Methemoglobinemia - Revision history

Danbot: Add MedicationDose entry (methylene blue) with SMW annotations

2026-03-20T18:38:29Z

Add MedicationDose entry (methylene blue) with SMW annotations

@@ Line 79: / Line 79: @@
 **Hyperbaric O2 when methylene blue ineffective or contraindicated
 **IV hydration and [[bicarbonate]] for metabolic acidosis
 ==Disposition==

DMartinPAC: /* Causes */

2025-11-03T16:05:10Z

Causes

← Older revision		Revision as of 16:05, 3 November 2025
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	**Aniline dyes		**Aniline dyes
	**Phenazopyridine<ref>Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.</ref>		**Phenazopyridine<ref>Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.</ref>
			**[[Sodium nitrite toxicity]]

	==Clinical Features==		==Clinical Features==

Rossdonaldson1: /* Clinical Features */

2023-03-15T18:46:06Z

Clinical Features

← Older revision		Revision as of 18:46, 15 March 2023
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	[[File:Eplasty16ic18 fig1.jpg\|thumb\|Cyanosis from methemoglobinemia.]]		[[File:Eplasty16ic18 fig1.jpg\|thumb\|Cyanosis from methemoglobinemia.]]
	[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]		[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]
			[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia.]]
	[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]		[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]
	~~[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia (due to sodium nitrite poisoning).]]~~
	{\| {{table}}		{\| {{table}}
	\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''		\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''

Rossdonaldson1: /* Clinical Features */

2023-03-15T18:44:06Z

Clinical Features

← Older revision		Revision as of 18:44, 15 March 2023
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	[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]		[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]
	[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]		[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]
			[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia (due to sodium nitrite poisoning).]]
	{\| {{table}}		{\| {{table}}
	\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''		\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''

Elcatracho: /* See Also */

2021-03-06T04:05:05Z

ClaireLewis at 19:36, 24 February 2021

2021-02-24T19:36:35Z

← Older revision		Revision as of 19:36, 24 February 2021
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	[[File:ChocolateBrownBlood (cropped).jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]		[[File:ChocolateBrownBlood (cropped).jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]
	[[File:MethemoglobinDiag.jpg\|thumb\|Color chart for the detection of the amount of methemoglobin in the blood.]]		[[File:MethemoglobinDiag.jpg\|thumb\|Color chart for the detection of the amount of methemoglobin in the blood.]]
			*Diagnosis requires high index of suspicion; lack of improvement in oxygen saturation with high-flow oxygen plus discrepancy in oxygen saturation >5% between measurements by ABG vs pulse oximetry ("saturation gap") should raise suspicion. Diagnosis is then confirmed by measuring level of methemoglobin in blood
	*Co-oximetry		*Co-oximetry
	**Measures relative levels of oxyhemoglobin, carboxyhemoglobin, methemoglobin, reduced hemoglobin		**Measures relative levels of oxyhemoglobin, carboxyhemoglobin, methemoglobin, reduced hemoglobin
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	**Mid-80s SpO2 due to light absorption of both oxyHb and deoxyHb		**Mid-80s SpO2 due to light absorption of both oxyHb and deoxyHb
	*"Chocolate brown" color of blood		*"Chocolate brown" color of blood

	Diagnosing methemoglobinemia requires a high index of suspicion. The lack of improvement in oxygen saturation with high-flow oxygen, and a gap in oxygen saturation >5% between ABG and pulse oximetry (saturation gap) should raise your suspicion. The diagnosis is confirmed by measuring the level of methemoglobin in blood.

	==Management==		==Management==

Elcatracho: /* See Also */

2021-02-24T02:15:06Z

Cmolson: /* Management */

2021-02-23T08:31:24Z

Management

← Older revision		Revision as of 08:31, 23 February 2021
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	*[[High-Flow Oxygen]]		*[[High-Flow Oxygen]]
	** All patients warrant supplemental oxygen. Symptoms ~~should~~ improve with a non-rebreather but the pulse oximeter reading will remain unchanged. This is a diagnostic clue.		** All patients warrant supplemental oxygen. Symptoms may improve with a non-rebreather but the pulse oximeter reading will remain unchanged and patients may remain cyanotic. This is a diagnostic clue.
	*[[Methylene blue]]		*[[Methylene blue]]
	**Treat if symptomatic '''OR''' asymptomatic with MetHb >25%		**Treat if symptomatic '''OR''' asymptomatic with MetHb >25%

Cmolson: /* Evaluation */

2021-02-23T06:47:30Z

Evaluation

← Older revision		Revision as of 06:47, 23 February 2021
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	**Mid-80s SpO2 due to light absorption of both oxyHb and deoxyHb		**Mid-80s SpO2 due to light absorption of both oxyHb and deoxyHb
	*"Chocolate brown" color of blood		*"Chocolate brown" color of blood

			Diagnosing methemoglobinemia requires a high index of suspicion. The lack of improvement in oxygen saturation with high-flow oxygen, and a gap in oxygen saturation >5% between ABG and pulse oximetry (saturation gap) should raise your suspicion. The diagnosis is confirmed by measuring the level of methemoglobin in blood.

	==Management==		==Management==

Cmolson: /* Management */

2021-02-23T06:44:24Z

Management

← Older revision		Revision as of 06:44, 23 February 2021
Line 62:		Line 62:

	==Management==		==Management==

			*[[High-Flow Oxygen]]
			** All patients warrant supplemental oxygen. Symptoms should improve with a non-rebreather but the pulse oximeter reading will remain unchanged. This is a diagnostic clue.
	*[[Methylene blue]]		*[[Methylene blue]]
	**Treat if symptomatic '''OR''' asymptomatic with MetHb >25%		**Treat if symptomatic '''OR''' asymptomatic with MetHb >25%

← Older revision		Revision as of 18:46, 15 March 2023
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	[[File:Eplasty16ic18 fig1.jpg\|thumb\|Cyanosis from methemoglobinemia.]]		[[File:Eplasty16ic18 fig1.jpg\|thumb\|Cyanosis from methemoglobinemia.]]
	[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]		[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]
			[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia.]]
	[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]		[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]
	~~[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia (due to sodium nitrite poisoning).]]~~
	{\| {{table}}		{\| {{table}}
	\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''		\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''

← Older revision		Revision as of 18:44, 15 March 2023
Line 20:		Line 20:
	[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]		[[File:Eplasty16ic18 fig3.jpg\|thumb\|Cyanosis resolved after methylene blue.]]
	[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]		[[File:ChocolateBrownBlood (cropped)2.jpg\|thumb\|Chocolate-brown blood due to methemoglobinemia.]]
			[[File:PMC4987464 CRIEM2016-9013816.001.png\|thumb\|Severe methemoglobinemia (due to sodium nitrite poisoning).]]
	{\| {{table}}		{\| {{table}}
	\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''		\| align="center" style="background:#f0f0f0;"\|'''MetHb level (%)'''

← Older revision		Revision as of 04:05, 6 March 2021
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	==See Also==		==See Also==
			*[[Toxicology (Main)]]
	*[[Toxidromes]]		*[[Toxidromes]]
	*[[Dyshemoglobinemia]]		*[[Dyshemoglobinemia]]

← Older revision		Revision as of 02:15, 24 February 2021
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	*[[Toxidromes]]		*[[Toxidromes]]
	*[[Dyshemoglobinemia]]		*[[Dyshemoglobinemia]]
			*[[Carbon monoxide]]
			*[[Cyanide toxicity]]

	==External Links==		==External Links==