In the type I form, the soluble form of the enzyme is deficient only in erythrocytes, and cyanosis is the only symptom. Type II hereditary methemoglobinemia is due to deficiency of the membrane-bound form of the enzyme, which is located in the outer mitochondrial membrane and the endoplasmic reticulum of somatic cells.

What part of the body does methemoglobinemia affect?

Autosomal recessive congenital methemoglobinemia is an inherited condition that mainly affects the function of red blood cells. Specifically, it alters a molecule within these cells called hemoglobin. Hemoglobin carries oxygen to cells and tissues throughout the body.

Which of the following is most likely to cause methemoglobinemia?

The most common cause of congenital methemoglobinemia is cytochrome b5 reductase deficiency (type Ib5R). This enzymatic deficiency is endemic in certain Native American tribes (Navajo and Athabaskan Alaskans). Most cases of methemoglobinemia are acquired and result from exposure to certain drugs or toxins.

What are the three possible causes of methemoglobinemia?

People have developed methemoglobinemia after having medical procedures that used certain topical anesthetics that are often sprayed on to the skin. These include benzocaine, lidocaine, and prilocaine.

Which local anesthetic causes methemoglobinemia?

Methemoglobinemia is a potentially severe complication of lidocaine and benzocaine, especially when used concomitantly.

Methemoglobinemia

40 related questions found

What drugs can cause methemoglobinemia?

Drugs that may cause Methemoglobinemia include nitrates derivatives (nitrates salt, nitroglycerin), nitrites derivatives (nitroprusside, amyl nitrite, nitric oxide), sulfonamides, dapsone, phenacetin, phenazopyridine, some local anesthetics such as prilocaine, topical anesthetics such as emla cream, benzocaine, ...

How common is methemoglobinemia?

Conclusions and relevance: The overall prevalence of methemoglobinemia is low at 0.035%; however, an increased risk was seen in hospitalized patients and with benzocaine-based anesthetics.

How was methemoglobinemia discovered?

Congenital cyanosis due to an abnormal amount of methemoglobin was initially reported early in this century. It was first suggested by Hitzenberger³ in 1932 that this was an inherited metabolic disease. Gibson ⁴ in 1948 identified idiopathic methemoglobinemia as a disease due to an inborn error of metabolism.

How does vitamin C treat methemoglobinemia?

Vitamin C is recommended for treatment of methemoglobinemia. It has been demonstrated that the reduction of the methemoglobin formation occurs at low vitamin C concentration in mice erythrocytes.

How many cases of methemoglobinemia are there?

Of the 319 cases, 7 were deaths, 32 cases were categorized as life threatening, and 216 were categorized as serious. A review of the 319 cases indicated that the development of methemoglobin emia after treatment with benzocaine sprays may not be related to the amount applied.

How does nitroglycerin cause methemoglobinemia?

Although enzymatic deficiencies and abnormal hemo- globins may result in methemoglobinemia, most cases result from drug or chemical exposure [7-141. Nitrates are metabolized in the liver by glutathione reductase to nitrites, which accelerate oxidation of oxyHb to metHb.

What is methemoglobinemia and how is it treated?

Methylene blue is used to treat severe cases of MetHb, and doctors may prescribe ascorbic acid to reduce the level of methemoglobin in the blood. In severe cases, a person may require a blood transfusion or exchange transfusion. Oxygen therapy will also be provided, if required.

Can blood turn into water?

Blood volume makes up approximately 8% of your body weight. About 55% of blood is comprised of plasma, of which 90% is water. So, although you donate less than a pint of blood at a time, almost half of this is water.

What was the cure for methemoglobinemia?

Methylene blue is the primary emergency treatment for documented symptomatic methemoglobinemia. It is given in a dose of 1-2 mg/kg (up to a total of 50 mg in adults, adolescents, and older children) as a 1% solution in IV saline over 3-5 minutes.

What disease is sometimes called the blue baby?

Infant methemoglobinemia is also called “blue baby syndrome.” It is a condition where a baby's skin turns blue. This happens when there is not enough oxygen in the blood. Methemoglobinemia is a condition that some babies are born with (congenital) or some develop early in life (acquired).

What medication converts methemoglobin back to hemoglobin?

The NADH-dependent enzyme methemoglobin reductase (a type of diaphorase) is responsible for converting methemoglobin back to hemoglobin.

How is methemoglobinemia treated in g6pd?

Treatment for methemoglobinemia with intravenous methylene blue is recommended if the blood methemoglobin level is >20%–30%. However, in G6DP deficiency, treatment with methylene blue is contraindicated because the reduction of methemoglobin is NADPH dependent.

How does methylene blue treat methemoglobinemia?

Methylene blue is an effective antidote for methemoglobinemia due to its own oxidizing properties. It oxidizes NADPH, forming the reduced product leukometh- ylene blue. Leukomethylene blue in turn acts as a reducing agent converting me- themoglobin to hemoglobin and thus restoring oxygen carrying capacity.

What causes methemoglobinemia in infants?

Methemoglobinemia among infants is a rare and potentially fatal condition caused by genetic enzyme deficiencies, metabolic acidosis, and exposure to certain drugs and chemicals. The most widely recognized environmental cause of this problem is ingestion of nitrate-containing water.

Does inbreeding cause blue skin?

After extensive inbreeding in the isolated community—their son married his aunt, for example—a large pedigree of “blue people” of both sexes arose. In “blue person disease,” excess oxygen-poor hemoglobin causes a dark blue complexion. Carriers may have bluish lips and fingernails at birth, which usually lighten.

Is Sulfhemoglobinemia real?

Sulfhemoglobinemia is a rare condition in which there is excess sulfhemoglobin (SulfHb) in the blood. The pigment is a greenish derivative of hemoglobin which cannot be converted back to normal, functional hemoglobin. It causes cyanosis even at low blood levels.

How long does it take to develop methemoglobinemia?

The onset of methemoglobinemia is usually within 20 to 60 minutes of drug administration. Normally, 5 g/dL of deoxyhemoglobin (compared with 1.5 g/dL [10%–15%] of methemoglobin) produces noticeable cyanosis.

Does oral gel cause methemoglobinemia?

FDA further advises that benzocaine oral drug products should only be used in adults and children 2 years and older if they contain certain warnings on the drug label because the local anesthetic benzocaine can cause the life-threatening condition, methemoglobinemia.

Is it OK if you swallow Orajel?

Avoid getting this medication in your eyes. Avoid swallowing the gel, liquid, or ointment while applying it to your gums or the inside of your mouth. The throat spray or oral lozenge may be swallowed gradually during use.