Porphyria is a condition that affects how heme is made and broken down by the body. Heme is the part of hemoglobin containing the iron atom that carries oxygen to the cells of the body.
Hemoglobin is the main oxygen-carrying component of blood. Part of the hemoglobin molecule is a protein (the "globin"). The other part is heme, a molecule known as a porphyrin. This part is built to contain the iron atom that carries oxygen to the cells of the body.
Heme is built (synthesized) from other porphyrins in a series of stages. The porphyrins are made in various places in the body. When one of the stages in heme construction goes awry, either because the body is missing a constructing tool (an enzyme) for genetic reasons, or due to a disruption of the pathway caused by a toxin, certain porphyrins build up to abnormal levels in the body.
Porphyrias are classified by where in the body the excess porphyrins are made. They include: erythropoietic, with extra production in the bone marrowhepatic, with extra production in the livererythrohepatic, with extra production in the bone marrow and liver
Symptoms vary, depending on the type of porphyria. Symptoms that may occur with most of the porphyrias include: severe abdominal pain, sometimes mimicking acute appendicitis chest painsensitivity to bright sunlightmuscle cramping and weaknessnumbness and tingling of the legs and arms
Hepatic porphyria may cause these additional symptoms: fevervomitingconstipationrapid heart beatliver diseasepsychiatric disturbances, such as depression or manialeg painskin discoloration, itching, and blisteringchanges in urine color to a red-brownchanges in tooth color
Most cases of porphyria are caused by genetic disorders. Some cases are caused by toxic substances, such as ingestion or exposure to lead or associated with chronic infections. Menstruation may increase symptoms in women.
Prevention of porphyria is not always possible. Avoiding things that trigger symptoms may decrease the risk of symptoms. These triggers include: excessive bright sunlightcertain medications, such as oral contraceptives, alcohol, and barbituratesGenetic counseling may be helpful to couples with a family history of porphyria.
The diagnosis of porphyria depends on the symptoms and what type of porphyria is suspected. Steps in diagnosis may include: a medical history, and history of activity or traumaa thorough medical examblood tests, including a complete blood count or CBC, which counts the number of each kind of cell in the blooda blood test to measure porphyrins in the bloodstool tests and cultures to look for any blood, infection, or porphyrins in the stoolurine tests to check for porphyrins and lead in the urine
A person with porphyria may have recurrent and severe symptoms. Some forms of porphyria may lead to gallstones or chronic skin or liver problems. Electrolyte or salt imbalances in the blood can occur. If untreated, porphyria may also lead to respiratory distress, shock, and death.
Porphyria is not contagious. It can be passed genetically to offspring.
Treatment depends on the type of porphyria. Treatment of acute, or short term, intermittent porphyria includes intravenous fluids and glucose. Other treatments may include: strong pain medications for abdominal pain.hematin, an enzyme inhibitor that can help prevent or treat attackstranquilizers to reduce anxietymedications such as beta-carotene to reduce light sensitivity and the effects of sunlighta diet high in carbohydrates surgery, removal of the spleen to treat anemia withdrawal of offending agents such as medicines or exacerbating conditions such as sunlight to sensitive skin
Pain medications may cause stomach upset, irritability, and drowsiness. Surgery can be complicated by bleeding, infection, or an allergic reaction to the anesthetic.
A person with porphyria may have relapses, in which the condition worsens and symptoms return.
The person is monitored for relapses. Blood and urine tests may also be used to monitor the levels of porphyrins in the blood and urine. Further treatment is given when symptoms or attacks occur. Any new or worsening symptoms should be reported to the healthcare professional.
Harrison's Principles of Internal Medicine, Fauci et al, 1998
Complete Guide to Symptoms, Illness, and Surgery, Griffith, 2000
Professional Guide to Diseases, Burlew et al, 1995