Metahemoglobinemia y hemólisis intravascular aguda después de una intoxicación por naftaleno en un paciente pediátrico / Methemoglobinemia and acute intravascular hemolysis after naphthalene poisoning in a pediatric patient

La intoxicación por naftaleno es poco frecuente en los niños. Es causada por la ingesta, la inhalación o el contacto con la piel de sustancias que contienen naftaleno. Los pacientes suelen tener orina de color marrón oscuro, diarrea acuosa y vómito bilioso. Los signos incluyen fiebre, taquicardia, hipotensión y valores bajos en la oximetría de pulso, incluso con oxigenoterapia. Los análisis de sangre detectan anemia hemolítica, metahemoglobinemia, insuficiencia renal e hiperbilirrubinemia. Además del tratamiento sintomático, se hacen transfusiones de eritrocitos y se les administran ácido ascórbico, azul de metileno y N-acetilcisteína. En este artículo, presentamos el caso de un paciente masculino de 23 meses de edad con metahemoglobinemia y hemólisis intravascular aguda que recibió atención en la unidad de cuidados intensivos durante cinco días por intoxicación por naftaleno. Si bien la intoxicación por naftaleno es muy poco frecuente, tiene consecuencias mortales y se debe ejercer precaución con su uso y venta.

Poisoning by naphthalene is uncommon in children. It is a type of poisoning brought on by ingesting, inhaling, or coming into touch with naphthalene-containing substances on the skin. Patients typically present with an initial onset of dark brown urine, watery diarrhea, and bile vomit. The signs include fever, tachycardia, hypotension, and low pulse oximetry readings even with oxygen support. Hemolytic anemia, methemoglobinemia, renal failure, and hyperbilirubinemia are all detected in blood tests. Erythrocyte transfusion, ascorbic acid, methylene blue, and N-acetylcysteine (NAC) therapies are provided to inpatients in addition to symptomatic treatment. We present a 23-month-old male patient who developed methemoglobinemia and acute intravascular hemolysis, who was followed up in the intensive care unit for five days due to naphthalene intoxication. Although naphthalene poisoning is very rare, it should be known that it has fatal consequences, and more care should be taken in its use and sale.

Intoxicación por Metahemoglobinizante, tipo Propanil

Las intoxicaciones por herbicidas propanil son frecuentes en las diferentes áreas agrícolas, sobre todo en los campos de cultivos de arroz. Se presenta el caso de un paciente agricultor, sin factores de riesgo, quien sufrió una intoxicación moderada por propanil. Pese a las limitaciones diagnósticas en cada centro hospitalario, la sospecha y los datos clínicos al ingreso pueden ser suficientes para la elaboración diagnóstica y su respectivo manejo.

Poisoning by propanil herbicides are common in different agricultural areas, especially in rice fields. We present the case of a farmer patient, without risk factors, who suffered a moderate intoxication by propanil. Despite the diagnostic limitations in each hospital, the suspicion and clinical data on admission may be sufficient for the diagnosis and its respective management.

Metemoglobinemia como efeito adverso do tratamento para hanseníase: relato de caso / Methemoglobinemia as an adverse effect of the treatment for leprosy: case report / Metahemoglobinemia como efecto adverso del tratamiento de la lepra: informe de caso

Introdução: O tratamento da hanseníase consiste em um regime de poliquimioterapia com as seguintes drogas: Rifampicina, Dapsona e Clofazimina. Entre os efeitos colaterais, a metemoglobinemia decorre do uso da Dapsona e requer atenção especial, pois enseja a necessidade de suspensão da medicação e, em casos graves, de internação hospitalar. Trata-se de uma complicação rara, na qual ocorre uma anomalia da hemoglobina, que impossibilita a captação e a liberação de oxigênio. É provocada pela ação da Dapsona, quando administrada em quantidade e em duração além das recomendadas. Destacam-se como sinais e sintomas a presença de cianose, baixa saturação de oxigênio e dispneia aos esforços, embora a PaO2 esteja de acordo com os valores de referência. O diagnóstico da metemoglobinemia é realizado pela co-oximetria. Pacientes com cianose ou sintomas de hipoxemia, com PaO2 suficientemente alta, apresentam elevada suspeição. Apresentação do caso: Apresenta-se um caso de metemoglobinemia identificado na Atenção Primária à Saúde (APS) durante um tratamento de hanseníase, que exigiu condução minuciosa, culminando na suspensão da poliquimioterapia, com resolução do evento adverso. Conclusão: O acompanhamento clínico rigoroso pela APS durante o tratamento da hanseníase possibilita o reconhecimento precoce de eventuais efeitos adversos da poliquimioterapia, bem como a adoção das devidas medidas.

