Urethral Obstruction In Cats
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table of Contents
- Overview
- Symptoms
- Diagnosis
- Treatment
- Outlook
In male cats, the urethra (the tube between the bladder and the outside world) is very long and narrow. If a male cat develops urinary tract disease, the urethra may become blocked with debris, or spasm due to inflammation. This obstructs the urethra and prevents the cat from passing urine. Also known as a blocked bladder, urethral obstruction is an emergency and can be rapidly fatal if untreated. Urethral obstruction can affect female cats, but is extremely rare.
What are the symptoms of urethral obstruction?
Often the first symptoms are those of urinary tract disease, such as frequent straining in the litter tray. In cases of urethral blockage, the cat will not pass any urine at all, and straining may become more frantic. Cats often lick themselves obsessively and may vocalise in distress.
If untreated, the bladder fills causing a distended, painful abdomen. Waste products build up in the blood, causing cats to become lethargic. They may refuse food or start to vomit. This is an emergency condition and can quickly become fatal if left untreated.
Which tests are used to diagnose urethral obstruction?
A urethral obstruction is strongly suspected on examination, as the bladder will be large, firm and painful. Underlying causes for the urinary tract disease should be considered, however, relieving the obstruction must take priority. Once the obstruction is relieved, investigation of the inciting cause is likely to include urine analysis, ultrasound and/or x-rays.
How is urethral obstruction treated?
Urethral obstruction makes cats very unwell, very quickly, and most will need to be stabilised before the obstruction can be relieved. Obstruction can cause a dangerous build-up of potassium in the blood, and put a lot of pressure on the kidneys. It is strongly recommended to perform blood tests to assess this. Stabilisation then typically involves administering intravenous fluids (a drip) and pain relief, but other treatment may be required.
Once stable, the cat will need to be sedated or anaesthetised and a catheter passed up the urethra into the bladder. This relieves the obstruction and allows urine to be drained. If the blockage is physical, rather than due to spasm, it can be very challenging to clear, and require the obstruction to be very slowly flushed out. Rarely, it is not possible to pass a catheter. Removing urine directly out of the bladder using a needle and syringe (known as cystocentesis) can help relieve pressure above the catheter, but carries a small risk of damage to the bladder if it is very full.
Once a catheter has been placed, the bladder will be flushed out and drained. There is much debate regarding how long the catheter should be left in place, and most vets will have their own preference based on experience and the individual situation. The catheter may be removed immediately, or left in place for 24-72 hours. During this time, it is recommended that your cat remains hospitalised to allow for close monitoring, fluids and pain relief.
Depending on the suspected cause for the urethral obstruction, and the results of urine analysis and imaging, other treatment may be advised. This could include, but is not limited to: anti-inflammatories, bladder support, muscle relaxants, increasing water intake, diet changes, environmental modification and antibiotics.
What is the outlook for cats with urethral obstruction?
The prognosis for cats with urethral obstruction varies from reasonable to guarded.
Once the catheter is removed, we must monitor them closely for recurrence of an obstruction. Cats who urinate voluntarily in the 12 hours post catheter removal, can usually be discharged and treated at home. A small number of cats will experience an almost immediate recurrence of obstruction, in which case, repeat catheterisation is usually required.
All cats have the potential to experience further blockages in the future. The closer together these episodes occur, the more guarded the prognosis for successful management. Cats who present very unwell, or who are very challenging to unblock, have a much more guarded prognosis for recovery, and sadly sometimes euthanasia may need to be considered.
Cats that respond well to treatment can do very well long-term, though urinary tract disease is a chronic condition and is likely to need life-long management.
Disclaimer
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.
Page last reviewed: 21st June 2024
Next review due: 21st June 2026