see neurology

• lesions of individual nerve bundles

• trauma, compression
• causes that may result in more than one nerve affected (ie. mononeuritis multiplex):
  • acute (usually vascular):
    • diabetes mellitus
    • polyarteritis nodosa, SLE, Rh.A
  • chronic:
    • multiple compressive neuropathies, esp. with joint deforming arthritis
    • sarcoid
    • amyloid
    • acromegaly
    • Lyme disease
    • leprosy
    • neoplasia (rare)

• median nerve
• ulnar nerve
• radial nerve
• sciatic nerve
• lateral popliteal nerve
• tibial nerve

• derangements of peripheral nerves which usually begin distally & spread proximally giving rise to 'glove & stocking' anaesthesia (peripheral neuropathy)
• distal motor weakness may also occur, & reflexes reduced
• different patterns are discernible with different causes
• pain & tenderness in affected muscles is notable in neuropathies of diabetes & alcoholics

• common causes of peripheral neuropathy:
  • Guillain-Barre syndrome
  • metabolic:
    • diabetes mellitus, renal failure, liver failure, alcohol, hypothyroidism, porphyria, hypoglycaemia xanthomatosis
  • CT diseases:
    • polyarteritis nodosa
  • malignancy:
    • incl. polycythaemia rubra vera
  • infections:
    • esp. leprosy, TB, syphilis
  • vitamin deficiencies:
    • B1
    • B6
    • B12 (subacute combined degeneration of the cord):
      • symmetric post. column loss (vibration & position sense) ⇒ ataxic gait
      • symmetric UMN signs in lower limbs with absent ankle jerks
      • knee reflexes may be absent, or, more often, exaggerated
      • peripheral sensory neuropathy (less common & mild)
      • optic atrophy, dementia
  • genetic:
    • Refsum's syndrome
    • Charcot-Marie-Tooth syndrome (HMSN Type I):
      • pes cavus, distal muscle atrophy, absent reflexes, thickened nerves, optic atrophy
  • toxins:
    • lead, metronidazole, phenytoin, vincristine, nitrofurantoin, amiodarone

• Guillain-Barre syndrome
• Charcot-Marie-Tooth syndrome
• acute intermittent porphyria
• lead poisoning
• diabetes
• NB. remember MND & NM junction disorders

• unusual & results in sensory ataxia & pseudoathetosis
• carcinoma eg. lung, ovary, breast
• paraproteinaemia
• B6 intoxication
• Sjogren's syndrome
• diabetes
• syphilis
• B12 deficiency (occas)

• diabetes
• alcohol
• B12 or B1 deficiency
• carcinoma
• porphyria
• arsenic or thallium poisoning
• hereditary
• NB. burning soles of feet may be painful periperal neuropathy, tarsal tunnel syndrome or an S1 lesion

• B12 deficiency
• conus medullaris lesion
• UMN lesion + cauda equina compression or peripheral neuropathy
• syphilis (tabo-paresis)
• Friedrich's ataxia
• diabetes (uncommon)
• adrenoleukodystrophy or metachromatic leukodystrophy

• ischaemic
• pressure - direct pressure on a nerve; compartment syndrome; etc.
• iatrogenic - injection into nerves
• penetrating wounds or thermal injury
• polyarteritis nodosa
• rheumatoid arthritis
• diabetic cranial neuropathies
• diabetic amyotrophy
• Guillain-Barré syndrome
• Acute intermittent porphyria
• Critical illness polyneuropathy
• Diphtheric neuropathy
• thallium toxicity

• Maintained exposure to toxic agents/medications
• Persisting nutritional deficiency
• Abnormal metabolic state
• Paraneoplastic syndrome
• chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

• Hereditary motor sensory neuropathies
• Dominantly inherited sensory neuropathy
• chronic inflammatory demyelinating polyradiculoneuropathy

• Guillain-Barré syndrome
• chronic inflammatory demyelinating polyradiculoneuropathy
• HIV/AIDS
• toxic
• porphyria

• FBE, ESR, glucose, U&E, TFT, B12, protein electrophoresis, syphilis serology, ANA, CXR
• consider: porphyria screen; nerve conduction studies & electromyography

• Rx cause

• see also bulbar palsy

• think of malignancy first
• nasopharyngeal carcinoma
• chronic meningitis eg. carcinoma, TB, sarcoid
• Guillain-Barre syndrome (usually spares I, II, & VIII)
• brainstem lesions:
  • usually due to vascular disease causing crossed sensory or motor paralysis(ie. cranial nerve lesions on one side & contralateral long tract signs)
  • pts with brainstem gliomas may have similar signs & may live for many years
• Arnold Chiari malformation - protrusion of the cerebellar tonsils through the foramen magnum, with the more severe types (II to IV) which may cause lower cranial nerve palsies, cerebellar limb signs & upper motor neurone signs in legs
• trauma
• lesion of base of skull (eg. Paget's disease, metastasis)
• rarely, mononeuritis multiplex (eg. diabetes)

• Am. Family Physician - 1998