The way you treat methemoglobinemia is by removing the cause of methemoglobinemia and providing supportive care through oxygen and using antidotes like methylene blue for severe cases.
Or if methylene blue is contraindicated then vitamin C or ascorbic aid can be used to treat methemoglobinemia.
Mild cases of methemoglobinemia may only require avoiding the trigger and severe cases of methemoglobinemia, might need blood transfusions, with hyperbaric oxygen as another option.
Methemoglobin is an oxidized form of hemoglobin which cannot carry oxygen, unlike normal hemoglobin, which can cause bluish skin also known as cyanosis and tissue oxygen deprivation if levels rise too high, which is then a condition called methemoglobin, which is caused and triggered by genetic issues, chemicals and certain drugs.
The things that are most likely to cause methemoglobinemia are exposure to oxidizing agents, especially certain medications (like benzocaine & dapsone), nitrates/nitrites (found in cured meats, contaminated water), and some recreational drugs.
Infants are very vulnerable to methemoglobinemia from nitrite poisoning from well water and these substances turn hemoglobin's iron from ferrous (Fe2+) to ferric (Fe3+) state, rendering it unable to carry oxygen, leading to cyanosis (bluish skin).
The drugs that can cause methemoglobinemia are nitrates/nitrites, dapsone, sulfonamides, local anesthetics like benzocaine & prilocaine, antimalarials (e.g., primaquine), and certain oxidizing agents.
These drugs convert hemoglobin to MetHb, and reduce delivery of oxygen, and dapsone is a leading cause of methemoglobinemia in both adults and kids, which is followed by topical anesthetics and nitric oxide.
Common drug classes and examples of drugs that can cause methemoglobinemia include.
Recreational drugs like cocaine or Amyl nitrite.
Analgesics like phenazopyridine (urinary analgesic), phenacetin.
Antimalarials like Primaquine, chloroquine.
Nitrates & Nitrites like Nitroglycerin, sodium nitrite, amyl nitrite, nitroprusside.
Local/Topical Anesthetics like Benzocaine (in oral gels, etc.), prilocaine (often in EMLA cream).
And antibiotics like sulfonamides or Dapsone.
Those most at risk for methemoglobinemia are infants under 3 months of age, the elderly or people with genetic conditions like G-6--D deficiency, kidney failure, anemia and HIV infections increase susceptibility to methemoglobinemia.
Methemoglobinemia can happen as fast as a few minutes or methemoglobinemia can happen slowly over hours, depending on the agent and cause of the methemoglobinemia.
Some topical anesthetics cause issues and methemoglobinemia within 20 to 60 minutes, and others like nitrite exposure or dapsone can take overs for the symptoms of methemoglobinemia to appear, even up to 10 hours or longer for transformation.
The first signs of methemoglobinemia are bluish skin also known as cyanosis, especially around the lips and nails, and the bluish skin with methemoglobinemia is often also accompanied with other symptoms like shortness of breath, fatigue, dizziness and headache.
The key indicator of methemoglobinemia is also hypoxia, which is low blood oxygen, that does not improve with oxygen.
Sometimes a person with methemoglobinemia may also have noticeably chocolate brown colored blood.
The symptoms of methemoglobinemia will also depend on the severity of the , but methemoglobinemia often starts with mild signs like paleness (10-20% MetHb)and progress to confusion, rapid heart rate and weakness (20-45% MetHb as levels rise.
The early signs of methemoglobinemia, which occur at MetHb of 10-20% are bluish tint to skin, lips and nail beds and is sometimes described as slate gray.
Pale skin or pallor and sometimes no symptoms in early methemoglobinemia in healthy people, but people with underlying issues may feel weakness or fatigue.
Moderate signs of methemoglobinemia at MetHb 2-45% are shortness of breath or dyspnea, headache and dizziness, fatigue and weakness, increased heart rate also known as tachycardia and Rapid breathing also known as tachypnea and nausea and vomiting.
The key diagnostic clues of methemoglobinemia are refractory cyanosis, with bluish skin color that does not go away with supplemental oxygen, chocolate brown colored blood.
And a pulse oximeter that shows low oxygen or SpO2 Gap, but arterial blood gas is (SaO2) is also low and inconsistent.
You should seek emergency care if you have symptoms like seizures, confusion, severe drowsiness, loss of consciousness or extreme difficulty breathing, as severe cases of methemoglobinemia with MetH>50% can be life threatening.
Methemoglobinemia is a blood disorder where too much methemoglobin forms, reducing the blood's ability to carry oxygen to the body, leading to symptoms like bluish skin (cyanosis), headache, dizziness, and shortness of breath, often triggered by certain drugs (like benzocaine, dapsone) or toxins (nitrates in water) and sometimes inherited, with treatment typically involving methylene blue and oxygen.