Talk about fur flying! There were literally tufts of hair strewn about when Vincent had a fight with another cat last week. “I didn’t find any wounds,” his owner reported, but she had been watching him carefully. Vinny had been behaving normally: eating, drinking, not limping, but his owner had noticed a lump on his back near where the tail meets the body. She thought it was painful, since he batted her hand away whenever she tried to touch it, and his tail was drooping down rather than in its usual jaunty upright position. When I hear a history like this, my first thought is abscess. Cat bite wounds are tiny and frequently close over on the surface, but fester underneath.This eventually leads to a pocket of pus under the skin, requiring drainage and treatment with antibiotics. I suggested Vinny come see me.
I began my examination by running my fingertips deep in his fur all over his back. I often find tiny wounds or scabs that owners miss, but not this time. No bite wounds. No abscess. Instead, just as his owner had described, there was a palpable hard bump at the top of the tail base. When I moved it ever so slightly, Vincent complained.
Let’s start with some anatomy. A cat’s spinal ( or vertebral) column is comprised of vertebrae, muscles, tendons, and ligaments, and extends from head to tail. The spinal cord is enclosed inside the vertebral column. It is the cylindrical tube of nerve fibers that carries information about sensation and movement to and from the brain to the body. A cat’s vertebral column has seven neck vertebrae (cervical), thirteen chest (thoracic), seven lower back (lumbar), three in the area passing through the pelvis (sacral), and finally ending with the tail (caudal). Most cats have 20 to 23 caudal vertebrae in their tails. The spinal cord only reaches to about the fifth lumbar vertebra, but the nerves continue, traveling a long distance from the lumbar region to innervate the tail, hind legs, anus, and bladder. If you look at a schematic of the path of all these long nerve fibers, extending from the lower back down into the hind end, it looks like a horse’s tail. Hence, this area has been dubbed “cauda equina” by anatomy nerds. That’s Latin for “horse’s tail.”
Injuries to the tail can include fractured vertebrae in which bone is actually broken, dislocation in which two vertebrae have been yanked apart and remain out of alignment, or a “tail pull” in which the cauda equina was stretched but not necessarily severed. Radiographs can identify vertebral fractures and/or dislocations, but other forms of “tail pull” injury may appear normal on X-rays and are diagnosed only through history and clinical symptoms. Much depends on the exact location and severity of the trauma. The higher up the injury, the greater the risk of spinal column damage. Tail injuries are also often accompanied by other things such as broken pelvis or hind legs.
Vinny’s lesion was localized, and far back enough that the only clinical symptom was a drooping tail. I was not concerned about spinal cord trauma, but what about injury to the cauda equina? Trauma to that collection of nerve fibers can still have serious consequences. I pinched the tip of his tail. He didn’t react. Did he have any sensation down there? I pinched harder. Vincent complained. I pinched even harder. The tip of his tail moved. Almost imperceptibly, but it moved. Good! This confirmed that nerves were intact. Bruised perhaps, over-stretched perhaps, but intact. He could feel what I was doing. He could voluntarily move his tail, even if only slightly. Cats like this almost always make a full recovery. Even cats who present with loss of all feeling and ability to move their tails eventually recover, as long as they are urinating and defecating normally.
Cats with higher up and/or more severe tail pull injuries are not always so lucky. These cats may exhibit urine retention, diminished anal tone, or even complete loss of anal sphincter function. Recovery rates vary but may be as low as 50 percent in cats with no anal tone. The problem is there are limited ways to predict who will regain function and who will not. And there is a lot of maintenance nursing care that needs to happen during the recovery period. Let’s take another hypothetical cat called Theo. Theo has a tail pull injury and is not able to urinate normally. We have to help him by manually expressing his bladder several times a day. This is usually not too difficult once you get the hang of it, but it has to be done religiously, day after day. Theo might also need laxatives, or even enemas, to help him defecate while we wait to see how much function he will regain.
Some of you might remember our old office cat, Freddy. This little guy suffered an injury far worse than a tail pull when he was thrown out a car window as a kitten. He was completely paralyzed in the hind end. We manually expressed both his urine and feces for seven happy, love-filled years before he eventually passed away from heart disease. One thing we did do for him was to amputate his tail. If Theo recovers bowel and bladder control but still cannot move or feel his tail, that tail becomes a liability. It can get caught in things. It will drag in the dirt. It will get soiled in the litterbox. There is no rush to go to surgery. Nerves heal slowly. There is no harm in a “wait and see” approach, as long as you maintain good hygiene, but eventually going “manx-style” may benefit everyone. As for Vincent, we expect him to be able to keep his tail and be back to normal in a month or so. We sent him home with anti-inflammatory pain medication and a prescription for “tincture of time.”