Methemoglobinemia (Blue People): Symptoms, Causes, and Treatment

Our skin is an organ that is often undervalued and recognized., which protects our body against a large number of harmful elements such as bacteria, fungi and solar radiation.

This important part of our body, however, in addition to protecting us on occasions, also warns us of the presence of alterations in other areas of our organism and that can have serious implications for health. This is what happens, for example, in jaundice, in which the skin acquires yellowish tones.

Another of the disorders in which abnormal staining of the skin appears is methemoglobinemia, a disorder of blood origin in which the skin turns bluish in color and which, depending on its type, can bring about fatal consequences.

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Methemoglobinemia: what it is, and symptoms

We call methemoglobinemia a rare blood disorder characterized by the presence of an excessive level of a subtype of hemoglobin called methemoglobin. This particular type of hemoglobin does not have the ability to carry oxygen.

, and at the same time interferes with the hemoglobin that is capable of doing so in such a way that the latter cannot release it in the different organs and tissues normally. This reduces the oxygenation of the body.

One of the most obvious and easily visible symptoms of this disorder is cyanosis, or blue coloration of the skin (although the tones can vary, it is usually an intense bluish color). This probably derives from the previously mentioned decrease in the oxygenation of the organism.. And not just the skin: the blood also changes color, losing its characteristic red to turn brownish.

However, skin coloration is not the only problem that can arise: if excess methemoglobin is too large, the lack of oxygen in the rest of the body can cause problems in the organs and even death. It is not uncommon for respiratory problems to also appear, this being generally one of the main causes of hospitalization.

In addition to the above, depending on the type of methemoglobinemia we can find ourselves with headaches, fatigue, seizures and respiratory problems potentially fatal (if due to acquired causes) or the onset of disability intellectual and maturational delays in the case of type 2 congenital methemoglobinemia that we will talk about subsequently.

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Typologies according to their causes

The causes of the appearance of this disorder can be multiple, and can appear both congenital and acquired.

Acquired methemoglobinemia is the most frequent and usually appears derived from consumption or exposure to oxidizing drugs or chemical substances such as bismuth nitrate, as well as elements used for the treatment of some ailments such as nitroglycerin or some antibiotics.

Regarding congenital methemoglobinemia, it is generally due to genetic transmission or the appearance of certain mutations. We can find two basic types.

The first one is generated by the genetic inheritance of both parents, both parents being carriers (although the majority have not expressed the disorder) of a mutation in certain genes that cause a problem with the cytochrome b5 reductase enzyme. This enzyme does not work properly in the body, which causes oxidation of hemoglobin.

Within this type of congenital methemoglobinemia we can find two large types: type 1 congenital methemoglobinemia is that the enzyme previously mentioned does not appear in the red blood cells of the organism and type 1 in which the enzyme does not appear directly in any part of the body. organism.

The other option within the congenital methemoglobinemias is the so-called hemoglobin M disease, in which this alteration appears due to the fact that hemoglobin is structurally altered from base. In these cases we are before an autosomal dominant disorder in which it is sufficient for one parent to carry the gene and transmit it to generate the alteration (something similar to what happens with Huntington's Korea).

Treatment of this condition

Although it may seem hard to believe, methemoglobinemia is a medical condition that has curative treatment in some cases.

In most cases the prognosis is positive and the patient can fully recover. Treatment mainly involves generating a reduction in methemoglobin levels and an increase in hemoglobin with oxygen-carrying capacity, injecting methylene blue (except in those patients who are at risk of G6PD deficiency, where it can be dangerous) or other substances with a similar effect.

If this does not work, a hyperbaric chamber treatment can be used. The consumption of vitamin C can also be useful, although its effect is less.

In the case of acquired methemoglobinemia, the withdrawal of the substance that has generated the alteration is also required. Milder cases may not require more than this measure, but in people with respiratory or heart problems, the treatment described above is required.

The changes with these treatments can be spectacular., changing the coloration of the skin at high speed.

However, in the case of congenital methemoglobinemia type 2 the disease is much more complicated and its prognosis is much more serious, the death of the minor being common during the early years.

Bibliographic references:

• Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 41. Available in: https://medlineplus.gov/spanish/ency/article/000562.htm
• Goldfrank, R. L, (2006). Goldfrank's Toxicologic Emergencies. 8th. Edition. New York. USES.
• Roman, L. (2011). An 18-year-old woman with methemoglobinemia after using topical anesthetic cream. Journal of the Clinical Laboratory, 4 (1).:45-49.