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1.
Adv Exp Med Biol ; 1232: 369-374, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893433

RESUMO

Multispectral/hyperspectral imaging is one of the imaging modalities to visualize and quantify blood supply in surface tissues such as skin or mucosa. The results of visualization can be potentially affected by various factors, for instance by elevated methemoglobin (MetHb) content (e.g., methemoglobinemia). The scope of the current study is to develop a robust approach for fabrication and validation of tissue-mimicking phantoms, which can be used to assess and improve tissue oximetry. METHODS: The realistic tissue mimicking gelatin-based phantoms with intralipid (4% v/v) and/or hemoglobins (oxy-, deoxyhemoglobins, and MetHb) were molded between two coverslips separated by 2-mm wires. The hemoglobin solutions were prepared by dissolving the lyophilized human hemoglobin powder (H7379, Sigma-Aldrich) in the deionized water. Sodium dithionite (85% purity, 157,953, Sigma-Aldrich) was used to reduce MetHb solution. The phantoms were imaged using a multispectral imaging device (Oxilight, Canada).To demonstrate the utility, the developed approach is applied to emulate elevated systemic MetHb content. RESULTS: Initial results show that elevated systemic MetHb (2.0-6.7% of total blood) does not impact the accuracy of tissue oximetry imaging. DISCUSSION: A robust method for fabrication and optical validation of biocompatible tissue-mimicking phantoms has been developed.The proposed phantom design allows combining different phantoms into multilayer (sandwich) structures, which can be used to emulate a wide range of topical and systemic conditions.


Assuntos
Gelatina , Oximetria , Imagens de Fantasmas , Canadá , Gelatina/química , Humanos , Metemoglobina/análise , Metemoglobinemia/diagnóstico , Oximetria/métodos , Oximetria/normas , Imagens de Fantasmas/normas
3.
J Spec Oper Med ; 19(3): 14-16, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31539427

RESUMO

Presumptive antirelapse therapy (PART) with primaquine for Plasmodium vivax malaria postdeployment is an important component of the US military Force Health Protection plan. While primaquine is well tolerated in the majority of cases, we present a unique case of an active duty Army Ranger without glucose-6-phosphatase dehydrogenase or cytochrome b5 reductase (b5R) deficiencies who developed symptomatic methemoglobinemia while taking PART following a deployment to Afghanistan.


Assuntos
Metemoglobinemia/induzido quimicamente , Metemoglobinemia/diagnóstico , Militares , Primaquina/toxicidade , Campanha Afegã de 2001- , Diagnóstico Tardio , Humanos
6.
Wien Klin Wochenschr ; 131(15-16): 381-384, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31267164

RESUMO

Healthy human blood contains only a trace amount of methemoglobin (Hb M), less than 1%. In Hb M iron is present in the oxidized ferric state (Fe3+) not in the reduced ferrous form (Fe2+) and this reduces the ability of hemoglobin to bind oxygen. The described rare hemoglobin variant Hb M­Hyde Park (also known as Hb M-Akita) results from the substitution of amino acid tyrosine by histidine at position 93 of the beta-globin chain of hemoglobin. The rare Hb variant Hb M­Hyde Park (Hb M­Akita) is mainly inherited autosomal dominant and causes methemoglobinemia. Due to the low frequency of inherited Hb M variants, the diagnosis is challenging. Here, we here report on a family with Hb M­Hyde Park (Hb M­Akita) whose members demonstrated Hb M > 10%, but were, asymptomatic except for chronic cyanosis. Due to human mobility and migration other hemogobin variants, such as beta-thalassemia minor have spread to Austria . A genetic combination of two different hemoglobin variants may result in severe anemia. Genetic counseling for patients with hemoglobin variants, including Hb M­Hyde Park (Hb M­Akita) and beta-thalassemia minor, is essential.


Assuntos
Hemoglobina M/genética , Metemoglobinemia , Áustria , Hemoglobinas Anormais/genética , Hemoglobinas Anormais/metabolismo , Humanos , Metemoglobinemia/sangue , Metemoglobinemia/diagnóstico , Metemoglobinemia/genética , Oxiemoglobinas/metabolismo , Talassemia beta/genética
7.
Am J Case Rep ; 20: 726-729, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31113928

