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

Neurofibromatosis Type 1 · Short Case

Candidate task: perform focused examination on a child with suspected Neurofibromatosis Type 1.
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: supine, then sitting, then standing.
👕 Exposure — allow full examination.
➡️ 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:

  • Skin: café‑au‑lait spots (≥6, >5mm pre‑pubertal, >15mm post‑pubertal), axillary/inguinal freckling, neurofibromas (cutaneous, subcutaneous, plexiform).
  • Head: macrocephaly (common), facial dysmorphism.
  • Eye signs: Lisch nodules (iris hamartomas), proptosis (optic glioma), strabismus.
  • Skeletal: scoliosis, tibial bowing (pseudarthrosis), short stature.
  • Neurological: learning difficulties, seizures, focal deficits.
  • Skin lesions: juvenile xanthogranulomas (rare).
👁 Red flags: visual loss (optic glioma), new/worsening neurological symptoms, bony pain (malignant transformation).
03 Focused Examination ▾

Systematic examination for diagnostic criteria:

  • Skin: count café‑au‑lait spots (≥5mm pre‑pubertal, ≥15mm post‑pubertal). Check axillary/inguinal freckling.
  • Neurofibromas: cutaneous (soft, fleshy), subcutaneous (firm), plexiform (diffuse, may be large).
  • Ophthalmology: Lisch nodules (slit‑lamp), optic gliomas (fundoscopy, visual acuity).
  • Head circumference: macrocephaly common.
  • Skeletal: scoliosis (Adam's forward bend test), tibial pseudarthrosis (anterolateral bowing), sphenoid wing dysplasia (pulsating exophthalmos).
  • Neurological: vision, hearing, motor, sensory, gait, coordination.
  • Blood pressure: hypertension (renal artery stenosis, phaeochromocytoma).
  • Growth: short stature, macrocephaly.
🔍 Key: NF1 diagnostic criteria: ≥2 of 7 features (NIH criteria).
04 General Physical Exam (Hands → Face → Chest → Abdomen → Limbs) ▾

Systematic examination:

  • Hands: neurofibromas, café‑au‑lait spots.
  • Face: Lisch nodules (iris), proptosis (optic glioma), dysmorphism.
  • Eyes: fundoscopy (optic glioma), visual acuity, visual fields.
  • Chest: scoliosis, murmurs (pulmonary stenosis, hypertension).
  • Abdomen: palpable masses (neurofibromas, phaeochromocytoma).
  • Back: scoliosis, kyphosis, neurofibromas.
  • Limbs: tibial pseudarthrosis (bowing), limb asymmetry (plexiform neurofibroma).
📏 Anthropometry: weight, height, OFC – plot on growth charts.
05 Developmental Assessment & Associated Signs ▾

Assess:

  • Motor milestones: may be normal or delayed.
  • Cognitive: learning difficulties (common ~50%), intellectual disability (less common).
  • Speech: delayed, language difficulties.
  • Behaviour: ADHD, autism (increased risk).
  • Seizures: ~8% (focal or generalized).
🧠 Red flags: learning difficulties, seizures, new neurological symptoms.

📋 Case Presentation – (fill in during exam)

This is a _____-year-old _____ child, referred for _____ (skin spots / learning difficulties / visual problems). On examination, the child appears _____ (well/unwell), with _____ (café‑au‑lait spots / neurofibromas / macrocephaly). Skin: café‑au‑lait spots _____ (number and size), axillary freckling _____ (present/absent). Eye findings: Lisch nodules _____ (present/absent), optic glioma _____ (present/absent), visual acuity _____. Head circumference: _____ cm (_____ percentile). Neurological exam: tone _____, reflexes _____, plantars _____. Skeletal: scoliosis _____ (present/absent), tibial bowing _____ (present/absent). Growth: weight _____ percentile, height _____ percentile. Associated signs: _____ (hypertension, seizures, learning difficulties).

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

• Legius syndrome – café‑au‑lait spots, no neurofibromas/optic gliomas.
• Neurofibromatosis type 2 – bilateral vestibular schwannomas, no café‑au‑lait (few).
• Schwannomatosis – multiple schwannomas, no vestibular involvement.
• McCune‑Albright syndrome – café‑au‑lait (irregular borders), polyostotic fibrous dysplasia.
• Tuberous sclerosis – ash‑leaf spots, angiofibromas, tubers.
• Watson syndrome – café‑au‑lait, pulmonic stenosis, intellectual disability.
• Noonan syndrome – café‑au‑lait, webbed neck, pulmonary stenosis.
• Multiple lentigines syndrome – multiple lentigines, hypertelorism, pulmonic stenosis.
• Familial café‑au‑lait spots – no other features.
• Ataxia‑telangiectasia – telangiectasia, ataxia, immunodeficiency.

