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Cureus 2022 Apr 15;14(4):e24152. Epub 2022 Apr 15.

Hematology, Guthrie Robert Packer Hospital, Sayre, USA.

Methemoglobin (MetHb) is a form of hemoglobin in which iron in Hb is in an oxidized form (ferric) instead of ferrous, making it difficult to bind with oxygen. Usually, MetHb is present in small quantities (<1%) in humans, but once MetHb increases beyond 3%, the condition is known as methemoglobinemia. It can be further classified into hereditary and acquired. Read More

Clin Toxicol (Phila) 2022 May 12:1-7. Epub 2022 May 12.

Wright State Boonshoft School of Medicine, Dayton, OH, USA.

Background: Historically, the first step in treating cyanide (CN) toxicity utilized antidotes to induce methemoglobinemia. This is concerning in patients who are already hypoxemic or have elevated carboxyhemoglobin. Hydroxocobalamin (OHCbl) is now the first-line antidote for CN toxicity and is not known to induce methemoglobinemia. Read More

Proc (Bayl Univ Med Cent) 2022 2;35(3):385-386. Epub 2022 Feb 2.

Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas.

Methemoglobinemia is a blood disorder in which red blood cells contain methemoglobin, a form of hemoglobin that contains iron in its oxidized state, at levels >1%, often leading to a hypoxic state. It can be acquired or congenital and has been associated with nitrate or nitrite exposure. "Poppers" and "Rush" are slang terms given to drugs of the chemical class called amyl nitrate or isobutyl nitrite, which are typically inhaled and can be found over the counter. Read More

Dermatol Ther 2022 May 4:e15551. Epub 2022 May 4.

Department of Dermatology, Base Hospital, Delhi Cantt, New Delhi.

Cureus 2022 Mar 25;14(3):e23496. Epub 2022 Mar 25.

Internal Medicine, Hospital Sultan Ismail, Johor, MYS.

Naphthalene-induced acute hemolysis with methemoglobinemia is a rare condition that commonly affects patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. It commonly presents with anemia, jaundice and features of methemoglobinemia such as cyanosis and falsely low pulse oximetry. We present a patient with naphthalene-induced methemoglobinemia and discuss the clinical features, pathophysiology and management of this oxidative hemolysis. Read More

J Paediatr Child Health 2022 Apr 27. Epub 2022 Apr 27.

Neonatal Unit, Homerton University Hospital, Homerton Healthcare NHS Foundation Trust, London, United Kingdom.

Pediatr Int 2022 01;64(1):e15134

Department of Critical Care and Anesthesia, National Center for Child Health and Development, Setagaya, Tokyo, Japan.

Molecules 2022 Apr 14;27(8). Epub 2022 Apr 14.

Chemistry Department, Faculty of Science, Sohag University, Sohag 82425, Egypt.

Drinking water containing nitrate ions at a higher concentration level of more than 10 mg/L, according to the World Health Organization (WHO), poses a considerable peril to humans. This danger lies in its reduction of nitrite ions. These ions cause methemoglobinemia during the oxidation of hemoglobin into methemoglobin. Read More

Cureus 2022 Mar 14;14(3):e23155. Epub 2022 Mar 14.

Intensive Care Unit, East Jeddah General Hospital, Jeddah, SAU.

Methemoglobinemia (MetHb) is a rare, life-threatening condition that occurs when the body is exposed to oxidative stress. It is typically corrected through the glucose-6-phosphate dehydrogenase (G6PD)-dependent shunt. G6PD deficiency is the most common enzymatic deficiency worldwide. Read More

J Assoc Physicians India 2022 Apr;70(4):11-12

RD Gardi Medical College, Ujjain.

Many novel drugs were used in COVID19 pandemic to improve outcome. One such molecule is Methylene blue which is a, tricyclic phenothiazine compound approved for the treatment of acquired methemoglobinemia and some other uses US FDA. This molecule was found to inhibit the interaction of COVID19 virus and target cells in dose dependent manner. Read More

J Assoc Physicians India 2022 Apr;70(4):11-12

B.R. Ambedkar Medical College and Hospital, Bangalore.

