Porphyria refers to a group of disorders that arise from problems in your body's production of a substance called heme.
Heme is found in all body tissues, but the largest amounts are in your red blood cells, bone marrow and liver. Your body uses enzymes to convert chemicals called porphyrins into heme. An inherited deficiency in one of these enzymes can interrupt this process, causing porphyrins to build up in your body.
Porphyrin buildup may cause signs and symptoms of porphyria. The specific signs and symptoms depend on which of your enzymes are abnormal, but your nervous system and skin are most often affected by porphyria.
Treatment depends on the type of porphyria you have. Although porphyria can't be cured, certain lifestyle changes may help prevent signs and symptoms of porphyria.
Porphyria is inherited. Some forms of the disease come from inheriting a defective gene from one of your parents (autosomal dominant pattern). Other forms come from inheriting defective genes from both parents (autosomal recessive pattern). These gene defects cause one or more of the enzymes involved in the process of converting porphyrin to heme to be abnormal.
Genetic defects alone don't predict who will experience signs and symptoms of porphyria. Researchers estimate that about
90 percent of people who inherit genes that result in a porphyria enzyme defect never develop any manifestations of the disease (latent porphyria).
Factors in addition to genetic defects can trigger porphyria. Although many factors may set off the disease, they all affect your body in a similar way. When exposed to the trigger, your body's demand for heme production increases. This overwhelms the deficient enzyme, which leads to an accumulation of porphyrin. The excess porphyrin causes the signs and symptoms of porphyria. Common triggers include :
- Drugs (barbiturates and sulfonamide antibiotics are most often cited, but others such as tranquilizers, birth control pills and sedatives also may cause symptoms)
- Alcohol use
- Menstrual hormones
- Sun exposure
Risk Factor :
Factors that increase your risk of porphyria include :
- Family history. Porphyria is an inherited disorder, passed from parents to children through defective genes.
- Sex. Porphyria affects women more often than it does men.
When to seek medical advice :
Many signs and symptoms of porphyria are similar to those of other more common illnesses or diseases. This can make it difficult to know if you're having an attack of porphyria.
Often, an episode of acute porphyria begins with neurological symptoms of severe abdominal pain, sometimes accompanied by vomiting or constipation. Muscle pain, confusion and disorientation also are common signs and symptoms of acute porphyria. In addition, the following may be signs and symptoms of acute porphyria :
- Muscle tingling, numbness, weakness or paralysis
Signs and symptoms of cutaneous and neurocutaneous porphyria, such as itching, painful skin redness (erythema), skin swelling (edema) and blisters, usually appear within several minutes of sun exposure.
Red urine, caused by increased levels of porphyrins, can be a sign of either type of porphyria.
If you experience these signs or symptoms of porphyria, call your doctor for an evaluation.
Porphyria is generally broken down into two categories :
- Acute porphyrias. These include forms of the disease that cause predominantly nervous system symptoms (neuron porphyrias) and, in some cases, skin symptoms, too (neurocutaneous porphyrias).
- Cutaneous porphyrias. These include forms of the disease that cause skin symptoms, but don't affect your nervous system.
Specific signs and symptoms depend on the type of porphyria you have, but common signs and symptoms of porphyria include the following :
- Severe abdominal pain
- Pain in your arms, legs or back
- Muscle pain, tingling, numbness, weakness or paralysis
- Red urine
- High blood pressure
Cutaneous porphyrias and neurocutaneous acute porphyrias
- Painful skin redness (erythema)
- Skin swelling (edema)
- Red urine
Signs and symptoms of cutaneous and neurocutaneous porphyria usually appear within minutes of sun exposure.
Acute porphyria attacks are rare before puberty and after menopause. Some forms of cutaneous porphyria begin to show signs and symptoms during infancy or childhood.
