Porphyria – how to recognize, types, difficult diagnosis

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Porphyria is quite a rare disease. Is there anyone who has never heard of vampires? These pale, shunned, bloodthirsty monsters? Vampire legends have fascinated people for centuries, but no less fascinating is the attempt to find the scientific seed of truth around which myths have grown up over the centuries about those who are eternally alive wandering in terrible castles at night.

Medicine has a certain answer to this question. Fairy-tale vampirism can be nothing more than a rare metabolic condition called porphyria, though equating a vampire with a porphyria sufferer is definitely an abuse. And it is worth adding that among those suffering from this disease, Vincent van Gogh.

Theoretically, everything is correct

All the confusion is due to the variety of symptoms of this rare disease, which in the old days could have aroused fear and become the source of amazing and exaggerated stories. Imagining a person with pale, blistering skin, who, due to their oversensitivity to daylight, only leaves the house after dark, howling horribly, excessively hairy, who suddenly experiences psychotic attacks, and it all has something to do with blood – it is not difficult to guess how the people of the Middle Ages terrified by such a view created the legendary tales of vampires. And since porphyrias are mostly hereditary diseases, and it was not unusual in those days to marry closely related people, it is easy to imagine that there were areas where the incidence of this disease was higher than elsewhere.

Porphyria has many names

Time, however, for the facts. When we talk about porphyria, we are not really talking about one disease. In fact, it is a group of diseases that have one common cause. These are heme production disorders. Hem is a chemical molecule that contains iron and is mainly produced in red blood cells (where it is part of hemoglobin) and in the liver (where it is an important component of some liver enzymes). The production of heme in our body is a complex process involving eight different enzymes. Impaired function of any of them leads to disturbances in heme production, its deficiency and the accumulation of substances formed in the intermediate stages of its synthesis, called porphyrins. Depending on which enzyme is malfunctioning, a different type of porphyria develops. There are eight different forms of porphyria. Four of them are called acute hepatic porphyrias, and the remaining ones are cutaneous porphyrias that are chronic diseases. The three most common porphyria: acute intermittent porphyria, late cutaneous porphyria, and erythropoietic protoporphyria are the best examples of the remarkable diversity of this group of diseases.

Acute intermittent porphyria belongs to the group of acute hepatic porphyria. It occurs in the form of sudden relapses that can be triggered by various medications (sedatives, antiepileptics, some antibiotics), sex hormones (both those administered in the form of tablets and those produced naturally in our body), as well as caloric deficiency resulting from starvation or the use of draconian diets. The disease manifests itself in severe abdominal pain, often requiring the use of opioid painkillers. A characteristic feature is the disproportion between the severity of pain and the lack of deviations from the norm in diagnostic tests. In addition, there is a mental disorder in the form of anxiety, hallucinations, character changes, which are often confused with psychotic attacks in the course of schizophrenia. Nervous disorders and muscle weakness (potentially life-threatening if the diaphragm and respiratory muscles are affected) are also often accompanied.

Late cutaneous porphyria is the most common porphyria. In its course, there is an excessive accumulation of iron in the body, which is not built into the heme molecule. The disease may be completely asymptomatic or there may be symptoms mainly affecting the skin. Due to the skin’s sensitivity to light, parts of the skin exposed to sunlight develop fluid-filled blisters that can leave unsightly scars. The causes exacerbating the course of the disease are the most common alcohol abuse, estrogens and iron preparations. However, it should be remembered that this form of porphyria may be associated with infection with the hepatitis C virus and HIV.

A much rarer disease is erythropoietic protoporphyria, the most important symptom of which is skin hypersensitivity to sunlight. It manifests itself in childhood and can take the form of urticarial rashes, redness and painful swelling of the skin, which intensifies in the spring and summer. The skin changes have nothing to do with the oozing blisters seen in late cutaneous porphyria.

Family problem

Due to the fact that porphyrias are predominantly genetically determined diseases and may occur in families, when a specific type of disease is diagnosed in one of the family members, it may be necessary to examine other relatives, especially children of the sick person. This is important for the application of appropriate prophylaxis.

Difficult diagnostics, various treatments

Due to the rarity of porphyria (the incidence of acute porphyria is approximately 5 cases / 100 people, the frequency of rarer forms is difficult to determine) and the fact that the symptoms of the disease may resemble other conditions (surgical, dermatological, psychiatric), diagnosis is difficult . For this purpose, it is necessary to perform specialized urine and fecal tests in search of excess excreted intermediate products of heme synthesis. It is also important to conduct genetic testing. It also happens that one patient may have disorders characteristic of different types of porphyria – then it is called the so-called double porphyria.

Getting the diagnosis right is important to getting the treatment right. For example, in acute intermittent porphyria, when an attack of abdominal pain occurs with accompanying psychiatric and neurological symptoms, hemin is administered to supplement the heme deficiency. If the drug is not immediately available, relief may be obtained by infusing glucose in high doses and appropriately selected painkillers and sedatives, which will not worsen the symptoms. The situation is quite different in late cutaneous porphyria, where the treatment does not consist of haem supplementation, but periodic blood bleeds intended to remove excess iron accumulated in the body. In erythropoietic protoporphyria, beta-cathoren preparations are administered. Prevention aimed at elimination of factors causing attacks of the disease or its exacerbation is extremely important (avoiding certain medications, exposure to sunlight, preventing skin damage as a result of exposure to too strong sunlight, e.g. during surgery).

Treatment and diagnosis of porphyria should be carried out in specialized centers. In Poland, the consultation and treatment center is the Institute of Hematology and Transfusion Medicine in Warsaw.

Text: lek. Paulina Jurek