may be
Positive microbial culture from sputum
dependent/upper regions of the lung where ARDS consolidation would be unexpected to extend to)
purulent in worse infections)
 Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published September 2, 2022 on www.thecalgaryguide.com

syok-luka-bakar-patogenesis-komplikasi-dan-temuan-klinis

syok-luka-bakar-patogenesis-komplikasi-dan-temuan-klinis

syok-hipovolemik-patogenesis-komplikasi-dan-temuan-klinis

syok-hipovolemik-patogenesis-komplikasi-dan-temuan-klinis

Syok Obstruktif: Patogenesis, komplikasi, dan temuan klinis

Syok Obstruktif: Patogenesis, komplikasi, dan temuan klinis

Syok Kardiogenik: Patogenesis, komplikasi, dan temuan klinis

Syok Kardiogenik: Patogenesis, komplikasi, dan temuan klinis

Syok Distributif: Patogenesis, komplikasi, dan temuan klinis

Syok Distributif: Patogenesis, komplikasi, dan temuan klinis

Acute Liver Failure: Pathogenesis and clinical findings

Acute Liver Failure: Pathogenesis and clinical findings
Authors: Juliette Hall Reviewers: Vina Fan, Ben Campbell, Mayur Brahmania* * MD at time of publication
      Acetaminophen Overdose
Accumulation of toxic NAPQI (a metabolite of acetaminophen)
NAPQI binds hepatocellular proteins
(see Acetaminophen Overdose: pathogenesis and clinical findings slide)
Drug-induced liver injury
Metabolism of drugs by the liver can produce reactive drug metabolites
Intracellular stress, mitochondrial injury, or immune response
Viral Hepatitis (i.e. HAV, HBV, HEV, HSV)
Acute infection or infection flare provokes an immune response against infected hepatocytes
Autoimmune Hepatitis
Autoimmune antibodies attack hepatocytes (see Auto-immune Hepatitis (AIH) slide)
Ischemia (i.e. from shock)
↓ O2 delivery to the liver
Hepatocellular hypoxia
Wilson’s Disease
Heritable mutation in the ATP7B gene
↓ Biliary excretion of copper
            Hepatic copper accumulation injures hepatocytes (see Wilson’s Disease slide)
       Accelerated rate of hepatocellular necrosis or apoptosis
 Hepatocyte death exceeds regeneration such that liver function is compromised within a short amount of time
Acute Liver Failure
An illness of <26 weeks duration in the absence of pre-existing cirrhosis, characterized by INR ≥1.5 and evidence of altered mentation (hepatic encephalopathy)
       Injured hepatocytes leak hepatic enzymes (AST, ALT, GGT) into circulation
↑ Liver enzymes
Hepatocellular inflammation
Stimulation of foregut
autonomic nerves
Right upper quadrant pain
↓ Toxin metabolism
Toxins build up and activate microglial cells (brain macrophage)
Oxidative stress and cerebral edema
Hepatic encephalopathy
Characteristic set of neuropsychiatric symptoms (see Hepatic Encephalopathy slide)
↓ Hepatocellular function and number
↓ Complement protein synthesis
↓ Ability to clear immune complexes and activate B cells
Accumulation of pigmented bilirubin
        ↓ Synthesis of coagulation factors
↑ INR
↓ Conjugation of bilirubin by the liver and ↓ transport into bile for excretion
            ↑ Serum bilirubin
Jaundice
Infection
 Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
 Complications
Published November 15, 2022 on www.thecalgaryguide.com

