**Question:** Tear drop bladder is seen in

A. Spinal cord injury
B. Pelvic fracture
C. Prostatectomy
D. Renal failure

**Core Concept:** Tear drop bladder is a clinical sign observed in patients with spinal cord injury, which results from the disruption of the autonomic innervation of the bladder leading to detrusor instability and urethral sphincter dysfunction.

**Why the Correct Answer is Right:** In spinal cord injuries, the segmental or higher level lesions disrupt the sympathetic and parasympathetic innervation to the bladder, causing detrusor overactivity and weak urethral sphincter muscles, leading to a tear-drop shaped bladder on ultrasound imaging. The bladder tends to become contracted and narrow (like a tear drop), with an increased bladder wall thickness, and a narrow neck that empties poorly.

**Why Each Wrong Option is Incorrect:**

A. Spinal cord injury is responsible for tear drop bladder, not renal failure. Renal failure is a consequence of spinal cord injury, not the cause of this sign.
B. Pelvic fracture may cause bladder injury and traumatic bladder rupture, but it is not responsible for the tear drop bladder sign.
C. Prostatectomy pertains to surgical removal of the prostate, which is unrelated to the tear drop bladder sign observed in spinal cord injury.

**Clinical Pearl:** The tear drop bladder sign should trigger a thorough neurological evaluation for spinal cord injury, as early detection and management can significantly improve patient outcomes.

**Correct Answer:** A. Spinal cord injury