We asked, and you answered! Here is a response to this month’s “You Make the Call” question on treatment options for a patient with recessive hereditary methemoglobinemia and Hb M-Iwate mutation.
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I believe hemoglobin (Hb) M disease is autosomal dominant — in this case, it is autosomal recessive.
This patient does not need any specific treatment unless he is symptomatic due to other factors that contribute to increasing methemoglobin (metHb) level like drugs, toxins, food, well water, etc. Arterial blood gas will be a better option to evaluate preoperatively.
This patient and his provider should be cautious about the benzocaine family of anesthetics. He should be provided with a medical alert system and a list of drugs and food to avoid, as well as how to properly treat infections.
Methylene blue and ascorbic acid are not advisable in Hb M disease; rather, they are contraindicated as the reducing enzyme is intact. If the patient is severely symptomatic with a metHb level greater than 40%, he can be given therapeutic whole blood exchange or hyperbaric oxygen.
If there is erythrocytosis, then phlebotomy is contraindicated.
Abdulrahman Saifudeen, MBBS, MD, MRCP
Kerala, India
