Pop goes the O₂: a case of popper-induced methaemoglobinamia

Abstract

A 39-year-old man presented to the emergency department after falling downstairs after he consumed a large quantity of alcohol. On examination, he had altered mental state (GCS 14), central cyanosis and low oxygen saturation of 86%, despite 100% oxygen being administered. His arterial blood gas confirmed diagnosis of methaemoglobinaemia with a methaemoglobin percentage of 14.08. He was treated successfully with methylthioninium chloride. The patient later admitted to use of recreational poppers (amyl nitrates) the previous evening. The emergency physician is challenged by the presentation of a patient with altered mental state and unexplained low oxygen saturation with concurrent alcohol intoxication but must have a high index of suspicion for methaemoglobinaemia particularly with a history of recreational drug ingestion.

Multimodal imaging of a patient with poppers maculopathy

“…Methaemoglobinaemia may develop secondary to the use of ‘poppers’ presenting as altered mental state and unexplained low oxygen saturation [ 9 ]. Patients who are unresponsive to standard methylene blue treatment may respond to hyperbaric oxygen therapy [ 10 ].…”

A severe case of methaemoglobinaemia in a Brazilian hairdresser

“…Diagnosis of methaemoglobinaemia is made by arterial blood gas analysis, which typically reveals normal PaO 2 and PaCO 2 , a normal ‘calculated’ haemoglobin oxygen saturation (despite a low measured oxygen saturation), an increased methaemoglobin concentration, and in severe cases such as the one we have described, a metabolic acidosis 9. The oxygen saturation gap between the oxygen saturation recorded using a pulse oximeter (SpO 2 ) and the calculated haemoglobin oxygen saturation on the arterial blood gas (PaO 2 ) is a classic feature in relevant cases.…”

“…The oxygen saturation gap between the oxygen saturation recorded using a pulse oximeter (SpO 2 ) and the calculated haemoglobin oxygen saturation on the arterial blood gas (PaO 2 ) is a classic feature in relevant cases. This is because conventional two-wavelength pulse oximeters used in clinical practice are not reliable at indicating the level of methaemoglobin concentration, whereas arterial blood gas analysis measures the actual dissolved oxygen concentrations and thus is not affected by the presence of dyshaemoglobins 9. Newer eight-wavelength pulse oximeters can accurately detect the percentage levels of methaemoglobin, but these are not widely used in clinical practice 10 11.…”

Metahemoglobinemia secundaria a inhalación de “poppers”: caso clínico y revisión de la literatura

“…Por otro lado, el consumo de nitritos volátiles se asocia a síntomas como palpitaciones, mareos, náuseas y síncope (Hunter et al, 2011), y se ha descrito retinopatía/ maculopatía secundaria a su consumo (Luis et al, 2016). A nivel internacional se han publicado cerca de 30 casos de metahemoglobinemia secundaria al abuso de esta sustancia, la mayoría de los cuales con resultados favorables y sin consecuencias relevantes; pero también han sido resportado algunos casos fatales (Malhotra & Hughes, 1996;Pajarón et al, 2003;Wilkerson, 2010;Hunter et al, 2011;Al-Lawati & Murch, 2012;McCabe et al, 2012;Bernasconi et al, 2014).…”