hypovolemic-shock

Hypovolemic Shock: Pathogenesis, Complications, and Clinical Findings
Authors: Dean Percy Miranda Schmidt Reviewers: Yan Yu Tristan Jones Frank Spence* Ben Campbell Ayaaz Sachedina* * MD at time of publication
Progressive ↓ in level of consciousness
Pulseless Electrical Activity
Acute Kidney Injury
↑ Reabsorption of salt and water in the kidney
Oliguria
(↓ urine output)
    Inflammation (pancreatitis, cirrhosis, post-operative, etc.)
Inflammatory mediators ­ vessel permeability and fluid leaks out
Trauma
Ruptured vessels leak fluid into potential spaces
Hemorrhagic losses
(GI bleed, postpartum hemorrhage, etc.)
↓ Intravascular volume
↓ Venous return to the heart
↓ Cardiac output (blood pumped from the heart)
Hypovolemic Shock
↓ Oxygen delivery to tissues due to low blood volume
Insufficient organ perfusion
Non-Hemorrhagic losses
(dehydration, GI losses, skin losses / burns, renal losses, etc.)
         ‘Third Spacing’ of fluid
(fluid located outside the intravascular or intracellular space; large collections can occur in the pelvis, thorax, GI tract, long bones of children, intra-abdominally, retroperitoneally)
P = Q x R; less ‘flow’ in the vessels (Q), with vessels not constricting enough to maintain resistance (R)à pressure (P) will drop
↓ Blood Pressure
Caution: young, healthy individuals can maintain blood pressure during circulatory collapse with ­ cardiac output and ­ vasoconstriction; do not use blood pressure as an indicator of shock severity in children
Carotid sinus baroreceptors sense low blood pressure ↓ Carotid sinus inhibition of sympathetic nervous system Release of sympathetic catecholamines (epinephrine and
↓ Pressure in venous circulation
Brain
Heart
Kidneys
↓ Blood in the right internal jugular vein
↓ Oxygen delivery to the brain
↓ Myocardial contractility (from lactic acidosis)
↓ Blood flow to kidneys
↓ Jugular Venous Pressure
                                        Catecholamines bind to beta-1 receptors in the sinoatrial node of the heart
Beta-1 receptor activation causes ↑ heart rate
Tachycardia
norepinephrine)
Catecholamines bind to and stimulate alpha-1 receptors in peripheral vessels
Vasoconstriction of peripheral vessels
↓ Blood flow to peripheral tissue
Catecholamines bind to and stimulate beta receptors in sweat glands
Diaphoresis
(sweating)
In all body tissues
Inadequate oxygen delivery
↓ ATP production
↑ Anaerobic metabolism
↓ Body temperature
Impaired neurological functioning
Renal ischemia
Activation of the renin-angiotensin aldosterone system
↓ Glomerular filtration rate
↓ Clearance of lactic acid by the kidney
↑ Lactic acid production
↓ Rate of activity of clotting enzymes
Lactic Acidosis
Unknown mechanism
Coagulopathy Hypothermia
             Trauma Triad of Death
           ↑ Capillary Cold, mottled refill time extremities
   Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published January 24, 2013, updated December 4, 2022 on www.thecalgaryguide.com

Wstrząs obturacyjny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs obturacyjny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs dystrybucyjny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs dystrybucyjny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs kardiogenny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs kardiogenny: Patogeneza, powikłania oraz zmiany kliniczne

