• Core features: bradykinesia + resting tremor + rigidity + postural instability.
• Other features: micrographia, hypophonia, shuffling gait, reduced arm swing, facial masking (hypomimia).
• Pathology: loss of dopaminergic neurons in substantia nigra pars compacta; Lewy bodies (α-synuclein).
• Treatment:
o Levodopa (+ dopa decarboxylase inhibitor): most effective for
bradykinesia/rigidity; long-term risk of dyskinesias, motor fluctuations.
o Dopamine agonists (e.g., ropinirole, pramipexole): risk of impulse control disorders.
o MAO-B inhibitors (e.g., selegiline): mild symptomatic benefit.
• Multiple System Atrophy (MSA):
o Early autonomic dysfunction (e.g., postural hypotension, erectile dysfunction).
o Cerebellar or pyramidal signs.
• Progressive Supranuclear Palsy (PSP):
o Early postural instability and falls.
o Vertical gaze palsy (esp. downgaze).
• Corticobasal degeneration:
o Asymmetric rigidity, apraxia, "alien limb" phenomenon.
• Type: action/postural tremor (e.g., holding cup).
• Improves with alcohol, worsens with stress.
• Rx: propranolol (first-line), primidone.
• Type: resting tremor, "pill-rolling."
• Improves with voluntary movement.
• Genetics: autosomal dominant, CAG trinucleotide repeat on chromosome 4.
• Clinical triad: chorea, psychiatric symptoms (depression, irritability), cognitive decline.
• Anticipation: earlier onset in successive generations.
• MRI: caudate nucleus atrophy ("boxcar ventricles").
• Post-streptococcal (Group A beta-haemolytic Strep)
• Associated with rheumatic fever (Jones criteria).
• Self-limiting, supportive treatment ± penicillin prophylaxis.
• Dystonia: sustained or intermittent muscle contractions → abnormal postures or repetitive movements.
o Causes: idiopathic, medication-induced (dopamine blockers), Wilson’s disease.
• Myoclonus: sudden, brief, shock-like involuntary movements.
o Causes: metabolic (e.g., uraemia), post-hypoxic, epilepsy-related, medications.
• Inheritance: autosomal recessive (ATP7B gene mutation).
• Pathophysiology: defective copper excretion → copper accumulation in liver, brain, cornea.
• Clinical:
o Hepatic: chronic liver disease, acute hepatitis, fulminant liver failure.
o Neuropsychiatric: dystonia, dysarthria, tremor, behavioural changes.
o Kayser–Fleischer rings (copper deposition in Descemet’s membrane).
• Investigations: ↓ serum ceruloplasmin, ↑ urinary copper excretion, hepatic copper quantification.
• Treatment: chelation (penicillamine), zinc (blocks absorption), liver transplant in fulminant cases.
Extra Revision Pearls
• Essential tremor clue → improves with alcohol
• Early falls clue → PSP (vs Parkinson’s)
• Vertical gaze palsy clue → PSP
• Chorea + behavioural symptoms clue → Huntington’s
• Young liver disease + neuropsychiatric clue → Wilson’s
• Pill-rolling clue → Parkinson’s
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Author & Educational Disclaimer
Author:
Dr Phillip Cockrell BM FRCP DipClinEd
Dr Phillip Cockrell is a UK Consultant Physician in Internal Medicine, currently working at Queen Alexandra Hospital, Portsmouth University Hospitals NHS Trust. He has previously worked as a registrar across Intensive Care Medicine, Gastroenterology, Cardiology, Stroke Medicine, Acute Medicine, and Respiratory Medicine.
He has held senior leadership roles including Associate Clinical Director of the Acute Medical Unit, Clinical Director of Internal Medicine, and Chief of Medicine. Dr Cockrell has over 15 years’ experience in postgraduate medical education, having lectured extensively across the MRCP syllabus and contributed to MRCP revision teaching and course development.
Dr Cockrell holds a Bachelor of Medicine (BM), Fellowship of the Royal College of Physicians (FRCP), and a Diploma in Clinical Education (DipClinEd). His teaching approach is based on structured consolidation of complex medical topics to support efficient and effective revision for postgraduate examinations.
Purpose of this content:
The material on this page is intended solely for educational purposes to support revision for the MRCP (UK) Part 1 examination. It reflects examination-relevant principles of internal medicine and is designed to aid learning and pattern recognition.
Medical disclaimer:
This content is designed for postgraduate medical examination revision and does not constitute medical advice, diagnosis, or treatment guidance and must not be used as a substitute for professional clinical judgement, local guidelines, or specialist consultation. Clinical decisions should always be made in the context of individual patient circumstances and current national guidance.
