Friday, May 13, 2011

All About Porphyria

Porphyria (poor-FEAR-ee-uh) refers to a group of disorders that result in a buildup of chemicals called porphyrins in your body. Although porphyrins are normal body chemicals, it’s not normal for them to build up. The cause is usually an inherited mutation.

Porphyria typically affects your nervous system or skin or both. The specific signs and symptoms of porphyria depend on which of your genes is abnormal. Porphyria is usually inherited, but environmental factors may trigger the development of symptoms in some types of porphyria.

Treatment depends on the type of porphyria you have. Although porphyria usually can’t be cured, certain lifestyle changes may help you manage porphyria.
Symptoms

There are two general categories of porphyria — acute and cutaneous. Signs and symptoms depend on the type of porphyria you have.

Acute porphyrias. These include forms of the disease that cause predominantly nervous system symptoms and, in some cases, skin symptoms, as well. Acute porphyria attacks are rare before puberty and after menopause in women. Signs and symptoms may last one to two weeks. Possible signs and symptoms include:

* Insomnia
* Anxiety or restlessness
* Severe abdominal pain
* Constipation
* Vomiting
* Diarrhea
* Pain in your arms, legs or back
* Muscle pain, tingling, numbness, weakness or paralysis
* Dehydration
* Excessive sweating
* Seizures
* Confusion
* Hallucinations
* Disorientation
* Paranoia
* Red urine
* High blood pressure

Cutaneous porphyrias. These include forms of the disease that cause skin symptoms as a result of oversensitivity to sunlight, but don’t affect your nervous system. Some forms of cutaneous porphyria begin to show signs and symptoms during infancy or childhood. If you have this form of porphyria, you may experience:

* Itching
* Painful skin redness (erythema)
* Skin swelling (edema)
* Blisters
* Red urine

When to see a doctor
Many signs and symptoms of porphyria are similar to those of other, more common conditions. This can make it difficult to know if you’re having an attack of porphyria. Any of the following symptoms should prompt you to seek immediate medical attention:

* Severe abdominal pain, sometimes accompanied by vomiting or constipation
* Muscle pain
* Confusion
* Disorientation
* Painful skin redness
* Skin swelling
* Blisters that appear soon after sun exposure
* Red urine

Porphyria arises from a disruption in your body’s production of a substance called heme.

Heme is found in all of your tissues, but the largest amounts are in your red blood cells, bone marrow and liver. Heme is a major component of hemoglobin, an iron-rich protein that gives your blood its red color. Hemoglobin enables red blood cells to carry oxygen from your lungs to all parts of your body, and to carry carbon dioxide from other parts of your body to your lungs so that it can be released when you exhale.

Eight enzymes convert chemicals called porphyrins into heme. In porphyria, an inherited mutation in one of the genes involved in heme production can cause an enzyme deficiency, which can lead to porphyrins building up in your body. Although porphyrins are normal body chemicals, it’s not normal for them to build up.

Most forms are inherited
Most of the porphyrias are inherited. Some forms of the disease come from inheriting a defective gene from one of your parents (autosomal dominant pattern). Some 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 porphyrins to heme to be abnormal.

Just because you have inherited a gene or genes that can cause porphyria doesn’t mean that you will exhibit signs and symptoms. You might have what’s called latent porphyria, and never have signs and symptoms. This is the case for most carriers of the abnormal genes.

Additionally, environmental factors may trigger the development of signs and symptoms in some types of porphyria. When exposed to the trigger, your body’s demand for heme production increases. This overwhelms the deficient enzyme, setting in motion a process that causes your signs and symptoms. 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)
* Dieting or fasting
* Smoking
* Infections or other physical stress
* Stress
* Alcohol use
* Menstrual hormones
* Sun exposure
* Excess iron in your body

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 diagnosis. Because porphyria’s signs and symptoms usually aren’t distinctive, laboratory tests are required to make a definitive diagnosis of porphyria and to determine which 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 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.

Source: http://www.mayoclinic.com

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