Neurofibromatosis

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

HISTORY (3 minutes)

  • Timing questions: when did back pain start, sudden/gradual onset, constant/intermittent, progressing, ever had back pain like this before?
  • SOCRATES
  • Back Pain Red Flags
    • Weakness/sensory disturbance/perianal sensation/bowels/bladder/walking/ worse when cough, strain, sneeze, lying down (cord compression/cauda equina)
    • Ever had cancer? Night sweats, weight loss, anorexia, smoking (cancer/mets)
    • Fever, ivdu, TB, HIV, diabetes, immunosuppression (infection/immunosuppression)
    • Steroids, Osteoporosis, Fx of osteoporosis, fractures (vertebral collapse)
    • Joint problems, skin, eyes, bowels, morning stiffness (inflammatory back pain)
    • Trauma
    • Bleeding, infection, tiredness (myeloma)
  • PMH, Fx, Dx, Sx
  • Neurofibromatosis questions:
    • Headache, visual disturbance, personality change (optic glioma/meningioma)
    • Seizures (epilepsy)
    • BP (hypertension secondary to RAS, phaeochromocytoma or coarctation of the aorta)
    • Palpitations, anxiety, sweating, tremor (phaeochromocytoma)
    • Hearing (acoustic neuroma)
    • School/college/university (reduced IQ)
    • Fx
    • Skin- skin discolouration, painful/bothersome lumps/bumps on skin. Any recent change in lesion? (sarcomatous change)
    • Ando pain/bloating/dyspepsia/bleeding (GI carcinoid, obstruction, bleeding)
    • Breathing (lung cysts, fibrosis)

EXAMINE (3 minutes)

  • Skin and armpits (neurofibromas, cafe au lait spots, axillary freckles)
  • Examine the back (kyphosis, scoliosis)
  • Examine Neuro- CNs 5-8, cerebellar, power, sensation
  • Examine eyes (lisch nodules)- VA, fundoscopy, VF, pupils, eye movements
  • CVS (murmur of coarctation), Resp (creps), Abdo ( inguinal freckles, renal bruits)
  • Offer to check the BP (phaeochromocytoma, renal artery stenosis, co-arctation)

ICE and EXPLANATION (2 minutes)

There are lots of causes for back pain. It may be related/unrelated to your neurofibromatosis. Need to get MRI scan of your spine to rule out any compression of your spinal cord. In the mean time, I’ll get you some analgesia.

VIVA

  • Autosomal dominant
  • 1 in 3000, M+F
  • Multisystem disorder
  • Type 1 Chr 17 NF1 gene (affects skin, neuro, bone)
  • Type 2 Chr 22 (bilateral acoustic neuromas, meningiomas, schwannomas)
  • Usually asymptomatic
  • It is a clinical diagnosis

Type 1 NF

  • 2 or more of:
    • Cafe au lait 6 or more > 15mm (year 1 and increase size and no. with age)
    • 2 neurofibromas or 1 plexiform                                (by puberty usually)
    • Freckling                                                 (by age 10 usually)
    • Optic nerve glioma
    • 2 Lisch nodules                                                 (by age 6 usually)
    • Bone eg. Sphenoid dysplasia
    • First degree relative with NF1

Investigations:

  • BP
  • CXR/CT chest (fibrosis, cysts)
  • Renal USS (renal artery stenosis)
  • Urinary metanephrines, MRI adrenals (Phaeochromocytoma)
  • Genetic testing
  • CT/MRI head
  • XR spine, MRI spine
  • Skin bx to exclude sarcoma
  • Slit lamp exam for lisch nodules

Management:

  • MDT: geneticist, neurologist, plastic surgeon, orthopaedic surgeon, opthalmologist
  • Monitor for compression/malignant change/raised BP/optic glioma
  • Treat epilepsy and hypertension
  • Remove spinal cord tumour and optic glioma and meningiomas
  • Remove painful or bothersome neurofibromas (e.g. under bra straps), or compressive or malignant ones.
  • Removal of plexiform neuroma on face risks damage to cranial nerves and it can recur
  • Annual BP , eye check, bone check and skin check

Differentials:

  • Lipomas e.g. Dercum’s disease
  • Cafe au lait spots- McCune-Albright syndrome, tuberous sclerosis

Written by Dr Sarah Kennedy

Resources used include those listed in the references section of this webpage