Wstrząs oparzeniowy: patogeneza, powikłania i zmiany kliniczne

Wstrząs oparzeniowy: patogeneza, powikłania i zmiany kliniczne

Leczenie wstrząsu: wyjaśnienie podstawowych mechanizmów

Leczenie wstrząsu: wyjaśnienie podstawowych mechanizmów

Burns - Full Thickness - Pathogenesis and Clinical Findings 2023

Full Thickness Burns: Pathogenesis and clinical findings
      Radiation
Sunlight, x-ray, nuclear
Emission/explosion can cause damage to keratinocytes (see Calgary Guide
Slide: Superficial Thickness Burns: Pathogenesis and Clinical Findings)
Author and Illustrator: Amanda Eslinger Tracey Rice Reviewers:
Sunawer Aujla Alexander Arnold Duncan Nickerson* Jori Hardin*
* MD at time of publication
Epidermis
Dermis
Sub-cutaneous tissue
Fire
Contact Scald Chemical Electrical
   Transfer of heat energy causes direct injury to keratinocytes
Hypoxic injury (lack of oxygen) causes ischemia-related cell death leading to necrosis
Full thickness burn
Non-uniform damage to the epidermal, dermal & subcutaneous layers at varying widths & depths due to unpredictable injury pattern
        Degraded
epidermal
& dermal layers cover granulated tissue
Ulceration covered by eschar: a thick, dried, black (necrotic) layer
Long-term risk of ulcers & infections
↑ Vascular permeability in subcutaneous layers
↑ Intravascular fluid leaves capillaries, ↓ uptake by lymph vessels
Edema
Compression of surrounding muscles, nerves & vessels
Ischemia and/or necrosis
↓ Immunologic
response due to impaired epidermal barrier function
↑ Microbial growth creating biofilm & secretion of chemicals that inhibit natural protective process
Irritated,
inflamed wound bed +/- exudate
↑ Risk of infection & septic shock
Destruction
of somatosensory structures
Hypoesthesia (↓ sensation to stimuli)
↑ Risk of
repeated injury due to ↓ response to noxious stimuli
Destruction of cutaneous capillary beds
↓ Healing due to ↓ dermal structures throughout wound
White or leathery appearance
Chronic wounds require surgical interventions
↑ Risk of contractures & skin barrier weakness
                    Legend:
 Mechanism of Injury
Pathophysiology
 Sign/Symptom
 Complication
 Published December 2, 2013, updated June 26, 2023 on www.thecalgaryguide.com

Burns - Full Thickness - Pathogenesis and Clinical Findings

Full Thickness Burns: Pathogenesis and clinical findings
      Radiation
Sunlight, x-ray, nuclear
Emission/explosion can cause damage to keratinocytes (see Calgary Guide
Slide: Superficial Thickness Burns: Pathogenesis and Clinical Findings)
Author and Illustrator: Amanda Eslinger Tracey Rice Reviewers:
Sunawer Aujla Alexander Arnold Duncan Nickerson* Jori Hardin*
* MD at time of publication
Epidermis
Dermis
Sub-cutaneous tissue
Fire
Contact Scald Chemical Electrical
   Transfer of heat energy causes direct injury to keratinocytes
Hypoxic injury (lack of oxygen) causes ischemia-related cell death leading to necrosis
Full thickness burn
Non-uniform damage to the epidermal, dermal & subcutaneous layers at varying widths & depths due to unpredictable injury pattern
        Degraded
epidermal
& dermal layers cover granulated tissue
Ulceration covered by eschar: a thick, dried, black (necrotic) layer
Long-term risk of ulcers & infections
↑ Vascular permeability in subcutaneous layers
↑ Intravascular fluid leaves capillaries, ↓ uptake by lymph vessels
Edema
Compression of surrounding muscles, nerves & vessels
Ischemia and/or necrosis
↓ Immunologic
response due to impaired epidermal barrier function
↑ Microbial growth creating biofilm & secretion of chemicals that inhibit natural protective process
Irritated,
inflamed wound bed +/- exudate
↑ Risk of infection & septic shock
Destruction
of somatosensory structures
Hypoesthesia (↓ sensation to stimuli)
↑ Risk of
repeated injury due to ↓ response to noxious stimuli
Destruction of cutaneous capillary beds
↓ Healing due to ↓ dermal structures throughout wound
White or leathery appearance
Chronic wounds require surgical interventions
↑ Risk of contractures & skin barrier weakness
                    Legend:
 Mechanism of Injury
Pathophysiology
 Sign/Symptom
 Complication
 Published December 2, 2013, updated June 26, 2023 on www.thecalgaryguide.com

