Tremors have been well documented in dogs however data is lacking about tremors in cats. A study by Liatis T et al, published in February 2025 classified the phenotype (appearance) and underlying etiology in 105 cats. Although a rare clinical sign, knowing common causes of tremors in cats can help direct further testing and treatment if you happen upon one of these cases.
What is a tremor?
Tremors are loosely defined as an involuntary, rhythmic movement of a body part with symmetric velocity in both directions. Picture a pendulum swinging in an arc. The pendulum swings just as wide from the center point in both directions, resulting in symmetric velocity in both directions. Tremors may be caused by central generators (such as the cerebellum) or peripheral generators (such as demyelination of a peripheral nerve).
Results
As mentioned, 105 cats met their inclusion criteria. This was a retrospective case-series utilizing medical records review and video assessment provided by owners.
Median age 1.1 years (range 10.8 months – 17.3 years)
Focal tremors were most common (62/105: 59%) followed by generalized tremors (43/105: 41%). Focal tremors included just the head in 58 cases or only a limb in 4 cases.
Intention tremors accounted for almost half of the cases, while nonintentional and both types accounted for the other half.
Top 7 causes of any tremor (focal or generalized): degenerative encephalopathy (19/105), FIP (17/105), hepatic encephalopathy (17/105), intoxication (permethrin and unknown cause: 16/105), polyneuropathy (8/105), suspected CNS lymphoma (4/105), and thiamine deficiency (3/105).
What is a degenerative encephalopathy? The authors included cerebellar cortical degeneration, lysosomal storage diseases, congenital spongiform encephalopathy and the dreaded “unspecified”.
What is the take away?
If you have a cat with a history of a tremor, especially an episodic head tremor, consider thr top 7 causes and fine tune your differential diagnoses list based on the cat’s signalment and history. Full CBC, serum biochemistry and a bile acid test are appropriate initial diagnostic tests for cats with tremors. Supplementation with thiamine, if a diet change or poor diet is present, should be considered. Brain MRI would be helpful to diagnose degenerative causes, FIP and the lymphoma causes. Lastly, interrogation of the owners regarding possible intoxication might indicate permethrin exposure. Other signs such as mydriasis and generalized hyperesthesia could be present in these cases as well.
Short and sweet TidBit Tuesday this week! I hope everyone is staying warm and successfully navigating the snow. Stay safe! Thanks for reading; I look forward to working with you soon!