Introduction: Leprosy treatment consists of a multidrug therapy regimen with the following drugs: Rifampicin, Dapsone, and Clofazimine. Among the side effects, methemoglobinemia results from the use of Dapsone and requires special attention, as it leads to the need to discontinue the medication and, in severe cases, hospitalization. It is a rare complication, on which there is hemoglobin anomaly, which makes it impossible to capture and release oxygen. It is caused by the action of Dapsone when administered in doses and duration beyond the recommended ones. The presence of cyanosis, low oxygen saturation, and dyspnea on exertion stand out as signs and symptoms, although the PaO2 is within the reference values. The diagnosis of methemoglobinemia is performed by co-oximetry. Patients with cyanosis or symptoms of hypoxemia, with sufficiently high PaO2, are highly suspicious. Case presentation: A case of methemoglobinemia identified in Primary Health Care (PHC) during a treatment for leprosy is presented, which required meticulous management, culminating in the suspension of multidrug therapy, with resolution of the adverse event. Conclusions: The strict clinical follow-up by the PHC during the treatment of leprosy allows the early recognition of possible adverse effects of multidrug therapy as well as the adoption of the necessary measures.

Introducción: El tratamiento de la lepra consiste en un régimen de poliquimioterapia con los siguientes fármacos: Rifampicina, Dapsona y Clofazimina. Entre los efectos secundarios, la metahemoglobinemia resulta del uso de Dapsona y requiere atención especial, ya que conlleva la necesidad de suspender la medicación y, en casos graves, la hospitalización. Es una complicación rara, en la que existe una anomalía de la hemoglobina, que imposibilita la captación y liberación de oxígeno. Es provocada por la acción de la Dapsona, cuando se administra en cantidad y duración superiores a las recomendadas. Los signos y síntomas son cianosis, baja saturación de oxígeno y disnea a mínimos esfuerzos, aunque la PaO2 está dentro de los valores de referencia. El diagnóstico de metahemoglobinemia se realiza por cooximetría. Los pacientes con cianosis o síntomas de hipoxemia, con PaO2 suficientemente elevada, presentan alta sospecha. Presentación del caso: Se presenta un caso de metahemoglobinemia identificado en Atención Primaria de Salud (APS) durante un tratamiento por lepra, que requirió una conducta exhaustiva, culminando con la suspensión de la poliquimioterapia con resolución del evento adverso. Conclusiones: El estricto acompañamiento clínico por parte de la APS durante el tratamiento de la lepra permite el reconocimiento precoz de los posibles efectos adversos decurrentes de la poliquimioterapia, así como la adopción de las medidas necesarias.

Importancia clínica del diagnóstico de la metahemoglobinemia / Clinical importance of the diagnosis of methemoglobinemia

Introducción: La metahemoglobina es una forma de hemoglobina en la que el grupo hemo, usualmente en forma ferrosa, es oxidado a forma férrica, lo que afecta el transporte de oxígeno. El incremento por encima de los valores de referencia se denomina metahemoglobinemia. Objetivo: Actualizar conceptos como prevención, manifestaciones clínicas, diagnóstico de laboratorio y tratamiento de elección de esta enfermedad, con la información disponible de la última década. Métodos: Se realizó una revisión de la literatura en inglés y español, a través del sitio web PubMed, el motor de búsqueda Google académico y Scielo, de artículos publicados en los últimos 10 años. Los términos de búsqueda usados incluyeron metahemoglobinemia, déficit de citocromo b5 reductasa, cianosis y cooximetría. Análisis y síntesis de la información: La metahemoglobinemia se puede clasificar en congénita y adquirida, esta última es la más frecuente. Es importante el diagnóstico de esta enfermedad que aunque es un padecimiento poco común, puede cursar con complicaciones graves e incluso la muerte. Puede ser evitable con diagnóstico temprano y tratamiento oportuno para reducir las complicaciones asociadas a este cuadro. Conclusiones: El diagnóstico y el tratamiento, profiláctico y terapéutico de la metahemoglobinemia en su etapa aguda o de mantenimiento, requieren la adecuada actualización del profesional de la salud(AU)

