SYMPTOM
Shaking or trembling
Involuntary body tremors that occur without cold exposure or obvious fearful stimuli.
Pain
Trembling and shaking are among the more visible manifestations of pain in companion animals, reflecting both the physiological stress response and the muscular tension that accompanies discomfort. Pain-related trembling may be localised to specific body regions or may be generalised depending on the source and severity. Animals experiencing acute pain may tremble more intensely than those with chronic discomfort, though persistent low-grade trembling can also accompany long-standing painful conditions.
Fear and Anxiety
The autonomic nervous system response to fear and anxiety produces a cascade of physiological changes that can include visible trembling or shaking. This response involves adrenaline release, increased muscle tension, and sympathetic nervous system activation that collectively produce involuntary muscle movements. The trembling may be triggered by identifiable stimuli such as loud noises, unfamiliar environments, or veterinary visits, or may occur in response to more diffuse anxiety that lacks an obvious trigger.
Neurological
Tremors originating from neurological conditions may differ in character from pain or fear-related shaking, sometimes presenting as rhythmic, repetitive movements that affect specific body regions or the entire body. Cerebellar disease, certain storage diseases, inflammatory brain conditions, and degenerative neurological processes can all produce tremor as a primary or accompanying sign. The specific pattern of the tremor — its frequency, distribution, whether it occurs at rest or during movement — can sometimes provide information about which neurological structures are involved.
Metabolic
Significant metabolic disturbances can produce trembling or shaking through effects on muscle and nerve function. Hypoglycaemia is a well-recognised cause of trembling, as falling blood glucose levels deprive muscles and nerves of their primary fuel source. Hypocalcaemia, electrolyte imbalances, and certain endocrine disorders can similarly affect neuromuscular function and produce visible trembling. These metabolically driven tremors may occur in specific contexts — after fasting, during periods of high energy demand, or in association with other systemic illness.
Toxic Exposure
Various toxic substances can produce neuromuscular signs including trembling, shaking, and muscle fasciculations. Exposure to certain pesticides, chemicals, plants, medications, and recreational drugs can disrupt normal nerve-muscle communication or directly affect the nervous system. Toxin-related trembling often has a relatively acute onset following exposure and may progress to more severe neurological signs.
Cold and Thermoregulatory
Shivering is a normal physiological response to cold that generates heat through rapid muscle contractions. Small dogs, lean dogs, and breeds with thin coats are particularly susceptible to cold-induced shivering. While normal thermoregulatory shivering resolves once the animal warms up, persistent shivering in warm environments or shivering that seems disproportionate to the ambient temperature may suggest other contributing factors.
Why timing matters
Early observation
Occasional trembling in specific, identifiable contexts — such as during thunderstorms, at the veterinary clinic, or after vigorous exercise — may represent situational responses that resolve when the triggering context passes. Early episodes that are clearly linked to identifiable triggers and resolve promptly may provide less cause for concern than trembling that occurs without apparent provocation. However, even early situational trembling can provide useful information about the animal's sensitivity to certain stimuli and its baseline neurological function.
Later presentation
Trembling that becomes more frequent, occurs in a wider range of contexts, or develops without identifiable triggers may suggest a changing underlying picture. Animals that previously only trembled during storms may begin trembling at any loud noise, or trembling that was previously confined to the limbs may spread to involve the whole body. Changes in the character of the trembling — from fine tremors to coarser shaking, or from intermittent to continuous — can also be informative.
Different causes of trembling follow different temporal patterns. Anxiety-related trembling may wax and wane with environmental stressors and may be influenced by seasonal factors such as storm seasons. Pain-related trembling may gradually increase in frequency and intensity as an underlying painful condition progresses. Neurological tremors may show a slowly progressive course or may remain relatively stable. Metabolic causes may produce episodic trembling that correlates with fluctuations in the relevant metabolic parameter. Tracking when trembling occurs, its duration, and any identifiable triggers helps build a picture over time.
Conditions commonly associated
Addisons Disease in Dogs
Noise Phobia in Dogs
Trembling is a hallmark fear response in dogs with noise phobia, often occurring alongside other signs of distress during exposure to triggering sounds.
Epilepsy in Dogs
Trembling may occur during the post-ictal period following seizures, or as part of focal seizure activity affecting motor control centres.
Syringomyelia (CM/SM)
Shaking or trembling may occur in CM/SM dogs, possibly related to pain or neurological involvement.
Noise Phobias
Noise phobias trigger involuntary shaking as part of the physiological fear response.
Syringomyelia
Pain-related trembling may occur in dogs with symptomatic syringomyelia.
When to explore further
Trembling or shaking that occurs at rest in a warm environment without any apparent emotional trigger may suggest a physiological cause rather than a behavioural response. The absence of identifiable external triggers distinguishes this pattern from fear or cold-related trembling and may point towards pain, metabolic, or neurological contributing factors.
Trembling that is accompanied by other signs of illness such as lethargy, appetite changes, vomiting, diarrhoea, or changes in urination may suggest that the shaking is part of a broader systemic process. The combination of trembling with these additional signs provides a more complete picture than the trembling alone.
Progressive worsening of trembling over days to weeks, particularly if it develops from intermittent to persistent or from localised to generalised, may indicate an evolving condition that warrants assessment. The trajectory of change can be as informative as the current severity of the trembling.
Trembling that develops acutely and is accompanied by other neurological signs such as loss of balance, head tilting, abnormal eye movements, or altered consciousness may suggest a neurological event. The acute onset and the presence of multiple neurological signs can together provide important context.
Trembling in a young animal, particularly a puppy, that occurs in specific situations such as after prolonged play or before meals, and that resolves with feeding or rest, may suggest metabolic factors such as blood glucose fluctuations that are particularly relevant in young, small-breed animals.
Recording episodes of trembling — including when they occur, how long they last, what seemed to precede them, and what brought relief — helps identify patterns that may not be apparent from individual events. Video recordings are particularly valuable as they capture the character, distribution, and intensity of the trembling in a way that verbal descriptions often cannot. Noting whether the trembling occurs at rest or during specific movements, whether it affects particular body regions or the whole body, and whether it can be stopped by touching or repositioning the animal all provide useful clinical details that can help characterise the nature of the trembling.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS