Respiratory failure in acute intermittent porphyria.

We report two patients of acute intermittent porphyria (AIP) who presented with acute respiratory failure. Only one such previous report could be found. Occasionally, neuropathy may be the presenting feature in AIP which may progress to respiratory embarrassment. The cause of this neuropathy has been hypothesized to be direct neurotoxicity of delta-ALA by interaction with GABA receptor, altered tryptophan metabolism and may be heme depletion in nerve cells.