Web-Vet TM Neurology Specialists
Tremors
Idiopathic head tremor syndrome (also known as head bobbing) is a paroxysmal movement disorder of unknown etiology with Doberman Pinschers, Bulldogs, Boxers, and Labrador retrievers appearing overrepresented. The head tremor can be in the vertical or horizontal plane and typically disappears when the dog is distracted (such as by offering food) or lying down with the head supported. The dog maintains normal mental state and can walk and function normally during the episode. Stressful events appear to play an important role as provocative factors. Many dogs experience low frequency of episodes with spontaneous remission often observed. Despite that some pet owners request treatment to try reducing the occurence of these episodes. No known effective treatment has been so far identified.
In this study, the authors investigate the use of imepitoin comparing it with placebo in dogs with frequent episodes of idiopathic head tremor. Their conclusion was that Imepitoin did not have a significant overall benefit.
Idiopathic generalised tremor syndrome (IGTS) in dogs
IGTS is a condition in which a dog develops, in the absence of metabolic or toxic causes, a sudden marked intention tremor of the head and limbs, that worsens with exercise, stress and excitement but disappears with sleep. The term white shaker syndrome was coined due to the high prevalence of this condition in young, mature (<2 years), small white-breed dogs, particularly the Maltese and West Highland white terrier. However, since the early reports of this condition it has become apparent that the condition is not breed specific and can occur in a dog of any colour or breed. Subsequently, the terms ‘sporadic acquired tremors of adult dogs’ and ‘idiopathic cerebellitis’ have been used to describe this condition. Other signs that may accompany the tremor are cerebellovestibular signs (as demonstrated in the video below) and an ocular tremor (opsoclonus). This retrospective study on 75 dogs with IGTS found that over 90% of affected dogs experienced concomitant neurological signs, 22.7% were hyperthermic and 41.3% had gastrointestinal signs. MRI was normal in most cases and CSF frequently revealed lymphocytic pleocytosis. The overall outcome was good following treatment with prednisolone (and in some dogs additional use of diazepam) but 21.3% experienced relapse and 13.2% were left with persistent clinical signs.
The aim of this study was to describe the semiology, magnetic resonance imaging (MRI) findings and outcome of 100 dogs with either IEHT or SEHT. The authors hypothesized that structural lesions affecting the middle cranial fossa or mesencephalic aqueduct could lead to SEHT.
Lesions on MRI in SEHT dogs were localized to the middle cranial fossa (15/29), cerebrocortex (3/29), brainstem (2/29), fourth ventricle (1/29) or multifocal (8/29) with thalamus involvement (6/8). Secondary compression of the mesencephalic aqueduct (19/29), third ventricle or interthalamic adhesion or both (14/29) was common. The most common underlying condition in dogs with SEHT was a pituitary mass. Dogs with SEHT were older, had additional neurological signs and were more likely to be euthanized after diagnosis compared to IEHT dogs. Two SEHT dogs had only tremor. In IEHT dogs, 8/10 owners reported that the tremor decreased or abated over time (range, 106‐2315 days) without treatment.
Tremor remission occurred in SEHT dogs treated for underlying meningoencephalitis.
Primary orthostatic tremor and orthostatic tremor-plus in dogs:60 cases (2003-2020)
Orthostatic tremor is a high-frequency tremor, predominantly of the limbs, triggered by weight-bearing. This disorder has been described in young giant breeds such as Great Danes with affected dogs appearing reluctant to lie down and demonstrating a constant tremor when standing. A characteristic feature is that the tremor disappears when walking, sitting and lying down. Neurological examination is often normal.
This study of 60 dogs with the condition has investigated the clinical syndrome in more depth and looked at response to treatment, retrospectively showing that many dogs can respond to several medical options.
Giant breed dogs represented most cases (83%) and most dogs were younger than 2 years of age at onset of signs, except for Retrievers which were all older than 3.5 years of age. The most common presenting complaints were pelvic limb tremors while standing and difficulty when rising or sitting down. Improvement of clinical signs occurred in most dogs treated medically with phenobarbital, primidone, gabapentin, pregabalin or clonazepam, but it was mostly partial rather than complete.
Episodic mandibular tremor in dogs: an idiopathic movement disorder or a manifestation of pain
The aim of this study was to describe clinical signs, MRI findings, and outcome of dogs with episodic mandibular tremor (EMT) investigating 11 dogs retrospectively and 31 dogs in an online survey.
All dogs had rapid and short-lasting (< 1 minute) episodes of EMT in the absence of other neurological signs. Lip smacking occasionally accompanied the tremor in 5 of 11 (45.5%) hospital dog cases. Excitement was a common trigger in 14 of 31 (45.2%) dogs from the survey. Cavalier King Charles Spaniel was the most common breed in both clinical and survey populations. Median age at presentation was 3 years for both hospital cases and the survey dogs. A concurrent medical condition was present in 8 of 11 (72.7%) hospital cases and 20 of 31 (64.5%) survey dogs. In 3 hospital dogs that underwent further investigations, no brain disease was present.
The video below is a small sample from the publication.