Health Encyclopedia

Porphyria

Definition

Porphyrias are a group of rare disorders passed down through families, in which an important part of hemoglobin, called heme, is not made properly. Heme is also found in myoglobin, a protein found in certain muscles.

Alternative Names

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

Causes, incidence, and risk factors

Normally, the body makes heme in a multi-step process. Porphyrins are made during several steps of this process. Patients with poryphyria have a lack (deficiency) of certain enzymes needed for this process. This causes abnormal amounts of porphyrins (or related chemicals) to build up in the body.

There are many different forms of porphyria. The most common type is porphyria cutanea tarda (PCT).

Drugs, infection, alcohol, and hormones such as estrogen may trigger attacks of certain types of porphyria.

Symptoms

Porphyrias involve three major symptoms:

Abdominal pain or cramping (only in some forms of the disease)
Light sensitivity causing rashes and scarring of the skin (photodermatitis)
Problems with the nervous system and muscles ( seizures, mental disturbances)

Attacks can occur suddenly, usually with severe stomach pain followed by vomiting and constipation. Being out in the sun can cause pain, sensations of heat, blistering, and skin redness and swelling. Blisters heal slowly, often with scarring or skin color changes. They may be disfiguring. Urine may turn red or brown after an attack.

Other symptoms may include:

Muscle pain
Muscle weakness or paralysis
Numbness or tingling
Pain in the arms or legs
Pain in the back
Personality changes

Attacks can sometimes be life threatening, producing severe electrolyte imbalances, low blood pressure, and shock.

Signs and tests

Your doctor will perform a physical exam, which includes listening to your heart. You may have a fast heart rate (tachycardia). The doctor may find that your deep tendon reflexes (knee jerks) do not work properly.

Blood and urine tests may reveal kidney problems or other problems. Special tests can measure porphyrins in the blood.

Some of the other tests that may be done include:

Blood gases
BUN
Creatinine clearance
Liver function tests
Serum creatinine
Serum potassium
Tests to measure the level of porphyrins and other chemicals linked to this condition
Urinalysis

Treatment

Some of the medicines used to treat a sudden (acute) attack of porphyria may include:

Hematin given through a vein (intravenously)
Pain medication
Propranolol to control the heartbeat
Sedatives to help you feel sleepy and less anxious

Other treatments may include:

Chloroquine
Fluids and glucose to boost carbohydrate levels, which helps limit the production of porphyrins
Removal of blood (phlebotomy)
Beta-carotene supplements

Depending on the type of porphyria you have, your doctor may tell you to:

Avoid all alcohol
Avoid drugs that may trigger an attack
Avoid injuring the skin
Avoid sunlight as much as possible and use sunscreen when outside
Eat a high-carbohydrate diet

Expectations (prognosis)

Porphyrias are life-long diseases with symptoms that come and go. Some forms of the disease cause more symptoms than others. Proper treatment and avoidance of triggers can help reduce the time between attacks.

Complications

Coma
Gallstones
Lung failure
Loss of movement (paralysis) that gets worse
Scarring of the skin

Calling your health care provider

Seek medical attention as soon as you have signs of an acute attack. Talk to your doctor about your risk for this condition if you have a long history of undiagnosed abdominal pain, muscle and nerve problems, and sensitivity to sunlight.

Prevention

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

References

Anderson K. The porphyrias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 229.

Review Date:3/2/2009
Reviewed By:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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