Methemoglobinemia (blue people): symptoms, causes and treatment

This rare disease causes the skin to take on a bluish hue.

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

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

Another of the disorders in which an abnormal skin staining appears is methemoglobinemia, a blood-borne disorder in which the skin becomes in which the skin turns bluish in color and depending on its typology can have fatal consequences.

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 capacity to carry oxygenIt interferes with the hemoglobin that is able to do so in such a way that the latter cannot release it into the various organs and tissues normally. This causes a reduction in the oxygenation of the organism.

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

However, skin coloration is not the only problem that can arise: if the excess of methemoglobin is too great, the lack of oxygen in the rest of the body can lead to organ problems and even death. It is not uncommon for respiratory problems to appear as well, and this is usually one of the main causes of hospitalization.

In addition to the above, depending on the type of methemoglobinemia headaches, fatigue, convulsions and life-threatening respiratory problems (in the with the potential for death (in the case of acquired causes) or the appearance of intellectual disability and maturational delays in the case of congenital methemoglobinemia type 2, which we will discuss later.

Typologies according to their causes

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

Acquired methemoglobinemia is the most common and is usually the result of as a result of the consumption of or exposure to oxidizing drugs or chemicals or chemical substances such as bismuth nitrate, as well as elements used for the treatment of some ailments such as nitroglycerin or some antibiotics.

As far as congenital methemoglobinemia is concerned, it is generally due to genetic transmission or the occurrence of certain mutations. There are two basic types.

The first is generated by genetic inheritance from both parents, with both parents being carriers (although most of them have not expressed the disorder) of a mutation of certain genes that cause a problem in the enzyme cytochrome b5 reductase.. This enzyme does not act correctly in the body, which generates an oxidation of hemoglobin.

Within this type of congenital methemoglobinemia we can find two main types: congenital methemoglobinemia type 1 is that the aforementioned enzyme does not appear in the red blood cells of the body and type 1 in which the enzyme does not appear anywhere in the body.

The other option within the congenital methemoglobinemias is the so-called hemoglobin M disease, in which this alteration appears because the hemoglobin is structurally altered at the base. In these cases we are dealing with an autosomal dominant disorder in which it is sufficient for one of the parents to carry the gene and transmit it to generate the alteration. and transmits it to generate the alteration (something similar to what happens with Huntington's chorea).

Treatment of this condition

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

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

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

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

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

However, in the case of congenital methemoglobinemia type 2, the disease is much more complicated and the prognosis is much more serious, with the death of the child being common during the first 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 at: https://medlineplus.gov/spanish/ency/article/000562.htm
• Goldfrank, R. L, (2006).Goldfrank's Toxicologic Emergencies. 8th. Edition. New York. USA.
• Roman, L. (2011). An 18-year-old woman with methemoglobinemia after use of topical anesthetic cream. Clinical Laboratory Journal, 4 (1):45-49.