Case history
Case history
A 55-year-old woman presents with acute onset of a left-wrist drop and deep aching pain in her dorsal left forearm. She has had no trauma to the arm and no neck pain. On examination she has weakness of her left wrist and finger extensors without sensory loss, consistent with a posterior interosseous neuropathy. She is otherwise neurologically intact. One month later she develops a right-foot drop with numbness over the dorsum of the right foot. On examination she has severe weakness of foot dorsiflexion and eversion, with loss of sensation in the dorsum of the foot and the lateral calf, consistent with a common peroneal mononeuropathy.
Other presentations
MNM may present with involvement of any peripheral nerve, either completely or partially. The most commonly affected nerves are median and ulnar nerves in the arm, and sciatic and peroneal nerves in the leg. Some aetiologies of MNM may also involve cranial nerves (such as VII, III, and VI cranial nerves) and can present initially as an isolated cranial mononeuropathy. Progression and extension of the neuropathy to adjacent nerves over time may give rise to confluent neuropathies with cumulative neuropathic deficit that may superficially mimic distal dying-back neuropathy. However, clinical evidence of multifocal or asymmetrical neuropathy is usually present at disease onset. Other manifestations depend on the underlying aetiology. Vasculitis in association with systemic lupus erythematosus or rheumatoid arthritis may be associated with long-standing and typical manifestations of these disorders as well as systemic symptoms such as fever, anorexia, and weight loss. Pain is a frequent symptom in vasculitic MNM, often with both neuropathic pain within the area of sensory loss and a deep pain in the affected extremity.
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