Tremor

Tremor is an involuntary, rhythmic, oscillating movement of a body part. Clinical category drives differential: (1) action / postural tremor (worst when arms are held out or when using the hands) — essential tremor (most common), hyperthyroidism, anxiety, drug-induced (lithium, valproate, beta-agonists, caffeine), alcohol withdrawal; (2) resting tremor (visible when the limb is fully relaxed) — Parkinson's disease, drug-induced parkinsonism (haloperidol, metoclopramide), vascular parkinsonism; (3) intention tremor (worsens approaching a target) — cerebellar disease (multiple sclerosis, stroke, alcohol-related cerebellar atrophy). Younger patients with new tremor need consideration of Wilson's disease (treatable inherited copper overload).

• Essential tremor — by far the commonest cause; action tremor of the hands, often family history; alcohol transiently relieves.
• Hyperthyroidism — fine fast tremor with weight loss, palpitations, heat intolerance.
• Anxiety, caffeine, stimulant medication — fine tremor with sympathetic features.
• Parkinson's disease — slow resting 'pill-rolling' tremor, usually starts in one hand.
• Drug-induced — lithium, valproate, beta-agonists (salbutamol), SSRIs, levodopa, antipsychotics.
• Alcohol withdrawal — coarse tremor in the morning in heavy drinkers.
• Cerebellar disease — intention tremor + ataxia.
• Wilson's disease — under-50, suspect with hepatic features.
• Hypoglycaemia, hypocalcaemia — acute electrolyte-driven tremor.

First-line panel: TSH and free T4 (always — hyperthyroidism is the most easily missed treatable cause), full metabolic with calcium, magnesium, glucose, LFTs (liver disease may suggest Wilson's), creatinine. Add caeruloplasmin + 24-hr urine copper if Wilson's suspected (any tremor under 40). MRI brain if cerebellar features. Mediora.AI flags hyperthyroidism + hypocalcaemia patterns; tremor classification is a neurology clinical exam, not a lab task.