Methemoglobinemia: What it is and What Causes it

Methemoglobinemia, boy that’s a mouthful isn’t it? But what is methemoglobinemia and what causes it? Methemoglobinemia is blood disorder in which an inordinate amount of methemoglobin, a form of hemoglobin, is produced in the bloodstream. Hemoglobin is the protein in red blood cells that carries and distributes oxygen to the rest of the body.

With methemoglobinemia, the hemoglobin can carry oxygen but is unable to release it effectively to body tissues.

Causes of Methemoglobinemia

A blood disorder? Why would you be writing about a blood disorder on a dental blog? Benzocaine. Benzocaine is a common anesthetic used to relieve pain during a dental procedure. In rare cases, a patient who has been administered benzocaine will develop methemoglobinemia. Because of this, it is not recommended that children under the age of 2 are given Benzocaine. The most popular form methemoglobinemia is Orajel, a numbing cream that can be found in virtually every dental office and pharmacy.

There are two types of this form of methemoglobinemia; Type 1 or erythrocyte reductase deficiency which occurs when red blood cells lack the enzyme to release oxygen throughout the body. There is also, Type 2 or generalized reductase deficiency which occurs when the enzyme doesn’t work anywhere in the body.

Methemoglobinemia Symptoms

Symptoms of methemoglobinemia occur within minutes or hours after the administration of benzocaine. If you notice any of the following symptoms in yourself or your child you must seek medical attention immediately.

  • pale, gray, or blue-colored skin, lips and nail beds
  • shortness of breath
  • fatigue
  • confusion
  • headache
  • light-headedness
  • rapid heart rate

orajel mouth treatmentIf it goes untreated, methemoglobinemia can cause serious brain damage and even death. Luckily there is a treatment for methemoglobinemia. A drug called methylene blue is used to lower the level of methemoglobin but also presents risks for individuals suffering from a blood disorder called G6PD deficiency. In this case ascorbic acid or hyperbaric oxygen therapy will be used to lower methemoglobin levels.

Methemoglobinemia Prevention

Methemoglobinemia is an incredibly rare condition and should not be of great concern to your family. However, if you have a family history of methemoglobinemia it is recommended you get a genetic profile to diagnose your susceptibility.

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