Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

  • Adverse Drug Reaction (e.g. Phenothiazines, β-Agonists)
  • Carbon Dioxide Retention (e.g. COPD)
  • Multiple Sclerosis (MS)
  • Cerebellar Ataxia: Many Causes, Including Tumour, Acoustic Neuroma, Friedreich’s Ataxia, CVA, Abscess

Rare Diagnoses

Ready Reckoner

Key distinguishing features of the most common diagnoses

AnxietyThyrotoxicosisDrug WithdrawalBenign EssentialParkinson’s Disease
Rest TremorNoNoNoNoYes
Suppressed by AlcoholPossibleNoPossibleYesNo
Otherwise WellPossibleNoNoYesNo

Possible Investigations


Possible:FBC, LFT.

Small Print:Syphilis serology and, in secondary care, MRI scan, lumbar puncture, visual evoked response, serum caeruloplasmin/blood copper, blood gases.

  • FBC: Macrocytosis in chronic alcohol excess.
  • LFT: For evidence of alcohol abuse or liver failure.
  • TFT: If hyperthyroidism suspected.
  • MRI most sensitive test for picking up CNS demyelination and tumours (e.g. cerebellar).
  • Lumbar puncture: CSF electrophoresis may show oligoclonal bands in MS, or evidence of meningoencephalitis.
  • Visual evoked response: Prolonged in MS.
  • Syphilis serology: In suspected syphilis.
  • Blood gases: Will reveal carbon dioxide retention.
  • Serum caeruloplasmin/blood copper: To diagnose Wilson’s disease.

Top Tips

  • Patients who present with their tremor are invariably worried about significant disease, especially Parkinson’s disease. Ensure that these anxieties are resolved during the consultation.
  • Essential tremor is characteristically suppressed by a small dose of alcohol. This can be a useful pointer from the history.
  • A tremor can have more than one cause and may not necessarily follow the neat patterns described, especially in the elderly.
  • The tremor of early Parkinson’s disease usually causes the patient few problems. It may therefore be noticed by the doctor when the patient presents with other symptoms, or be presented by concerned relatives or friends.

Red Flags

  • Have a low threshold for arranging TFT: Anxiety can closely mimic thyrotoxicosis and vice versa.
  • Parkinson’s disease may well present with a consultation for frequent falls. Look for other signs such as mask face, small handwriting, slow movement, festinant gait and difficulty rising from chair.
  • Think of alcohol problems in isolated middle-aged and elderly men developing postural tremor.
  • Intention tremor with nystagmus or dysarthria suggests significant cerebellar pathology.
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