Introduction: Methemoglobin is a form of hemoglobin in which the heme group, usually in the ferrous form, is oxidized to the ferric form, which affects oxygen transport. The increase above the reference values ​​is called methemoglobinemia. Objective: To update concepts such as prevention, clinical manifestations, laboratory diagnosis and treatment of choice for this disease, with the information available from the last decade. Methods: A review of the literature in English and Spanish was carried out, through the PubMed website, the academic Google search engine and Scielo database, of articles published in the last 10 years. Search terms used included methemoglobinemia, cytochrome b5 reductase deficiency, cyanosis, and co-oximetry. Analysis and synthesis of information: Methemoglobinemia can be classified into congenital and acquired, the latter being the most common. It is important to diagnose this disease, which, although it is a rare condition, can cause serious complications, and even death, which are avoidable with early diagnosis and timely treatment that reduce the complications associated with this condition. Conclusions: The diagnosis and treatment, prophylactic and therapeutic, of methemoglobinemia, in its acute or maintenance stage, require adequate updating of the health professional(AU)

An unusual case of methemoglobinemia resulting from self-administration of nitrobenzene in a psychiatric patient

Nitrobenzene, when consumed in large enough doses, can cause methemoglobinemia. By reducing oxygen unloading and oxygen binding, methemoglobinemia reduces oxygen delivery. This is a case of 55-year-old man who is a known case of psychiatric disorder was brought to the emergency room with an alleged history of deliberate consumption of nitrobenzene liquid approximately 10 mL in the morning of the day at his residence. He also instilled 2 drops in the right ear and was taken to a private hospital where the initial management with gastric lavage, multidose activated charcoal and methylene blue was given. He was then referred to the government tertiary care setting for further management. Prompt intravenous methylene blue treatment increases PaO2 in patients with methemoglobinemia.

Progress in neonatal methemoglobinemia / 国际儿科学杂志

Neonatal methemoglobinemia is a rare disorder characterized by cyanosis and hypoxemia, which could be caused congenitally by cytochrome b5 reductase enzyme deficiency or hemoglobin M disease, and could be acquired by the exposure to lidocaine, nitrites and other drugs.Blood gas analysis is a simple and accessible way to detect methomoglobin.Methemoglobinemia is related to numerous diseases in neonates, including diarrhea, acidosis, late-onset sepsis.Methylene blue is an effective drug for decreasing MetHb levels.Other therapeutic options, such as vitamin C, N-acetylcysteine and vitamin B2, could also be useful.This article reviews the progress of neonatal methemoglobinemia.

Metahemoglobinemia, una entidad de diagnóstico complejo. Reporte de un caso

Methemoglobinemia is a rare condition with serious consequences if not diagnosed. We report the case of a 64-year-old woman with a history of allergy to sulfa drugs and a recent diagnosis of a small vessel vasculitis (ANCA-p) who started induction therapy with corticosteroids and rituximab. Due to the need for infectious prophylaxis, and considering her history, dapsone was administered instead of cotrimoxazole after ruling out glucose-6-phosphate dehydrogenase deficiency. During the admission to the hospital for her second dose of rituximab, and while being asymptomatic, she persistently presented a pulse oximetry ≪ 90% despite the administration of O2. Therefore, the infusion was postponed to study the patient. The arterial gasometric study by direct potentiometry revealed an O2 saturation of 98%, with a saturation gap > 5%. Considering the use of dapsone, a methemoglobinemia was suspected and confirmed by co-oximetry (methemoglobinemia 9%). Dapsone was suspended and one week later, her methemoglobinemia was absent.

