Holmes' tremor (rubral or midbrain outflow tremor) refers to a hyperkinetic movement disorder characterized by mild resting and more severe postural and action tremor often with associated brainstem symptoms, dystonia and cerebellar deficits. This syndrome should prompt lesional evaluation with neuroimaging focused on the dorsal midbrain, cerebellar outflow tracts, and thalamus. Herein we report a 26-year-old previously healthy male who presented with 4 years of progressive horizontal diplopia, right Parinaud syndrome, and appendicular ataxia. Neuroimaging revealed a right dorsal midbrain enhancing lesion which completely resolved with intravenous methylprednisolone prompting a diagnosis of neuroinflammatory syndrome. Subsequent clinical and radiographic evaluations, however, revealed steadily progressive left dorsal midbrain syndrome with an expansile enhancing lesion which culminated 4 years from symptom onset with a right upper extremity low-frequency rest, postural and action tremor, ataxic dysarthria, and mild right dystonia with dysdiadochokinesia. Uncomplicated brainstem biopsy confirmed intracranial germinoma and the patient underwent definitive radiation therapy with dramatic radiographic response and partial clinical improvement. This case, which to our knowledge is only the second report of intracranial germinoma presenting as Holmes' tremor, highlights the critical importance of definitive tissue diagnosis in the evaluation of lesional brainstem pathology presenting as Holmes' tremor. Steroid responsiveness can be seen in non-inflammatory pathology including intracranial germinoma. Prompt evaluation and appropriate treatment are important as Holmes' tremor responds poorly to symptomatic therapies and response to radiation therapy is favorable for germinomas.
Even though I haven’t dealt with this myself, I still found it very interesting, and this was such a help to others who have experienced it! And we never know what we might experience with our dogs in the future, so it’s always good to be educated on these different things, so we don’t panic if it does happen to our dogs. Especially since it’s so difficult to figure out when we should panic, and when we should just wait things out. Can’t say how much money I’ve spent at the vet’s for basically what just ended up being for my own peace of mind! 🙂
Your vet’s treatment plan will take into account the severity of the tremors and your dog’s overall health. The primary treatment for shaker syndrome is corticosteroids. The steroids reduce the inflammatory response in the body. After beginning treatment, tremors generally resolve in a week. Your vet will gradually taper off the steroid dosage to none at all. Expect to return regularly to the vet for follow-up visits in the first month of treatment.
Steroids are usually given for a few months before being halted, but if symptoms recur treatment will be given for a longer period. Some dogs require a lifetime of regular immunosuppressive treatment to maintain health.