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

A. Increased proteinuria
B. Hematuria
C. Acute kidney injury
D. Rapidly resolving kidney function

**Core Concept:** Post streptococcal glomerulonephritis (PSGN) is a kidney disease that occurs after an infection with Streptococcus pyogenes. It is a complication of rheumatic fever and is characterized by inflammation of the glomeruli (glomerular filtration units) in the kidneys.

**Why the Correct Answer is Right:** Post streptococcal glomerulonephritis is associated with the presence of immune complex deposition in the glomeruli, which leads to inflammation and damage. This results in increased proteinuria (excess protein leakage from the kidneys), hematuria (blood cells in the urine), and sometimes acute kidney injury. Kidney function may improve over time, but this depends on the severity of the disease and appropriate treatment.

**Why Each Wrong Option is Incorrect:**

A. **Increased proteinuria**: This is true, as immune complex deposition leads to protein leakage from the kidneys, resulting in proteinuria.

B. **Hematuria**: While hematuria can be a feature of PSGN, not all cases present with blood in the urine. Some cases may have minimal hematuria or no hematuria at all.

C. **Acute kidney injury**: PSGN can cause acute kidney injury in severe cases, but it is not always a feature of the disease. Kidney function may improve over time, as mentioned above.

D. **Rapidly resolving kidney function**: PSGN can cause acute kidney injury in some cases, but the recovery of kidney function depends on the severity of the disease and appropriate treatment. Treatment can improve kidney function, but kidney damage may persist or progress in some cases, leading to chronic kidney disease or end-stage renal disease.

**Clinical Pearl:** Post streptococcal glomerulonephritis is a clinical entity that should be considered in the differential diagnosis of a child presenting with acute kidney injury, proteinuria, and hematuria. Prompt diagnosis and treatment are crucial to minimize long-term kidney damage and preserve renal function.