What is the treatment for methemoglobinemia?
What is the treatment 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 causes increased methemoglobin?
Methemoglobinemia occurs when red blood cells (RBCs) contain methemoglobin at levels higher than 1%. This may be from congenital causes, increased synthesis, or decreased clearance. Increased levels may also result from exposure to toxins that acutely affect redox reactions, increasing methemoglobin levels.
What enzyme are people with methemoglobinemia missing?
The genetic form of methemoglobinemia is caused by one of several genetic defects, according to Tefferi. The Fugates probably had a deficiency in the enzyme called cytochrome-b5 methemoglobin reductase, which is responsible for recessive congenital methemoglobinemia.
How is methemoglobinemia detected?
To diagnose methemoglobinemia, your doctor may order tests like:
- complete blood count (CBC)
- tests to check enzymes.
- examination of blood color.
- blood levels of nitrites or other drugs.
- pulse oximetry to check the saturation of oxygen in your blood.
- DNA sequencing.
How can methemoglobinemia be prevented?
Recognition and avoidance of precipitating factors are important for prevention of methemoglobinemia, especially in susceptible populations. Monitoring of well water levels may be needed.
How long does methemoglobinemia take to develop?
The onset of methemoglobinemia is usually within 20 to 60 minutes of drug administration.
What chemicals can cause methemoglobinemia?
Methemoglobinemia is commonly caused by exposure to medical substances, such as benzocaine and dapsone, that oxidize hemoglobin to MetHb; exhaust fumes from internal combustion engines; herbicides and pesticides; and chemicals, such as nitrobenzene and aniline [5-11].
Is methemoglobinemia a genetic disorder?
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.
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.
What are the effects of methemoglobinemia?
Methemoglobinemia is a condition of elevated methemoglobin in the blood. Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and blue-colored skin (cyanosis). Complications may include seizures and heart arrhythmias.
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.
Is methemoglobinemia reversible?
Sulfhemoglobinemia should be considered in cases presenting with oxygen desaturation and cyanosis, especially if methemoglobinemia can be excluded. Unlike methemoglobinemia, which is reversible with a known antidote, methylene blue, sulfhemoglobinemia is irreversible with no known antidote.
Who is at risk for methemoglobinemia?
Acquired methemoglobinemia is more frequent in premature infants and infants younger than 4 months, and the following factors may have a role in the higher incidence in this age group: Fetal hemoglobin may oxidize more easily than adult hemoglobin.
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.
Can dapsone cause low oxygen levels?
Acquired methemoglobinemia from dapsone therapy results in an inability of hemoglobin to bind oxygen causing reduced oxygen delivery [3]. Prolonged reduction in oxygen delivery results in diffuse tissue hypoxia and cell death.
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.
How quickly does methylene blue work?
Reports suggest that methylene blue up to six doses a day have resulted in improvement of symptoms within 10 minutes to several days.
What is methylene blue used for?
METHYLENE BLUE (METH uh leen bloo) is used to treat methemoglobinemia. This is a condition in which the blood loses its ability to carry oxygen through the body.
What route is the administration of methylene blue for individuals with inherited methemoglobinemia?
Methemoglobinemia is treated with supplemental oxygen and methylene blue (1–2 mg/kg) administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase.
What are the 5 hemoglobin M variants?
Five variants have so far been known as Hb M (Figure 1). Four of them, namely, Hb M Iwate [α87(F8)His → Tyr], Hb M Boston [α58(E7)His → Tyr], Hb M Hyde Park [β92(F8)His → Tyr], and Hb M Saskatoon [β63(E7)His → Tyr], have either the proximal (F8) or the distal (E7) histidine replaced by tyrosine (1−3).
Is methylene blue toxic?
Methylene blue is a safe drug when used in therapeutic doses (<2mg/kg). But it can cause toxicity in high doses.
How common is methemoglobinemia from Orajel?
We estimate that more than 400 cases of benzocaine-associated methemoglobinemia have been reported to FDA* or published in the medical literature since 1971.
Can too much benzocaine turn your skin blue?
Doctors said the condition was a rare, sometimes life-threatening reaction to benzocaine, a medication commonly used as a topical anesthetic. The woman’s blue skin was caused by methemoglobinemia, a condition in which blood stops releasing oxygen into the surrounding tissue.
How long do the effects of benzocaine last?
Lidocaine and benzocaine products can take as little as five minutes to take effect, and the numbing effects wear off after about 90 minutes.