Can Mononeuritis multiplex (multiple mononeuropathy) present as part of a polyneuropathy?

Mononeuritis Multiplex in Polyneuropathy

Yes, mononeuritis multiplex can present as part of a polyneuropathy, particularly in certain conditions where what initially appears as multiple isolated nerve involvement evolves into a more diffuse polyneuropathy pattern. 1

Relationship Between Mononeuritis Multiplex and Polyneuropathy

• Mononeuritis multiplex is characterized by asymmetric involvement of multiple peripheral nerves, presenting with altered sensation, pain, muscle weakness or atrophy 2
• While mononeuritis multiplex and polyneuropathy are typically distinct clinical entities, they can overlap in certain conditions 3
• Nerve biopsy is generally accepted as useful in the diagnosis of mononeuritis multiplex due to vasculitis, but there are no specific studies regarding its role in distinguishing when mononeuritis multiplex presents as part of distal symmetric polyneuropathy 1

Clinical Scenarios Where Overlap Occurs

• In vasculitic neuropathies, what begins as mononeuritis multiplex may progress to a more diffuse, symmetric polyneuropathy-like presentation as the disease advances 2
• Chronic inflammatory demyelinating polyneuropathy (CIDP) can present with atypical forms, including multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), which has features of both mononeuritis multiplex and polyneuropathy 4
• Motor and sensory demyelinating mononeuropathy multiplex (MSDMM) represents an intermediate link between CIDP (a polyneuropathy) and multifocal motor neuropathy, suggesting a spectrum of disease rather than distinct entities 5

Diagnostic Considerations

• Nerve conduction studies and electromyography are essential to differentiate between multiple mononeuropathy and polyneuropathy patterns 3
• The distinction can be challenging as some cases initially presenting as mononeuritis multiplex may evolve into a more diffuse polyneuropathy pattern over time 3
• Nerve biopsy may be particularly valuable in cases where mononeuritis multiplex is suspected within the context of a more diffuse polyneuropathy, especially when vasculitis is suspected 1

Specific Conditions Where Overlap Occurs

• Vasculitic neuropathies (including polyarteritis nodosa and eosinophilic granulomatosis with polyangiitis) often begin as mononeuritis multiplex but can evolve into polyneuropathy 2, 6
• Diabetic neuropathy typically presents as symmetric polyneuropathy but can occasionally manifest as mononeuritis multiplex, particularly in acute inflammatory demyelinating presentations 3
• Leprosy can present as mononeuritis multiplex that may eventually develop into a more diffuse polyneuropathy pattern 7

Clinical Implications

• The recognition of mononeuritis multiplex within the context of polyneuropathy is crucial as it may indicate specific underlying etiologies requiring targeted treatment 3
• Treatment approaches differ significantly depending on whether the presentation is primarily mononeuritis multiplex (often requiring immunosuppression) or primarily polyneuropathy (often requiring treatment of underlying cause) 2, 3
• Early diagnosis and treatment of conditions presenting with mononeuritis multiplex are essential to prevent progression to more diffuse polyneuropathy and permanent neurological deficits 2

Diagnostic Pitfalls to Avoid

• Misinterpreting a rapidly progressive mononeuritis multiplex as a polyneuropathy can lead to delayed diagnosis of potentially treatable vasculitis 2
• Failing to recognize that what appears to be a polyneuropathy may have begun as mononeuritis multiplex can result in missed diagnostic opportunities 3
• Relying solely on clinical presentation without confirmatory electrodiagnostic studies may lead to misclassification, as advanced mononeuritis multiplex can clinically mimic polyneuropathy 3, 4