Your cat has a hard time telling you when she's ill. Here are some of the major cat illness symptom categories and how to spot problems.

Pay attention to changes in your cat's behavior as this can indicate signs of illness. Cats tend to disguise signs of pain and illness as a throw-back to their wild days.

Elimination problems -- Cats may experience a number of issues involving urination, defecation, and litter boxes.

Some urinary tract problems can be life threatening. FLUTD (feline lower urinary tract disease) is a label for a group of problems that can involve crystals, stones, infection, or inflammation.

Cats self-groom regularly, but excessive licking in the anal or groin area can be a sign of illness. If your cat is urinating more often than normal, this can be a sign of an illness such as diabetes.

Constipation is fairly common in cats. Treatments are available for this, and include store bought and veterinarian prescribed treatments such as lactulose.

Impacted anal glands my also be a factor which will require treatment. It should be noted that long term constipation may lead to a serious bowel condition known as megacolon.

If your cat makes frequent but unsuccessful trips to the litter box, or is howling or crying out while attempting to use the box, she may have some physical problem that needs attention. Also, a common sign of trouble is the act of scooting across the floor while dragging the rear end.

If your cat is not urinating or defecating or is missing the litter box, contact your veterinarian immediately. Inappropriate elimination is common and is the number one cause that adult cats are brought to shelters. It has a number of physical and behavioral causes. You should address any medical problems first.

Other things to look for are evidence of blood in urine or feces, including black tarry stools. Diarrhea may indicate intestinal disease and can lead to dehydration, which can be fatal.

Eye and mouth problems -- The haw, or nictating membrane, is a "third eyelid" that you will sometimes see when a cat's eyes are open. This is often an indication of illness. Check your cat's eyes for cloudiness, pupils of uneven size, or discharge.

Ulcers in the mouth, bad breath, and loose teeth are signs of disease. Pallor of the gums and lips is a sign that your cat may be anemic.

Hair and skin problems -- Poor coat or problem skin can be a sure sign of cat illness. In fact, the coat and skin of your cat can be used as a measure of overall health.

A poor or oily looking coat is a sign of illness. If you notice that cat has stopped grooming, it's a sure sign of a problem.

Parasites are usually easily spotted on the skin or coat on the belly. Your cat should be checked at least once per week. Also look for excessive dryness or flaking, hair loss, skin growths, and any kind of swelling or skin eruption.

There are certainly other health problems that your cat may encounter, but these are a few of the major categories. Keeping alert to your cat's routine, and being sensitive to any of the possible above problems is an integral part of cat care.