Acute porphyrias: a case report and review.

As befits a hematologic class of disorders, the word “porphyria” derives from the Greek word porphuros, which means red or purple (1). The porphyrias (Table 1 and Table 2) are a group of rare metabolic disorders arising from reduced activity of any of the enzymes in the heme biosynthetic pathway. The disorders may be either acquired (for instance, through a toxin acting on one of the enzymes) or inherited through a genetic defect in a gene encoding these enzymes. These deficiencies disrupt normal heme production, with symptoms especially prominent when increased heme is required. Porphyrin precursors, overproduced in response to synthetic pathway blockages, accumulate in the body (1–31), cause diverse pathologic changes, and become the basis for diagnostic tests. In this review we focus on the two neuroporphyrias (acute intermittent porphyria and plumboporphyria) and the two neurocutaneous porphyrias (hereditary coproporphyria and variegate porphyria). These four entities, of all the porphyrias, are the only ones with neuropsychiatric manifestations. We use a case of variegate porphyria to illustrate how the manifestations may be broad, the relevance in neuropsychiatric disorders overlooked, and the diagnosis unsuspected. Given the variable and nonspecific clinical features, we emphasize the need to carefully interpret excretion patterns and concentrations of porphyrin precursors in urine and stool to make a specific diagnosis. The workup of any potential case needs to be individualized, taking into consideration both the history and the symptoms at the time of evaluation. We discuss the complexities of making a diagnosis of porphyria. Without carefully gathering a history and having a clear understanding of what laboratory tests can and cannot show, making the diagnosis will be delayed, possibly resulting in increased morbidity and use of medical and financial resources. When evaluating complicated neuropsychiatric cases of uncertain cause, we advocate maintaining a high degree of awareness for porphyria.