A female patient Nandini presents with upper respiratory tract infection. Two days after, she develops hematuria. Probable diagnosis is –
**Core Concept**
The question is testing the association between an upper respiratory tract infection (URTI) and the subsequent development of hematuria, which is the presence of blood in the urine. This clinical scenario is related to the concept of post-infectious glomerulonephritis (PIGN), a condition where the immune system reacts to an infection and causes inflammation in the glomeruli, the filtering units of the kidneys.
**Why the Correct Answer is Right**
The correct answer is related to PIGN, which is often caused by infections such as streptococcal pharyngitis or URTI. The immune system produces antibodies against the infecting organism, which can also bind to the glomerular basement membrane, leading to the activation of complement and the release of inflammatory mediators. This results in the deposition of immune complexes in the glomeruli, causing inflammation and damage to the kidney's filtering units. The hematuria in this case is a result of the bleeding from the damaged glomeruli.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not relate to the clinical scenario of hematuria following an upper respiratory tract infection.
**Option B:** This option is incorrect because it does not directly relate to the development of hematuria in this specific clinical context.
**Option C:** This option is incorrect because it does not accurately describe the probable diagnosis in this case.
**Clinical Pearl / High-Yield Fact**
A classic exam trap is to associate hematuria with a kidney stone or a tumor, but in this case, the key is to consider the temporal relationship between the URTI and the development of hematuria, which points towards PIGN as the probable diagnosis.
**Correct Answer: C. Post-infectious glomerulonephritis (PIGN)**