The Pharmacotherapy of Blood Intoxication (Methmoglobinemia) Induce by Exposure to Ortho-Chlorobenzylidenemalononitrile (CS) in Public Protests

Background:Acquired Methemoglobinemia(MetHb)is a rare, but potentially serious and unfamiliarity with this complication may delay diagnosis and appropriate therapy. Presentation:A case ofmethemoglobinemiaoccurring in male teenage demonstrator as a complication of re-current exposure to ortho-chlorobenzylidenemalononitrile (CS) in public protests , the patient became cyanotic with a decrease in his level of consciousness, by the effect of hydrogen cyanide as by-product of (CS), resulting in a toxicmethemoglobinemia level in his blood.Methemoglobin is incapable of carrying oxygen and is formed when the ferrous iron in the heme molecule is oxidized to the ferric state. The diagnosis should be entertained when cyanosis, unresponsive to 100% oxygen therapy, appears suddenly, especially when exposure to an oxidant agent is established. Treatment:The patient received a 1 mg/kg dose of methylene blue intravenously. A cooximetry done 1 hour later showed a methemoglobin level of 43%. A second 1 mg/kg dose of methylene blue was given and another hour later the methemoglobin level had dropped to 13%. The patient also showed clinical improvement with resolution of the cyanosis and return of his mental status to baseline. Conclusion:Methylene blue is the specific antidote, but should be reserved for more severe cases or if co-morbid conditions make mild hypoxia un advisable

Anaesthetic management of a young primigravida with 8 months amenorrhea, rheumatic heart disease, hypothyroidism and met-hemoglobinimea schedule for cesarean section

A young patient, primigravida with rheumatic heart disease, hypothyroidism and met-hemoglobinemia had central and peripheral cyanosis was scheduled for caesarean section under general anesthesia in two days. Author managed met-hemoglobinemia with ascorbic acid keeping methylene blue as standby. Haemoglobin saturation was 89% at room air and 92% with supplemental oxygen. Initial met-haemoglobin levels were 31.54% (normal values <1%). After optimizing thyroid and RHD status (moderate MR and mild MS), she was given tablet ascorbic acid 2 gram thrice a day with methylene blue as standby. Conventional balanced general anesthesia technique was used and she was followed up in postoperative period with ICU care. A healthy live female baby was extracted and mother had stable vital parameters. Postoperative treatment with ascorbic acid was continued. Repeated methaemoglobin levels showed a drop from preoperative value of 31.54% to 11.39% by 3rd postoperative day and 8.05% at the end of 1st week. At the time of discharge, she did not have any cyanosis. Ascorbic acid is a good alternative drug with limited experience in met-hemoglobinemia. Author present a case of a met-hemoglobinemia treated with ascorbic acid successfully to emphasize the use of ascorbic acid as an alternative method without any adverse effects.

Metahemoglobinemia secundaria a inhalación de "poppers": caso clínico y revisión de la literatura / Methemoglobinemia secondary to amyl nitrite inhalation. A case report and literature review

El nitrito de amilo, conocida como "poppers", se ha masificado como droga recreacional en parte por sus efectos con objetivos sexuales. Su consumo se asocia a complicaciones psiquiátricas y médicas. Reportamos el caso de un paciente que se presenta con metahemog-lobinemia moderada secundaria a la inhalación de nitrito de amilo asociado a alcohol. Al ingreso presenta cianosis peribucal y en extremidades, disociación entre oximetría de pulso y presión parcial de oxígeno en gases arteriales, además de metahemoglobinemia 29,9%. Se descartan otras intoxicaciones y causas primarias de metahemoglobinemia. Se maneja con oxigenoterapia, hidratación y ácido ascórbico, presentando una evolución favorable. Presentamos el primer caso en Chile de metahemoglobinemia secundaria al consumo de nitrito de amilo con fines recreativos.

Amyl nitrite, known as "poppers", has become popular as a recreational drug for sexual purposes. Its consumption is associated with psychiatric and medical complications. We report the case of a patient presenting with moderate methemoglobinemia secondary to amyl nitrite inhalation associated with alcohol. At admission, perioral and extremities cyanosis, a dissociation between pulse oximetry and partial pressure of oxygen in arterial gases, and methemoglobinemia 29.9% were present. Other intoxications and primary causes of methemoglobinemia were ruled out. The patient receives oxygen therapy, hydration, and ascorbic acid, presenting a favorable evolution. We report the first Chilean's case of methemoglobinemia secondary to amyl nitrite consumption for recreational purposes

Food poisoning associated methemoglobinemia: Time to wake up / 世界急诊医学杂志（英文）

@#With interest we read the recent article on methemoglobinemia by Chan et al.[1] Through this letter, we would like to add few additional comments regarding methemoglobinemia and its relevance in medicine practice with regards to food poisoning.

