Cyanosis and
dyspnea are common complaints in adults and have broad differential diagnoses, of which rare ones such as
congenital methemoglobinemia should always be considered in the differential diagnosis.
Methemoglobinemia might be acquired or congenital. Patients' symptoms vary from severe
shortness of breath, mental status changes, and
cyanosis to none. The diagnosis of
congenital methemoglobinemia is challenging and requires high index of
suspension, especially in older patients. In addition, when diagnosed the treatment of
congenital methemoglobinemia is oral
ascorbic acid which is readily available. We present a rare case of a 33-year-old lady, who had a long history of recurrent episodes of
cyanosis,
headache, and
fatigue. After excluding cardiopulmonary causes,
methemoglobin levels were measured and found to be high, and the chart review revealed high levels of
methemoglobin in all her previous episodes, without exposure to any offending agent. This raised the concern of a late diagnosis of
congenital methemoglobinemia. The patient was treated with a high dose of
ascorbic acid resulting in resolution of the symptoms.
Congenital methemoglobinemia is a rare diagnosis that needs a high index of suspicion, especially in adults. A thorough history, physical examination, and multiple laboratory tests are needed to confirm the diagnosis and rule out other causes.