The Acute Porphyric Attack: A Difficult Diagnosis for a Potential Lethal Event in Emergency Medicine

Abstract

The porphyrias are a heterogeneous group of metabolic disorders due to an inherited (but in some forms the disturbance may also be acquired) enzymatic deficiency in the metabolic pathway of heme biosynthesis. The variable degree of block in the heme biosynthetic pathway due to the enzyme deficiency results in accumulation of different metabolic intermediates, whose toxicity is responsible for the peculiar (cutaneous and/or neurovisceral) clinical pictures observed in each of these diseases. According to the clinical features, the porphyrias are classified as "acute" (or neuropsychic) [characterized by acute neurovisceral crises (the acute porphyric attack) involving the autonomic and/or central nervous system, but also the liver and the kidney] and "on acute" (or dermatological) (mostly presenting with cutaneous lesions, due to photosensitivity).

Rhodococcus equi Pneumonia in Kidney Transplant Recipient Affected by Acute Intermittent Porphyria: A Case Report

“…AIP attacks are characterized by severe abdominal pain, often accompanied by nausea, vomiting, tachycardia, and hypertension. The acute attacks may be complicated by neurologic manifestations (ie, neuropathy, confusion, coma) leading to potentially fatal consequences [32,33]. The identified precipitating factors are hormonal fluctuations, fasting, smoking, infections, and exposure to porphyrogenic drugs such as antibiotics.…”

Mechanisms of Neuronal Damage in Acute Hepatic Porphyrias

“…From a clinical perspective, neurovisceral acute porphyric attacks (APAs) are the most dramatic manifestations of AHPs [ 2 , 3 , 4 , 5 , 6 ]; they are usually unleashed by external triggers, such as fasting, alcoholic intake, the luteal phase of menstrual cycles, or porphyrinogenic drugs [ 7 ] (antiepileptics, barbiturates, griseofulvin, hormonal replacement therapy, etc.) and display a wide range of neuropathic manifestations [ 2 , 3 , 4 , 5 , 8 , 9 ].…”

“…During porphyric crises, increased levels of the heme precursors δ -amino levulinic acid (ALA) and porphobilinogen (PBG) are measured in urine, indicating an enhanced activity of liver ALA synthase (ALAS1), the first enzyme in the heme biosynthetic pathway [ 3 , 6 ]. ALAS1 is probably overexpressed as a result of greater demands for heme under “porphyrinogenic” stress conditions.…”