Pathophysiology

Question 1

COVID

Answer 1

CoV envelope spike glycoprotein binds to the cellular receptor of ACE2 (epithelium of the nose, mouth, lungs, heart, BV, kidneys, liver, and GIT)

SARS-CoV-2 reduces expression of ACE2 -> acute lung injury and dec RAS regulation -> dysfunctional immune response -> ARDS (main cause of death)

Cell entry > viral replication > damaged pneumocytes > stimulation of cellular and humoral immunity > release of inflammatory mediators > vasodilation and increased capillary permeability > alveolar edema and atelectasis > hypoxemia

Question 2

Acute Pharyngitis

Answer 2

Bacterial invasion through the capsule of the tonsils (complication of acute tonsillitis)

Etiologic agents: GABHS and mixed anaerobes, S. viridans