A most common cause of urinary obstruction in a male infant is –
**Core Concept**
The question is testing the knowledge of a common cause of urinary obstruction in male infants, which is related to the anatomical development of the genitourinary system. The most common cause is a congenital anomaly that affects the urethra.
**Why the Correct Answer is Right**
The correct answer is a condition where the male urethra is obstructed due to an incomplete or abnormal development of the urethral plate during embryogenesis. This results in a narrowing or blockage of the urethra, leading to urinary retention and obstruction. The condition is often associated with a palpable abdominal mass, which is a characteristic sign of this condition.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because hypospadias, a condition where the urethral opening is on the underside of the penis, is not the most common cause of urinary obstruction in male infants.
**Option B:** This is incorrect because posterior urethral valves (PUV) are a condition that typically presents with obstructive uropathy in older male infants, not the most common cause in the neonatal period.
**Option C:** This is incorrect because meatal stenosis, a narrowing of the urethral meatus, is a less common cause of urinary obstruction in male infants.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that a palpable abdominal mass in a male infant should raise suspicion for a urinary obstruction, particularly in the context of a history of polyuria, polydipsia, or failure to thrive.
**Correct Answer: A. Posterior urethral valves are a common cause of urinary obstruction in male infants.