Obstructive Urinary Retention

The inability to urinate causes urinary retention, which causes the bladder to swell. Both blockage and non-obstruction are potential causes of urinary retention. Your urinary tract becomes blocked and urine cannot flow freely if there is an impediment (such as bladder or kidney stones). This is the cause of acute urine retention, which could be fatal.

CAUSES

1. Prostate enlargement: Urinary retention in adult men is often due to an enlarged prostate gland.

2. Urethral strictures 

3. Urethral foreign bodies 

4. Paraphimosis and phimosis 

CLINICAL FEATURES

1. Symptoms: Urinary symptoms include hesitancy, frequency, nocturia, urgency, and a decrease in the amount and force of the urine stream, resulting in “dribbling.”

2. Physical examination findings include increased pain to suprapubic palpation and dullness to percussion over the distended fluid-filled bladder.

DIFFERENTIAL DIAGNOSES 

— Neurogenic causes

— Drug-induced retention

— Urinary retention secondary to pain

— Psychogenic causes

— Renal failure

— Abdominal aortic aneurysm

— Bowel obstruction

— A gravid uterus

EVALUATION

1. Physical examination readily identifies an obstructive etiology. A rectal examination should be performed to identify prostatic enlargement.

2. Urinary catheterization: A postvoid residual of more than 300 mL of urine confirms the diagnosis.

3. Laboratory studies

— Urinalysis should be performed to rule out infection.

— Renal and electrolyte panel. Blood urea nitrogen, creatinine, and electrolyte levels should be assessed to rule out renal insufficiency.

4. Imaging: Ultrasound can reveal a distended bladder. CT of the abdomen and pelvis is often obtained in search of a kidney stone or other potential cause (malignancy).

THERAPY

1. Acute relief: Catheterization should provide acute relief.

2. Definitive therapy: The source of the obstruction should be treated.

DISPOSITION

Most patients with mechanical obstruction may be discharged home with an indwelling catheter and a leg bag (and antibiotics). A follow-up with a urologist should be arranged.