🔹 Investigations – Diagnosis

• Clinical criteria – ≥2 of 7 NIH diagnostic criteria.
• Genetic testing – NF1 gene mutation (confirmatory).
• Brain MRI – optic gliomas, unidentified bright objects (UBOs), other tumours.
• Ophthalmology – slit‑lamp for Lisch nodules, visual acuity.

🔹 Investigations – Aetiology

• Genetic testing – NF1 mutation (chromosome 17q11.2).
• Parental examination – to identify familial cases (AD, ~50% new mutations).
• Prenatal testing – if family history (chorionic villus sampling, amniocentesis).
• Detailed family history – for autosomal dominant inheritance.

🔹 Investigations – Exclude Others

• Brain MRI – optic glioma, UBOs, other tumours.
• Ophthalmology – Lisch nodules, visual fields.
• Skeletal survey – scoliosis, pseudarthrosis.
• Blood pressure – hypertension (renal artery stenosis, phaeochromocytoma).
• Audiology – hearing (NF2 if bilateral).
• Genetic testing – to differentiate from Legius (SPRED1).

🔹 Investigations – Rule Out Complications

• Brain MRI – optic glioma progression, other CNS tumours.
• Ophthalmology – visual acuity, visual fields (optic glioma).
• Orthopaedics – scoliosis monitoring.
• Blood pressure – monitor for hypertension.
• Developmental assessment – learning difficulties.
• Audiology – if hearing loss.
• Malignant transformation – watch for rapid growth of plexiform neurofibromas (MPNST).

🔹 Management – Across Organ Systems

Neurological

Optic glioma: monitor vision, MRI; treatment (chemotherapy) if progression. Seizures: AEDs.

Ophthalmology

Annual visual acuity, visual fields, fundoscopy; slit‑lamp for Lisch nodules.

Orthopaedic

Scoliosis: bracing/surgery if progressive. Tibial pseudarthrosis: orthopaedic management.

Dermatological

Neurofibromas: surgical removal if symptomatic/cosmetic. Plexiform: monitor for growth.

Cardiovascular

Hypertension: workup (renal artery stenosis, phaeochromocytoma), antihypertensives.

Developmental

Early intervention, educational support, learning difficulties: special education, psychological support.

Genetic Counselling

Recurrence risk (50% if parent affected, ~50% new mutation). Prenatal diagnosis available.

Malignancy

Watch for MPNST (rapid growth, pain in plexiform). Early referral if suspected.

📈 Prognosis

  • Variable: wide spectrum – from mild skin lesions to severe complications.
  • Life expectancy: reduced by ~10-15 years (mainly due to malignancy, vascular disease).
  • Optic glioma: ~15% develop; most are low‑grade, some progress.
  • Learning difficulties: ~50% (mild to moderate).
  • Malignant peripheral nerve sheath tumours (MPNST): 8‑13% lifetime risk (poor prognosis).
  • Vascular disease: hypertension, stroke (renal artery stenosis, vasculopathy).
  • Scoliosis: ~10% (may require surgery).

📋 Follow‑up Schedule

  • Multidisciplinary: neurology, ophthalmology, orthopaedics, dermatology, genetics.
  • Ophthalmology: annually (visual acuity, fundoscopy).
  • Neurology: annually (neurological exam, development).
  • Brain MRI: as clinically indicated (symptomatic optic glioma, new symptoms).
  • Blood pressure: annually (screen for hypertension).
  • Scoliosis: clinical monitoring; X‑ray if suspected.
  • Skin: monitor neurofibromas for growth/pain (MPNST risk).
  • Development: school performance, learning difficulties.
  • Transition: plan for adult care (NF clinic).
💡 Examiner expectation: ability to recognise diagnostic criteria (≥2 of 7 NIH criteria), identify complications (optic glioma, MPNST, hypertension, scoliosis), and discuss multidisciplinary management. Know the red flags: visual loss, new/worsening neurological symptoms, rapid growth of plexiform neurofibroma (malignancy).
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Mock OSCE · Neurofibromatosis · Based on Wyne‑Harris, Nelson & Pediatric Clinical Advisor