Methemoglobinemia due to local anesthesia: a rare cause of cyanosis and chest pain after placement of implantable cardioverter defibrillator / Journal of Rural Medicine

Although methemoglobinemia is rare in adulthood, it may have fatal consequences if unnoticed. We planned to implant an implantable cardioverter defibrillator ICD in a 50-year-old male patient for primary prevention. Following sterile draping, prilocaine 5 mg/kg (400 mg) was injected subcutaneously for local anesthesia. We injected an additional dose of 200 mg due to pain during subclavian vein puncture. A DDD-R ICD was placed successfully within approximately 40 minutes. The patient complained of sudden chest pain and dyspnea 15 minutes after bed rest and was transferred to the coronary care unit due to cyanosis and deterioration of general status. Physical examination revealed blood pressure of 110/80 mmHg, pulse rate of 110 bpm, and otherwise unremarkable signs. Peripheral oxygen saturation was determined as 83% by pulse oximeter. Possible pneumothorax and cardiac perforation were excluded by emergency chest radiograph and echocardiography. Blood gas analyses was performed to assess for methemoglobinemia, which revealed pH 7.41, pCO2 40 mmHg, oxygen saturation 98.2%, and methemoglobin 7.9% that peaked to 12.3%. Methylene blue (1%) was slowly injected over 10 minutes at a dose of 1 mg/kg. Cyanosis waned and methemoglobin values decreased to 4.1%, 2.1%, and 1.1% at 2, 8, and 16 hours following the administration, respectively. The patient was safely discharged 2 days after implantation of pacemaker. Methemoglobinemia should be considered in cases presenting with cyanosis, non-diagnostic ECG, and a discrepancy in oxygen saturation between pulse oximetry and blood gas analyses.

My mother is looking blue / 世界急诊医学杂志（英文）

@#A 76-year-old Chinese female presented by ambulance to the Emergency Department complaining of dizziness, headache and fatigue. Her son claimed that the patient “turned blue” three hours prior to onset of the patient’s symptoms. Paramedics noted the patient’s SpO2 was 83% on room air with no improvement with a non- rebreather mask. Past medical history was significant for diabetes and hypertension. Family, social and medication history were non-contributory. Patient denied ingestion of any traditional Chinese medicines but did have some choy sum (a variety of green vegetable) for lunch five hours prior to arrival. On examination, the patient appeared agitated, but alert. Purple lips and fingers were noted (Figure 1). Physical examination: heart rate 55 beats/minute, pulse oximetry 87%, respiratory rate 16 breaths/minute, blood pressure 143/51 mmHg. Bedside investigations: chest X-ray (clear lung fields and cardiomegaly); ECG (sinus rhythm, slight bradycardia at 53 beats/minute); hemoglobin 9.3 g/dL; glucose 10.9 mmol/L (196.2 mg/dL).

Nitrate and nitrite poisoning in sheep and goats caused by ingestion of Portulaca oleracea / Intoxicação por nitratos e nitritos em ovinos e caprinos causada pela ingestão de Portulaca oleracea

