Do you routinely obtain a sural nerve biopsy in patients with EMG evidence of mononeuritis multiplex and clinically suspected polyarteritis nodosa?   

Sural nerve biopsy can be quite helpful in cases of mononeuritis multiplex, particularly in those with isolated peripheral nerve involvement or patients who are seronegative with systemic features that do not allow for differentiation between PAN and other types of systemic vasculitis, in particular...