FLUTD/Urethral Blockage (Feline Lower Urinary Tract Disease)

By April 20, 2021 No Comments


FLUTD/urethral blockage is commonly seen problem predominantly in male cats.  This is when calcium deposits are formed in the kidney or urinary bladder and get stuck in the urethra when the cat is trying to urinate.  FLUTD is mostly seen in male cats due to their longer and narrower urethra, as compared to the females.  When the acidity of your cat’s urine changes (pH value) to become less acidic, it is easier for struvite crystals to form.  The higher acidity in the urine helps dissolve any unwanted formations of calcifications or crystals in the urinary bladder or urethra.


A cat with urethral blockage is usually easily noticed.  It the cat goes to the bathroom indoors, you will see unnecessary urination habits (urinating outside of the litter box and in odd parts of the house), straining to urinate and usually they are very vocal.  Even if your cat is an outdoor cat, once it comes inside he or she will be very lethargic and show all the symptoms listed above.  It is not known exactly why, but some cats are more prone to developing FLUTD than others.    If left untreated, urethral blockage will be fatal.


An X-Ray is an important first step in the diagnosis of FLUTD.  We are then able to see if there are any stones in the kidneys, urinary bladder or the urethra that are causing the problem.  A doctor is also able to palpate (feel and put pressure) on the bladder area in order to see if they can express the bladder/put pressure on the bladder area so urination occurs.  There is such thing as a partial or complete blockage.  In both cases, urinary catheterization and I.V. fluids is the best choice in treatment.  A urine sample must be collected and sent to the Lab for further analysis.  This will let us know what kind of sediment is in the urine (blood, crystals, acidity of the urine, etc.).

An I.V. catheter is placed in the cat after X-Rays and diagnoses is confirmed.  This is done primarily because of the reason that the extra fluids going into the vein will dilute the urine, and produce more of it so a natural ‘flushing of the bladder’ occurs.  A urinary catheter is placed secondly so urination can be continuous.  The bladder urethra is then flushed out with a normal saline solution (to dissolve/break-up calcifications).  After sufficient flushing, and there is no resistance in moving the urinary catheter through the urethra, the catheter will be secured to the cat with a temporary suture and a bag to collect the continuous urine is placed.  Ideally, the catheter should be in the urethra for 2-3 days – depending on how severe the blockage is.  Associated antibiotics and anti-inflammatory medications will be given during hospitalization, and when the doctor believes it is time, the cat will be sent home.

Once the cat is home, sporadic urination habits are normal for a couple of days after the urinary catheter is removed.  A conversation with the vet about probable diet changes (‘Urinary SO’ and ‘Dissolution’ formulas are wet food examples), that may be necessary after Lab results have come back.  This may be a temporary or permanent change, as male cats can get blocked/FLUTD more than once.


Questions commonly asked

How quickly can crystals form?

Urethral crystals can develop within a few weeks or may take months to form.  This can tend to depend mostly on the pH value contained in the cat’s urine.

Can crystal formations be prevented?

Prevention is possible in many cases. Most of the time a specialized diet or medication is appropriate.  Periodic urinalysis may be helpful in some cases to detect early recurrence of the problem and allow adjustments in diet or treatment.  What can also help, is changing the litter in the litter box.  Cats with a history of urethral blockage should use litter in the form of cut up strips of newspaper or another substance – not  gravel or sand-like litter as the grainy litter can irritate the genital area and cause further problems.

What are the clinical signs of urethral blockage?

The most common symptoms of urethral blockage in the cat are hematuria (blood in the urine) and dysuria (straining to urinate). Hematuria occurs because the stones rub against the bladder wall, irritating and damaging the tissues and causing bleeding. Dysuria may occur from inflammation and swelling of the bladder walls or the urethra, from muscle spasms or due to a physical obstruction to urine flow caused by the presence of the crystals. Veterinarians assume that the condition is painful, and can cause the bladder to rupture if left untreated.


If left untreated, FLUTD will be fatal.  The urinary bladder will rupture if no urine is being voided and septicemia will result, as the high bacteria and acidity levels will damage and infect the rest of the body.  If urethral obstruction is removed, the prognosis for the cat is good, however reoccurrence is a possibility.