Urinary tract obstruction, or being unable to urinate, is a common condition seen in male cats.
The condition is painful and distressing for cats, and - without rapid intervention - can be fatal. So it is vital that anyone living with a cat, especially a male cat, knows what to look out for.
There isn't a single underlying cause for urinary tract obstruction. In part, it relates to feline anatomy.
Male cats have a very narrow urethra in a reasonably (close your ears, male cats) small penis.
What that means is that swelling of this area - or anything obstructing the urethra - can totally impede the flow of urine.
Some diets predispose cats to form crystals or even stones in their urine, which can block the urethra.
Similarly, urinary tract infections can lead to mucus or blood clots which cause blockage.
Stress also plays a role.
We know that changes to a cat's environment, conflict between cats (either within or between households), changes in the weather, or issues associated with the litter tray (such as unclean litter or change in the type of litter or tray) are associated with urinary tract obstruction in cats.
Overweight, exclusively indoor cats have an increased risk, as do cats living in multi-cat households and those who eat an exclusively dry food diet.
The most obvious signs of urinary tract obstruction are multiple, unproductive attempts to use the litter tray with little to no urine produced; straining to urinate; and vocalising while urinating.
Some owners mistake attempts to urinate for signs of constipation. Because the condition is painful, cats may attempt to urinate outside of the litter tray.
They may also be seen licking their nether regions more than usual.
In severe cases, affected cats may vomit, be off their food, or have a very painful abdomen.
Affected cats should be taken to a veterinarian immediately.
This is not a condition where you should "wait and see".
Being unable to urinate isn't only painful - it means toxins that would normally be excreted by the body build up in the blood stream.
Severely affected cats can suffer cardiac arrest.
In some cases, what looks like obstruction is actually a urinary tract infection which can be treated with antibiotics and pain relief.
These cats are still at risk of obstructing so should be monitored carefully.
Other cats may need to have their urethra catheterised (usually performed under a general anaesthetic) so that the bladder can be emptied and flushed.
Blood tests are usually performed to monitor kidney function and guide fluid therapy, and most affected cats need to be on a drip.
They may require several days of hospitalisation.
Your veterinarian may perform an x-ray or ultrasound to determine whether there are stones (uroliths) in the urinary tract.
My own cat Hero suffers from uroliths, and I've had to perform three bladder surgeries to remove these.
Pain relief is essential.
Some cats also require medication to relieve stress while their urinary tract heals. Prescription diets may be indicated to dissolve crystals and prevent recurrence.
Where obstruction is recurrent, or if the urethra is scarred, surgery may be required.
If you live with a cat, it is important to keep a close eye on their bathroom habits.
Not close enough to put them off their game, but close enough to have a sense of how often they are using their tray, and whether there is something in it when they're finished.
The earlier cats are treated, the better the outcome.
Dr Anne Quain BVSc (Hons), MANZCVS (Animal Welfare), Dip ECAWBM (AWSEL) is a lecturer at the Sydney School of Veterinary Science and a practising veterinarian.