Peripheral capillary oxygen saturation (SpO2) measured by pulse oximeter is a simple and reliable objective measurement in routine medical practice that approximates the level of oxygen in arterial blood. Measurements with this inexpensive and non-invasive method also provide heart rate and an indication of tissue perfusion. Low perfusion (due to hypothermia, low cardiac output, profound anemia, etc. Read More

Clin Toxicol (Phila) 2022 Apr 19:1-4. Epub 2022 Apr 19.

Department of Poisoning and Occupational Diseases, Emergency Medicine, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, China.

Introduction: While 4-chloro-1-nitrobenzene has oxidising properties and can lead to methaemoglobinaemia and haemolysis, such reports are rare. We herein describe two cases of 4-chloro-1-nitrobenzene poisoning after skin exposure and detail relevant clinical characteristics and treatment outcomes.

Case Presentation: A 45-year-old man and his 32-year-old male co-worker presented at our department shortly after skin exposure to 4-chloro-1-nitrobenzene. Read More

Clin Toxicol (Phila) 2022 Apr 13:1-6. Epub 2022 Apr 13.

Department of Emergency, Acceptance and General Pediatrics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.

Introduction: Methemoglobinemia (MetHb) is a rare inherited or acquired cause of cyanosis in children. Owing to its rarity, case reports and case series are mostly available in the current literature. This study reports data on a large sample of children with acquired MetHb. Read More

J Food Sci 2022 Apr 22;87(4):1423-1448. Epub 2022 Mar 22.

Department of Clinical Pharmacology & Toxicology, Western Sydney Health, NSW, Sydney, Australia.

Cureus 2022 Feb 21;14(2):e22466. Epub 2022 Feb 21.

Family Medicine, California Hospital Medical Center, Los Angeles, USA.

Here, we present the case of a 64-year-old male with a rare cause of cyanosis due to dapsone-induced methemoglobinemia who was treated successfully with methylene blue and high-dose Vitamin C. Our case emphasizes the importance of history taking, knowledge, and high index of suspicion of drug-induced methemoglobinemia, especially in the presence of saturation gap. This condition can be fatal if left untreated. Read More

Acute Med 2022 ;21(1):50-52

MBChB MRCP (UK) BSc (Hons), Department of Respiratory Medicine, University Hospital Wishaw, 50 Netherton Street, Wishaw ML2 0DP.

Type 1 congenital methaemoglobinaemia is a rare cause of cyanosis which may manifest in affected individuals during concomitant illness. Treatment indications and aims differ from that of acquired methaemoglobinaemia. Type 1 methaemoglobinaemia is a distinct condition from the type 2 form which has a high mortality rate in infancy. Read More

J Am Coll Emerg Physicians Open 2022 Apr 17;3(2):e12702. Epub 2022 Mar 17.

Department of Emergency Medicine Mayo Clinic Rochester Minnesota USA.

Sodium nitrite ingestion poses a considerable public health threat. The incidence of sodium nitrite self-poisoning in the United States has been trending upward since 2017. Our case report describes an intentional sodium nitrite ingestion with favorable outcomes. Read More

J Pak Med Assoc 2022 Feb;72(2):363-365

Department of Nephrology, Sultan Abdulhamid Han Training and Research Hospital, Istanbul, Turkey.

The development of methaemoglobinaemia due to prilocaine, which is used for local anaesthesia, is a rare, life-threatening, but well-known side effect. The development of this side-effect in a pregnant patient with chronic kidney disease can lead to foetal distress. The case presented here is of a 21-year old pregnant female with chronic kidney disease who required haemodialysis in the 22nd week of pregnancy due to the progression to end-stage kidney disease. Read More

J Dent (Shiraz) 2022 Mar;23(1):29-32

Dentist, Shiraz, Iran.

Statement Of The Problem: Methemoglobinemia is a potentially life-threatening rare medical condition, which refers to an increase in the level of oxidized form of hemoglobin (methemoglobin). Excessive replacement of hemoglobin with methemoglobin leads to functional hypoxia and even fatal conditions.

Purpose: The aim of this study was to evaluate the effect of two common local anesthetic agents namely lidocaine and articaine administered for hemostasis during surgery on methemoglobin level. Read More

J Med Case Rep 2022 Mar 14;16(1):106. Epub 2022 Mar 14.

