Clinical and Breed Characteristics of Idiopathic Head Tremor Syndrome in 291 Dogs: A Retrospective Study.

Linda G Shell,John Berezowski,Belle M Nibblett,Patrick Kelly,Mark Rishniw

doi:10.1155/2015/165463

Abstract

Objective. To establish signalment and phenomenology of canine idiopathic head tremor syndrome (IHTS), an episodic head movement disorder of undetermined pathogenesis. Design. Retrospective case series. Animals. 291 dogs with IHTS diagnosed between 1999 and 2013. Procedures. Clinical information was obtained from an online community of veterinary information aggregation and exchange (Veterinary Information Network, 777 W Covell Boulevard, Davis, CA 95616) and conducted with their approval. Information on breed, sex, age of onset, tremor description, mentation during the event, effect of distractions and drugs, diagnostics, presence of other problems, and outcome was analyzed. Results. IHTS was found in 24 pure breeds. Bulldogs, Labrador Retrievers, Boxers, and Doberman Pinschers comprised 69%; mixed breeds comprised 17%. Average onset age was 29 months (range: 3 months to 12 years). First episode occurred before 48 months of age in 88%. Vertical (35%), horizontal (50%), and rotational (15%) movements were documented. Possible trigger events were found in 21%. Mentation was normal in 93%. Distractions abated the tremor in 87%. Most dogs did not respond to antiepileptic drugs. Conclusions and Clinical Relevance. This retrospective study documents IHTS in many breeds including Labrador Retrievers, Boxers, and mixed breeds.

Highlights

Canine idiopathic head tremor syndrome (IHTS), sometimes referred to as episodic rapid repetitive myoclonus, is generally regarded as a benign condition manifesting as episodic uncontrolled head tremors that start and stop spontaneously
The cause of IHTS is unknown, affected Doberman Pinschers were traced to a common sire suggesting the condition may be inherited [1]
No diagnostic tests have been identified to date that allow a more specific diagnosis of IHTS

Summary

Introduction

Canine idiopathic head tremor syndrome (IHTS), sometimes referred to as episodic rapid repetitive myoclonus, is generally regarded as a benign condition manifesting as episodic uncontrolled head tremors that start and stop spontaneously. These head tremors have been reported to occur in “vertical” (“yes”) or “horizontal” (“no”) directions. Affected dogs appear alert during the tremors [1]. Recent reports in the literature have characterized IHTS phenomenology in Doberman Pinschers [2] and English Bulldogs [3]. The cause of IHTS is unknown, affected Doberman Pinschers were traced to a common sire suggesting the condition may be inherited [1]

Methods

Results

Conclusion