This Is a Veterinary Emergency — Do Not Wait
If your male cat is repeatedly squatting in the litter tray, straining to urinate, and producing little or nothing, this is a medical emergency. A urethral blockage prevents the bladder from emptying, and within 24 to 48 hours the resulting build-up of toxins in the bloodstream — particularly potassium — can cause fatal cardiac arrhythmias. Do not adopt a wait-and-see approach. Contact your veterinary practice immediately, or your nearest emergency animal hospital outside of normal hours.
Why Male Cats Are Almost Exclusively Affected
Urethral blockages occur in both sexes but are overwhelmingly more common in male cats. The reason is anatomy. The male urethra — the tube that carries urine from the bladder to the outside — is significantly narrower than in female cats. This narrow passage is far more vulnerable to obstruction by even small accumulations of material. Neutered males are at the same risk as entire males; neutering does not protect against blockage.
What Causes a Blockage?
Several things can obstruct the male urethra:
- Urethral plugs — the most common cause, these are accumulations of mucus, sloughed cells, proteins, and sometimes crystals that form a soft, compressible plug in the narrow part of the urethra
- Crystals — struvite (magnesium ammonium phosphate) and calcium oxalate crystals can form in the urine and lodge in the urethra, particularly in cats with abnormal urine pH or inadequate water intake
- Urethral spasm — the urethra can go into painful muscular spasm following inflammation, which may itself partially obstruct urine flow
- Tumours — rare, but should be considered in older cats with a blockage that does not resolve or recurs without an obvious cause
In young male cats, the most common underlying condition is feline idiopathic cystitis (FIC), also called feline lower urinary tract disease (FLUTD). This is a stress-related inflammation of the bladder that has no identifiable bacterial cause. FIC produces urethral plugs and spasm, and is strongly linked to emotional stress, changes in routine, multi-cat household tension, and insufficient environmental enrichment.
Recognising the Signs
A blocked cat often shows signs that can be confused with constipation by owners unfamiliar with the condition. If you see a male cat repeatedly visiting the litter tray, look carefully — he is trying to urinate, not defecate. Key signs to watch for include:
- Straining in the litter tray repeatedly with little or no urine produced
- Crying or vocalising while trying to urinate — a sign of significant pain
- Frequent licking of the genital area
- Small spots of blood in the litter tray or on bedding
- Lethargy and reluctance to move
- Loss of appetite or complete refusal to eat
- Vomiting — a sign that toxins are accumulating in the bloodstream
- Hiding or withdrawal from normal behaviour
- In advanced cases, open-mouth breathing, collapse, or an unresponsive state
In a cat with a complete blockage, the bladder will be distended and feel like a hard, tense sphere — sometimes described as feeling like a golf ball — in the lower abdomen. This is not something to attempt to feel for at home if you suspect a blockage; go to the vet immediately.
Why Timing Matters: The Potassium Danger
The kidneys filter potassium from the blood and excrete it in urine. When urine cannot leave the body, potassium accumulates rapidly in the bloodstream. Elevated potassium — called hyperkalaemia — interferes directly with the electrical activity of the heart. It can cause irregular heart rhythms (arrhythmias) and, without intervention, cardiac arrest. This progression can begin within 24 hours of a complete blockage and may be fatal within 48 hours.
This is why no amount of home monitoring is appropriate once a blockage is suspected. The internal damage being done is not visible from the outside.
Emergency Treatment
At the veterinary practice, a blocked cat will receive emergency assessment and, if stable enough, will be sedated or anaesthetised so a urinary catheter can be passed to relieve the obstruction. The catheter allows the bladder to drain and may be left in place for 24 to 48 hours while the urethra recovers and the bladder regains normal muscle tone.
Treatment also involves:
- Intravenous fluids to correct dehydration, flush the kidneys, and help normalise potassium levels
- Cardiac monitoring if the potassium level is significantly elevated
- Blood tests to assess kidney function and electrolyte balance
- Pain relief, as urethral blockage and catheterisation are painful
- Monitoring after catheter removal to confirm the cat is urinating normally before discharge
In cats that block repeatedly and do not respond to medical management, a surgical procedure called a perineal urethrostomy (PU) may be recommended. This surgery creates a permanent, wider opening for urine to exit, reducing the likelihood of future obstruction.
Prevention: Diet, Hydration and Stress Management
While not every case of urethral blockage can be prevented, several measures significantly reduce the risk — particularly the recurrence risk in cats that have already blocked once.
Diet and Hydration
- Feed a wet (tinned or pouch) diet as the primary food source — wet food dramatically increases daily water intake compared to dry food and dilutes the urine, reducing crystal formation
- Avoid dry food-only diets in male cats, particularly those with a history of urinary problems
- Where prescription diets are recommended by your vet — such as Hills c/d, Royal Canin Urinary SO, or similar — use them consistently
- Provide multiple fresh water sources, including water fountains if the cat prefers moving water
- Weight management matters — overweight cats have higher rates of urinary disease
Stress Reduction
Because FIC is strongly stress-related, reducing sources of stress in the cat's environment is a genuine medical priority rather than a lifestyle preference. Practical steps include:
- Provide at least one litter tray per cat in the household, plus one extra
- Keep litter trays in quiet, private locations away from food and water
- Provide hiding spots, vertical space, and areas where the cat can retreat undisturbed
- Minimise unpredictable changes to routine, visitor traffic, or other animals in the home
- Consider pheromone diffusers such as Feliway, which have some evidence of benefit in stress-related urinary disease
- Environmental enrichment — play, puzzle feeders, and varied stimulation — supports emotional wellbeing in cats prone to stress-related flare-ups
Once a cat has experienced a urethral blockage, the recurrence rate is significant. Maintaining dietary and environmental management long-term, combined with prompt veterinary attention at the earliest sign of urinary straining, gives the best chance of keeping future episodes from becoming life-threatening.