Abstract

Polyneuropathies represent a relatively common group of disorders, the diagnosis of which can be complex in certain clinical contexts. Diagnostic evaluation is based on clinical presentation, laboratory investigations, and electroneuromyography (ENMG). ENMG facilitates the differentiation between demyelinating and axonal pathologies, assesses the extent of peripheral nerve involvement, and aids in prognosing
outcomes. We present two clinical cases that highlight the potential for polyneuropathies to follow a rapid and severe course. The first case involves Guillain-Barré syndrome, while the second illustrates that beriberi – a thiamine (vitamin B1) deficiency-related polyneuropathy typically considered chronic – can also present with an acute onset.