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.
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.
Porphyrias involve three major symptoms:
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:
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:
- 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
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.
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.
Genetic counseling may be of benefit to prospective parents with a family history of any type of porphyria.
Anderson K. The porphyrias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 229.