Methemoglobinnivåer

Methemoglobinnivåer refer to the concentration of methemoglobin in the blood. Methemoglobin is a form of hemoglobin where the iron atom is in the ferric (Fe3+) state, rather than the usual ferrous (Fe2+) state. This ferric state prevents methemoglobin from binding and transporting oxygen effectively.

Normal blood typically contains a very small amount of methemoglobin, usually less than 1% of the total hemoglobin. Levels above this normal range are considered abnormal and can indicate a condition known as methemoglobinemia. Methemoglobinemia can be congenital, inherited through genetic mutations affecting the enzymes that reduce methemoglobin back to hemoglobin, or acquired, due to exposure to certain drugs, chemicals, or toxins.

Symptoms of methemoglobinemia are related to the reduced oxygen-carrying capacity of the blood. Mild cases might present with cyanosis, a bluish discoloration of the skin and mucous membranes, particularly noticeable in the lips and nail beds, even with adequate oxygen saturation on pulse oximetry. Higher levels can lead to more severe symptoms such as headache, dizziness, fatigue, shortness of breath, and in critical cases, cardiac arrhythmias, seizures, and coma.

Diagnosis is made by measuring methemoglobin levels in a blood sample. Treatment depends on the severity of the condition and the underlying cause. For mild acquired methemoglobinemia, supportive care and removal of the offending agent are often sufficient. For more severe cases, especially those with significant symptoms, the antidote methylene blue is administered intravenously. Methylene blue acts as an electron acceptor, facilitating the enzymatic reduction of methemoglobin back to functional hemoglobin.