Mononeutritis multiplex is a major presenting feacture of –
**Core Concept**
Mononeuritis multiplex is a clinical syndrome characterized by the simultaneous or near-simultaneous involvement of two or more peripheral nerves, resulting in a multifocal pattern of neuropathy. This condition can be caused by various underlying diseases, including vasculitis, diabetes mellitus, and infections.
**Why the Correct Answer is Right**
Mononeuritis multiplex is a hallmark feature of polyarteritis nodosa (PAN), a type of systemic vasculitis that affects medium-sized and small arteries. The inflammation of these arteries leads to ischemia and damage to the surrounding nerves, resulting in the characteristic multifocal neuropathy. The involvement of multiple nerves in a non-length-dependent pattern is a key feature that distinguishes mononeuritis multiplex from other forms of neuropathy.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while diabetes mellitus can cause neuropathy, it typically presents as a length-dependent sensorimotor neuropathy, rather than mononeuritis multiplex.
**Option B:** This option is incorrect because while infections can cause neuropathy, they typically present as a single focal lesion rather than a multifocal pattern.
**Option C:** This option is incorrect because while sarcoidosis can cause neuropathy, it typically presents as a single or paired nerve involvement, rather than the multifocal pattern seen in mononeuritis multiplex.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with suspected mononeuritis multiplex, it is essential to consider systemic vasculitis as a potential underlying cause, particularly polyarteritis nodosa.
**Correct Answer: D. Polyarteritis nodosa**