Shock por quemaduras

Shock por quemaduras: Patogénesis, Complicaciones, y Hallazgos clínicos

Tatalaksana Syok Penjelasan dari mekanisme dasar

Tatalaksana Syok: Penjelasan dari mekanisme dasar

Overview of burns

Overview of Burns: Pathogenesis and Types
Authors: Haley Shade, Amanda Eslinger* Reviewers: Christy Chong, Parker Lieb, Sunawer Aujla, Alexander Arnold*, Yan Yu*,Duncan Nickerson*, Donald McPhalen* Illustrator: Devjyoti Dutta* * MD at time of publication
Contact Electrical Chemical Radiation (excluding sunburn) Less common Burns from any source can result in 3 damage zones
      Common
Fire Scald
      Zone of coagulation:
innermost zone; maximum damage through necrosis and irreversible tissue loss
Zone of stasis: middle zone; decreased tissue perfusion, potentially salvageable
Zone of hyperemia:
outermost zone; tissue perfusion is increased, damage is reversible
Epidermis, dermis, and subcutaneous tissue
Full Thickness (3rd degree burn)
  Normal Skin
Epidermis only
Superficial Thickness (1st degree burn)
Epidermis and superficial (papillary) dermis
Superficial Partial Thickness (2nd degree burn)
Epidermis and deep (reticular) dermis
Deep Partial Thickness (2nd degree burn)
Skin and deep tissues, muscle, fascia, nerves, blood vessels, bone
Composite tissue injury
(4th degree burn)
Compartment syndrome
       Epidermal layer Dermal-Epidermal Junction
Superficial (Papillary) Dermis
Deep (Reticular) Dermis
                    Note: The total burn surface area (TBSA) can be estimated using the rule of nines (1st degree burns are not included): Head and Neck: 9% total, Chest and Upper Back: 9% each, Arm: 9% each, Leg: 18% each (front and back),
Abdomen and Lower Back: 9% each, Genital Area: 1%
Refer to Complications of Burns
Burn Shock
  Refer to Burn Shock: Pathogenesis, Complications, and Clinical Findings
 Legend:
 Pathophysiology
 Mechanism
 Sign/Symptom/Lab Finding
 Complications
 Published November 8, 2023 on www.thecalgaryguide.com

