Methemoglobinemia-induced Cardio-respiratory Failure Secondary to Topical Anesthesia

Saha, Sandeep; Kordouni, Mohammad R; Siddiqui, Mumtaz A.; Arora, Rohit

doi:10.1097/01.mjt.0000208876.69103.c7

Cited by 13 publications

(12 citation statements)

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“…In RBCs, there are both major (95%) and minor (5%) pathways to reduce methemoglobin back to its oxygen-carrying state. Cytochrome-b 5 reductase (also known as NADH methemoglobin reductase) is the primary pathway involved in this reduction [1][2][3][4][5]. An additional enzyme, nicotinamide adenine dinucleotide phosphate (NADPH) methemoglobin reductase, is also capable of reducing methemoglobin; although its activity is quite limited during normal physiologic conditions, it becomes highly significant in the presence of methylene blue (see Fig.…”

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

“…In contrast, NADPH methemoglobin reductase utilizes NADPH formed by the hexose monophosphate shunt by the enzyme glucose-6-phosphate dehydrogenase (G6PD) to reduce methylene blue to leukomethylene blue, which in turn donates an electron to reduce methemoglobin [6]. As discussed below, a deficiency in G6PD has important implications for the treatment of methemoglobinemia [1,4].…”

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

“…Auto-oxidation from O 2 forms a baseline methemoglobin fraction of approximately 0.5% [4]. An abnormally elevated methemoglobin fraction is generally defined as greater than 1% [3,8,9].…”

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

“…It is important to realize that patients with baseline functional anemia (e.g., sickle cell anemia or carboxyhemoglobinemia) will become symptomatic at lower methemoglobin fractions [1]. In addition to decreased arterial blood oxygen content, as methemoglobin fractions increase greater than 10%, there is a left shift of the oxygen dissociation curve leading to an impaired unloading of oxygen at the tissue level [1,2,4,7,9]. hemoglobin concentrations would be expected to have a few symptoms due to the presence of adequate functional hemoglobin, while an anemic patient with a similar fraction may be quite symptomatic [8].…”

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

“…Both chronic and acute illness as well as underlying comorbidities may also predispose the development of methemoglobinemia. While certain xenobiotics are capable of directly oxidizing ferrous (Fe 2+ ) iron to its ferric (Fe 3+ ) state, some of these act indirectly and must first be metabolized [2,4]. Many cases of clinically significant methemoglobinemia involve the cumulative effect of various stressors, with or without a predisposing congenital condition.…”

Section: What Are the Causes Of Congenital Methemoglobinemia?mentioning

confidence: 99%

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Case Files of the Medical Toxicology Fellowship at Banner Good Samaritan Medical Center in Phoenix, AZ: Methemoglobinemia Following Dapsone Exposure

Canning

Levine

2011

J. Med. Toxicol.

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Acquired methemoglobinemia is a common, potentially fatal syndrome that can occur as a result of exposure to numerous xenobiotics. A case report of a 14-month-old female who developed methemoglobinemia following a dapsone ingestion. The child was treated with numerous boluses of methylene blue and ultimately required a continuous infusion of methylene blue. The common causes of methemoglobinemia, as well as the underlying pathophysiology, diagnosis, and treatment strategies are discussed.Keywords Methemoglobinemia . Methemoglobin . Dapsone . Cyanosis . Poisoning . Methylene blue Case PresentationA 14-month-old female infant presented to the emergency department (ED) with a chief complaint of cyanosis. The child had no significant past medical history and appeared normal throughout the prior day, except for some mild rhinorrhea and a single episode of non-bloody, non-bilious emesis the night prior to admission. An additional episode of emesis occurred the morning of admission. There were no other complaints, and the remainder of the review of systems was negative. The patient's mother noted cyanosis around the face and lips, prompting evaluation in the ED. The patient's room air oxygen saturation by pulse oximetry (SpO 2 ) was 87%, and a chest X-ray was negative. She was transferred to a pediatric tertiary care center for further evaluation of suspected congenital heart disease.On arrival to the referral center, the child was noted to be tachycardic, tachypneic, and cyanotic in mild respiratory distress. The pertinent abnormal vital signs were a heart rate of 212 beats per minute and a respiratory rate of 48 breaths per minute. The SpO 2 on 15 L of oxygen administered via a non-rebreather mask was 88%. The remainder of the physical examination was unremarkable. The venous blood gas (VBG) drawn on arrival revealed a pH of 7.42, a pCO 2 of 30 mmHg, a pO 2 of 43 mmHg, HCO 3 of 18.8 mmol/L, and methemoglobin, "high." The initial venous blood drawn for the laboratory testing was noted to have a brownish hue. The hemoglobin concentration was 13.0 g/dL, and the remainder of the baseline complete blood count and comprehensive metabolic profile were normal.Given the elevated methemoglobin fraction and clinical picture consistent with methemoglobinemia, the child received a 2-mg/kg IV bolus of methylene blue. The child's symptoms improved promptly and a repeat examination of the patient approximately 1 h later revealed an asymptomatic, playful child without cyanosis. A repeat VBG at this time revealed a methemoglobin fraction of 13.3%. The child was transferred to the PICU for further observation.

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Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%

“…Auto-oxidation from O 2 forms a baseline methemoglobin fraction of approximately 0.5% [4]. An abnormally elevated methemoglobin fraction is generally defined as greater than 1% [3,8,9].…”

Section: What Is the Pathophysiologic Basis For Methemoglobin Formation?mentioning

confidence: 99%