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- Diagnosis of methemoglobinemia clinical and is confirmed by an arterial blood gas with co-oximetry
- Diagnostic clues are the presence of refractory hypoxemia, saturation gap, and chocolate-colored blood,
- Treatment with methylene blue should not be delayed for co-oximetry results.
What are the treatment options for methemoglobinemia?
- Acetanilid
- Alloxan
- Aniline
- Arsine
- Benzene derivatives
- Benzocaine
- Bivalent copper
- Bismuth subnitrate
- Bupivacaine hydrochloride
- Chlorates
What medications cause methemoglobinemia?
The prognosis of acquired methemoglobinemia usually is also good and patients improve once the offensive food, drug, chemical is identified and stopped. Potential Complications of methemoglobinemia include: seizures, shock and death.
What is the prognosis of acquired methemoglobinemia?
What Is Methemoglobinemia?
- Congenital methemoglobinemia. Methemoglobinemia can be congenital, which means you’re born with the condition. ...
- Acquired methemoglobinemia. This is also known as acute methemoglobinemia. ...
- Diagnosing methemoglobinemia
- Methemoglobinemia treatment. ...
- Complications of methemoglobinemia. ...
- Outlook for methemoglobinemia. ...
- Preventing methemoglobinemia. ...
What causes elevated methemoglobin?

When do you give methylene blue 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.
How do you treat high methemoglobin?
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.
What happens if methemoglobinemia is left untreated?
This abnormal state of hemoglobin alters its ability to bind and release oxygen. These effects lead to tissue hypoxia and functional anemia. Untreated, severe methemoglobinemia can lead to death.
Does methemoglobinemia resolve on its own?
The condition is benign. There is no effective treatment for people with a congenital form who develop an acquired form. This means that they should not take drugs such as benzocaine and lidocaine. People who acquire methemoglobinemia from medications can completely recover with proper treatment.
How is congenital methemoglobinemia treated?
Increased MetHb concentration above 10% should be the indication for treatment of methemoglobinemia in neonates. Mainstay of therapy is IV administration of methylene blue (0.5-2mg/kg over 5 min) with or without placement in hyperbaric oxygen chamber.
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 quickly does methemoglobinemia occur?
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.
What is normal methemoglobin level?
The physiologic level of methemoglobin in the blood is 0% to 2%. Methemoglobin concentrations of 10% to 20% are tolerated well, but levels above this are often associated with symptoms. Levels above 70% may cause death. Symptoms also depend on the rapidity of its formation.
What is Type 2 methemoglobinemia?
Type II recessive hereditary methaemoglobinaemia (RHM) is a rare disease due to generalized NADH-cytochrome b5 reductase (cytb5r) deficiency. It results in mild cyanosis and severe neurological impairment. The clinical features and long-term outcome are poorly documented, and there are no systematic reviews.
What medication converts methemoglobin back to hemoglobin?
Amyl nitrite is administered to treat cyanide poisoning. It works by converting hemoglobin to methemoglobin, which allows for the binding of cyanide (CN–) anions by ferric (Fe3+) cations and the formation of cyanomethemoglobin.
How do you diagnose methemoglobinemia?
The diagnosis is confirmed by direct measurement of methemoglobin by a multiple wavelength co-oximeter. On a blood gas, normal PaO2 concentrations are usually found on analysis. Clinical cyanosis in the presence of normal arterial oxygen tensions is highly suggestive of methemoglobinemia.
What are the signs of methemoglobinemia?
Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and blue-colored skin (cyanosis). Complications may include seizures and heart arrhythmias. Methemoglobinemia can be due to certain medications, chemicals, or food or it can be inherited from a person's parents.