Death Cardiovascular Respiratory and Neurologic Mechanisms

Death: Cardiovascular, Respiratory and Neurologic Mechanisms
Mitochondria in tissues unable to utilize O2
Reduced hemoglobin in blood to carry O2
Low oxygen content in blood (CaO2)
Hypoxemia (Type I Respiratory Failure): low dissolved oxygen in blood (PaO2)
Lungs can’t oxygenate blood fast enough
Lungs can’t rid blood of CO2 fast enough
Hypercapnia / hypercarbia (Type II Respiratory Failure): elevated dissolved CO2 in blood (PaCO2)
Cerebral vasodilation
Toxins: e.g. cyanide, pesticides, arsenic Severe anemia
        Distributive problems:
Systemic inflammation (sepsis, anaphylaxis, pancreatitis), adrenal insufficiency, vasodilatory drugs
Obstructive problems: Cardiac tamponade*, tension pneumothorax* or massive pulmonary embolism*
Hypovolemic* problems (low blood volume): Hemorrhage, dehydration, widespread skin disruption or burns
Cardiac valve dysfunction
Myocardial infarction* or cardiomyopathy
Cardiac arrhythmia or heart block
Disturbed electrical activity in cardiomyocytes
Peripheral metabolic disturbances
Hypokalemia*, Hyperkalemia* Acidosis* (including renal failure) Hypothermia*
Toxins* (e.g. cocaine, beta blockers, tricyclics) Severe thyroid derangement
Inappropriate systemic vasodilation
Adjacent forces impair heart filling
Low cardiac preload
Low stroke volume (SV; depends on valves, contractility, preload)
Decreased systemic vascular resistance (SVR)
Low blood pressure (BP = CO x SVR)
Decreased cardiac output (CO = SV x HR)
Disseminated intravascular coagulationàwidespread thrombi that occlude blood flow (also causes hemorrhage, see relevant box at left)
Methemoglobinemia: some hemoglobin gets stuck in a state that can’t carry O2
Hemoglobin has reduced capacity to carry or release O2
Drugs: e.g. dapsone, nitrates
Carbon monoxide poisoning
            Circulatory collapse / shock: inadequate perfusion of tissue with blood
Respiratory collapse: blood has insufficient useable O2 content
                                Ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT)
Hypoxia*: inadequate O2 delivery or utilization in tissues
Hypoxia creates metabolic disturbances that impair cardiac cells. Alternatively, any of the preceding conditions marked with (*) can directly trigger cardiac arrest first
Pulseless Electrical Activity (PEA): organized activity on ECG with no cardiac output (can be preceded or mimicked by pseudo-PEA, in which there is still some output on ultrasound)
Low atmospheric pressure or oxygen content Severe lung disease
Asthma, COPD, interstitial lung disease, congestive heart failure, pulmonary hypertension, pulmonary embolism, lung collapse / atelectasis
Acute respiratory distress syndrome
Pneumonia, aspiration pneumonitis, inhalational injury, systemic inflammation, drowning
Severe hypoventilation
Respiratory fatigue, advanced COPD, chest wall disorders, neuromuscular disorders, upper airway obstruction, toxins (e.g. opioids, botulism)
       Can degenerate at any time
   Asystole: no cardiac electrical activity or output
Death
Respiratory arrest: cessation of breathing
Inability to protect airway
Decreased level of consciousness
          Note
This is a broad overview of the many scenarios that can result in death. For detailed explanations of the various disease mechanisms, refer to the corresponding slides.
* = reversible causes of cardiac arrest (Hs and Ts)
Author:
Ben Campbell
Reviewers:
Yan Yu*
Huma Ali*
* MD at time of publication
Bradycardia
(low heart rate, HR)
Unopposed parasympathetic stimulation of heart (can also cause vasodilation, see Distributive problems)
Disruption of spinal cord sympathetic control
Injury to cervical or upper thoracic spinal cord
Irreversible cessation of cardiac, respiratory, and brain function
      Prolonged seizure initially causes increased cardiovascular activity, until the system fatigues
Disruption of respiratory control center in medulla
Expanding skull contents squeeze brainstem (herniation)
Increased intracranial pressure
Edema from intracranial hemorrhage, trauma, brain mass
Edema, inflammation, hypoxia and/or metabolic derangements cause diffuse neuron dysfunction
Central nervous system infection
Dementia, particularly with delirium
Massive ischemic stroke
    Seizure
activity prevents or alters breathing
Metabolic disturbances that affect the central nervous system Hypoglycemia Hypocalcemia, hypercalcemia Hyponatremia, hypernatremia Uremia
Acute liver failure (hyperNH4) Many drugs / toxins Withdrawal (e.g. EtOH)
          Status epilepticus
Brainstem lesion (e.g. stroke, neoplasm, inflammatory)
 Nervous System Insult
 Legend:
 Pathophysiology
 Mechanism
 Sign/Symptom/Lab Finding
 Complications
 Published November 11, 2023 on www.thecalgaryguide.com
 Respiratory System Insult
Cardiovascular System Insult Cardiogenic problems

Complication of MI - Acute Mitral Regurgitation

Complication of MI: Acute mitral regurgitation
Authors: Victória Silva Reviewers: Juliette Hall, Raafi Ali *Angela Kealey * MD at time of publication
S3
Indicates rapid overfilling of ventricle
S1 S2 S3
  Calcified plaque formation (atherosclerosis**) commonly in the posterior descending artery
Plaque ruptures
Exposed plaque contentsàPlatelet adhesion and aggregation
Artery becomes partially or completely occluded
Mitral Regurgitation**
(Back flow of blood from left ventricle to left atrium during systole)
↑ Left atrial pressure
Blood from left atrium backs up into pulmonary venous system
↑ Pulmonary venous pressure
↑ Hydrostatic pressure in alveolar capillaries
↑ Fluid leak from alveolar capillaries to interstitium (pulmonary edema**)
↓ Gas exchange
Attempt at
physiologic compensation à ↑ Respiratory rate
Tachypnea
Holosystolic murmur
Heard loudest over the mitral valve (5th intercostal space, mid-clavicular line), with radiation to the axilla
↑ Volume of blood to left ventricle during diastole
                    ↓ Blood supply to the portion of the ventricle that supports the papillary muscle à↓ Muscle movement
Left ventricle dysfunction
↓ Blood supply to the posterior medial papillary muscle
Cell death (myocardial infarction)
Papillary muscle ischemia (muscle is intact but cannot contract)
↑ Blood in right atriumà↑ Blood in superior vena cava
↑ Blood in internal jugular vein
↑ Jugular venous pressure (JVP)
Redistribution of interstitial fluid when lying flat (reduced effect of gravity)
↓ Forward blood flow from left ventricle to aorta
↓ Stroke volume (SV)
↓ Cardiac output (CO) CO = SV x HR (heart rate)
Sympathetic nervous system attempts to physiologically compensate
↑ Heart rate
Tachycardia
↓ Blood pressure (BP) because BP = CO X SVR (systemic vascular resistance)
Cardiogenic shock**
               Papillary muscle rupture
         Papillary muscle unable to provide adequate tension on mitral valve
Mitral valve unable to stay closed during systole
Orthopnea
Difficulty breathing
Dyspnea
Paroxysmal nocturnal dyspnea
    **See corresponding Calgary Guide slides for more details
   Legend:
 Pathophysiology
Mechanism
 Sign/Symptom/Lab Finding
 Complications
 Published November 25, 2023 on www.thecalgaryguide.com

