**Question:** Causes of acute retention of urine include all/except:

A. Urinary tract obstruction
B. Neurological disorders
C. Anxiety
D. Medications affecting bladder function

**Core Concept:** Acute retention of urine is a clinical condition characterized by an abrupt inability to void urine, resulting from mechanical or functional obstruction of the urinary tract, or neurological disorders affecting bladder function.

**Why the Correct Answer is Right:** Option C ("Anxiety") is not a direct cause of acute retention of urine, although it could contribute to bladder dysfunction in certain cases. Anxiety is a psychological factor, whereas acute retention of urine is a physical condition.

**Why Each Wrong Option is Incorrect:**

A. Urinary tract obstruction (e.g., stone, tumor, stricture) is a direct cause of acute retention of urine as it obstructs the flow of urine from the bladder, leading to increased bladder pressure and eventually urine stasis.

B. Neurological disorders (e.g., stroke, multiple sclerosis, spinal cord injury) can indirectly cause acute retention of urine by impairing the autonomic and/or motor function of the bladder, leading to decreased bladder compliance or absent detrusor contractions.

D. Medications affecting bladder function (e.g., anticholinergics, alpha-blockers, opioids) can cause acute retention of urine by impairing the smooth muscle relaxation and detrusor contractions, leading to bladder outlet obstruction or decreased bladder capacity.

**Clinical Pearl:** Acute retention of urine can be categorized into:

1. Mechanical causes (obstruction, anatomical abnormalities): These include urinary tract obstruction due to stone, tumor, stricture, etc.
2. Functional causes (neurological disorders, medications): These include neurological deficits affecting bladder function and medications affecting bladder motility and reflexes.

**Correct Answer:** Causes of acute retention of urine include all except "Anxiety" (Option C). Acute retention of urine can result from mechanical causes (obstruction, anatomical abnormalities) such as urinary tract obstruction due to stone, tumor, stricture, etc., or functional causes (neurological disorders, medications) such as neurological deficits affecting bladder function and medications affecting bladder motility and reflexes.