Note: It is essential to distinguish between Parkinsonism and Parkinson's Disease (PD). 👉 Parkinsonism is a syndrome – a set of features (tremor, rigidity, akinesia, postural instability). 👉 Parkinson’s Disease is a specific idiopathic neurodegenerative disorder due to dopaminergic cell loss in the substantia nigra. 👉 Parkinsonism can occur in many other conditions: stroke, drugs, toxins, head injury, and atypical neurodegenerative syndromes. Classic clinical signs remembered by TRAP: Tremor 🤲, Rigidity 🪢, Akinesia/Bradykinesia 🐢, and Postural Instability 🚶‍♂️⚖️

📌 Most Common Causes of Parkinsonism

Parkinson's Disease (PD): Most frequent cause; due to degeneration of dopaminergic neurons in substantia nigra pars compacta.
Drug-Induced Parkinsonism: Dopamine-receptor blockers (antipsychotics, metoclopramide) 🚫 dopamine pathways.
Vascular Parkinsonism: Multiple small strokes in basal ganglia → lower body parkinsonism, poor levodopa response.
Atypical Parkinsonism: PSP, MSA, CBD - faster progression, extra features, and poor levodopa response.

🧾 Other Causes

Wilson’s Disease 🟢: Copper accumulation, consider in young patients.
Carbon Monoxide Poisoning 🛢️: Basal ganglia damage after inhalation.
Post-Encephalitic Parkinsonism 🦠: Historically after encephalitis lethargica.
Head Injury 🥊: Chronic trauma (e.g., boxers → “pugilistic parkinsonism”).
MPTP Toxicity 💉: Synthetic opioid contaminant causing irreversible PD-like syndrome.

⚠️ Symptoms

Tremor: “Pill-rolling” at rest, unilateral onset.
Bradykinesia: Slowness in initiating movement; reduced arm swing while walking.
Rigidity: “Cogwheel” or “lead-pipe” stiffness on exam.
Postural Instability: Falls, impaired balance, difficulty turning.
Other features: hypomimia (masked facies 🎭), hypophonia (soft voice), micrographia ✍️.

📊 Causes of Tremor

Category	Causes	Clinical / Investigations	Treatment
🟢 Resting Tremor	Idiopathic PD, Drug-induced, Wilson’s Disease	Neuro exam, MRI brain, Ceruloplasmin (Wilson’s), drug history	Levodopa, stop offending drug, Penicillamine (Wilson’s)
🟡 Action Tremor	Essential tremor, Hyperthyroidism, Physiological (stress, caffeine)	TFTs, Family Hx, drug review	Propranolol, avoid triggers, treat thyroid
🔴 Cerebellar Tremor	MS, Alcohol degeneration, Stroke/Tumour	MRI brain, B1 levels, Neuro exam	Treat cause, physio, ↓ alcohol
⚪ Dystonic Tremor	Cervical dystonia, Task-specific dystonia	Neuro exam, EMG	Botulinum toxin, physio, clonazepam

🧾 Causes of Parkinsonism

Category	Cause	Associated Features	Examples
Primary	Idiopathic PD	TRAP, asymmetry, levodopa responsive	Parkinson’s Disease
Secondary	Drug-induced	Bilateral, no tremor, temporal link	Haloperidol, Risperidone, Metoclopramide
Secondary	Vascular	Lower-limb > upper, “marche à petits pas” gait	Small vessel strokes in basal ganglia
Atypical	PSP	Early falls, vertical gaze palsy	Tauopathy
Atypical	MSA	Autonomic failure, poor levodopa response	MSA-P, MSA-C
Atypical	CBD	Asymmetry, apraxia, alien limb	Corticobasal degeneration
Hereditary	Genetic	Early onset, family history	Parkin mutation, LRRK2, Wilson’s
Other	NPH	Triad: gait disturbance, incontinence, dementia	Improves after CSF drainage

💡 Exam Pearl: • PD = asymmetrical, resting tremor, levodopa responsive. • Drug-induced = bilateral, no tremor, reversible. • Vascular = lower limb predominant, gait problems. • PSP = vertical gaze palsy + early falls. • MSA = autonomic failure. • CBD = alien limb + apraxia.

Cases - Parkinsonism & Tremors

Case 1 - Idiopathic Parkinson’s Disease: A 68-year-old man presents with a 2-year history of slowness and difficulty buttoning shirts. His wife notes a resting “pill-rolling” tremor of the right hand and reduced arm swing when walking. Exam: cogwheel rigidity, bradykinesia, shuffling gait. Diagnosis: Idiopathic Parkinson’s disease. Management: Start levodopa + dopa-decarboxylase inhibitor (co-careldopa), physiotherapy, occupational therapy; later consider dopamine agonists or MAO-B inhibitors.
Case 2 - Drug-Induced Parkinsonism: A 62-year-old woman with schizophrenia develops bilateral resting tremor, rigidity, and bradykinesia 6 months after starting risperidone. Symptoms are symmetric, unlike typical idiopathic PD. Diagnosis: Antipsychotic-induced parkinsonism. Management: Review psychiatric meds (switch to atypical antipsychotic with lower EPS risk, e.g. quetiapine); symptomatic therapy (anticholinergics like procyclidine in selected cases).
Case 3 - Essential Tremor (Mimic): A 70-year-old woman complains of long-standing tremor in both hands, worse when holding a cup or writing, and improved with alcohol. Exam: action tremor, no rigidity or bradykinesia. Diagnosis: Essential tremor (not parkinsonism). Management: Propranolol or primidone if functionally disabling; otherwise reassurance.

Teaching Commentary 🤲

Parkinsonism = clinical syndrome of resting tremor, rigidity, bradykinesia, and postural instability. - Causes: idiopathic Parkinson’s disease, drugs (antipsychotics, metoclopramide), vascular parkinsonism, atypical parkinsonian syndromes (MSA, PSP, CBD). - Key exam clue: asymmetry → think Parkinson’s disease; symmetry → drug-induced or other causes. Essential tremor is a common mimic but is an action tremor, not resting, and often improves with alcohol. Management is tailored: dopaminergic therapy in PD, drug review in secondary parkinsonism, beta-blockers/primidone in essential tremor.

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Parkinsonism