Three outbreaks of poisoning by Portulaca oleracea were reported in sheep and goats in Northeast Brazil. In the first outbreak, 8 out of 20 sheep were affected and later died. In the second outbreak, three goats and one sheep died out of a flock of 30 animals that included both species. In the third outbreak, two out of 19 sheep were affected, and they recovered after a treatment of 2% methylene blue at a dose of 4 mg/kg body weight. In the first and second outbreaks, the animals ingested P. oleracea after it was cut and offered in feeders. In the third outbreak, the flock was grazing in an area that had been invaded by the plant. To determine the toxicity, P. oleracea was administered experimentally at a dose of 80g/kg of body weight to seven sheep, weighing 19-30 kg. One control sheep received green grass. One to four hours after P. oleracea ingestion, the animals showed clinical signs of poisoning characterized by cyanotic mucous membranes, bloat, ruminal pH of 8-9, pollakiuria, aerophagia, involuntary movements of the upper lip, apathy, tachypnea and tachycardia. Five animals recovered, including one that was treated with 1% methylene blue, and two animals died. During necropsy, the mucous membranes were brownish, and the blood was dark brown. Diphenylamine tests of the plant and of rumen contents were positive for nitrates. Positive results for nitrates were also found in 24 samples of P. oleracea that were collected in different places in the states of Pernambuco and Paraíba. We conclude that P. oleracea accumulates nitrates at toxic levels and may cause poisoning in sheep and goats.(AU)

Relatam-se três surtos de intoxicação por Portulaca oleracea em ovinos e caprinos no Nordeste do Brasil. No primeiro surto morreram oito de 20 ovinos. No segundo morreram três caprinos e um ovino de um total de 30 animais das duas espécies. No terceiro surto foram afetadas duas ovelhas de um rebanho de 19 animais, que se recuperaram após o tratamento com azul de metileno a 2% na dose de 4 mg/kg/vivo. Nos surtos 1 e 2 os animais ingeriram P. oleracea cortada e oferecida no coxo e no surto 3 estavam pastoreando em uma área invadida pela planta. Para determinar a toxicidade de P. oleracea foram utilizados oitos ovinos, sendo sete experimentais e um controle, com peso entre 19 e 30 kg. A planta foi administrada por via oral, na dose de 80 g/kg/peso corporal. O animal controle recebeu capim verde e concentrado. Entre uma a quatro horas após a ingestão da planta os animais apresentaram sinais clínicos caracterizados por mucosas cianóticas, timpanismo gasoso, pH ruminal de 8-9, polaquiúria, aerofagia, movimentos involuntários do lábio superior, apatia, taquipnéia e taquicardia. Cinco animais se recuperaram, incluindo um que foi tratado com azul de metileno a 2%, e dois morreram. Na necropsia observaram-se mucosas de coloração marrom e sangue marrom escuro. O teste de difenilamina realizado na planta e no conteúdo ruminal foi positivo para nitratos. Resultados positivos para nitratos foram detectados em 24 amostras coletadas em diferentes locais dos estados de Pernambuco e Paraíba. Conclui-se que P. oleracea acumula nitratos em níveis tóxicos, e quando ingerida por ovinos e caprinos pode provocar intoxicação e morte.(AU)

Metahemoglobinemia inducida por dapsona: presentación de un caso pediátrico / Methemoglobinemia due to Dapsone: a pediatric case report

La metahemoglobinemia es una patología caracterizada por la presencia de altas concentraciones de metahemoglobina en sangre. Esta es una forma oxidada de la hemoglobina, muy afín al oxígeno, que es incapaz de cederlo a los tejidos. Es una entidad poco frecuente, con baja sospecha diagnóstica. Aunque puede ser congénita en recién nacidos con cianosis, es más frecuente la adquirida por fármacos y tóxicos. En la Argentina, no se conoce la incidencia real de esta patología. El objetivo es comunicar un caso de metahemoglobinemia en una paciente pediátrica que ingresó al Hospital Magdalena V. de Martínez con cianosis en la cara y las extremidades, en mal estado general, con el antecedente de ingesta de varios comprimidos de dapsona, y se constató concentración sérica de metahemoglobina del 35%. El tratamiento consistió en la administración endovenosa de azul de metileno. Su evolución fue favorable.

Methemoglobinemia is a condition characterized by a high blood concentration of methemoglobin. Methemoglobinemia is a disorder that occurs when hemoglobin in the blood is oxidized to form methemoglobin, rendering it unable to transport oxygen. Although it can be congenital in cyanotic newborn, it is more often an adverse medication effect. The aim is to report a pediatric methemoglobinemia case, assisted in Magdalena V. de Martínez Hospital, with cyanosis in face and limb, in poor condition, that consumed dapsone accidentally. Her methemoglobin concentration was 35%. Intravenous methylene blue was administered with favorable outcome.

