Diseases that Cause Aggression


Help me, Einstein,

My people are mad at me. Sometimes I just feel sick and don’t want to be touched. When the little girl hangs onto me or pets me, I’ve been known to give her a warning nip. Then someone screams at me or hits me. I just want to stop the hurting. When I cry out at night to tell them how bad I feel, they yell at me to shut up. I’m trying to communicate my pain in the only way I can, but they don’t understand. I’m just…

Thomas N. Payne

Hey Tom,

You’ve been trying your best to let your family know that you feel like dog droppings. Sometimes you have to hit them over the head with a food bowl (or bite the hand that feeds you) to get their attention.

We kitties always have good reasons for behavior changes. My vet bud tells me humans occasionally bring him kitties to be killed cuz they’ve suddenly become “mean”, but they’re not really mean, they’re sick. Any time a kitty’s behavior suddenly changes, that’s a red flag. Sudden aggression often means something’s bothering you medically. Instead of a thump on the nose, your testy actions should win you an all-expense paid round-trip ticket to visit your friendly vet.

Medical Causes of Aggression

*Almost anything can cause you to feel down in the mouth, from dental problems to cancer. Pain causes humans to snap at their spouses; it’s the same with kitties. We try to tell them that our tooth is killing us by calling out or biting when our faces are touched. Since humans don’t understand Felinese, they don’t know that we’re sending out a Siamese-style S.O.S.

*Hypertension (high blood pressure) is called the silent killer, even though the cat himself may not be silent. It’s one of the most common causes of those nighttime screaming marathons. Some vets believe high blood pressure causes headaches that can inspire you to scream, “Ow, my head!” Hypertension also causes numbness, cognitive problems, seizures, strokes and aggression.

Vets treat hypertension with calcium channel blockers or beta blockers (not the fish) and by cutting back on sodium in your diet. Hypertension isn’t a loner. It’s often related to other behavior-changing diseases: usually kidney disease, thyroid disease or diabetes—in that order. If you treat the underlying disease, the hypertension often resolves itself. Once the high blood pressure goes down, we feel better.

*Hyperthyroidism will also qualify you for a dog-calling contest. A lot of hyperthyroid kitties seem A-OK, but it turns out they R-NOT. Cuz the body is secreting more thyroid than it should, you’ll become more active and alert—kinda like being on speed. You also become irritable and anxious. You’re really thirsty. So that makes you drink and pee more. Sometimes you may start going outside the litter box. Even though you’re eating enough food to satisfy a sumo, hyperthyroidism will make you skinny as a runway model. Hyperthyroidism can also cause high blood pressure. Tada, back to the brain-busting headaches and talking, talking, talking.

Vets used to surgically remove the thyroid, but they don’t do that much anymore. Today they treat hyperthyroidism with drugs that are usually cheap and effective. Sometimes they give us the Chernobyl treatment, a one-time shot of radioactive iodine. Vets have to isolate us for a few days cuz we really are radioactive. They monitor the rads with a Geiger counter just like in the old movies. And talk about toxic poo! Litter box attendants have to wear protective gear before scooping the pan. After a few weeks we’re usually okay and safe to be around.

*Fleas or fur mats can also make kitties talkative or grumpy.

*Hyperesthesia is a mysterious syndrome that causes all kinds of misunderstandings between kitties and their humans. Hyperesthesia, which means “sensitivity to touch,” causes the skin to twitch and ripple spontaneously or when touched. Out of thin air you might jump up, call out, and then race around the house as if trying to get away from something. These poor guys lash out because they’re hypersensitive to touch or even to the sensation of air current brushing against their fur. Sometimes these kitties over groom themselves. There’s a trigger, but humans may be hard-pressed to figure out what that trigger is. So the more stimulated kitties become, the more likely they are to have an episode, and I’m not talking about My Cat From Hell.

There isn’t a test for hyperesthesia, so the only way to diagnose it is to rule out everything else. Vets admit they don’t really know for sure what causes it. Hyperesthesia is a syndrome with many potential causes. Some researchers think it could be a form of epilepsy cuz some kitties respond to anti-seizure medication. (In some cases it could be a behavior problem and vets may treat these kitties by stimulating the environment.)

Even if you don’t suffer from hyperesthesia, too much petting can still turn pleasure into pain. I’ve heard it said that, “Too much of a good thing is a bad thing.” That can be true of petting. When we’ve passed pleasure petting, it can escalate into pain. Humans who get attacked during a love-in would be smart to tune in to the cat’s ears and tails for signs that the blood-letting is getting ready to commence. It doesn’t take a pet psychic to figure out if your ears are twitching or turned back or your tail is thumping, there’s pain in the future.

*Arthritis-Like kitties with headaches, arthritic kitties will also call out, “Ow, it hurts,” when their joints provide a more accurate weather prediction than a Weather Channel meteorologist. It also might make getting into and out of the litter box a challenge.

*Kitty Alzheimer’s-If you’re a really old feline, kitty Alzheimer’s, senility or cognitive dysfunction can make you talk to the walls. You may even get lost on the way to the litter box.

Cats are little predators. And while mice and lizards are our favorite entrées, cats, especially sick or weak kitties, appear at the top of Wily Coyote’s menu. Unlike dogs, who are more likely to show when they feel poopy, we kitties are experts at hiding symptoms. After all, we don’t want to draw attention to our weakness.

So your humans need to watch for hints that you’re feeling like something the cat dragged in. They should take you to vet as soon as they notice you’re acting differently: eating more, not eating at all, suddenly active, suddenly laying around, hiding, biting, scratching, vocalizing or peeing/pooping someplace beside the litter box.

While I’m no fan of sharp things, Thomas your humans need to take you to vet to find out what’s making you do a Dracula impersonation. Hopefully it won’t be long before you’re up to a good love-making session. They’ll be happy to find out that you prefer purring to piercing too.

Thanks to Drew D. Weigner, DVM, ABVP a cat specialist in the Greater Atlanta area for sharing his smarts.



About the Author

Dusty Rainbolt, ACCBC is AdoptAShelter.com's editor-in-chief. She is past president of the Cat Writers' Association. With three decades of animal rescue under her collar, Dusty has rescued and rehomed over 1500 cats. She's author of Kittens for Dummies and Cat Wrangling Made Easy. Her new paranormal mystery, Death Under Crescent Moon, can be purchased to benefit your favorite AdoptAShelter.com charity at Amazon.com.