**Question:** True about a child with post streptococcal glomerulonephritis is

A. The child will present with acute kidney injury
B. The diagnosis is confirmed by measuring antistreptolysin O (ASO) titre
C. The condition is typically seen in adolescents
D. The treatment involves only supportive care

**Correct Answer:**

**Core Concept:** Post streptococcal glomerulonephritis (PSGN) is a renal complication that occurs as a result of a bacterial infection caused by Streptococcus pyogenes (group A beta-hemolytic Streptococcus). It is commonly seen in children and adolescents, although any age group can be affected. PSGN can lead to acute kidney injury, which is a critical aspect of the condition.

**Why the Correct Answer is Right:** Post streptococcal glomerulonephritis is a result of the immune response triggered by the infection. The immune response leads to a cascade of events, including the production of immune complexes and deposition of these complexes in the glomeruli. This leads to inflammation, damage, and eventually, acute kidney injury which manifests as decreased renal function in the child.

**Why Each Wrong Option is Incorrect:**

A. Post streptococcal glomerulonephritis is characterized by acute kidney injury, not only in children but also in adults. So, stating that the child will present with acute kidney injury is correct, but it should be generalized for all age groups affected by PSGN.

B. Measuring antistreptolysin O (ASO) titre is a laboratory test used to diagnose streptococcal infections, including PSGN. ASO titre can help confirm the diagnosis but is not the sole indicator of PSGN.

C. Although PSGN can affect adolescents, stating that it is typically seen in adolescents is incorrect. PSGN can occur in children, adolescents, and adults as well.

D. Supportive care is essential in managing PSGN, but active treatment is required to prevent progression to chronic kidney disease. Antibiotics are prescribed for the underlying streptococcal infection, and renal replacement therapy may be required in severe cases.

**Clinical Pearls:**

**Core Concept:** Diagnosis of PSGN relies on clinical evaluation, laboratory findings (like ASO titre), and renal biopsy to confirm the presence of immune complex deposition and mesangial proliferation.

**Why Each Wrong Option is Incorrect:**

A. While ASO titre is a helpful diagnostic tool, it is not the sole indicator of PSGN. Other tests like urine analysis, renal function tests, and imaging studies are also essential in confirming the diagnosis.

B. Antibiotics are crucial for treating the underlying streptococcal infection, which is the primary cause of PSGN. Antibiotics help to prevent further kidney damage by eliminating the causative organism.

C. Although renal biopsy is not always necessary, it can provide information about the extent of kidney damage, histopathological findings, and help identify other possible causes of nephritis.

D. Supportive care is essential, but active treatment, such as antibiotics, is crucial