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Sickle cell disease signs

Sickle cell disease

central-retinal-artery-occlusion-pathogenesis-and-clinical-findings

Central Retinal Artery Occlusion: Pathogenesis and clinical findings Inflammatory Disease: Cardiogenic Embolism: Hypercoagulable state: Hematologic Disease: (i.e. GCA, SLE, GPA) (i.e. Valvular, arrhythmias, congenital defects) (i.e. OCP, Protein C&S deficiency, ATIII deficiency) (i.e. leukemia/lymphoma, sickle cell, polycythemia) Endothelial cell damage Abnormal blood flow 1` coagulation and/or 1 blood viscosity and creates hypercoagulable state causing localized stasis 4, anti-coagulation inflammation Abbreviations: • GCA — Giant Cell Arteritis • SLE — Systemic Lupus Erythematosus • GPA — granulomatosis with polyangitis • OCP — Oral contraceptive pill • ATIII — Anti-thrombin Ill Thrombus formation Blockage of central retinal artery Central Retinal Artery Occlusion (CRAO) Authors: Graeme Prosperi-Porta Reviewers: Stephanie Cote Usama Malik Johnathan Wong* * MD at time of publication Carotid Artery Atherosclerosis Atherosclerotic plaque dislodges from carotid artery The retina becomes pale 4, perfusion of retinal Slow retinal artery blood Acute retinal edema Ganglion cells and axons from NI, perfusion arterioles due to upstream flow allows for caused by ischemia results death due to ischemia CRAO segmentation of the blood column in a blurred appearance of the retina results in disc pallor seen months after CRAO The choroidal vessels supplying the macula via the posterior ciliary artery become more prominent within a background of retinal pallor

Acute Chest Syndrome (Sickle Cell Disease)

Hemolytic Anemia - Pathophysiology

Hemolytic Anemia: Pathophysiology behind the Normocytic Anemia Note • Extreme bone marrow compensation for hemolysis (↑ RBC synthesis/reticulocytosis) may result in slightly macrocytic anemia (because reticulocytes have larger volumes than RBCs) Defects in the RBC’s environment Defects in RBC membranes Ex. Hereditary Spherocytosis: mutation causing deficiency of RBC structural proteins like ankyrin or spectrin RBC membranes become weakened and form blebs that break off ↓ RBC surface area while volume remains constantà RBC becomes spherical Spherocytes in spleen trapped and phagocytosed by splenic macrophages (extravascular hemolysis) Defects in RBC internal contents (thalassemia, hemoglobinopathies, and metabolic defects) Ex. Sickle Cell Disease: point mutation in hemoglobin (Hgb) structure (GluàVal) Inappropriate Hgb polymerization in low oxygen environments due to mutationàRBC becomes rigid, forms a sickle shape Inflexible RBCs become trapped in the spleen’s sinusoid membranes àphagocytosed by splenic macrophages (extravascular hemolysis) Infection triggers immune system activation Autoimmune processes TTP/HUS (abnormal platelet aggregation blocking blood vessels) Production of abnormal antibodies and immune complexes targeted against RBC surface antigens Immunoglobulin-bound RBCs are marked for destruction by the immune system (by either the cell- mediated or complement- mediated pathways) DIC (fibrin deposition blocking blood vessels) Artificial heart valve RBCs are sheared when they flow past an abnormal surface Rate of hemolytic RBC destruction > rate of bone marrow RBC synthesis (reticulocytosis) ↓ total number of RBCs in the body (despite normal RBC production/volume) Normocytic anemia Authors: Yan Yu Katie Lin Man-Chiu Poon* Reviewers: Andrew Brack Julia Heighton JoyAnne Krupa Lynn Savoie* * MD at time of publication Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Re-Published June 15, 2019 on www.thecalgaryguide.com

Priapism

Priapism: Pathogenesis Post-cavernosal venous occlusion ↑ nitric oxide from cavernous nerve plexus and cavernosal sinus endothelia Impaired detumescence (erection-ending) pathways Post-cavernosal venous drainage is mechanically obstructed e.g. sickle cell disease, dialysis etc. Ischemic (Low-flow): Inadequate venous function Blood pools in corpora cavernosa Cavernosal cell metabolism uses O2 and releases CO2 into pooled blood Trabecular smooth muscle relaxes Cavernosal artery smooth muscle relaxes Lack of norepinephrine action on penile SM Post-cavernosal venules are compressed against tunica albuginea Trabecular smooth muscle and cavernosal artery smooth muscle do not contract ↑ pressure in corpora ↑PCO2 ↓pH Acidosis ↓PO2 Tissue hypoxia Tissue damage Irreversible fibrosis leading to erectile dysfunction Priapism Prolonged erection lasting more than 4 hours; in absence of sexual stimulation; not relieved by ejaculation Trauma to penis or adjacent areas Authors: Arsalan Ahmad Reviewers: Alec Mitchell Darren Desantis* Yan Yu* * MD at time of publication Cavernosal artery is damaged Excessive, unregulated arterial blood flow into corpora cavernosa Pain Non-ischemic (High-flow): Uncontrolled arterial flow ↑ volume of blood in corpora ↑ pressure in corpora Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published September 22, 2019 on www.thecalgaryguide.com