🧠 MOCK OSCE · FCPS, MCPS, MD PAEDIATRICS ⏱ 10 min · ATAXIA

Ataxia · Short Case

Candidate task: perform focused neurological examination on a child with ataxia.
Then discuss differential diagnosis, investigations, management & follow‑up.
Pre‑exam Protocol
⏤ · Wash, Warm, Introduce, Position, Expose, Approach ▾

Standard pre‑examination protocol – must be demonstrated:

🖐 Wash hands with sterilizing solution.
🔥 Warm hands and stethoscope.
👋 Introduce yourself to child & parent.
🧍 Position child: seated, then standing for gait.
👕 Exposure — allow full neurological exam.
➡️ Approach from the right side.
✔ CPSP marker: Pre‑exam Protocol is observed and scored.
1. Clinical Examination (≈6 min)
02 General Look (Inspection from end of bed) ▾

Key observations:

  • Posture: wide‑based stance, truncal sway, head titubation.
  • Gait: unsteady, staggering, heel‑toe impairment.
  • Speech: scanning dysarthria (cerebellar).
  • Eye signs: nystagmus (horizontal, vertical), abnormal saccades.
  • Muscle bulk: wasting (neuropathy, Friedreich).
  • Skin: neurocutaneous stigmata (NF, ataxia‑telangiectasia).
  • Dysmorphism: (Joubert, Dandy‑Walker).
👁 Red flags: acute onset, fever, headache, vomiting → posterior fossa mass / ADEM / cerebellar abscess.
03 Focused Neurological Examination ▾

Systematic cerebellar & sensory exam:

  • Gait: observe walking, heel‑toe tandem, standing with eyes open/closed (Romberg).
  • Upper limbs: finger‑nose test (intention tremor, dysmetria), rapid alternating movements (dysdiadochokinesis).
  • Lower limbs: heel‑shin test, toe‑finger test.
  • Truncal ataxia: sitting unsupported, check for titubation.
  • Eye movements: nystagmus, saccadic intrusion, smooth pursuit.
  • Speech: scanning dysarthria.
  • Tone: hypotonia (cerebellar).
  • Reflexes: pendular knee jerks (cerebellar).
  • DTRs & plantar: loss of ankle jerks + extensor plantars (Friedreich).
  • Sensation: dorsal column (vibration, proprioception) – impaired in sensory ataxia.
🔍 Key: distinguish cerebellar ataxia (intention tremor, dysmetria) from sensory ataxia (positive Romberg, loss of proprioception).
04 General Physical Exam (Hands → Face → Chest → Abdomen → Limbs) ▾

Systematic examination:

  • Hands: pes cavus, hammer toes (Friedreich), tremor.
  • Face: telangiectasia (ataxia‑telangiectasia), optic atrophy.
  • Eyes: Kayser‑Fleischer rings (Wilson), cherry‑red spot (Tay‑Sachs).
  • Chest: scoliosis, cardiomyopathy (Friedreich).
  • Abdomen: hepatosplenomegaly (storage disorders).
  • Skin: café‑au‑lait spots (NF1), hypopigmented macules (tuberous sclerosis).
📏 Anthropometry: head circumference (macrocephaly – Alexander, microcephaly – congenital).
05 Developmental Assessment & Associated Signs ▾

Assess:

  • Motor milestones: delayed or regression (ataxia‑telangiectasia, Friedreich).
  • Cognitive: intellectual disability (Joubert, congenital ataxias).
  • Speech: dysarthria, language delay.
  • Hearing: deafness (mitochondrial, Refsum).
  • Associated: seizures (epileptic encephalopathies, metabolic).
🧠 Red flags: regression → neurodegenerative (NCL, mitochondrial, etc.).

📋 Case Presentation – (fill in during exam)

This is a _____-year-old _____ child, referred for _____ (unsteadiness / difficulty walking / regression). On examination, the child appears _____ (well/unwell), with _____ (wide‑based gait / truncal ataxia). Neurological exam: finger‑nose _____ (intention tremor / dysmetria), heel‑shin _____, DTRs _____ (brisk / absent), plantars _____ (flexor / extensor), sensation _____ (intact / impaired). Eye findings: nystagmus _____ (present/absent), fundi _____ (normal/optic atrophy/cherry‑red spot). Growth: weight _____ percentile, height _____ percentile, head circumference _____. Associated signs: _____ (skin lesions, hepatosplenomegaly, scoliosis).

