He had been turning to the right for two and a half years. Not occasionally, and not as a quirk. The circling had become the organizing fact of his day, and the immune drugs that were supposed to control the disease underneath it had stopped doing enough.
The dog is a three-year-old working cocker spaniel named Sidney, and his case appears in Veterinary Record Case Reports. What makes it worth reading is not the diagnosis. It is that after two and a half years of correct neurological treatment, the thing that finally improved his quality of life came from a completely different specialty.
Circling to the Right After Sudden Blindness in One Eye
Sidney's illness announced itself with an abrupt loss of vision in his left eye and decreased postural reactions. MRI found lesions in the right thalamus and the internal capsule, and he was diagnosed with meningoencephalomyelitis of unknown etiology, an immune-mediated inflammation of the brain and spinal cord that veterinarians shorten to MUE or MUO.
The condition is a diagnosis of exclusion. Veterinarians reach it after imaging, spinal fluid analysis and infectious disease testing rule out other causes of brain inflammation, and immunosuppression is central to treatment because there is no known pathogen to target. It is rarely cured outright.
Sidney circled to the right, the same side as his lesions. Circling is a recognized sign of disease affecting the forebrain, and it turns up in other dogs with inflammatory brain conditions, including one young spaniel whose encephalitis was eventually traced to antibodies against a neuronal receptor.
He was started on immune-modulating treatment with dexamethasone, leflunomide and cytarabine, and the initial response was very good. Circling and blindness were, at that point, a neurology problem with a neurology answer.
When the Immune Treatment Stopped Being Enough
It did not hold. Sidney relapsed repeatedly and deteriorated gradually. His medications stopped producing the response they once had, and follow-up imaging showed brain atrophy.
His owner did not simply wait it out. She read everything she could find about the condition, taught him a verbal cue she called Left Left to redirect the circling, and worked on getting him to walk calmly on a lead.
By then the circling had become something more than a neurological sign. It had taken over his day.
That distinction matters clinically. A repetitive movement that starts as the direct output of a brain lesion can, with enough repetition, take on the features of a compulsive behavior that persists on its own terms. Veterinary teams run into the same ambiguity in other settings, including a dachshund whose post-surgical behavior sat somewhere between a neurological sign and a behavioral disorder, and dogs whose compulsive behavior needed an interdisciplinary approach rather than a single specialty.
The Referral That Changed the Treatment Plan
After the repeated relapses and the atrophy on MRI, the referring neurologist, Vera Pisco, sent Sidney to Emma Gatehouse at Langford Vets in Bristol for behavioral assessment.
The first step was pregabalin alongside structured tracking of his behavior. Two months passed without improvement.
Then he was prescribed fluoxetine, the SSRI sold for dogs under the brand name Reconcile and approved for use in dogs for separation anxiety. Within a month, according to his owner's account published alongside the report, Sidney was calmer and no longer circling with the same intensity.
At the time of publication, he remained on the drug, had stopped steroids, and continued his other medication. His owner wrote that he was looking and behaving the best he had since the diagnosis, and that his hydrotherapist and physiotherapist agreed.
Combining behavior modification with an SSRI is an established approach in veterinary behavioral medicine, and published work has tracked fluoxetine alongside a behavior program in dogs with other problem behaviors, though that report followed only eight dogs with no comparison group. What is unusual here is the setting. Fluoxetine is normally reached for in dogs with anxiety, aggression, or compulsive disorders, not in a patient whose repetitive behavior has a documented structural cause on MRI.
What This Case Does and Does Not Tell Dog Owners
This is one dog. A single case report cannot show that fluoxetine reduces circling in dogs generally, and it cannot separate the drug's effect from the behavioral management, the natural course of his disease, or his owner's changed handling. The improvement was also described by the owner rather than measured against a formal scale.
It also should not be read as a reason to treat circling as a behavior problem first. Persistent circling in a dog is a red flag for structural brain disease. Sidney's own history started with sudden blindness and abnormal postural reactions, and the diagnostic work came first because it needed to.
What the report argues is narrower and more useful. When a dog with a confirmed neurological diagnosis keeps performing a repetitive behavior after the underlying disease has been treated as far as it can be, adding a behavioral assessment is not giving up on neurology. In Sidney's case, it was the step that changed his day.
Owners noticing repetitive circling, pacing, or other unexplained changes in a pet's behavior should raise it with a veterinarian rather than assume it is a quirk.
Key Questions Answered
What was wrong with the dog? He was diagnosed with meningoencephalomyelitis of unknown etiology, an immune-mediated brain and spinal cord inflammation, with lesions in the right thalamus and internal capsule.
Why do dogs circle? Persistent circling is a recognized sign of forebrain disease, and dogs commonly turn toward the side of the lesion. Sidney's lesions were on the right, and he circled right.
What finally reduced the circling? A behavioral referral, structured behavioral management, and fluoxetine. Pregabalin had been tried first without improvement.
Does this mean circling dogs need antidepressants? No. This is a single case in a dog with an established neurological diagnosis. It does not show that fluoxetine helps circling in general.
Should owners assume circling is behavioral? No. Circling warrants veterinary examination and, in many cases, imaging, because it commonly signals structural brain disease.
What is the broader lesson from the case? That repetitive behaviors driven by brain disease may keep going after the disease itself has been treated, and that behavioral medicine can be part of the answer rather than an alternative to neurology.
