Porphyria - Enzyme defect with consequences

Porphyria is a group of rare metabolic disorders with multiple manifestations. Porphyria can be acute or chronic, cause mild or life-threatening symptoms, and affect a wide variety of organs. The diagnosis is therefore often not easy to make. Learn more about the causes, symptoms, diagnosis and treatment of porphyria.

How does porphyria develop?

As different as the forms are, they all have one thing in common: the formation of porphyrins is always disturbed. Porphyrins are chemical compounds, mostly with metals. They are responsible for the color of proteins, such as the green chlorophyll in plants and the red color of blood cells and muscles.

Porphyrins are an important component in the human and animal organism, are broken down in the liver via intermediates and then give the bile its greenish color. Various enzymes, especially in the bone marrow and the liver, are involved in this process of remodeling, remodeling and decomposition. If one or more of them are missing or are not working properly, this process is disrupted. Such an enzyme defect may be inherited or acquired (for example after lead poisoning).

Which forms are there?

There is not just one classification, but several that are made according to different criteria. Thus, a distinction is made according to origin (innate - acquired), place of enzyme formation (bone marrow - liver) and course form (acute - chronic). Depending on where the affected enzymes are predominantly formed, the

  • erythropoietic form (disorder in the blood-forming bone marrow) and
  • hepatic form (disorder in the liver cells) as well
  • a combination of these two (erythrohepatic form) distinguished.

For example, if the incorporation into blood cells or muscle protein is disturbed, the concentration of porphyrins and their precursors in the blood increases; the specialist then speaks of porphyrinemia. In case of disturbed remodeling, these tend to deposit in the skin and other tissues and damage them. Also, the concentration in the urine (porphyrinuria) or stool may be increased.

How is the disease expressed?

The symptoms depend on which enzyme is affected. In practice, the classification into forms with a sudden onset (Porphyria acuta) and with a chronic course (Porphyria chronica) has proven itself, as they are associated with typical symptoms.

In acute forms, abdominal pain, cardiovascular complaints, neurological disorders and mental disorders such as depression occur. However, signs of chronic porphyria are changes in the skin when it is exposed to light.

Two important forms at a glance

By far the most common is the

  • Porphyria cutanea tarda (PCT), a chronic form that is likely to be inherited or acquired. Typical feature is the blistering of light-exposed skin, for example the back of the hand or neck. It comes to increased pigmentation and hair growth. In most cases, damage to the liver also occurs. The excreted urine darkens under the influence of light pink or brown.
  • The porphyria acuta intermittens (AIP) is a hereditary, life-threatening form. It usually shows for the first time in early adulthood. Certain factors such as infections and medications, but also stress, alcohol and hunger can trigger an acute attack. The symptoms are manifold. The spectrum ranges from abdominal colic with nausea and vomiting to fever, cardiac arrhythmia and elevated blood pressure to mental and neurological changes such as paralysis, emotional disorders, seizures and disturbances of consciousness. There may even be respiratory paralysis. Therefore, the person affected in an acute attack in an intensive care unit must be cared for. Even with this form, the urine darkens.

How is the diagnosis made?

Decisive are first the medical history and the symptoms with the mixture of symptoms. The final diagnosis and differentiation of the form is made by determining porphyrins and their precursors in the blood, urine and stool. Possibly. genetic tests are also carried out.

Which therapy is there?

In all forms, the most important thing is to avoid the triggers. In the case of PCT, sunscreen ointments can be used to support them. By taking the malaria drug chloroquine, it can be attempted to dissolve the porphyrins out of the tissue. However, this treatment is temporary. Aderlässe are also used. In AIP, the symptoms are treated intensively in an acute attack.

The course depends on the shape and whether the triggers are to be avoided. Healing is still not possible with any porphyria.

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