shakiness

Shakiness, commonly referred to as tremor, is an involuntary oscillating movement of a body part produced by alternating muscle contractions. It is most noticeable in the hands but can involve the head, voice, legs, or trunk. Shakiness can be a normal physiological response to factors such as fatigue, anxiety, caffeine, or low blood sugar, or it can indicate an underlying medical condition or medication effect.

Tremor patterns are useful in characterization. Rest tremor occurs when the limb is supported and at rest, whereas postural tremor appears when maintaining a position. Action tremor occurs during voluntary movement and intent tremor worsens toward a target. Frequency and distribution help distinguish common causes: essential tremor typically presents as a postural/action tremor with 4–8 Hz frequency; Parkinsonian tremor is often a resting tremor around 4–6 Hz and may diminish with movement; cerebellar tremor is usually an intention tremor that worsens near a target.

Common causes include essential tremor, Parkinson’s disease, cerebellar disorders, dystonia, and orthostatic tremor. Metabolic and systemic conditions such as hyperthyroidism, hypoglycemia, electrolyte disturbances, and medication effects (stimulants, certain antidepressants, and other drugs) can also produce shakiness. In some cases, tremor results from multiple contributing factors.

Evaluation involves a detailed history and neurological examination to characterize the tremor’s pattern, distribution, triggers, and associated signs. Basic laboratory tests (thyroid function, blood glucose, electrolytes) and imaging or further studies may be pursued if a neurological disorder is suspected.

Treatment targets the underlying cause and, when needed, provides symptomatic relief. For essential tremor, beta-blockers or anticonvulsants may help; for Parkinsonian tremor, dopaminergic therapy is used; dystonic and cerebellar tremors may respond to botulinum toxin, physical therapy, or other interventions. In refractory cases, options include deep brain stimulation. Prognosis varies with the cause and may range from benign to progressive. Situations with sudden, severe, or rapidly worsening tremor warrant urgent evaluation.