Angioedema Bradykinin Mediated

Angioedema – Bradykinin Mediated: Pathogenesis and clinical findings
   Drug Induced
Angiotensin converting enzyme inhibitor, dipeptidyl peptidase-4 inhibitor, or neprilysin inhibitor use
Hereditary
Type II
Acquired
          Thrombolytic use
Activate factor XII
Factor XII initiates bradykinin synthesis
Type I
Type III
Gain of function gene mutation in bradykinin cascade activators (factor XII) & precursors (kininogen), triggered by ↑ systemic estrogen
Rheumatologic disorders & B- cell lymphoproliferative disease
Complement cascade activation results in ↑ C1 protease production
C1 esterase inhibitor is utilized to neutralize C1 protease, with its consumption exceeding its synthesis
Plasma cell proliferation (i.e., dyscrasia/ monoclonal gammopathy)
Immunoglobulin G antibodies act against C1 esterase inhibitor to render it non-functional
 Genetic or spontaneous mutation in C1 esterase inhibitor gene
       C1 esterase inhibitor deficiency
C1 esterase inhibitor dysfunction
       Inhibition of angiotensin converting enzyme, dipeptidyl peptidase-4, or neprilysin induced metabolism of bradykinin
↓ Bradykinin (peptide hormone) degradation in plasma
Misfunctioning C1 esterase inhibiter is unable to inactivate bradykinin cascade members
↓ C1 esterase inhibiter results in inadequate inactivation of bradykinin cascade members
      ↑ Bradykinin protein production in plasma
Cutaneous Tissue
Mucosal Tissue
Epidermal layer
 Dermal-Epidermal Junction
  Dermal layer
Subcutaneous layer
    Systemic bradykinin excess
Bradykinin-2 receptor binding on endothelial and vascular smooth muscle cells Hyperpermeability pathway activation, with the transcription of some signalling molecules taking hours Released pro-inflammatory mediators act on venules & arterioles in subcutaneous & submucosa tissues
Relaxation of vascular smooth muscle Dissociation of endothelial cell junctions
↑ Capillary blood flow ↑ Vascular permeability
↑ Plasma release into interstitial tissues (specific regions of the body hypothesized to be affected due to local differences in endothelial structure and its response to permeability inducing stimuli)
Dilation & ↑ permeability of vasculature results in fluid release into surrounding tissues
    Mucosal Layer
Muscularis mucosae
  Submucosal layer
 Muscularis externa
                Intestinal edema (Fluid buildup in Intestine tissues)
Intestinal swelling (↑ intra-abdominal pressure)
Laryngeal edema (Fluid buildup in larynx)
Swelling in larynx ↓ air flow into & out of lungs
Asphyxia (body is deprived of oxygen) Dyspnea (difficult in breathing)
Author: Aaron Varga Reviewers: Tracey Rice Sunawer Aujla Shahab Marzoughi Maharshi Gandhi Jori Hardin* Yan Yu* * MD at time of publication
Peripheral edema (Fluid buildup in extremities such as the hands, ankles, and feet)
       Ascites, bowel obstruction, &/or hypovolemic shock
 Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published Mar 21, 2024 on www.thecalgaryguide.com

