Predominant arm weakness in acute idiopathic polyneuritis: a distinct regional variant.

Acute idiopathic polyneuritis is a heterogeneous disorder with a number of clearly established variants. We describe four patients who present with an acute neuropathy predominantly affecting the arms which we believe should be considered as a distinct variant of acute polyneuritis. In two cases a primary demyelinating process affecting both motor and sensory nerves is suggested whereas in the other two the features were of a pure motor axonal degeneration. The relationship between these neuropathies, other variants of acute idiopathic polyneuritis and multifocal motor neuropathy is considered.