Porphyria

Alternative names:

acute intermittent porphyria; congenital erythropoietic porphyria; erythropoietic protoporphyria; hereditary coproporphyria

Definition:

A group of inherited disorders involving abnormalities in the production of heme pigments (the base material responsible for hemoglobin (red blood cell pigment), myoglobin (reddish muscle cell pigment) and another group of materials called cytochromes. Porphyrias are characterized by three major findings: photodermatitis (light sensitivity causing rashes), neuropsychiatric complaints and visceral complaints abdominal pain, cramping, and so on.

Causes, incidence, and risk factors:

The porphyrias may be inherited as either autosomal dominant or autosomal recessive traits depending on which type of porphyria is involved. Some types of porphyria have their onset in early childhood, some at puberty, and others during adulthood.

A classical attack of acute porphyria generally begins with colicky abdominal pain (severe) followed by vomiting and constipation. Personality changes may develop during an acute attack as well as peripheral paresthesia (numbness and tingling), weakness, paralysis, sensory changes and muscle pain. Acute attacks can be lifethreatening, producing severe electrolyte imbalances, low blood pressure and shock.

Urine may become red following an attack. In congenital erythropoietic porphyria, the urine is constantly red.

Exposure to sunlight can cause reddening, pain, sensations of heat, blistering and edema in the skin. These lesions heal slowly, often with scarring or pigment changes and can be disfiguring.