The 10-year-old boy with gross hematuria, loin pain, diarrhea urine examination is normal. Serum C3 levels are normal diagnosis is –
**Core Concept**
The child presents with gross hematuria and loin pain, suggesting a renal or urinary tract pathology. The presence of normal serum C3 levels helps to narrow down the differential diagnosis, as it is often decreased in conditions involving the complement system.
**Why the Correct Answer is Right**
The normal serum C3 levels, combined with the child's symptoms, suggest a diagnosis of **Urinary Tract Infection (UTI)**. The loin pain and hematuria could be due to the infection causing inflammation and irritation of the renal parenchyma. The normal serum C3 levels help to rule out conditions like Post-Streptococcal Glomerulonephritis (PSGN) or Hemolytic Uremic Syndrome (HUS), which are associated with decreased C3 levels.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** This is incorrect because PSGN typically presents with decreased serum C3 levels, which is not the case here. PSGN is also often associated with a history of streptococcal infection.
* **Option C:** This is incorrect because IgA Nephropathy (Berger's disease) typically presents with episodic hematuria, often following an upper respiratory tract infection, and is not typically associated with normal serum C3 levels.
* **Option D:** This is incorrect because Alport Syndrome is a genetic disorder affecting the type IV collagen in the glomerular basement membrane, leading to chronic kidney disease. It is not typically associated with acute symptoms like loin pain and hematuria.
**Clinical Pearl / High-Yield Fact**
In cases of gross hematuria, it is essential to investigate for a urinary tract infection, especially in children, as it is a common and treatable cause of hematuria.
**Correct Answer: C. IgA Nephropathy (Berger's disease)**