SEARCH RESULTS FOR: Diphtheria

Pityriasis Rosea

Pityriasis Rosea: Pathogenesis and clinical findings Authors: Leah Johnston Reviewers: Lauren Lee Stephen Williams Ben Campbell Laurie Parsons* * MD at time of publication Pityriasis Rosea Epidermal layer Dermal-Epidermal Junction Dermal layer Psoriasiform hyperplasia, parakeratosis, spongiosis and Preceding viral infection, reactivation of latent Human Herpesvirus (HHV-6 or HHV-7) Female sex (2:1 female to male ratio) Risk factors Recent vaccinations: Bacillus Calmette-Guerin (BCG), influenza, H1N1, diphtheria, smallpox, hepatitis B, and Pneumococcus Red blood cell lymphocytes extravasation Perivascular dermal infiltrates: lymphocytes, monocytes, and eosinophils Spongiosis (intercellular fluid accumulation in epidermis) Erythematous, pink-salmon or brown coloured lesions Altered production of melanin by epidermal melanocytes Post-inflammatory hyperpigmentation or hypopigmentation Prodromal symptoms: fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, and/or sore throat Age 10 to 35 Exact mechanism unknown Activation of T-cell mediated host immune response ↑ Signal proteins in serum including interleukin 17 (IL-17), interferon gamma (IFN-γ), vascular endothelial growth factor (VEGF), and induced protein 10 (IP-10), leading to increased capillary permeability Spring and fall seasons Fluid extravasation from blood vessels Red blood cell extravasation Often asymptomatic, can be pruritic Cell infiltration isn’t as intense or doesn’t produce as dramatic an inflammatory response as other skin conditions ↑ CD4 lymphocytes, monocytes, eosinophils and Langerhans cell infiltration into the dermis and epidermis Pityriasis Rosea Activation of B cells and production of anti- keratinocyte IgM antibodies Parakeratosis (incomplete keratinocyte maturation) and proliferation of epidermal cells (known as psoriasiform hyperplasia) Thickened epidermal layer Scale A self-limited, papulosquamous eruption that is characterized by round or oval-shaped, erythematous to brown patches or plaques with scaling borders that typically occur on the trunk and proximal extremities and tend to follow Langer’s lines. Often initially presents with a larger herald patch as the first sign. Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published January 30, 2023 on www.thecalgaryguide.com

Vaccine Mediated Immunity Comparing Vaccine Subtypes

Vaccine-Mediated Immunity: Comparing Vaccine Subtypes Live Attenuated Vaccines mRNA Vaccines Inactivated Component, Recombinant, Toxoid, Polysaccharide-Protein Conjugate Vaccines Measles/Mumps/Rubella (MMR), Varicella, Rotavirus, Influenza COVID-19 Serial passage in sub-optimal culture conditions weaken pathogen Pathogen maintains ability to slowly replicate (attenuated) Vaccine components (live attenuated pathogen, adjuvants, stabilizers, preservatives) are formulated & administered Attenuated pathogen enters host cells & replicates, mimicking natural infection Identify target protein of specific pathogen RNA polymerase transcribes DNA for target protein into mRNA (in vitro transcription) mRNA is purified & concentrated mRNA is encapsulated in lipid nanoparticles to prevent degradation Vaccine components (mRNA, lipid nanoparticles, adjuvants, preservatives) are formulated & administered Host cells take up mRNA & synthesize the antigenic protein Diphtheria, Tetanus, Pertussis, Pneumococcus, Meningococcus, Haemophilus influenzae type b, Influenza, Hepatitis B, Human Papilloma Virus Polio (IPV), Hepatitis A Antigen-presenting cells (APCs) take up intracellular & extracellular antigens Infected cells & APCs present intracellular antigens to CD8+ T cells via major histocompatibility complex-I (MHC-I) molecules Robust cell-mediated immunity ↑ Lymphocyte counts Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Authors: Tanis Orsetti Reviewers: Jessica Hammal Emily J. Doucette James D. Kellner* * MD at time of publication Inactivated Whole Virus Vaccines Identify target protein of specific pathogen (antigenic protein) Pathogen is inactivated using chemicals/detergents/heat Large quantity of antigenic protein produced in a laboratory setting Pathogen is unable to replicate Vaccine components (pathogen, adjuvants, stabilizers, preservatives) are formulated & administered APCs take up extracellular antigens APCs present extracellular antigens to CD4+ cells via major histocompatibility complex-II (MHC-II) molecules Activated CD4+ T helper cells stimulate B lymphocytes B lymphocytes produce antibodies specific to pathogen Robust humoral immunity ↑ Pathogen-specific antibody titers Published May 31, 2025 on www.thecalgaryguide.com