Cianosis en un paciente de 14 años: Presentación de un caso de metahemoglobinemia / Cyanosis in 14-year-old patient: Methemoglobinemia: case report

La cianosis es la coloración azulada de la piel y las mucosas debida al aumento de la concentración de hemoglobina reducida en los capilares o a la presencia de metahemoglobina en concentraciones mayores de las normales. Es importante pensar en metahemoglobinemia como diagnóstico diferencial frente a un paciente con cianosis que no responde a la administración de oxígeno cuando no existen causas cardiorrespiratorias que la justifiquen, dado que requiere de otros métodos diagnósticos y de tratamiento específico. Se presenta el caso de un paciente adolescente de 14 años de edad con cianosis secundaria a metahemoglobinemia de probable etiología congénita. Se discuten las causas, forma de presentación, diagnóstico y tratamiento.

The bluish coloration of skin and mucous membranes, called as cyanosis, could be explained by high reduced hemoglobin in the capillaries, or the presence of elevated methemoglobin concentration. It is important to think of methemoglobinemia as a differential diagnosis in a cyanotic patient who does not respond to oxygen administration once cardiorespiratory causes are discarded; since it requires other diagnostic methods and specific treatment. We described a case of cyanosis in a fourteen-year-old adolescent with probable congenital methemoglobinemia. We discussed their probable causes, clinic presentation, diagnosis and treatment.

Benzocaine, Methemoglobinemia and Methylene Blue / 대한소아치과학회지

The aim of this review is to introduce about the issue of benzocaine and methemoglobinemia. Through blocking the pain during dental treatment, fear and anxiety of patients will be reduced. Thus, anesthetic agent containing benzocaine is commonly used while controlling the pain of patients during treatment. However, on May 28, 2018, the Ministry of Food and Drug Safety reported a medication safety report about restricting the use of benzocaine-containing agents in infants under 24 months and children. Also, they recommended a cautious use to adolescents and adults to prevent methemoglobinemia (MHb). This report was published due to an advice from Food and Drug Administration (FDA) on May 23, 2018. When using agents containing benzocaine, dentists must consider the probability of MHb and prepare for early diagnosis and appropriate action. Since 1930s, methylene blue is known to cure MHb patients. Therefore, the proper use of methylene blue for emergencies and diagnosis methods for early diagnosis of MHb should be familiar to dentists planning for the use of topical anesthetic agents. Dentists should be trained for emergency situation of MHb caused by the use of benzocaine.

Metahemoglobinemia severa secundaria a sobredosis de dapsona, reporte de caso / Severe metahemoglobinemia associated with dapsone overdosis. Case report / Metemoglobinemia severa secundária à sobredosagem de Dapsona, relato de um caso

Resumen: La metahemoglobinemia es una entidad clínica causada por la oxidación de la hemoglobina (Hb), específicamente del grupo hemo, transforma el hierro de un estado ferroso (Fe2+) a férrico (Fe3+++), dando como resultado la metahemoglobina (MetHb), la cual no es capaz de realizar enlaces con el oxígeno (O2) y por lo tanto no puede trasportarlo, condicionando una disminución en la oxigenación tisular. La Hb puede oxidarse debido a alteraciones genéticas de expresión variable o más frecuentemente por efecto adverso de sustancias exógenas, destacando fármacos como la dapsona. Se describe el cuadro clínico, diagnóstico y tratamiento de una paciente con metahemoglobinemia adquirida por sobredosis de dapsona.

Abstract: Methemoglobinemia is a clinical entity caused by oxidation of hemoglobin (Hb) specifically heme, transforming iron from a ferrous state (Fe2+) to a ferric state (Fe3+++), resulting in methemoglobin (MetHb), which is not capable of bonding with oxygen (O2), and therefore cannot transport it, conditioning tissue irrigation. Hb may oxidize due to variable expression genetic abnormalities expression, or more frequently, as an adverse effect related to exogenous substances, such as dapsone. This work describes the clinical picture, diagnosis and treatment of a patient with metahemoglobinemia-acquired secondary to dapsone overdose.

