What is porphyria?

Causes and Symptoms

Porphyria refers to a group of diseases that share a common feature: a defect in the chain of chemical reactions that produce hemoglobin, the protein responsible for the transport of oxygen by the blood. These metabolic errors cause a buildup of porphyrins, resulting in two main types of illness: nervous system attacks and skin
lesions.

There are two major groups of porphyrias: erythropoietic and hepatic. In erythropoietic porphyria, the porphyrins are synthesized in the bone marrow; in hepatic porphyrias, they are produced in the liver. Each of these porphyrias has several subtypes. For example, acute intermittent porphyria (AIP) is a hepatic porphyria most common in young adults and adults in early middle age. Its attacks are triggered by alcohol, certain drugs, and hormonal changes (such as those accompanying pregnancy). Some patients experience two to three episodes per year, while others may have as few as three in a lifetime.

Since all forms of porphyria are rare, a physician may not suspect the disease at first. The symptoms of porphyria include abdominal disturbances, nausea, vomiting, reddish urine, and prickling sensations in the hands and feet. The hallmarks that distinguish porphyrias, however, are the skin and nervous system effects. Except for AIP, all the porphyrias cause extreme photosensitivity of the skin because the porphyrins that are deposited in the skin are excited by the ultraviolet aspect of sunlight. This reaction results in skin lesions, which may lead to disfigurement. The neurological disturbances of porphyria range from mild mental confusion to delirium and hysteria. If a porphyria is suspected, urine, stool, and blood tests are done to detect the presence of porphyrins.

Treatment and Therapy

Avoiding triggering factors is primary in the control of porphyria attacks. Alcohol and drugs, which may cause an attack, should be stopped. Protective clothing should be worn to prevent the irritating effects of sunlight. For certain porphyrias, drugs are available to suppress the formation of porphyrins. In the case of AIP, a simple increase in the consumption of carbohydrates is enough to inhibit the production of porphyrin-forming substances. The treatment of porphyrias is largely aimed at relieving its symptoms.

Bibliography:

American Porphyria Foundation. http://www.porphyriafoundation.com.

Goldman, Lee, and Dennis Ausiello, eds. Cecil Textbook of Medicine. 23d ed. Philadelphia: Saunders/Elsevier, 2007.

Greer, John, et al., eds. Wintrobe’s Clinical Hematology. 12th ed. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health, 2009.

"Learning about Porphyria." National Human Genome Research Institute, April 18, 2013.

Parish, Kathy. “What’s Wrong with This Patient?” RN 53, no. 7 (July, 1990): 43–45.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Porphyria. San Diego, Calif.: Icon Health, 2002.

"Porphyria." Mayo Clinic, May 7, 2011.

Rakel, Robert E., and Edward T. Bope, eds. Conn’s Current Therapy. Philadelphia: Saunders/Elsevier, 2007.

Wood, Debra. "Porphyria." Health Library, November 26, 2012.