Rheumatological conditions may be complicated by a
variety of both central and peripheral nervous system disorders. Common complications such as
entrapment neuropathies are familiar to rheumatologists but accurate diagnosis of less
common neurological disorders may be challenging; careful clinical reasoning is essential,
supplemented where necessary by imaging, neurophysiology, and other special investigations
including cerebrospinal fluid examination. Complications vary according to the nature of the
background condition. In rheumatoid arthritis, neurological involvement is typically related
to the mechanical consequences of advancing disease; most commonly, entrapment neuropathies such as carpal
tunnel syndrome and cervical myelopathy due to atlantoaxial subluxation. By contrast,
neurological involvement in systemic lupus erythematosus (SLE) tends to occur earlier in the
disease course, with a much wider range of manifestations. The management of stroke or
seizures in SLE is not necessarily any different from that in the general population, unless
complicated by the antiphospholipid syndrome. However, less common neurological syndromes
may demand more specific investigation and treatment. For example, longitudinally extensive
transverse myelitis and recurrent optic neuritis (neuromyelitis optica, or Devic’s disease)
is frequently associated with antibodies to aquaporin-4, and is highly likely to relapse
unless treated vigorously with humoral immunosuppression. Nervous system involvement in
vasculitis is common. Finally, not all neurological disorder in rheumatological disease is
necessarily due to the underlying condition; neurological complications of disease-modifying
therapy are increasingly recognized, in particular central and peripheral nervous system
demyelination associated with TNF-α inhibitors.
The neuropathology of “typical” Friedreich's ataxia in Quebec