Many signs and symptoms of porphyria are similar to those of other more common diseases. Also, because porphyria is rare, many doctors have not seen cases of the disorder before, making it more difficult to reach an accurate diagnosis quickly. Because its signs and symptoms usually aren't distinctive, laboratory tests are required to make a definitive diagnosis of porphyria and to determine the form of the disease you have.
If your doctor suspects porphyria, he or she may recommend the following tests :
- Urine test. If you have a form of acute porphyria, a urine test may reveal elevated levels of two substances: porphobilinogen and delta-aminolevulinic acids, as well as other porphyrins.
- Blood test. If you have a form of cutaneous porphyria, a blood test may show an elevation in the level of porphyrins in the liquid part of your blood (plasma).
- Stool sample test. Analysis of a stool sample may reveal elevated levels of some porphyrins that may not be detected in urine samples. This test may help your doctor determine your specific type of porphyria.
Possible complications of porphyria include :
- Dehydration. Vomiting due to an attack of acute porphyria can lead to dehydration, which may require that you receive fluids through a vein (intravenously).
- Breathing difficulties. Acute porphyrias can cause muscle weakness and paralysis, which can cause breathing problems. If left untreated, they also can lead to respiratory failure.
- Low sodium in your blood. Called hyponatremia, this is usually linked to problems with sodium and water handling in your body. But, in rare cases, low blood sodium may be a sign that porphyria has damaged your kidneys.
- High blood pressure. Porphyrin buildup can damage your kidneys and can result in high blood pressure (hypertension).
- Chronic kidney failure. Porphyrin buildup may cause your kidneys to gradually lose their function over time. Kidney function at less than 10 percent to 15 percent of normal capacity is considered end-stage kidney disease, which usually requires dialysis or a kidney transplant.
- Liver damage. Some forms of porphyria cause excessive porphyrins in your liver, which may lead to severe liver damage that may eventually require a liver transplant.
- Permanent skin damage. When your skin heals after cutaneous porphyria, it may have abnormal bumps (milia) and coloring (pigmentation). Scars may remain on your skin, as well, and lasting skin problems may cause your hair to fall out.
Treatment of acute porphyrias focuses on eliminating symptoms. This may require hospitalization in severe cases. Treatment may include :
- Stopping medications that may have triggered symptoms
- Medication to control pain
- Prompt treatment of infections or other illness that may have caused symptoms
- Intravenous sugar (glucose) to maintain an adequate intake of carbohydrates
- Intravenous fluids to combat dehydration
- Hematin (heme arginate), a medication that is a form of heme, which can reduce the burden placed on your body to produce heme, thus lowering porphyrin levels
Treatment of cutaneous porphyrias focuses on reducing the amount of porphyrins in your body to help eliminate your symptoms. This may include :
- Phlebotomy. Phlebotomy involves drawing a certain amount of blood from one of your veins. This reduces the iron in your body, which decreases porphyrins. You may need to undergo phlebotomy several times before cutaneous porphyria goes into remission.
- Activated charcoal. Taken orally, this medication can absorb excess porphyrins and help your body get rid of them more quickly than usual. Doctors also use the medication cholestyramine for this purpose.
Long-term treatment of cutaneous porphyrias may include daily doses of beta carotene. Your body converts beta carotene to vitamin A, which is necessary for healthy eyes and skin. Beta carotene may increase your skin's tolerance to sunlight.
Although there's no way to prevent porphyria, if you have the disease, taking the following steps may help prevent Symptoms:
- Avoid medications known to trigger acute attacks. (Ask your doctor for a list of safe and unsafe drugs.)
- Don't use alcohol or illicit drugs.
- Avoid fasting and "crash" dieting.
- Don't smoke.
- Avoid sun exposure as much as possible.
- When you're outdoors, wear protective clothing and use sunscreen.
- Treat infections and other illnesses promptly.
- Reduce stress.
Because porphyria is an inherited disorder, your siblings and other family members should consider undergoing genetic testing to determine if they have the disease.