Parkinsonian Syndromes

Parkinsonian Syndromes

By in Default, Disease Encyclopedia

Overview‌

Parkinsonian syndromes are a clinical diagnostic concept used by neurologists to describe a group of disorders characterized by ‌bradykinesia‌ (slowed movement), along with other symptoms such as ‌tremor‌, ‌rigidity‌, and ‌postural instability‌. These syndromes arise from diverse causes, including cerebrovascular disease, atherosclerosis, infections, toxins, trauma, medications, and genetic disorders. They are classified into four categories:

  1. ‌Primary Parkinson’s disease (PD)‌.
  2. ‌Parkinson-plus syndromes‌ (e.g., multiple system atrophy, progressive supranuclear palsy).
  3. ‌Secondary parkinsonism‌ (drug-induced, vascular, infectious, etc.).
  4. ‌Genetic neurodegenerative parkinsonism‌ (e.g., Wilson’s disease, Fahr disease).

‌Etiology‌

  1. ‌Primary Parkinson’s Disease (80% of cases)‌:
    • Caused by ‌degeneration of dopaminergic neurons‌ in the substantia nigra, leading to reduced striatal dopamine.
    • Responds well to ‌levodopa therapy‌.
  2. ‌Parkinson-Plus Syndromes‌:
    • ‌Multiple system atrophy (MSA)‌: Includes MSA-P (parkinsonian subtype) and MSA-C (cerebellar subtype).
    • ‌Progressive supranuclear palsy (PSP)‌: Vertical gaze palsy and early postural instability.
    • ‌Corticobasal degeneration (CBD)‌: Asymmetric rigidity and cortical sensory loss.
    • ‌Dementia with Lewy bodies (DLB)‌: Fluctuating cognition and visual hallucinations.
    • Poor response to levodopa.
  3. ‌Secondary Parkinsonism‌:
    • ‌Drug-induced‌ (most common): Antipsychotics (e.g., phenothiazines, butyrophenones), calcium channel blockers.
    • ‌Vascular‌: Subcortical infarcts affecting basal ganglia.
    • ‌Toxic‌ (e.g., carbon monoxide, manganese).
    • ‌Infectious‌ (e.g., post-encephalitic parkinsonism).
  4. ‌Genetic Causes‌:
    • ‌Wilson’s disease‌: Kayser-Fleischer rings, low serum ceruloplasmin.
    • ‌Fahr disease‌: Basal ganglia calcification.
    • ‌Dopa-responsive dystonia (DRD)‌: Childhood-onset, improves with levodopa.

‌Clinical Features‌

  1. ‌Primary Parkinson’s Disease‌:
    • ‌Cardinal symptoms‌: Resting tremor (4–6 Hz), rigidity, bradykinesia, postural instability (late feature).
    • ‌Non-motor symptoms‌: Depression, constipation, REM sleep behavior disorder, cognitive decline.
  2. ‌Parkinson-Plus Syndromes‌:
    • ‌MSA‌: Early autonomic dysfunction (orthostatic hypotension, urinary retention), cerebellar or parkinsonian features.
    • ‌PSP‌: Vertical gaze palsy, frequent falls, pseudobulbar palsy.
    • ‌CBD‌: Alien limb phenomenon, apraxia, asymmetric dystonia.
    • ‌DLB‌: Fluctuating cognition, recurrent visual hallucinations.
  3. ‌Secondary Parkinsonism‌:
    • ‌Drug-induced‌: Rapid onset, symmetric symptoms, prominent autonomic signs (e.g., sweating).
    • ‌Vascular‌: Lower-body predominance, gait freezing, poor levodopa response.
  4. ‌Genetic Parkinsonism‌:
    • ‌Wilson’s disease‌: Hepatic cirrhosis, neuropsychiatric symptoms.
    • ‌Fahr disease‌: Seizures, intellectual disability.
    • ‌PKAN (Hallervorden-Spatz disease)‌: “Eye-of-the-tiger” sign on MRI.

‌Diagnostic Workup‌

  • ‌Imaging‌:
    • ‌MRI‌: Rules out structural lesions (e.g., infarcts, basal ganglia calcification).
    • ‌Functional imaging (PET/SPECT)‌: Reduced striatal dopamine uptake in PD.
  • ‌Lab tests‌: Exclude Wilson’s disease (serum copper/ceruloplasmin), thyroid dysfunction, infections.

‌Diagnostic Criteria (UK Parkinson’s Disease Society Guidelines)‌

  1. ‌Bradykinesia‌ + ≥1 of:
    • Rigidity.
    • Resting tremor.
    • Postural instability (not due to visual/vestibular/cerebellar causes).
  2. ‌Exclusion of secondary causes‌ (e.g., drugs, strokes).
  3. ‌Supportive features‌: Asymmetric onset, significant levodopa response.

‌Red Flags for Parkinson-Plus Syndromes‌:

  • Early falls, poor levodopa response, vertical gaze palsy, severe dysautonomia.

‌Treatment‌

  1. ‌Pharmacotherapy‌:
    • ‌Levodopa-carbidopa combinations‌: First-line for PD.
    • ‌Dopamine agonists‌ (e.g., pramipexole, ropinirole).
    • ‌MAO-B inhibitors‌ (e.g., selegiline).
    • ‌Anticholinergics‌ (for tremor-predominant PD).
  2. ‌Advanced Therapies‌:
    • ‌Deep brain stimulation (DBS)‌: For refractory motor fluctuations.
    • ‌Duodopa infusion‌: Continuous intestinal levodopa delivery.
  3. ‌Non-Motor Symptom Management‌:
    • Antidepressants, cholinesterase inhibitors (for dementia), laxatives.

‌Prevention‌

  • ‌Vascular risk control‌: Manage hypertension, diabetes, smoking cessation.
  • ‌Avoid high-risk medications‌: Use atypical antipsychotics (e.g., quetiapine) if needed.
  • ‌Genetic counseling‌: Prenatal testing for familial neurodegenerative disorders.

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