MedlinePlus Medical Encyclopedia: Porphyria

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Porphyria

Contents of this page:
Illustrations Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests	Treatment Expectations (prognosis) Complications Calling your health care provider Prevention

Illustrations

Porphyria cutanea tarda on the hands

Alternative names Return to top

Acute intermittent porphyria; Hereditary coproporphyria; Congenital erythropoietic porphyria; Erythropoietic protoporphyria

Definition Return to top

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 (such as abdominal pain or cramping).

Causes, incidence, and risk factors Return to top

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 begin in early childhood, some at puberty, and others begin 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.

Symptoms Return to top

Red urine
Sensitivity to sunlight
Blister (bulla) formation on exposure to sunlight
Skin swelling (edema) on exposure to sunlight
Photodermatitis
Crampy abdominal pain (may be extremely severe)
Constipation
Vomiting
Pain in the limbs
Pain in the back
Personality change
Numbness or tingling
Muscle pain
Muscle weakness or paralysis

Signs and tests Return to top

Tachycardia
Loss of deep tendon reflexes
Electrolyte changes (see chem-20) - hyponatremia
Decreased kidney function as may be shown by the following tests:
- Urinalysis
- Serum creatinine
- Creatinine clearance
- BUN
- Serum potassium
- Arterial blood gases

Tests:

PROTO blood test (measures porphyrins, blood)
Enzyme assay for:
- Uroporphyrinogen decarboxylase
- Protoporphyrinogen oxidase
- Porphobilinogen PBG deaminase
- Coproporphyrinogen oxidase
- ALA dehydratase
- Uroporphyrinogen III cosynthase
- Ferrochelatase

Treatment Return to top

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) Return to top

The porphyrias are life-long intermittent illnesses, but with good long-term management, the affected person can expect long problem-free periods.

Complications Return to top

Progressive muscle paralysis
Respiratory failure
Gallstones
Disfigurement
Coma

Calling your health care provider Return to top

Call your health care provider if you have any of the above symptoms suggestive of a porphyria. If you have already been diagnosed with a porphyria, call your health care provider at the first signs of an acute attack.

Prevention Return to top

Genetic counseling may be of benefit to prospective parents with a family history of any type of porphyria.

Update Date: 6/5/2003

Updated by: Ezra E. W. Cohen, M.D., Section of Hematology/Oncology, Department of Medicine, The University of Chicago, Chicago, IL. Review provided by VeriMed Healthcare Network.

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