Generalized Tremors in Dogs

In the Literature

Liatis T, Bhatti SFM, De Decker S. Generalized tremors in dogs: 198 cases (2003-2023). J Vet Intern Med. 2025;39(3):e70062. doi:10.1111/jvim.70062

The Research …

Tremors are involuntary, rhythmic, back-and-forth movements with a symmetrical flexion and extension of antagonistic muscles around a joint axis.¹ Generalized tremors involve thoracic and pelvic limbs and can be caused by a variety of underlying diseases in dogs; differentiating the underlying cause can be challenging.

This retrospective study evaluated the underlying cause of generalized tremors in 198 dogs to determine whether the final diagnosis had specific clinical features. The 2 most common causes were intoxication (most frequently caused by unknown agents, mycotoxins, and metaldehyde) and idiopathic generalized tremor syndrome (IGTS; previously known as little white shaker syndrome, shaker dog syndrome, and corticosteroid-responsive tremor syndrome). IGTS can occur in various dog breeds of all coat colors, as well as in cats.² Additional common causes of generalized tremors included hypocalcemia, meningoencephalomyelitis of unknown etiology, hypercalcemia, and degenerative encephalopathies.

Dogs with generalized tremors resulting from intoxication were young to middle aged and male with a hyperacute onset (≤24 hours after exposure) and nonprogressive symmetrical presentation. Dogs with intoxication more often exhibited behavioral changes and hypersalivation than dogs with IGTS. Bilateral mydriasis, abnormal mentation, and hyperesthesia were also more commonly observed. Generalized tremors due to intoxication often persisted under general anesthesia and resolved within 48 hours of supportive care (eg, IV fluids, activated charcoal, intralipid emulsion therapy).

Compared with dogs with intoxication, dogs with IGTS were younger and female with an acute, progressive, often lateralizing (ie, asymmetrical) neurologic presentation. Dogs with IGTS were more often presented with a reduced appetite, with tremors starting >24 hours later. Titubation (ie, head nodding), head tilt, ataxia, menace response deficits, nystagmus or opsoclonus (ie, rapid multidirectional eye movement), and other cranial nerve deficits were more common in dogs with IGTS. Tremors related to IGTS ceased under general anesthesia. Dogs with IGTS were more likely to have intentional head tremors in addition to generalized tremors. All dogs with IGTS responded to immunosuppressive corticosteroid treatment.

… The Takeaways

Key pearls to put into practice:

• Intoxication (most often by an unknown agent) and IGTS are the most common diagnoses associated with generalized tremors in dogs.

• CBC, serum chemistry profile (including glucose, electrolytes, and ionized calcium), blood ammonia concentration, and bile acids should be considered for dogs with generalized tremors.

• Generalized tremors caused by intoxication can be characterized by hyperacute onset and nonprogressive nature, with symmetrical tremors and abnormal mentation being the only abnormal neurologic examination findings. In this study, tremors resolved within 48 hours with supportive care alone.

• IGTS has an acute onset with a progressive history and lateralized vestibulocerebellar signs (eg, nystagmus, menace response deficits, head tilt, ataxia) in addition to generalized tremors. Corticosteroids are necessary for tremor resolution.² MRI, cerebrospinal fluid analysis, and serologic testing prior to corticosteroid treatment are ideal if a more definitive diagnosis is desired and to rule out other causes of vestibulocerebellar signs. An empiric course of prednisone may be considered if neurologic signs worsen, risks of empiric treatment are understood, and advanced diagnostics are not an option.