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MONONEURITIS MULTIPLEX |
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The pattern of a mononeuropathy multiplex is one of the most important patterns
to recognize and differentiate from the length-dependent, dying-back, axonal
polyneuropathy. The clinical presentation is distinctive:
there is an
asymmetric, stepwise progression of individual cranial and/or peripheral
neuropathies often over days to weeks. Over time, a confluent pattern may develop, which
may be difficult to distinguish from a generalized polyneuropathy. When the
etiology involves inflammation, the term mononeuritis multiplex
is used.
In most
cases, the individual neuropathies are of named nerves (i.e., median, ulnar,
peroneal, etc.) as opposed to small nerve twigs. Mononeuropathy multiplex is
associated with a
limited differential diagnosis (see list below) and
most often occurs in the setting of VASCULITIS and vasculitic neuropathy. As each
subsequent nerve is infarcted, pain develops (often severe), followed hours or
days later by weakness and numbness in the nerve’s distribution. Although other
organ systems are often involved, the initial clinical presentation of systemic
vasculitis may involve only the peripheral nervous system. Indeed, there are well-recognized cases in which vasculitis remains confined to the peripheral
nervous system. |
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Above: The most common pattern of
mononeuritis multiplex is an asymmetric neuropathy, that affects medium and
large nerves. This is in contradistinction to the typical pattern of most
peripheral neuropathies that are symmetric and length dependent ("stocking-glove
pattern").
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Differential Diagnosis of Mononeuropathy Multiplex
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Vasculitis
◊ Polyarteritis nodosa
◊ Churg-Strauss syndrome
◊ Wegener's
syndrome
◊ Hypersensitivity
◊ Cryoglobulinemia
◊ Systemic lupus erythematosus
◊ Rheumatoid arthritis
◊ Sjögren’s syndrome
◊ Chronic active
hepatitis
• Diabetes
• Inflammatory demyelinating polyneuropathy
• Multiple entrapments (hereditary and acquired)
• Infection (e.g., Lyme, leprosy, HIV)
• Infiltration
◊ Granulomatous disease (e.g., sarcoid)
◊ Neoplasm (e.g., lymphoma,
leukemia, carcinoma)
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Evaluation
•
Serology for autoimmune disorders (ANA, ESR, RF, ANCA, Hep B, Hep C,
cryoglobulins)
• EMG
• Nerve. muscle or
other involved tissue biopsy |
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Above: Muscle biopsy in a patient with
mononeuritis multiplex. The biopsy demonstrates an inflammatory
infiltrate and fibrinoid necrosis of small vessel, consistent with vasculitis. |
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• Serology for
Lyme, HIV (selected patients) •
Systemic Evaluation for malignancy or sarcoid (depending on risks and other
symptoms) |
Treatment
The treatment ultimately depends upon the etiology. Mononeuritis multiplex
from vasculitis requires urgent treatment to prevent further progression and
disability. In the case of systemic vasculitis (e.g., polyarteristis nodosa),
delay in therapy can result in renal, mesenteric and cardiac ischemia, and its
accompanying morbidity and risk of mortality. Mononeuritis multiplex from
vasculitis is typically treated with immunosuppressive therapy, usually with
steroids, often with the addition of cytoxic drugs, such as cyclophosphamide. |
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