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Urethral obstruction in cats – how to spot it and what to do about it

By April Murphy, RVN, ISFMCert, FN


Urethral obstruction is a condition mainly seen in male cats because their urethra is long and narrow, which means it is more likely to become blocked. The urethra is a tube which drains urine from the bladder through to the penis, ready to be expelled from the body. When this mechanism is blocked, the bladder fills with urine with nowhere to expel it, so it gets bigger and bigger, and toxins build up in the bladder rapidly as well as fluid and electrolyte abnormalities.

Urethral obstruction is a painful condition and is life-threatening. Acute kidney injury (AKI) can result followed by death if this is not managed promptly. Due to the increased potassium levels seen with this condition, cats may develop heart abnormalities.

This condition has many causes including urethral spasms which can block the urine flow, mucus (which forms a plug), and crystals and small stones can clump together and block the urethra.

As mentioned previously, male cats are more likely than female cats to get this condition. Other risk factors include indoor-only cats, those that are overweight and on a dry diet only. One common cause of urethral obstruction is feline idiopathic cystitis (FIC), which is inflammation of the bladder which occurs secondary to stress. A cat which is stressed may develop urinary issues.


Signs to spot

Clinical signs of urethral obstruction are the following:

• Straining to urinate with little or no urine passed

• Frequent visits to the litter tray

• Vocalising

• Discomfort shown when petting their abdomen/near the tail area

• Excessive licking of genital area

• Vomiting

• Lack of appetite

• Lethargy

• Hiding behaviour

• Agitation

• Blood in urine

• Inappropriate urination (may urinate in other places than the litter tray if indoors)

If your cat is showing any of these clinical signs, please take them to a veterinary practice, IMMEDIATELY! This is an emergency and is life-threatening. Death can occur within a few days if left untreated.

What the vet will do

When your pet is at the veterinary practice, the practice will check them over and palpate their bladder. A blocked bladder feels very large and firm on palpation. DO NOT ATTEMPT TO PALPATE YOUR CAT’S BLADDER AT HOME.

A veterinary professional is trained to palpate bladders. A bladder is very fragile and your cat will be in a lot of pain and discomfort. If the vet concludes that your cat has a urethral obstruction, they will need to be admitted to the practice for hospitalisation, further investigation and treatment.

Investigations include taking x-rays to identify if the cause is because of a stone, ultrasound to see the size of the bladder and identify any abnormalities, a biopsy may be required depending on findings, a blood test to check their kidney parameters and electrolyte levels and a urine sample to check for any abnormalities like crystals.

Your pet may also need to have a urinary catheter placed to allow drainage of urine and to allow veterinary staff to measure input and output to ensure your pet is urinating efficiently. Placement of a urinary catheter is carried out under a sedation or general anaesthetic.

Usually, the urine build-up is drained and then the bladder is flushed with sterile saline. Pain relief is administered to eliminate any discomfort; intravenous fluids may be administered as well as other medications like antibiotics if any indication of a urinary infection, plus anti-spasmotics (if caused by urethral spasms) and anti-nausea medication.

Depending on your pet’s potassium levels, they may need a heart scan to check their heart function. Urinary toxins that build cause life-threatening rhythm disturbances.



While in hospital, it would be a sensible idea to bring some of their food from home as well as any toys/blankets/bedding to make their stay as comfortable as possible. Having items which remind them of home will make them feel comforted.

However, the practice may have a discussion with you about your pet’s diet and a dietary change may be required. A urinary diet may be considered, feeding a wet diet with added water. Encouraging water consumption by the use of feeding broths or the use of a cat water fountain is beneficial.



Once a cat has had urethral obstruction, it is likely to happen again at some point. In recurrent cases, an operation called perineal urethrostomy may be discussed. This is where an opening is made in the urethra above the blockage to allow passage of urine.

As discussed previously, stress may be a factor which contributes to urinary issues. A cat may be stressed due to boredom, having a dirty litter box or not having enough food, water and litter sources, if there is another cat in the household or a new cat in the neighbourhood and if there is any change to their routine. This includes any building work taking place, a partner moving in, moving house or the arrival of a new pet or baby.

Signs of stress are varied and include hiding, being less tolerant of people, urinating and/or defecating outside the litter box, eating or drinking less, overeating, overgrooming, looking tense (body crouched and they may hiss) and vomiting and diarrhoea. A stressed cat will have their ears flat to their head and have a worried expression.

If you notice any signs of stress or are concerned that your cat may be stressed, it is worth considering if there have been any changes recently and also calling your veterinary practice for a consultation in case the symptoms are due to an underlying condition.

There are fortunately many ways to reduce stress:

• Ensuring your cat has plenty of toys and a scratching post.

• Making sure you have the correct number of sources in the household. Ideally, there should be one litter box per cat plus an extra one. There should be one water and one food bowl each per cat.

• The use of perches and multilevels are essential as cats like to climb and be high. Activity centres with multilevels are great!

• A product to consider using would be Pet Remedy or Feliway. Feliway works by using pheromones which help to calm cats down whereas Pet Remedy is a natural product and uses valerian, vetiver, sweet basil and clary sage. Pet Remedy also helps other pets in the household including dogs, rabbits, guinea pigs and parrots!

Following the five pillars of healthy feline enrichment is vital to ensure that your cat has everything they need. According to the AAFP and ISFM Feline Environmental Needs Guidelines (, these are:


Pillar 1 – provide a safe place

Pillar 2 – Provide multiple and separated key environmental resources: food, water, toileting areas, scratching areas, play areas, and resting or sleeping areas

Pillar 3 – provide opportunity for play and predatory behaviour

Pillar 4 – provide positive, consistent and predictable human-cat social interaction

Pillar 5 – provide an environment that respects the importance of the cat’s sense of smell


I cannot express enough the matter of urgency if you notice any symptoms of urethral obstruction in your cat. My cat has had this issue and I empathise so much to any patient who is going through this and any client too because it is a difficult condition but if spotted quickly, it can be treated. Lots of patience, time and lots of TLC will help your cat.


April Murphy, RVN, ISFMCert, FN, has been a Registered Veterinary Nurse for three years and has worked in a variety of vet practices. She is passionate about feline care and nursing. She loves spending time with her family, her cat, and enjoys writing.

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