Neurofibromatosis

In Station 5 you may be asked to assess a patient with back pain who you then discover has neurofibromatosis.

1. Key History-Taking Points

Timing & Character of Back Pain (SOCRATES)

• Onset: when did the back pain start, sudden vs gradual
• Character: constant vs intermittent, progressive, ever had this before?
• Complete SOCRATES — Site, Onset, Character, Radiation, Associated features, Timing, Exacerbating/relieving factors, Severity

Back Pain Red Flags

• Cord compression / cauda equina: leg weakness, sensory disturbance, perianal sensation, bowel or bladder dysfunction, difficulty walking; worse on coughing, straining, sneezing or lying down
• Malignancy: prior cancer history, night sweats, weight loss, anorexia, smoking
• Infection: fever, IV drug use, TB, HIV, diabetes, immunosuppression
• Vertebral collapse: steroid use, known osteoporosis, fragility fractures
• Inflammatory back pain: joint problems, skin changes, eye inflammation, bowel symptoms, prolonged morning stiffness (>30 min), improves with activity
• Trauma
• Myeloma: bone pain, bleeding tendency, recurrent infection, tiredness

Neurofibromatosis-Specific Questions

• Headache, visual disturbance, personality change: optic glioma or meningioma
• Seizures: epilepsy (CNS involvement)
• Blood pressure: hypertension secondary to renal artery stenosis, phaeochromocytoma, or coarctation of the aorta
• Palpitations, anxiety, sweating, tremor: phaeochromocytoma
• Hearing loss or tinnitus: acoustic neuroma (especially NF2)
• Educational history: school, college, university — reduced IQ can occur in NF1
• Skin: skin discolouration, painful or bothersome lumps/bumps; any recent change in a lesion (sarcomatous change)
• GI symptoms: abdominal pain, bloating, dyspepsia, PR bleeding (GI carcinoid, obstruction, bleeding)
• Breathing: breathlessness, cough (lung cysts, fibrosis)
• Family history: NF is autosomal dominant — any relatives affected?

Past Medical, Drug & Family History

• Known diagnosis of NF1 or NF2; when and how diagnosed
• Previous surgery, complications, surveillance arrangements
• Current medications and allergies
• Family history — first-degree relatives with NF

2. Key Examination Findings

Skin & Axillae

• Neurofibromas: soft, flesh-coloured, pedunculated or sessile cutaneous nodules
• Café-au-lait spots: flat, pale-brown macules ≥6 spots (>15 mm in adults) = diagnostic criterion
• Axillary and inguinal freckling (Crowe's sign)
• Note any lesion with recent change in size, colour or consistency (possible sarcoma)

Spine & Musculoskeletal

• Inspect for kyphosis and scoliosis
• Assess range of movement, tenderness, step deformity

Neurological Examination

• Cranial nerves 5–8: facial sensation, facial movements, hearing (VIII), facial nerve palsy
• Cerebellar: finger-nose, heel-shin, gait, Romberg
• Power and sensation in limbs — look for signs of cord compression or peripheral nerve involvement

Eyes

• Visual acuity
• Visual fields (optic glioma can cause field defects)
• Pupils and eye movements
• Fundoscopy (optic disc pallor, optic atrophy)
• Lisch nodules — iris hamartomas, best seen on slit-lamp; offer referral to ophthalmology

Cardiovascular, Respiratory & Abdominal

• CVS: listen for murmur of coarctation of the aorta
• Respiratory: auscultate for crackles (fibrosis, cysts)
• Abdomen: listen for renal bruits (renal artery stenosis); inspect inguinal region for freckling
• Offer to measure blood pressure — phaeochromocytoma, renal artery stenosis, coarctation

3. Specific Investigations

Baseline

• Blood pressure (at every visit)
• Full blood count, renal function, LFTs

Imaging

• CXR / CT chest: pulmonary fibrosis, lung cysts
• Renal ultrasound: renal artery stenosis
• CT / MRI head: optic glioma, meningioma, acoustic neuroma (especially NF2)
• X-ray spine / MRI spine: scoliosis, vertebral dysplasia, cord or nerve root compression
• MRI adrenals: phaeochromocytoma

Biochemical

• 24-hour urine or plasma metanephrines: phaeochromocytoma

Other

• Genetic testing: NF1 gene (chromosome 17) or NF2 gene (chromosome 22)
• Skin biopsy: to exclude sarcomatous change in a suspicious lesion
• Slit-lamp examination: Lisch nodules (ophthalmology referral)

4. Management

• Multidisciplinary team: geneticist, neurologist, plastic surgeon, orthopaedic surgeon, ophthalmologist
• Surveillance: monitor for cord/nerve compression, malignant change, raised blood pressure, optic glioma
• Annual checks: blood pressure, eye examination, bone assessment, skin examination
• Epilepsy: treat with appropriate anti-epileptic medication
• Hypertension: treat underlying cause (RAS, phaeochromocytoma, coarctation) and BP itself
• Surgical removal:
  • Spinal cord tumours, optic gliomas, meningiomas when causing symptoms
  • Painful or functionally bothersome neurofibromas (e.g. under bra straps)
  • Compressive or malignant neurofibromas
  • NB: removal of plexiform neurofibroma on the face risks cranial nerve damage and lesions can recur
• ICE explanation for this station: "There are many causes of back pain. It may or may not be related to your neurofibromatosis. We need an MRI scan of your spine to rule out any compression of the spinal cord. In the meantime, I will arrange appropriate analgesia."

Neurofibromatosis Cheat Sheet