Choque Hipovolemico

Choque Hipovolêmico: Patogênese, Complicações e Manifestações Clínicas

Tratamento do Choque: Explicacao dos mecanismos basicos

Massive Transfusion Protocol

Massive Transfusion Protocol: Considerations and rationale
Massive transfusion protocol (MTP) is a tool used by clinicians when there is a need to rapidly administer a large amount of blood products, including packed red blood cells (pRBCs), fresh frozen plasma (FFP), and platelets. Complications of MTP are commonly referred to as “The Lethal Triad” referring to hypothermia, acidosis and coagulopathy.
Authors: Kayleigh Yang Arzina Jaffer
Reviewers: Jasleen Brar,
Luiza Radu, Karl Darcus*
* MD at time of publication
Intervention
Indications Initial Response Pathophysiology Transfusion Targets
    ≥ 3 pRBCs unit transfusion requirement in 1 hour
Shock index (heart rate/systolic blood pressure) > 1
Blood volume loss >50% in ≤3 hours
ABC Score ≥ 3 of: 1. Penetrating mechanism of injury 2. Systolic blood pressure < 90 mmHg 3. Heart rate > 120 beats per minute 4. Evidence of hemoperitoneum or hemopericardium on ultrasound (positive FAST U/S exam)
RABT Score ≥ 2 of: 1. Penetrating mechanism of injury 2. Shock index > 1 3. Positive FAST U/S 4. Known or suspected pelvic fracture
Call for help
Activate institution's MTP protocol
Send for STAT type and screen
Establish large-bore intravenous access
Fluid resuscitation
Collect and send STAT bloodwork including hemoglobin, platelet, INR, fibrinogen, electrolytes, creatinine and arterial blood gas (ABG).
             Citrate present in blood products to avoid clotting during storage
Stored pRBCs break down and release potassium due to time mediated degeneration
Temporary accumulation of citrate in patient's blood with rapid use of blood products
Citrate chelates calcium
Less negative cell membrane resting potential
Anaerobic metabolism
Promotes hypocalcaemia
Changes in membrane excitability
Lactic acid buildup
Coagulopathy
(see coagulation cascade slide)
Cardiac dysrhythmias (peaked T-waves, atrial block, “sine wave”, asystolic EKG changes)
Metabolic acidosis
End organ damage
Continued blood loss
Volume overload
Avoid hypocalcemia
Avoid hyperkalemia
pH 7.35-7.45
Bleeding source control
Hemoglobin >70-90
Platelets >50 INR <1.5 Fibrinogen >1.5
Avoid dilutional coagulopathy (clotting factor dilution)
Mean Arterial Pressure (MAP) >60mmHg
Temperature >35.0°C
Slow (over 5-10 minutes) IV calcium administration
Inhaled beta agonists
Insulin/Dextrose
EKG monitoring
Sodium bicarbonate
Increase minute ventilation
Fastest control method to prevent further blood loss (i.e., packing wounds)
Early tranexamic acid administration
Administer pRBCs, FFP, and platelets in a 1:1:1 ratio (fibrinogen replacement indicated if <1.5 despite FFP)
Minimize crystalloid use
Administer crystalloids in a 3:1 ratio to estimated blood loss until blood products available
Administer vasopressors to meet target, do not overshoot
Temperature monitoring Fluid warming
            ↑ [Potassium] in pRBCs solution
Administration of pRBCs ↑ potassium in patient's blood
              Blood loss
↓ Hemoglobin
Tissue hypoperfusion
Tissue hypoxia
               ↑ Diluent volume
↓ Concentration of clotting factors
Tissue death
↓ Coagulation ability
↑ Transfusion requirements
      Early fluid resuscitation
Rapid transfusion of cooled or room-temperature blood products/fluids
↑ Blood pressure
Development of hypothermia
↑ Bleeding and clot dislodgement potential
           ↓ Enzyme activity in the coagulation cascade
↓ Coagulation ability
     Legend:
 Pathophysiology
 Mechanism
Targets
 Intervention
Published Sept 5, 2024 on www.thecalgaryguide.com