Diphtheria

Diphtheria: Pathogenesis and clinical findings Travel to endemic areas Immunity (primarily acquired through vaccination) is incomplete, absent, or waning Poor hygiene environments Exposure to respiratory droplets or direct contact with infected surface Colonization of the pharynx or cutaneous sites with corynebacterium diphtheriae (C. diphtheriae) C. diphtheriae proliferate locally & secrete diphtheria exotoxin Exotoxin enters nearby host cells & inhibits host cell protein synthesis Local epithelial tissue necrosis & activation of inflammatory response Accumulation of dead cells, fibrin, bacteria & inflammatory cells Lymphatic & hematogenous spread of exotoxin to distant tissues (preferentially tissues with ↑ metabolic activity) Author: Julia Fox Reviewers: Steven Quan, Emily J. Doucette, James D. Kellner* *MD at time of publication **See corresponding Calgary Guide slide Cutaneous Diphtheria Cutaneous skin breakdown Vesicle/pustule formation Superficial, non-healing ulcers with grey pseudomembrane Respiratory Diphtheria Presence of inflammatory mediators in the pharynx Mucosal edema & sensitization of nociceptors Dense necrotic pseudomembrane forms & adheres to larynx, pharynx, or tonsils Pseudomembrane dislodgment or extension into the airway Diphtheria antigens drain to cervical lymph nodes Cervical lymphadenitis Pain & inflammatory response at infection site (eg. pharyngitis, tonsillitis, etc.) Diphtheritic membrane (grey mucous membranes) Localized airway obstruction (severe laryngeal cases) Bull neck appearance Systemic Manifestations Protein synthesis inhibition in myocardial cells Protein synthesis inhibition in neurons & Schwann cells Focal myocardiocyte necrosis, inflammation, & fibrosis Demyelination, ↓ myelin regeneration, & axonal injury Myocarditis** Damaged myocardium disrupts conduction pathways & contractility Cranial nerve conduction impaired first (especially CN IX, X, III) due to ↓ length, ↑ metabolic activity & proximity to mucosal infection sites ECG changes (arrhythmias & heart block) Palatal & pharyngeal paralysis Oculomotor palsy Dysphonia, dysphagia, & loss of gag reflex Protein synthesis inhibition in glomeruli & renal tubular epithelial cells Tubular necrosis & interstitial inflammation Renal failure Endothelial injury ↑ glomerular permeability Long peripheral nerve conduction impaired later (2-6 weeks after initial infection) Ascending muscle weakness Paresthesia & numbness Acute tubular necrosis Granular casts in urine Proteinuria Microscopic hematuria Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published Dec 18, 2025 on www.thecalgaryguide.com