Division of Pediatric Critical Care, Department of Pediatrics, Harbor-UCLA Medical Center, 1000 W Carson St, Building N-25, Box 491, Torrance, CA, 90502, USA.

Background: Glucose-6-phosphate dehydrogenase deficiency is a rarely recognized predisposing factor for rhabdomyolysis. Rhabdomyolysis with coronavirus disease 2019 has been increasingly seen during the pandemic. We report the uncommon occurrence of coronavirus disease 2019 pneumonia, severe rhabdomyolysis, and acute renal failure in the setting of glucose-6-phosphate dehydrogenase deficiency. Read More

Eur J Case Rep Intern Med 2022 28;9(2):003191. Epub 2022 Feb 28.

Division of Pulmonology and Critical Care, Allegheny Health Network, Pittsburgh, PA, USA.

Introduction: Phenazopyridine is an over-the-counter urinary analgesic commonly used to alleviate the burning and urgency associated with lower urinary tract infections. Methaemoglobinaemia is an uncommon adverse effect of phenazopyridine use. We report a case of methaemoglobinaemia in a patient prescribed daily phenazopyridine to treat urethral and bladder irritation caused by a chronic indwelling Foley catheter. Read More

BMJ Case Rep 2022 Mar 7;15(3). Epub 2022 Mar 7.

North Middlesex University Hospital, London, UK.

A man in his 20s presented with severe left-sided chest pain, shortness of breath and acute confusion. Initial examination revealed central cyanosis, normal heart sounds, vesicular breath sounds in both lung fields and a bruised right calf. The patient reported that he had recently injured his right leg and that he had not taken medication prescribed for blood clots for several days. Read More

Cureus 2022 Jan 28;14(1):e21678. Epub 2022 Jan 28.

Pediatric Infectious Disease Department, La Paz University Hospital, Madrid, ESP.

We report the case of a three-month-old boy who presented with poor weight gain, loose stools, and poor oral intake for three weeks. Physical examination revealed a pale infant with abdominal distension and cyanosis. Oxygen saturation was normal, but the laboratory showed important methemoglobinemia. Read More

BMJ Case Rep 2022 Mar 1;15(3). Epub 2022 Mar 1.

Emergency Medicine, Khon Kaen University, Khon Kaen, Thailand.

is a tropical herb found in Asia. The entire plant, especially the leaves, is used in herbal medicine for several therapeutic purposes. Acute intravascular haemolysis and methaemoglobinaemia have been reported in patients who consume this herb. Read More

BMJ Case Rep 2022 Feb 28;15(2). Epub 2022 Feb 28.

Pediatrics, Albany Medical Center, Albany, New York, USA

Methaemoglobinaemia is a potentially life-threatening condition characterised by hypoxaemia, cyanosis, pallor, fatigue, metabolic acidosis, headache and in severe cases, coma or death. Topical anaesthetics have been reported to cause methaemoglobinaemia. Topical benzocaine was specifically implicated in roughly 66% of anesthetic-induced methaemoglobinaemia cases in a large systematic review in adults. Read More

Brain Sci 2022 Jan 29;12(2). Epub 2022 Jan 29.

Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, 00146 Rome, Italy.

Recessive hereditary methemoglobinemia (RHM) due to NADH-cytochrome b5 reductase deficiency is a rare disease caused by pathogenic variants in . Unlike type I, in RHM type II (RHM2), the enzymatic defect affects erythrocytes and all body tissues, thus resulting in cyanosis and neurological impairment. Although the first description of RHM2 dates back to the mid-1950s, detailed clinical and neuroimaging information are available for only a few patients. Read More

Top Companion Anim Med 2022 Feb 22;49:100649. Epub 2022 Feb 22.

Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA.

A 6-month-old mixed breed dog was referred for evaluation of a potential disorder of sex development (DSD) and lower than expected energy level. Genitourinary examination revealed ambiguous external genitalia, hypospadias, and a subtle pouch of skin that resembled an empty scrotum. Corrective surgery was planned and subsequently aborted after cyanosis was identified preoperatively and an arterial blood gas analysis by co-oximetry identified increased methemoglobin (MetHb) concentration (35%, normal <2%) with normal arterial oxygen tension. Read More