RESUMO

BACKGROUND Glucose-6-phosphate dehydrogenase deficiency (G6PD-D) is the most common red blood cell enzymopathy disorder. Severe hemolysis due to G6PD-D may rarely manifest as methemoglobinemia. Although acute hemolytic crises are usually induced by the exposure to certain oxidative stresses, diabetic ketoacidosis may also elicit hemolytic reactions in G6PD deficient persons. CASE REPORT A 17-year-old male with type 1 diabetes mellitus presented with diabetic ketoacidosis and features of hemolytic anemia which turned to be G6PD-D related. Interestingly, the arterial blood gas of the patient showed an elevated methemoglobin level (8.1%). CONCLUSIONS G6PD-D induced hemolysis is conventionally caused by oxidative stress, however, we report here a case of G6PD-D induced methemoglobinemia as a complication of diabetic ketoacidosis that has not been, as far as we know, previously reported.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Cetoacidose Diabética/complicações , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Metemoglobinemia/diagnóstico , Adolescente , Deficiência de Glucosefosfato Desidrogenase/etiologia , Humanos , Masculino , Metemoglobinemia/etiologia
8.
BMJ Case Rep ; 12(3)2019 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-30936348

RESUMO

A 14-year-old boy of Asian origin presented with a history of bluish discolouration of the finger and toenail bed with associated mild fatiguability on exertion since early childhood. Clinical examination revealed bilaterally symmetric uniform central cyanosis with no associated clubbing. Cardiovascular and respiratory system examination was normal. Pulse oximetry revealed an oxygen saturation of 87% in all four limbs. Transthoracic and transoesophageal echocardiography showed no evidence of shunt lesions. In view of the past diagnosis of pulmonary arteriovenous fistulae made at 4 years of age, a repeat cardiac catheterisation study was done, which revealed no shunt at any level. Interestingly, arterial oxygen tension of the chocolate-brown blood was normal in all the samples, suggesting the possibility of methaemoglobinaemia. Co-oximetry revealed methaemoglobin levels of 36%, confirming the diagnosis. Secondary causes were ruled out. The family was counselled about the hereditary nature of the condition.


Assuntos
Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Cianose/etiologia , Metemoglobina/metabolismo , Metemoglobinemia/congênito , Unhas Malformadas/patologia , Adolescente , Gasometria , Cateterismo Cardíaco , Cor , Aconselhamento Diretivo , Fadiga , Testes Genéticos , Humanos , Masculino , Metemoglobinemia/diagnóstico , Metemoglobinemia/tratamento farmacológico , Oximetria , Resultado do Tratamento
10.
Pediatrics ; 143(3)2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30733239

RESUMO

Congenital methemoglobinemia is a rare condition caused by cytochrome b5 reductase deficiency, cytochrome b5 deficiency, or hemoglobin M disease. Newborn pulse oximetry screening was developed for the early detection of critical congenital heart disease; however, it also enables the early identification of other hypoxemic conditions. We present the case of a term neonate who was admitted to the neonatal unit after a failed pulse oximetry screening at 3 hours of age. Oxygen saturations remained between 89% and 92% despite an increase in oxygen therapy. Chest radiograph and echocardiogram results were normal. A capillary blood gas test had normal results except for a raised methemoglobin level of 16%. Improvement was seen on the administration of methylene blue, which also resulted in an increase in oxygen saturations to within normal limits. Further investigation revealed evidence of type I hereditary cytochrome b5 reductase deficiency as a result of a CYB5R3 gene mutation with 2 pathogenic variants involving guanine-to-adenine substitutions. Although mild cyanosis is generally the only symptom of type I disease, patients may later develop associated symptoms, such as fatigue and shortness of breath. If an early diagnosis is missed, these patients are likely to present later with a diagnostic conundrum and be subject to extensive investigation. This case represents the success of pulse oximetry screening in the early identification of subclinical hypoxemia in this infant. After the exclusion of other pathologies, a routine investigation of capillary blood gas provided the information that led to a diagnosis, which allowed for early and effective management.


Assuntos
Metemoglobinemia/congênito , Triagem Neonatal/métodos , Oximetria/métodos , Feminino , Humanos , Recém-Nascido , Metemoglobinemia/sangue , Metemoglobinemia/diagnóstico , Metemoglobinemia/tratamento farmacológico , Azul de Metileno/uso terapêutico
12.
A A Pract ; 12(4): 96-98, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30052534

RESUMO

We present a case of a 73-year-old cancer patient with low transcutaneous oxygen saturation who was transferred to the intensive care unit after deployment of the rapid response team. Differential diagnosis remained broad until methemoglobinemia (MetHb) was detected.MetHb was induced by administration of rasburicase, which was given to prevent tumor lysis syndrome. In a follow-up examination, glucose-6-phosphate dehydrogenase deficiency was found to be the cause of MetHb after rasburicase exposure.Diagnosis was made by either measuring arterial MetHb or CO oximeter. Treatment options involve transfusion and methylene blue, if glucose-6-phosphate dehydrogenase deficiency is not present.


