Cat not urinating —
is this an emergency?

Recognize the signs

A blocked cat may not look dramatically ill at first — which makes this emergency deceptively easy to miss. By the time a cat is visibly in distress, the situation is already serious. Know what to look for:

• Frequent trips to the litter box with little or no urine produced
• Straining — crouching in the litter box for long periods without urinating
• Crying, vocalizing, or growling while in the litter box
• Licking excessively at the genitals
• Bloody urine — or urine that is dark or discolored
• Vomiting alongside urinary symptoms
• Lethargy, hiding, or loss of appetite — signs the kidneys are failing
• Collapse — a late and critical sign

Why male cats are uniquely vulnerable

The male cat's urethra — the tube that carries urine from the bladder out of the body — is extremely narrow, particularly at the tip (the penile urethra). Plugs of crystalline material that would easily flush through a female cat's wider urethra can completely obstruct the male cat's, with no urine able to pass at all.

Once completely blocked, the situation escalates quickly. The bladder continues filling and becomes painfully distended. The kidneys, unable to drain urine, begin to fail. Potassium — normally excreted in urine — builds up in the blood. High potassium is directly toxic to the heart. Without treatment, the heart stops.

What to expect during treatment

When a blocked cat arrives, we move quickly. Blood is drawn to assess kidney function and potassium levels — this tells us how sick the cat already is. IV catheter placement begins immediately for fluids and to stabilize any electrolyte abnormalities. Once stable enough for sedation, we pass a urinary catheter to relieve the obstruction and flush the bladder.

Most blocked cats require 24 to 72 hours of hospitalization. The urinary catheter is typically left in place for the first 24 hours to allow the urethra to recover from the obstruction and inflammation.