Childhood Immunization Schedule

Alberta Health Services Childhood Immunization Schedule: Why we immunize Diphtheria** toxin Bacteria colonize upper respiratory epithelium & secrete exotoxin that enters local cells Sore throat, low grade fever, lymphadenopathy, stridor or wheeze, gray pseudomembrane in the airway ↑ Mortality from CNS, respiratory & cardiac disease Tetanus** toxin Pertussis** metabolites Polio virus Haemophilus influenzae type B Hepatitis B virus Streptococcus pneumoniae Rotavirus Neisseria meningitidis Measles** virus Mumps virus Rubella virus Varicella zoster virus** Human papillomavirus (HPV) Spores enter contaminated wounds & bacteria produce tetanospasmin to invade central nervous system (CNS) Muscle rigidity spasms, hyperreflexia, autonomic dysfunction, laryngeal spasms ↑ Mortality from respiratory obstruction & failure Bacteria attach to ciliated respiratory epithelial cells & release toxins Prolonged paroxysmal cough, inspiratory “whoop” sound, emesis, apnea, cyanosis, leukocytosis ↑ Risk of pneumonia, seizures & encephalopathy Virus invades oropharynx/GI tract & replicates in lymphoid tissue before hematogenous spread to motor neurons ↑ Risk of paralytic poliomyelitis & respiratory failure Bacteria colonize the nasopharynx & invade the bloodstream & CNS Virus invades hepatocytes via specific receptors & replicates within liver cells Bacteria colonize the nasopharynx & may invade the lungs, bloodstream, or meninges Virus invades mature enterocytes in the small intestine Bacteria colonize the nasopharynx & enter the bloodstream to cross the blood–brain barrier Virus invades respiratory epithelium & spreads to regional lymphoid tissue & bloodstream Virus infects upper respiratory tract (URT) & disseminates via viremia to salivary glands & other organs Virus invades URT & enters the bloodstream & regional lymphoid tissue Virus infects URT & lymphoid tissue before invading neural tissue Virus infects anogenital & oropharyngeal basal layer epithelium tissue Influenza virus Virus invades upper & lower respiratory epithelium Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)** Viral invasion of mucous membranes & may invade extrapulmonary tissues Legend: Muscle weakness, asymmetric reduction in tone, quadriplegia Fever, fatigue, shortness of breath, nausea, emesis, headache, stiff neck, altered mental status, otitis media** Fatigue, anorexia, nausea, jaundice, arthralgia, right upper quadrant pain Otitis media**, sinusitis, pneumonia**, meningitis**, bacteremia Gastroenteritis with emesis, fever, diarrhea, malaise & dehydration Fever, headache, neck stiffness, altered level of consciousness, purpuric rash Koplik spots, conjunctivitis, fever, rhinorrhea, cough, diarrhea, otitis media, pneumonia Parotitis, headache, fever, malaise, sensorineural hearing loss, orchitis, mastitis, oophoritis, pancreatitis Fever, lymphadenopathy, rash, congenital anomalies such as hearing loss, cataracts & cardiac defects ↑ Mortality from meningitis, pneumonia & sepsis ↑ Risk of cirrhosis, hepatic malignancy, & liver failure ↑ Mortality from respiratory, CNS & cardiac dysfunction ↑ Mortality from hypovolemic shock & CNS infection ↑ Mortality from sepsis, multiorgan failure & necrosis ↑ Mortality from pneumonia & encephalitis ↑ Mortality from meningitis & encephalitis ↑ Mortality from congenital rubella Vesicular & pruritic rash, fever, malaise, pneumonia, encephalitis, cellulitis ↑ Morbidity from necrotizing fasciitis, CNS, soft tissue & respiratory infections Often asymptomatic, or may present with painless anogenital warts ↑ Risk of anogenital & head & neck malignancy Fever, cough, myalgia, malaise, cough, headache, emesis, diarrhea, abdominal pain, febrile seizures ↑ Mortality from widespread multiorgan infection Fever, cough, fatigue, shortness of breath, anosmia, ageusia, pneumonia, multiorgan dysfunction ↑ Mortality from respiratory distress & multiorgan failure DTaP-IPV-Hib-HB vaccine Given at 2, 4 & 6 months old Protects against diphtheria, Tetanus, Pertussis, Polio, Haemophilus influenzae type B, & Hepatitis B DTaP-IPV-Hib vaccine Given at 18 months old Protects against diphtheria, Tetanus, Pertussis, Polio, & Haemophilus influenzae type B Pneumococcal conjugate vaccine Given at 2, 4 & 12 months old (additional 4th dose given at 6 months if at ↑ risk of invasive pneumococcal disease) Authors: McKayla Kirkpatrick, Stacey Holbrook Reviewers: Merry Faye Graff, Emily J. Doucette, Charissa Chen, Amanda Ang, Danielle Nelson* * MD at time of publication Tdap-IPV vaccine Given at 4 years old Tdap vaccine Given in Grade 9 Protects against diphtheria, Tetanus, Pertussis, & Polio Protects against diphtheria, Tetanus, & Pertussis HB vaccine Given in Grade 6 Protects against Hepatitis B virus Protects against Streptococcus pneumoniae Rotavirus vaccine Given at 2 & 4 months old Protects against rotavirus Meningococcal conjugate (MenconC) Given at 4 & 12 months old MenC-ACYW (Meningococcal type A, C, Y, W-135) in Grade 9 Protects against Neisseria meningitidis MMR-Var vaccine (e.g., Priorix-Tetra) Given at 12 & 18 months old Protects against measles, mumps, rubella & varicella Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications HPV vaccine Given in Grade 6 (2-3 doses over 6 months) Seasonal influenza vaccine Given annually starting at 6 months or older COVID-19 vaccine Given at 6 months or older Published Aug 19, 2015; updated Dec 31, 2025 on www.thecalgaryguide.com Protects against HPV Protects against influenza viruses predicted to circulate each fall & winter Protects against SARS-CoV2