Porphyria is 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 (e.g., abdominal pain , cramping).
Alternative Names
Acute intermittent porphyria; Hereditary coproporphyria; Congenital erythropoietic porphyria; Erythropoietic protoporphyria
Causes, incidence, and risk factors
The porphyrias may be inherited as either autosomal dominant (caused by inheriting one abnormal copy of the gene) or autosomal recessive (requires inheritance of two abnormal genes) 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), and is then followed by vomiting and constipation . Personality changes may develop during an acute attack, in addition to peripheral paresthesia ( numbness and tingling ), weakness , paralysis , sensory changes, and muscle pain . Acute attacks can be life-threatening, producing severe electrolyte imbalances , low blood pressure , and shock . Urine may become red or brown following an attack. 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.
Treatment
During an acute attack, these treatments can be expected.
Maintain electrolyte balance
Monitor blood gasses Increase carbohydrate intake (may be IV glucose solutions)
Pain medication as needed Sedation for restlessness and agitation
Propranolol for hypertension
Intravenous hematin Long-term management:
Avoid all alcohol Avoid drugs which may precipitate an attack High carbohydrate diet Avoid sunlight Sunscreen (if not contraindicated) Avoid skin trauma Beta-carotene Consider splenectomy
Expectations (prognosis)
The porphyrias are life-long intermittent illnesses, but with good long-term management, the affected person can expect long problem-free periods.
Prevention
Genetic counseling may be of benefit to prospective parents with a family history of any type of porphyria.