Porphyria

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at October 1, 2016
StartDiseasesPorphyria

Porphyria refers to a group of disease caused by the excessive buildup of porphyrins in the blood. The condition can lead to a variety of problems with the central nervous system or the skin, depending on the type of porphyria in question.

Contents

Definitions & Facts

Porphyria is a relatively uncommon disease, with an incidence rate of about one in 25,000 people in the United States, but the symptoms are so distinctive. Some scholars have suggested that the disease could have played a role in developing the vampire and werewolf myths. Vlad the Impaler, George III of England, and Vincent van Gogh have been rumored to have suffered from porphyria. The claims are common, but also dubious.

There are at least eight different versions of the disease with different symptoms. There are many different types of porphyria. Acute intermittent porphyria causes problems with the nervous system, and porphyria cutanea tardea (cutaneous porphyria) causes problems with the skin.

Symptoms & Complaints

Acute porphyria is characterized by sudden, acute attacks rather than ongoing problems. These attacks most often involve intense abdominal pain, and they frequently include vomiting, sudden increases in blood pressure (hypertension), and an accelerated heart rate (tachycardia).

Some patients also suffer from loss of motor control and seizures. They occasionally involve temporary mental symptoms such as confusion and hallucinations.

Cutaneous porphyria does not lead to acute attacks. Most patients suffer from skin problems such as extreme sensitivity to light. The most common symptom in that case is pain after a short period of exposure, with most patients experiencing it after thirty minutes.

Other patients suffer from blisters and sores as well as hirsutism. The latter symptom is the reason for why this disorder is sometimes linked to the werewolf myth.

Causes

Porphyria occurs when a patient has too many porphyrins in their body. Porphyrins are a natural part of the process that create heme, which is a precursor to hemoglobin and other important compounds. Heme is produced by the bone marrow and, to a lesser extent, by the liver. A healthy body will convert the porphyrins to other compounds relatively quickly, but a patient who suffers from porphyria cannot do so. The porphyrins build up in the patient's body, and in sufficient quantities, they cause the disease.

Most cases result from inherited genetic mutations which cause deficiencies in one of the enzymes that converts porphyrins into other compounds. Chronic symptoms result from the porphyrins themselves, while acute symptoms can result from their reaction with other chemicals.

The attacks that characterize acute porphyria are unpredictable, but several causes have been discovered. Most of them are chemicals, especially medications, that react with the enzymes that produce heme in the liver. These chemicals include a number of anesthetics and anticonvulsants, and some sulfonamides and sulfonylureas.

Certain environmental toxicants have been known to cause porphyria such as a fungicide that poisoned thousands in Turkey, causing porphyria. Smoking, alcohol abuse, and HIV are also linked to acquired cases of this disease.

Diagnosis & Tests

Most diagnoses for porphyria require chemical testing. Porphyria shares many symptoms with other, more common diseases, so it is unlikely to be diagnosed through symptoms alone. The most common way to detect porphyria is to analyze the porphyrin content of urine, blood, or stool samples by conducting clinical urine tests, blood tests, and stool tests.

If the patient suffers from acute porphyria, the samples must be taken during an attack in order to detect the disease. Samples that are taken at other times usually return false negatives, which can complicate the diagnosis process. Many physicians choose to take several samples during different attacks to reduce the risk of inadvertently taking a sample after the patient's porphyrin levels had already started to decrease.

Some samples that are taken during an attack can also return a false negative, which increases the important of taking multiple samples. Most physicians need to send samples to a specialized lab for analysis, so this process can take several weeks.

Physicians can also choose to examine the organs that porphyria can impact, especially the liver. These tests help to confirm a diagnosis of porphyria by by both ruling out other conditions that have similar symptoms and by identifying potential non-genetic causes for the disease. Genetic testing can also help identify genetic mutations associated with the disorder.

Treatment & Therapy

Treatment for porphyria is designed to reduce the intensity of the symptoms. Successful treatment can make patients significantly more comfortable and reduce the risk of death during an attack, but it cannot cure the disease entirely. Heme arginate and hemin can be used to make attacks end relatively quickly and reduce their symptoms, but they only work if they are taken very shortly after the attack begins.

Many people who suffer from acute porphyria wear a medical alert bracelet to make sure that treatment can happen as quickly as possible. This is especially important for people who have trouble communicating during their attacks, since most medical personnel would prioritize treatment for other, more common diseases if they did not know the patient's medical history.

Many patients also undergo treatment to manage their pain from the disease. Opiates are common due to both their effectiveness and the fact that many other options can trigger attacks. Phenothiazine is a common choice to manage nausea, but it is not always effective.

Prevention & Prophylaxis

Most cases of porphyria are genetic, so they cannot be prevented, but the disease's symptoms are another matter entirely. It is easiest to treat acute attacks before they begin. Weakness and low blood sodium are warning signs, and treatment often begins as soon as the are detected.

Eating a balanced diet is important. Acute cases of this disease can affect people who significantly reduce their carbohydrate levels and/or fast for more than 24 hours.

Patients can prevent the symptoms of cutaneous porphyria by avoiding exposure to sunlight. Sunscreen is usually insufficient, but patients can reduce their risk by covering as much of their skin as possible when they need to go outdoors during the day.