Assuntos
Deficiência de Glucosefosfato Desidrogenase/complicações , Supressores da Gota/efeitos adversos , Metemoglobinemia/diagnóstico , Urato Oxidase/efeitos adversos , Idoso , Humanos , Masculino , Metemoglobinemia/induzido quimicamente , Neoplasias/tratamento farmacológico , Oximetria
13.
Med Klin Intensivmed Notfmed ; 114(4): 345-349, 2019 May.
Artigo em Alemão | MEDLINE | ID: mdl-29666878

RESUMO

BACKGROUND: This case report presents a case of symptomatic methemoglobinemia (MetHb 31.6%) after inhalation of volatile nitrites (poppers). METHODS: The patient's medical history and symptoms are discussed together with pathophysiology of methemoglobinemia, diagnostics, and antidote therapy. Pulse oxymetry, arterial blood gas analysis, and CO-oximetry receive particular attention as well as antidote therapy with methylene blue. RESULTS: The patient was treated successfully with intravenous methylene blue. Within 60 min methemoglobinemia returned to normal values (MetHb 0.6%). CONCLUSION: Stimulating compounds such as volatile nitrites (poppers) may lead to potentially fatal methemoglobinemia. Swift and accurate diagnosis and targeted therapy with methylene blue can lead to rapid recovery.


Assuntos
Metemoglobinemia , Nitritos , Adulto , Antídotos , Humanos , Masculino , Metemoglobinemia/diagnóstico , Metemoglobinemia/etiologia , Azul de Metileno/uso terapêutico , Nitritos/efeitos adversos , Oximetria
14.
Ir Med J ; 111(3): 718, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-30376235

RESUMO

An increase in invasive group A streptococcus (GAS) cases referred to the paediatric infectious disease (PID) department of the Children's University Hospital (CUH), Temple Street, prompted review of all invasive GAS cases in 2016. All of the 10 cases identified occurred over a 16-week period from February to June, of which 6 (60%) required admission to the paediatric intensive care unit. The median length of stay was 21.5 days. Seven had active chickenpox infection at diagnosis. This study highlights the significant morbidity of invasive GAS in children in Ireland. Most cases were associated with a vaccine preventable illness, which should prompt reappraisal of the absence of varicella vaccine from the national immunisation schedule in Ireland.


Assuntos
Reanimação Cardiopulmonar , Serviços Médicos de Emergência , Metemoglobinemia/induzido quimicamente , Metemoglobinemia/tratamento farmacológico , Azul de Metileno/administração & dosagem , Nitritos/efeitos adversos , Administração por Inalação , Biomarcadores/sangue , Transtornos da Consciência/etiologia , Cianose/etiologia , Emergências , Feminino , Humanos , Infusões Intravenosas , Metemoglobina/análise , Metemoglobinemia/complicações , Metemoglobinemia/diagnóstico , Pessoa de Meia-Idade , Nitritos/administração & dosagem , Índice de Gravidade de Doença , Resultado do Tratamento , Volatilização
15.
Med. clín (Ed. impr.) ; 151(7): 278-280, oct. 2018.
Artigo em Espanhol | IBECS | ID: ibc-173949

RESUMO

Antecedentes y objetivo: La metahemoglobinemia es un cuadro de intoxicación aguda típico de niños menores de un año. Se produce por un exceso de nitratos que producen la oxidación del hierro de la hemoglobina impidiendo su adecuada unión al oxígeno. Es más frecuente en lactantes debido a su inferior actividad enzimática. Pacientes: Dos casos de lactantes de 15 meses con cuadros de metahemoglobinemia tras ingesta de verduras, atípicos por la edad de los pacientes y por la severidad inicial en el primer caso, que llegó a simular un cuadro séptico. En ambos casos se logró la resolución del cuadro con adecuada oxigenoterapia. Conclusiones: Aunque la clínica más frecuente es cianosis asociada a dificultad respiratoria, la metahemoglobinemia puede presentarse con cuadros más severos y confusos y en mayores de un año. El tratamiento de elección es oxigenoterapia a altas concentraciones y azul de metileno como antídoto por vía intravenosa únicamente en casos seleccionados. La ingesta de vegetales es el principal causante de este cuadro, por lo que es importante dar la información adecuada a los padres sobre el consumo y la conservación de estos alimentos


Background and objectives: Methaemoglobinaemia is a typical acute intoxication disorder in children under one year old. It is produced by excess nitrates which induce the haemoglobin's iron oxidation, preventing its adequate binding to oxygen. It is more frequent in infants due to its lower enzymatic activity. Patients: Two cases of 15-month-old infants with methaemoglobinaemia after the intake of vegetables, atypical by the age of the patients and the initial severity in the first case that simulated a septic syndrome. Both cases evolved well with adequate oxygen therapy. Conclusions: Although the most frequent clinical manifestation is cyanosis associated with respiratory distress, methaemoglobinaemia can present with more severe and confusing symptoms. The main treatment is oxygen therapy at high concentrations and methylene blue as an intravenous antidote only in selected cases. The intake of vegetables is the main cause of this in infants, so it is important to give adequate information to parents about the consumption and preservation of these foods during the first year of life


