**Question:** Which of the following is not true of acute PSGN (Post Streptococcal glomerulonephritis)?

A. Acute PSGN is a post-infectious glomerulonephritis that occurs after streptococcal infection.
B. It is a common complication of untreated streptococcal pharyngitis and skin infections.
C. The immune complex deposition in the kidneys leads to inflammation and damage.
D. The clinical presentation includes hypertension, hematuria, and proteinuria.

**Correct Answer: C. The immune complex deposition in the kidneys leads to inflammation and damage.**

**Core Concept:** Post-streptococcal glomerulonephritis (PSGN) is a type of glomerulonephritis that develops post-infection with Streptococcus pyogenes (group A Streptococcus). It is a common complication of untreated streptococcal pharyngitis (strep throat) and skin infections.

**Why the Correct Answer is Right:** PSGN arises due to the immune complex deposition in the kidneys, leading to inflammation and damage to the glomeruli. This immune complex formation involves the production of antibodies against streptococcal antigens, which circulate and bind to streptococcal antigens present in the kidney. This interaction triggers the deposition of immune complexes in the kidneys, leading to glomerular inflammation, activation of the complement system, and subsequent damage to the glomeruli.

**Why Each Wrong Option is Incorrect:**

A. Immune complex deposition is the primary mechanism in PSGN, not "inflammation and damage" as mentioned in option C.
B. While untreated streptococcal infections can lead to PSGN, the statement "The immune complex deposition in the kidneys leads to inflammation and damage" is incorrect. Immune complex deposition is the primary event, but the subsequent inflammation and damage are not the direct consequences of this event.
D. Clinical presentation includes hypertension, hematuria, and proteinuria, not "inflammation and damage." Hypertension, hematuria, and proteinuria are symptoms and signs associated with PSGN, whereas the correct answer focuses on the underlying mechanism (immune complex deposition) rather than the clinical manifestations.

**Clinical Pearl:** The clinical presentation of PSGN includes hypertension, hematuria, proteinuria, and sometimes, renal failure. Early diagnosis and treatment are crucial to prevent progression to end-stage renal disease. In severe cases, complications like hypertension, congestive heart failure, and cerebral complications may occur.