My cat, Whiskers, hasn’t been acting like himself lately. He’s usually a playful cat, always chasing after his toys and wanting attention, but he’s been much more lethargic and withdrawn for the past few days. He also seems to be eating less and I noticed he coughed a bit earlier. I’m worried he might be getting sick.
What are the most common signs of illness in cats, considering changes in behavior, appetite, activity levels, and any observable physical symptoms like coughing, sneezing, or changes in their litter box habits? And are there any specific signs that should trigger an immediate visit to the vet?

Answer

The most common signs of illness in cats include:

Changes in Appetite and Weight:

• Loss of appetite (anorexia): A cat that suddenly stops eating or eats significantly less than usual is a major cause for concern. This can indicate a variety of problems, from dental issues to organ failure.
• Increased appetite (polyphagia): While sometimes benign, a sudden increase in appetite, especially if accompanied by weight loss, can be a sign of hyperthyroidism, diabetes, or intestinal malabsorption.
• Weight loss: Unexplained weight loss, even with a normal appetite, should always be investigated. It can be associated with chronic diseases like kidney disease, cancer, diabetes, or parasites.
• Weight gain: Rapid or significant weight gain can indicate fluid retention (ascites) due to heart or kidney problems, or simply overeating coupled with lack of exercise.

Changes in Litter Box Habits:

• Increased urination (polyuria): A cat that’s suddenly drinking and urinating much more than usual may have kidney disease, diabetes, or hyperthyroidism.
• Decreased urination (oliguria/anuria): Straining to urinate or producing very little urine is an emergency, especially in male cats, as it could indicate a urinary blockage.
• Urination outside the litter box: This can be due to a behavioral issue, but it’s also a common sign of urinary tract infections (UTIs), bladder stones, or other urinary problems. Painful urination will make them associate pain with the box.
• Changes in stool consistency: Diarrhea or constipation can indicate gastrointestinal upset, infections, parasites, or dietary issues.
• Blood in urine (hematuria) or stool (hematochezia/melena): Blood in the urine or stool is always a serious sign and requires immediate veterinary attention. Dark, tarry stools (melena) indicate digested blood, suggesting bleeding higher in the digestive tract. Bright red blood (hematochezia) usually comes from the lower digestive tract.

Respiratory Issues:

• Coughing: Coughing in cats can be a sign of asthma, heartworm disease, respiratory infections, or foreign bodies in the airway.
• Sneezing: Frequent sneezing can indicate an upper respiratory infection (URI).
• Nasal discharge: Discharge from the nose can be clear, yellow, green, or bloody, depending on the cause.
• Difficulty breathing (dyspnea): Labored breathing, rapid breathing (tachypnea), or open-mouth breathing are signs of a severe respiratory problem and require immediate veterinary care.
• Wheezing: A whistling sound during breathing, often associated with asthma or other respiratory conditions.

Gastrointestinal Issues:

• Vomiting: Occasional vomiting might be benign, but frequent or projectile vomiting, or vomiting accompanied by other signs like lethargy or loss of appetite, warrants investigation. Look for blood or bile in the vomit.
• Diarrhea: Loose or watery stools can be caused by a variety of factors, including dietary changes, infections, parasites, and inflammatory bowel disease (IBD).
• Constipation: Difficulty passing stool or infrequent bowel movements can be caused by dehydration, dietary issues, or underlying medical conditions.
• Regurgitation: Passive expulsion of undigested food, often related to esophageal problems.

Changes in Behavior:

• Lethargy: A decrease in activity level or a general lack of energy can be a sign of illness.
• Hiding: Cats often hide when they’re not feeling well.
• Increased vocalization: Excessive meowing or howling can be a sign of pain, anxiety, or cognitive dysfunction.
• Aggression: A normally friendly cat that suddenly becomes aggressive may be in pain or feeling threatened.
• Changes in grooming habits: A cat that stops grooming itself may be feeling ill or depressed. Conversely, excessive grooming in one area could indicate pain or irritation.
• Confusion or disorientation: Cognitive dysfunction in older cats can manifest as confusion, disorientation, or changes in sleep-wake cycles.

Other Physical Signs:

• Eye discharge: Discharge from the eyes can be a sign of conjunctivitis, upper respiratory infection, or other eye problems.
• Third eyelid protrusion: Elevation of the nictitating membrane (third eyelid) can indicate illness, pain or Horner’s Syndrome.
• Skin problems: Hair loss, itching, redness, lumps, or bumps on the skin can be caused by allergies, parasites, infections, or tumors.
• Lameness: Limping or difficulty walking can be a sign of injury, arthritis, or other musculoskeletal problems.
• Swollen abdomen: A distended abdomen can indicate fluid accumulation, organ enlargement, or tumors.
• Pale gums: Pale or white gums can be a sign of anemia or shock.
• Jaundice (yellowing of the skin and eyes): Jaundice indicates a problem with the liver or gallbladder.
• Bad breath (halitosis): Can indicate dental disease, kidney disease, or diabetes.
• Drooling: Can be a sign of nausea, dental disease or oral pain.
• Seizures: Seizures can have various causes, including epilepsy, brain tumors, or toxins.
• Uncoordinated movement (ataxia): Can be due to neurological problems.
• Tremors: Trembling or shaking can be a sign of pain, fear, or neurological problems.

Changes in Sleeping Patterns

• Sleeping significantly more or less than normal can be a sign of underlying health problems.

It’s important to remember that this is not an exhaustive list, and some cats may exhibit different signs of illness than others. Any sudden or significant change in your cat’s behavior or physical condition should be discussed with a veterinarian as soon as possible. Early detection and treatment can often improve the outcome for many feline illnesses.