Resumo: A metemoglobinemia é uma entidade clínica causada pela oxidação da hemoglobina (Hb), especificamente do grupo heme, transformando o ferro de um estado ferroso (Fe2+) para um estado férrico (Fe3+++), dando como resultado a Meta-hemoglobina (MetHb), que não é capaz de fazer ligações com o oxigênio (O2) e, portanto, não pode transportá-lo, condicionando a diminuição na oxigenação tissular. A Hb pode oxidar-se devido a alterações genéticas de expressão variável, ou mais freqüentemente devido ao efeito adverso de substâncias exógenas, destacando drogas como a Dapsona. Descrevemos o quadro clínico, diagnóstico e tratamento de um paciente com metemoglobinemia adquirida por sobredosagem de dapsona.

Metahemoglobinemia relacionada con ingesta de puré de acelgas / Methemoglobinemia due to ingestion of chard puree

La metahemoglobinemia es un síndrome clínico dado por la presencia de una forma aberrante de hemoglobina, ocasionada por diversos agentes oxidantes. Se describe un caso clínico de metahemoglobinemia severa asociada a la ingesta de puré de acelgas con alto contenido en nitratos y nitritos. Paciente de un año, con antecedentes de comunicación interauricular (CIA), que presentó un cambio en coloración de la piel 7 h antes, en forma progresiva, acompañado de vómitos. Ingresó al Departamento de Emergencia con cianosis generalizada que no mejoró con oxigenoterapia, taquicardia y tendencia a hipotensión arterial. En cuidados intensivos se realizó ecocardiograma que evidenció CIA sin repercusión hemodinámica. Metahemoglobinemia 37%. Se realizó dosis de azul de metileno al 1% por vía intravenosa, con franca mejoría clínica a la hora de la administración del antídoto y descenso de niveles de metahemoglobina. Alta médica a las 36 horas del ingreso. Existía una relación cronológica entre la exposición a nitratos por ingesta de un puré de acelgas y la aparición del cuadro. Los niveles de nitratos hallados en dicho alimento fueron muy elevados considerando estándares internacionales, lo que sumado a una inadecuada conservación del alimento cocido los días previos, permitió confirmar el planteo etiológico realizado. Resulta importante sospechar esta entidad patológica poco frecuente frente a cianosis que no mejora con oxígeno, y prevenir cuadros similares al descrito mediante una adecuada manipulación y conservación de las verduras con alto contenido en nitratos.

Methemoglobinemia is a clinical syndrome due to the presence of an aberrant form of hemoglobin, caused by various oxidizing agents. The study reports a case of severe methemoglobinemia associated with the ingestion of chard puree with high levels of nitrates and nitrites. A 1-year-old patient with a history of atrial septal defect (ASD), who progressively showed change of skin color 7 hours earlier, accompanied by vomiting. She was admitted to the Emergency Department with generalized cyanosis not improving with oxygen therapy, tachycardia and tendency to hypotension. In the intensive care unit, an echocardiogram showed ASD without hemodynamic complications. Methemoglobinemia 37%. A 1% methylene blue dose was administered intravenously, with clinical improvement one hour after antidote administration and decrease in methemoglobin levels. Medical discharge at 36 hours of admission. There was a chronological relationship between nitrates exposure by ingestion of chard puree and the clinical onset of methemoglobinemia. The toxic cause was confirmed after high nitrates levels were found in this vegetable considering international standards, and an inadequate preservation of the cooked chard on previous days. It is important to suspect this rare pathological entity when cyanosis fails to improve with oxygen, and to prevent poisonings similar to those described by an adequate manipulation and preservation of vegetables with high nitrate levels.

A Case of Methemoglobinemia Caused by Primaquine / 대한내과학회지

Primaquine is often administered for the hypnozoite stage of Plasmodium vivax and Plasmodium ovale. Primaquine (with clindamycin) is also an alternative drug for treatment of pneumocystis pneumonia when trimethoprim/sulfamethoxazole cannot be used. Primaquine may cause methemoglobinemia, an altered state of hemoglobin in which the ferrous state of heme is oxidized to the ferric state. We report a case of methemoglobinemia caused by a standard dose of primaquine plus clindamycin in a 27-year-old female recipient of a kidney transplant who was diagnosed with pneumocystis pneumonia.