Abstract Intro Methemoglobinemia is a rare but potentially life-threatening condition caused by elevated levels of methemoglobin, leading to impaired tissue oxygen delivery. Cases may be congenital or acquired (due to exposure to oxidizing agents). Common exposures in children include topical anesthetics, nitrates from contaminated water or food, and medications. Typical presentation is cyanosis unresponsive to oxygen, with infants often having other non-specific symptoms such as respiratory distress or lethargy. Case Description A 10-month-old female with developmental delays and suspected genetic disorder presented to the emergency department from daycare with cyanosis. Cyanosis was noted upon awakening from a nap. There were no preceding signs of illness other than an episode of emesis after eating banana puree and rice cereal approximately one hour prior. There were no known exposures to topical anesthetics or any nitrate-containing foods. Water at home and daycare was reportedly city tap water. On EMS arrival, she was cyanotic and unresponsive, but with good peripheral pulses. Clinical seizure was reported so midazolam was given enroute. In the ED, she was started on supplemental oxygen without improvement. She had marginal improvement in saturations with positive pressure ventilation, but was ultimately intubated for persistent hypoxia. Initial lab work revealed severe metabolic acidosis with a markedly elevated PaO2 and lactic acidosis. The blood was noted to be chocolate brown in color, raising suspicion for methemoglobinemia. She was admitted to the pediatric ICU for continued hypoxia without hypoxemia. She had a brief trial of nitric oxide without improvement before methylene blue was given due to suspicion for methemoglobinemia based on the appearance of her blood. A pre-treatment methemoglobin level was unable to be obtained due to lab instrument error. She received a total of three doses of methylene blue, with normalization of methemoglobin levels. Discussion This case highlights the diagnostic and therapeutic challenges of acquired methemoglobinemia and emphasizes the importance of prompt recognition given the potential for significant morbidity and mortality. Given the clinical recognition of the toxidrome despite the lack of typical exposure history (e.g. topical anesthetic, nitrates), the rationale to give methylene blue was both diagnostic and therapeutic. This abstract is funded by: None
Sandell et al. (Fri,) studied this question.