This has the potential to be a symptom of one of the most serious cat emergencies any feline faces: urinary obstruction. This condition, which is fatal if not treated, occurs when cats are unable to urinate. For anatomical reasons, it occurs almost exclusively in males. Cats with the condition suffer agonizing pain, and then rapid progression to kidney failure, potentially bladder rupture, and high blood-potassium levels that cause cardiac arrest. Initial symptoms may be subtle: Affected cats may urinate outside the litter box, strain but produce only small quantities of urine, vocalize, or groom their genitals excessively. Therefore, any male cat with any urinary irregularity whatsoever should be checked by a vet immediately. Be aware that female cats with urinary irregularities should also see the vet. They are not likely to die from the problem, but they are likely to be suffering from discomfort that warrants treatment.