Porphyria Health Article

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