Rapid sequence induction and intubation

Rapid Sequence Induction & Intubation (RSII): Indications & considerations
“Full stomach”: ↑ risk of regurgitation, vomiting, aspiration Life-threatening injury or illness requiring immediate or rapid airway control
         ↓ Gastro- esophageal sphincter competence (elderly, pregnancy, hiatus hernia, obesity)
↑ Intragastric pressure (pregnancy, obesity, bowel obstruction, large abdominal tumors)
Delayed gastric emptying (narcotics, anticholinergics, pregnancy, renal failure, diabetes)
↓ Level of consciousness (drug/alcohol overdose, head injury, trauma or shock state)
Respiratory & ventilatory compromise (i.e., hypoxic or hypercapnic respiratory failure)
Achalasia (esophageal motility disorder resulting in impaired swallowing)
Dynamically deteriorating clinical situation (i.e., trauma)
GI bleed
   Impaired airway reflexes
↓ Muscle tone of structures in the airway (i.e., tongue, pharyngeal walls, & soft palate)
     Patients who did not stop GLP-1 agonist preoperatively as advised
Impaired clearance of secretions or vomitus
↓ Safe apnea time before hemodynamic decompensation
   Unprotected airway
Need for rapidly securing airway while avoiding aspiration & hemodynamic compromise
Rapid sequence intubation (RSI): Simultaneous administration of induction agent (unconsciousness) & neuromuscular blocking agent (paralysis) to achieve intubation conditions (~45-60 seconds after IV push) for rapid control of an emergency airway
     Preoxygenation
Deranged physiologic conditions (i.e., hypotension, acidosis, hypoxemia)
Reduced tolerance for
apnea (period with no ventilation or oxygenation)
Pre-oxygenate with high flow O2 (15L) to create a large pulmonary & tissue reservoir of oxygen
↓ Significant oxygen desaturation during apnea
↑ Oxygen saturation on pulse oximetry
Induction
Laryngoscopy & intubation are a potent sympathetic nervous system stimulus
Airway manipulation causes a surge in catecholamines
Paralysis
Visualization & passage of endotracheal tube requires relaxation of vocal cords & surrounding muscles
Neuromuscular blocking agents facilitate paralysis
Rescue
     Some induction agents (i.e., propofol) are vasodilators
Hemodynamically unstable or patients in shock
     Hypotension
          Tachycardia
↑ Intracranial pressure (ICP)
Hypertension
Suppress cough & gag reflex
Prevent laryngospasm (involuntary closure of vocal cords to airway manipulation)
Minimize movement during procedure
Vasoactive agents (i.e., ephedrine, phenylephrine) ↑ systemic vascular resistance
Atropine & glycopyrrolate ↑ heart rate
      Lidocaine (Na+ channel blocker) & opioids (μ receptor agonist) ↓ transmission of pain
↓ Sympathetic response, myocardial demand & physiologic stress
Anesthetics (i.e., propofol) achieve unconsciousness for paralysis & intubation
↓ Airway trauma & damage to vocal cords
Bag mask ventilation typically avoided in this step to ↓ gastric insufflation & risk of aspiration
           Cricoid pressure (Sellick maneuver): posterior displacement of cricoid ring to compress esophagus against C-spine to prevent passive regurgitation of gastric contents to airway. Applied from start of induction, released when placement of endotracheal tube is confirmed by capnography.
Intubation
↑ Blood pressure and/or cardiac output
Authors: Jen Guo Reviewers: Priyanka Grewa Luiza Radu Leyla Baghirzada* * MD at time of publication
   Legend:
 Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published November 18, 2024 on www.thecalgaryguide.com