2. Viva Discussion (≈4 min)
06 Viva · Differential, Investigations, Management, Follow‑up ▾
🔹 Differential Diagnosis

• Acute cerebellar ataxia – post‑infectious, usually benign
• ADEM – multifocal demyelination, encephalopathy
• Posterior fossa tumour – progressive, raised ICP
• Friedreich ataxia – AR, sensory loss, areflexia
• Ataxia‑telangiectasia – telangiectasia, immunodeficiency
• Joubert syndrome – molar tooth sign, hypotonia
• Metabolic ataxias – abetalipoproteinaemia, Refsum
• Mitochondrial – MELAS, Leigh, NARP
• Drugs/toxins – anticonvulsants, alcohol
• Functional – non‑organic

🔹 Investigations – Diagnosis

• Brain MRI – posterior fossa, cerebellar atrophy, demyelination, molar tooth.
• Spinal MRI – if myelopathy / cord lesion.
• Neurophysiology – nerve conduction studies (Friedreich), VEPs, BAERs.
• Genetic testing – Friedreich (FXN), ataxia‑telangiectasia (ATM), Joubert (multiple genes).

🔹 Investigations – Aetiology

• Metabolic screen: lactate, pyruvate, amino acids, organic acids, ammonia, carnitine.
• Lysosomal enzymes: if storage disorder suspected.
• Copper / caeruloplasmin: for Wilson disease.
• Vitamin E: for abetalipoproteinaemia / vitamin E deficiency.
• CSF: lactate, cells, protein, oligoclonal bands.

🔹 Investigations – Exclude Others

• Lumbar puncture: encephalitis, ADEM, multiple sclerosis.
• EEG: if seizures or encephalopathy.
• Toxicology screen: drugs, heavy metals.
• Autoimmune screen: anti‑GAD, anti‑Yo (paraneoplastic).
• Celiac screen: gluten ataxia.

🔹 Investigations – Rule Out Complications

• Echocardiography: cardiomyopathy (Friedreich).
• Ophthalmology: retinitis pigmentosa (Refsum, abetalipoproteinaemia).
• Audiology: sensorineural hearing loss (mitochondrial, Refsum).
• Scoliosis survey: X‑ray (Friedreich).
• Immunoglobulin & lymphocyte subsets: ataxia‑telangiectasia.

🔹 Management – Across Organ Systems

Neurological

Symptomatic: physiotherapy, occupational therapy, speech therapy. Treat specific cause (e.g., steroids for ADEM).

Nutrition

Dietary modification: vitamin E supplementation, fat‑soluble vitamins (abetalipoproteinaemia), gluten‑free (gluten ataxia).

Orthopaedic

Scoliosis bracing/surgery (Friedreich), physiotherapy for contractures.

Cardiac

Monitor cardiomyopathy (Friedreich): echo, ECG; ACE inhibitors if LV dysfunction.

Immunological

IVIG for immunodeficient (ataxia‑telangiectasia); treat infections promptly.

Genetic Counselling

Recurrence risk (AR, AD, X‑linked). Carrier testing and prenatal diagnosis.

Rehabilitation

Multidisciplinary: physiotherapy, occupational therapy, speech therapy, orthotics.

Metabolic

Specific therapies: vitamin E, coenzyme Q10, riboflavin, ketogenic diet (GLUT1).

📈 Prognosis

  • Acute cerebellar ataxia: excellent; full recovery in >90%.
  • Friedreich ataxia: progressive; wheelchair by 2nd‑3rd decade; cardiomyopathy major cause of death.
  • Ataxia‑telangiectasia: progressive; death by 20s–30s (infection, malignancy).
  • Joubert syndrome: variable; depends on severity of cerebellar and systemic involvement.
  • ADEM: good with steroids; residual deficits in some.
  • Metabolic ataxias: variable; some responsive to specific therapies.

📋 Follow‑up Schedule

  • Acute ataxia: review in 4‑6 weeks; repeat MRI if not resolving.
  • Chronic ataxia: 6‑12 monthly neurology review; monitor for progression.
  • Friedreich: annual cardiology (echo, Holter), diabetes screening, scoliosis monitoring.
  • Ataxia‑telangiectasia: monitor for infections, malignancy; Ig levels, AFP.
  • Metabolic: regular metabolic monitoring, dietitian, physiotherapy.
  • Genetic: family counselling and prenatal diagnosis for future pregnancies.
💡 Examiner expectation: ability to differentiate acute vs chronic, progressive vs static, and cerebellar vs sensory vs vestibular ataxia. Systematically discuss investigations (imaging, metabolic, genetic) and management (symptomatic, specific, multidisciplinary). Know the red flags: acute onset + headache + vomiting → urgent imaging to rule out posterior fossa tumour or abscess.
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Mock OSCE · Ataxia · Based on Wyne‑Harris, Nelson & Pediatric Clinical Advisor