Assuntos
Humanos , Masculino , Lactente , Metemoglobinemia/diagnóstico , Oxigenoterapia , Nitratos/toxicidade , Metemoglobinemia/terapia , Metemoglobinemia/etiologia , Nitratos/efeitos adversos , Lactente , Cianose
16.
J Ayub Med Coll Abbottabad ; 30(2): 301-303, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29938442

RESUMO

A 51-year-old male was referred to the diabetes clinic by the GP with low HbA1c (13 mmol/mol). His complaints were dizziness and intermittent palpitations for the last two years. No precipitating cause could be identified. He denied any chest pain, shortness of breath or syncope. He had a background of schizophrenia, epilepsy, coeliac disease, depression and dermatitis herpetiformis. He was on dapsone, venlafaxine, procyclidine, furosemide, diazepam, omeprazole, meloxicam and folic acid. On examination, his pulse was 82 beats per minute, blood pressure 131/74 mm of Hg, respiratory rate was 14/minute and his saturations on room air were 94%. Neurologic, cardiovascular, respiratory and abdominal examination was unremarkable. His investigations showed Hb of 121g/L (130-180) WCC 7.8*10 g/L (4-11), platelets 182*10 (150-400), MCV 83 fl (80-100), TSH 2.53 mU/L (0.4-4.0 mU/L), anti TTG 14.9 (normal). Renal, liver function, serum folate, vitamin B12 and complement levels were within normal limits with a negative ANCA and ANA. His oral glucose tolerance test was negative for diabetes with fasting and twohour post prandial blood sugar of 4.8mmol/L and 6.9 mmol/L respectively. Because of the history of chronic Dapsone use and possibility of drug induced low HbA1C, patient was investigated along those lines. The low Hba1c was attributed to haemolysis secondary to dapsone. HbA1c improved to 42 mmol/mol within three months following discontinuation of dapsone. His haemoglobin level also normalized (142 g/L). Clinicians should consider haemolysis as a possible factor falsely reducing HbA1c while interpreting results in these patients. This is of particular importance in patients with diabetes.


Assuntos
Glicemia/metabolismo , Dapsona/efeitos adversos , Hemoglobina A Glicada/deficiência , Metemoglobinemia/induzido quimicamente , Anti-Infecciosos/efeitos adversos , Diabetes Mellitus/diagnóstico , Diagnóstico Diferencial , Jejum/sangue , Hemoglobina A Glicada/metabolismo , Humanos , Masculino , Metemoglobinemia/sangue , Metemoglobinemia/diagnóstico , Pessoa de Meia-Idade
17.
Arch. argent. pediatr ; 116(3): 429-432, jun. 2018. tab, ilus
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-950020

RESUMO

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.


Assuntos
Humanos , Masculino , Adolescente , Cianose/etiologia , Metemoglobinemia/congênito , Cianose/diagnóstico , Diagnóstico Diferencial , Metemoglobinemia/complicações , Metemoglobinemia/diagnóstico
18.
Arch Argent Pediatr ; 116(3): e429-e432, 2018 06 01.
Artigo em Espanhol | MEDLINE | ID: mdl-29756717

RESUMO

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.


Assuntos
Cianose/etiologia , Metemoglobinemia/congênito , Adolescente , Cianose/diagnóstico , Diagnóstico Diferencial , Humanos , Masculino , Metemoglobinemia/complicações , Metemoglobinemia/diagnóstico
19.
Neth J Med ; 76(4): 194-197, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29845943

RESUMO

A 61-year-old Ghanaian woman presented with dizziness and low oxygen saturations whereupon a methaemoglobin level of 24.9% was obtained. Initially it was thought to be caused by an unknown toxin. However, failure to normalise spontaneously and a short recurrence following administration of methylene blue suggested a congenital cause. Subsequently a novel variant in the CYB5R3 gene, coding for Cytochrome b5 reductase, was demonstrated. Absence of polycythaemia prompted additional analysis for a concomitant haemoglobinopathy.


Assuntos
Citocromo-B(5) Redutase/deficiência , Citocromo-B(5) Redutase/genética , Metemoglobina/metabolismo , Metemoglobinemia/congênito , Metemoglobinemia/genética , Feminino , Humanos , Metemoglobinemia/diagnóstico , Pessoa de Meia-Idade
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