Mononeuropathy Multiplex

Synonyms:

Mononeuropathy multiplex a.k.a. mononeuritis multiplex

Diagnosis:

This is a clinical plus electrophysiological diagnosis

Clinical features:

a syndrome with involvement of at least two separate nerves. Usually sensorimotor.

Findings on investigations:

+NCS:

  • Axonal, asymmetrical i.e. >50% difference between sides, distribution of multiple separate nerves
  • Decreased SNAP
  • Decreased CMAP
  • Motor conduction velocities: mild decrease (remaining >75% of lower limit of normal),
  • Distal latencies: normal or <25% increase
  • F-waves: normal or <25% increase

+EMG:

  • Denervation, axonal, multifocal

Investigations to consider:

  • ESR, CRP, ANA screen, ENA panel (anti- dsDNA, anti-Sm, anti-RNP, SSA, SSB, anti-Jo-1, antitopoisomerase ‘formerly anti Scl-70’, antinucleolar, anticentromere), ANCA (c-ANCA, p-ANCA), Complement C3, C4 and CH50
  • Anti-GM1: multifocal motor neuropathy
  • ACE levels and Ca++: raised in sarcoidosis
  • Lyme serology, HIV serology

Nerve biopsy:

  • Vasculitis, leprosy

Causes of Mononeuropathy multiplex a.k.a. mononeuritis multiplex:

Vasculitis: (axonal), common

  • Rheumatoid arthritis (axonal)
  • SLE, systemic sclerosis
  • Polyarteritis nodosa
  • Wegener’s granulomatosis
  • Cryoglobulinemia (rare)

Infections:

  • HIV(axonal)
  • Lyme disease
  • Mycobacterium leprae (Leprosy)

Demyelination:

  • Mutifocal form of CIDP (demyelinating)
  • Multifocal motor neuropathy MMN (demyelinating)

Others:

  • Diabetes mellitus, common
  • Sarcoidosis, rarely
  • Amyloidosis
  • Hypereosinophilia syndrome
  • Sickle cell disease
  • Subacute asymmetric idiopathic polyneuropathy
  • Migrant sensory neuritis a.k.a. Wartenberg’s disease (pure sensory, axonal)

Causes of mononeuritis multiplex with lymphocytic meningitis:

  • Lyme Neuroborreliosis
  • Neurosarcoidosis
  • Zoster sine herpete
  • Uveo-meningeal syndromes

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