Porphyria

Definition

Porphyria is a group of metabolic disorders in which enzymes involved in heme synthesis are partially or completely deficient. This causes large amounts of substances called Porphyria to build up in the body and cause problems (mainly in the skin or nervous system).
Porphyria is a building block for heme. And heme is the iron-containing part of the hemoglobin in red blood cells that carries oxygen.
There are several types of Porphyria . Some of the most common types are:
  • Acute intermittent porphyria
  • Porphyria cutanea tarda
  • Erythropoietic protoporphyria
  • Congenital erythropoietic protoporphyria (Gunther's disease)

Causes

Most Porphyria are hereditary. One subtype, porphyria cutanea tarda, is acquired. Porphyria occurs when a genetic or acquired defect causes a shortage in any one of the several enzymes needed for heme production.

Risk Factors

A risk factor is something that increases your chances of getting a disease or condition. The most common risk factor for Porphyriais having a family member with this disease. Also, whites are at greater risk than blacks or Asians.
If you have Porphyria, certain factors can increase your risk of a Porphyriaattack. These include: drugs, chemicals, alcohol, dieting, and sunlight. Triggers for specific types of Porphyriaare listed below:
Acute Intermittent Porphyria :
  • Drugs, such as:
    • Barbiturates
    • Sulfa drugs
    • Seizure drugs
    • Steroid hormones such as:
      • Estrogen
      • Progesterone
  • Hormonal changes related to the menstrual cycle
  • Weight-loss diets or fasting
  • Infections
  • Alcohol
  • Stress
  • Surgery
  • Cigarette smoke
Porphyria Cutanea Tarda
  • Iron
  • Alcohol
  • Estrogens
  • Hydrocarbons
  • Certain pesticides or chemicals
Erythropoietic Protoporphyria
  • Sunlight
  • Weight-loss diets or fasting
Congenital Erythropoietic Protoporphyria
  • Sunlight

Symptoms

Porphyria can cause skin or nervous system problems. Symptoms depend on the type.
Acute Intermittent Porphyria
Nervous system symptoms usually occur after puberty. Gastrointestinal symptoms are caused by nerves that affect the intestinal tract. Attacks can last from days to weeks. Symptoms of future attacks resemble the initial episode, and may include:
  • Abdominal pain and cramping
  • Nausea and vomiting
  • Constipation
  • Painful urination or urinary retention
  • Pain in limbs, head, neck, or chest
  • Muscle weakness
  • Loss of sensation
  • Tremors
  • Sweating
  • Rapid heart rate
  • High blood pressure
  • Breathing problems
  • Heart arrhythmia
  • Seizures
  • Mental symptoms such as:
    • Hallucinations
    • Restlessness
    • Depression
    • Anxiety
    • Insomnia
    • Confusion
    • Paranoia
Porphyria Cutanea Tarda
Symptoms may include:
  • Sun sensitivity
  • Sun-exposed skin is fragile
  • Minor injury may damage the skin
  • Blisters on the face, hands, arms, feet, and legs
  • Skin heals slowly
  • Skin susceptible to infection
  • Skin thickens and scars
  • Skin color changes
  • Excess hair growth
  • Reddish urine, in infancy or childhood
Erythropoietic Protoporphyria Symptoms may include:
  • Sun sensitivity
  • Redness or swelling, but usually no blisters
  • Itching or burning sensation
  • Long-term skin and nail changes
Possible complication: Gallstones Congenital Erythropoietic Protoporphyria Symptoms may include:
  • Reddish urine, in infancy
  • Sun sensitivity, beginning in early infancy
  • Sun-exposed skin is fragile
  • Blisters on sun-exposed skin
  • Blisters open and are prone to infection
  • Skin color may change
  • Skin thickens
  • Excess hair growth
  • Scarring
  • Reddish-brown teeth
Possible complications:
  • Enlarged spleen
  • Hemolytic anemia

Diagnosis

The doctor will ask about symptoms and medical history and perform a physical exam. Tests differ for the various types of Porphyria and may include blood, urine, or stool tests to check for excess Porphyria or to check for a specific enzyme deficiency.

Treatment

For all types of Porphyria, treatment includes the following:
  • Avoiding known triggers and drugs that can precipitate an attack
  • Eating a high-carbohydrate diet
For types of porphyria that affect the skin, protect the skin from injury or infection. Specific treatment depends on the type of porphyria. Acute Intermittent Porphyria You may need to be hospitalized during an attack. In the hospital, you may be given the following:
  • Heme by vein in the form of hematin, heme albumin, or heme arginate
  • Glucose by vein
  • Drugs to control symptoms such as pain, nausea, anxiety, and insomnia
Porphyria Cutanea Tarda Treatment may include:
  • Blood removal weekly to monthly
  • Low doses of antimalarial drugs, such as:
    • Chloroquine (Aralen Phosphate)
    • Hydroxychloroquine (Plaquenil)
  • Radiology imaging to monitor for increased risk of liver cancer
Erythropoietic Protoporphyria
Treatment may include:
  • Oral beta-carotene
  • Maintaining normal iron levels with food or supplements
  • Medication to aid excretion of porphyrins in stool, such as:
    • Activated charcoal
    • Cholestyramine
  • In some cases:
    • Blood transfusions
    • Heme by vein in the form of hematin, heme albumin, or heme arginate
    • Spleen removal
Congenital Erythropoietic Protoporphyria Treatment may include:
  • Oral beta-carotene
  • Oral charcoal, to aid excretion of porphyrins in stool
In some cases:
  • Blood transfusions
  • Spleen removal
  • Bone marrow transplantation

Prevention

Genetic testing may identify people at risk for Porphyria. If people in your family have Porphyria, you can be tested. And you can talk to a genetic counselor when deciding to have children. The genetic mutation cannot be corrected, but attacks can be prevented or controlled. Steps to avoid Porphyriaattacks and complications include the following:
  • Avoid drugs and other triggers of a porphyria attack.
  • Protect skin from injury or infection, if you have a type that affects the skin.
  • To prevent menstrual attacks, talk to your doctor about menstrual cycle suppressing medications.