The
porphyrias are a heterogeneous group of
metabolic diseases resulting from a variable catalytic defect of one of the eight
enzymes involved in the
heme biosynthesis pathway; they are mostly inherited diseases, but in some circumstances the metabolic disturbance may be acquired. The specific patterns of tissue overproduction (and hence accumulation and excretion) of toxic
heme precursors, associated with each enzymatic deficiency, are responsible for the characteristic biochemical and clinical features of each of these diseases. Moreover, even in the presence of a specific inherited enzymatic defect, many different environmental factors (such as drugs, calorie restriction,
hormones, sunlight exposition,
infections, etc.) often play a key role in triggering the clinical expression of the various forms of
porphyrias. The
porphyrias are often misdiagnosed diseases, due their multiform clinical manifestations, able to mimic many other more common diseases. For this reason, many different specialists, such as surgeons, psychiatrists, gastroenterologists, neurologists, emergency physicians and dermatologists may be variably involved in the diagnostic process, especially for the forms presenting with acute and life-threatening clinical features. According to the clinical features, the
porphyrias can be classified into neuropsychiatric (characterized by neurovisceral crises involving autonomic and central nervous system but also the liver and the kidney with possible consequences in terms of neurological, psychic, cardiac, respiratory, liver and kidney functions), dermatological (mostly presenting with cutaneous lesions due to photosensitivity), and mixed forms. From a strictly clinical point of view,
porphyrias presenting with neurovisceral attacks are also referred as
acute porphyrias: they are the object of the present review. An accurate diagnosis of
acute porphyria requires knowledge and the use of correct diagnostic tools, and it is mandatory to provide a more appropriate therapeutic approach and prevent the use of potentially unsafe drugs, able to severely precipitate these diseases, especially in the presence of life-threatening symptoms. To date, availability of a relatively stable
haem preparation (
haem arginate) has significantly improved the treatment outcome of acute porphyric attacks, so the knowledge about the diagnosis and the management of these diseases may be relevant for physicians working in internal medicine, neurology and emergency units.