Tail Chasing & Self-Injury

Trouble at both ends
Have you ever heard the expression, “Like a dog chasing its tail?” This actually happens.

Milo is a handsome miniature poodle who, in his youth, was a happy little guy sporting a fuzzy plume from his derriere. This was no longer the case. As he entered my exam room he often looked back at his rear end and sometimes barked frantically while reaching for the red and swollen stub of what remained. The plastic cone he wore seemed to add to his frustration. Rob, the man who loved Milo, was desperate for help.

My practice manager Carolyn is our first contact with the worried pet parents who call my office. Having been an essential part of my veterinary work for a long time, she gathers the facts and listens to the feelings. Carolyn brought Milo’s case to me right away.

Milo had a history of seizures that had plagued him for the previous two years. Our neurologist diagnosed epilepsy and prescribed anticonvulsant medication that she hoped would also reduce the tail chasing. Rob explained that the medication decreased the frequency of his dog’s convulsions but the spinning and aggressive tail biting had worsened. On the phone, he described severe tissue damage and smoldering infection. Milo needed help ASAP. I suspected serious trouble with his tail, along with two different areas of his brain.

The brain, considered the most complex organ in the body, is essential to life itself. It’s the site of behavior, emotions, learning, and most other physical actions. I embraced this specialty early in my career, even before my residency training, because it’s challenging and because behavior is the reason people have pets. Neurology is closely related to behavior medicine, involving somewhat different areas of the nervous system. Milo’s tail chasing and mutilation were in my wheelhouse.

A disorder of Milo’s neural circuitry was the underlying cause of his bizarre behavior but his acutely painful tail was the screaming priority, having already endured two surgeries. The exposed vertebra at the tip made it especially vulnerable.

Milo’s pain needed to end fast
Quiz: Why did Milo chase and bite his tail?
a) He was bored
b) Attention-seeking
c) He was compulsive
d) He needed a different home

Milo’s repeated biting of his tail had resulted in a rapidly advancing wound. When I first met this sweet little guy it was immediately clear that his two previous surgeries, while well-intentioned attempts to the eliminate infected tissue, accomplished nothing. His agitation, spinning, growling, and biting at the more recent amputation site only triggered another raging infection.

Repetitive behaviors and self-mutilation are not newly recognized in dogs but recent research has brought the cause to light, allowing us to get our arms around most of these cases. Milo’s attention to his tail didn’t start with the swelling, infection, and self-inflicted injury; it began in his brain. Tackling the underlying cause for his overwhelming need to twist and snap would take months. Getting his rear end misery under control had to happen ASAP.

Milo was exhausted and panting the first time I set him on my exam table. One of our gentle veterinary nurses held him quietly as I checked every body system. A careful look at the angry site of his recent tail surgery, revealed a portion of an exposed vertebra that was extremely sensitive. I’d seen this before. No amount of excellent wound management could coax skin and muscle to cover that small bone with its unprotected nerves. I brought Milo to my colleague, veterinary surgeon Dr. Kendra Freeman.

Rob, Milo’s person, is among the most committed pet parents I have ever known. He was ready for whatever was necessary. The drying bone needed to be removed and the wound closed such that – as long as it was left alone – it would heal properly. Dr. Freeman did the job right. Milo’s tail ended up a little shorter but it recovered completely and pain-free.

Ah, the quiz: Boredom is not a diagnosis. Dogs don’t hurt themselves to feel needed. Milo could not have had a better home. The correct answer is c).

Disorders of the brain are rarely simple
Compulsive disorders are a harsh reality for anybody who is saddled by a literally uncontrollable requirement to engage in repetitive, (stereotypic) behaviors. Most are related to somewhat normal activities, but they’re exaggerated, serving no useful purpose. They’re regarded as ritualistic because the sequences appear the same each time. And they may continue for a long time, and are usually difficult or impossible to interrupt.

Well-intentioned people have tried all manner of corrections, along with attempts to redirect the mental focus of these sad pets. They are wasting everybody’s time and energy while repetition strengthens the responsible neural pathways in the brain. Until dogs like Milo are treated appropriately, they get worse. The underlying problem in this poor little guy’ noggin needed the best modern medicine had to offer.

Milo’s compulsive attention to his rear end is rooted in his brain’s anatomy. He has a dysfunction called a cortico-striatal-thalamocortical loop. Once his spinning and snapping started, it continued on autopilot. For another affected dog, the symptoms might be different, like flank sucking, rear end checking, fly biting, circling, pacing, or shadow or light chasing. A few drink excessive quantities of water. Spinning and self-mutilation are among the more common presentations. Tailoring the right medication for Milo would be the only way of helping him out of this jungle.

Milo’s early symptoms might have made his diagnosis easy to miss. His person, Rob, explained that the behavior started a year earlier with his boy sniffing at the tip of his tail. One week later he began to spin slowly and then chase his tail, sometimes triggered by normal household noises. Pretty soon Milo could no longer sleep during the day. It was worse when he was confined to his crate.

Milo is better & he feels great
Brains are certainly interesting. Parts of their anatomy, and the chemicals that conduct their complex work, can change during life. Practice makes perfect because repetition through the neural circuits upstairs makes them stronger. Neuroplasticity is the name for these gradual changes that can transform behaviors and physical functions.

Just derailing Milo’s vicious cycle of spinning and tail biting would help him because the responsible pathways in his brain would weaken from disuse. I told his family to avoid reprimands; telling him to stop would only draw his attention back to the problem. Punishment was also off the table. Instead, they were to leave a leash attached to this pupster’s harness full time. At the earliest hint that he might turn toward his long suffering rear end, their job was to completely ignore, grab the leash, and head to another room. As Milo relaxed they would quietly reinforce. Repeat hundreds of times.

The feedback loop in Milo’s brain, at the center of all this mayhem, needed attention because it was wired wrong. With brain transplant surgery the stuff of 1930s B movies, we instead rely on research-based modern medicine.

Many compulsive cats and dogs respond well to SSRI medications, like fluoxetine or sertraline. Milo improved after treatment with Reconcile (fluoxetine) but he still chased and reached for his tail much too often. Completely eliminating repetitive, compulsive behaviors is rarely achievable; a more realistic objective is to diminish them as much as possible. Our goal for Milo was a more peaceful life and a complete end to his self-injury.

Simply raising Milo’s fluoxetine dose would risk side effects. Like most compulsive dogs he needed a tailored combination of drugs that would safely control his symptoms. After adding clonazepam, along with his anticonvulsant meds, we achieved almost normal behavior. In the bad old days routine events like a neighbor visiting, would trigger excitement and tail chasing. Now Milo only looks back at his rump for 10-15 seconds and then acts like any normal dog. OMG! In behavior medicine we call that a home run.