جستجوی مقالات مرتبط با کلیدواژه « Methemoglobinemia » در نشریات گروه « پزشکی »

Methemoglobinemia is one of the rare causes of cyanosis, encountered in the Emergency Department. It can be congenital or acquired, affecting the oxygen binding capacity of hemoglobin, thus shifting the oxyhemoglobin dissociation curve to the left. It is potentially life-threatening, but it responds well to specific therapies, if recognized and intervened early. MetHb levels >70% are often described as incompatible with life.

Case:

 Here, we describe two cases of near-fatal MH (MetHb levels >70%), one with intentional and the other with accidental ingestion of substance-producing MH, and its management which highlights how timely diagnosis and prompt appropriate treatment in the Emergency Department can be lifesaving. Both cases were at physiological extremes on arrival to the ED. However, the early clinical suspicion and prompt diagnosis of methemoglobinemia, which was confirmed by blood co-oximetry, helped expedite the delivery of specific anti-dote for methemoglobin, i.e., intravenous methylene blue. Both patients responded well to the treatment and were hemodynamically stable within 6 hours

Cyanosis, which does not respond to oxygen, and low saturation levels not responding to oxygen therapy should raise the suspicion of Methemoglobinemia (MH). Early diagnosis and prompt administration of methylene blue are the key factors for survival.

‘Prinso’ is a fabric stain remover, which is consisted of two sachets, one containing brown crystals (potassium permanganate) and the other white granules (calcium oxalate). The product is made by small scale manufacturers of Sri Lanka and has become popular as a remover of stains. Recently, deliberate self-poisoning with ‘Prinso’ has become common in both rural and urban areas of Southern Province of Sri Lanka. A prospective clinical study was conducted in Teaching Hospital Ratnapura, Sri Lanka over 3 years commencing from July 2017. Epidemiological data, clinical features, treatments, and outcomes were collected. The data were analyzed through SPSS software version 21, using descriptive statistics. There were 274 (9.5%) patients with ‘Prinso’ poisoning out of which 140 (51%) were males and 134 (49%) were females. All were deliberate self-poisonings and 117 (43%) ingested oxalate alone; 31 (11%) ingested only permanganate, and 126 (46%) ingested both chemicals. The age ranged from 13-80 years (mean 31.6 ± 14 years) and the most commonly affected age group was 12-31 years (165;60%). The majority of patients were unemployed (108;39%) and 22 (8%) schooling children. Most patients (n=145;53%) were admitted to hospital within 1-4 hour of the ingestion (median 2 hrs and IQR 2-4 hrs) from Ratnapura (n=74;27%). Most of them (n=78;28.5%) were treated at hospital for 3 days (mean 4.8 days, IQR 2-6 days). Decontamination was done for 88% (n=239). Gastrointestinal symptoms including nausea (n=90;33%), vomiting (n=193;70%) and epigastric pain (n=141;52%) occurred frequently. The main complications among the patients were acute kidney injury [AKI] (110;40%), hypocalcemia (38;14%), hypotension (29;11%), ECG changes (27;10%), and methemoglobinemia (26;9.5%). Hemodialysis was done for 39 (14%) and 20 (7%) were treated at intensive care unit from which 13 (5%) were intubated. Methylene blue (antidote) was given to 25 (9%). Leukocytosis was observed in 118 (43%) patients and 236 (86%) were recovered. Despite medical attempts, 22 (8%) died. Case fatality rate for ‘Prinso’ poisoning was found to be 6.6% (90% CI 2.3-13.4;P < 0.05). ‘Prinso’ is a deadly poisoning household agent and AKI is the most common clinical manifestation.

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.
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.
This prospective cohort study was conducted from January 2017 to December 2019. Demographic data including age, gender, and weight of patients were collected. Sixty patients were randomly divided into three groups (n=20) regarding the local anesthetic agent administered for hemostasis during surgery as lidocaine group (group 1), articaine group (group 2), and control group (no local anesthetic; group 3). The patients were candidates for orthognathic surgery, reconstruction of the maxillary and mandibular atrophic ridges with autogenous grafts, and reconstruction of maxillofacial fractures. The methemoglobin level was measured before surgery and six hours after the initiation of surgery.
The mean age and weight of patients were not significantly different among the three groups (p= 0.891 and p= 0.416, respectively). No significant differences were observed among the three groups regarding the gender distribution (p= 0.343) or type of surgery (p= 0.990). Statistical analysis did not show any significant difference in the mean baseline methemoglobin level among the three groups (p= 0.109). Although the mean methemoglobin values increased in the three groups, paired sample t-test did not show any significant change in the values at six hours after the initiation of surgery compared with baseline in any of the three groups (p= 0.083 for group 1, p= 0.096 for group 2, and p= 0.104 for group 3).
The results demonstrated that administration of lidocaine and articaine plus epinephrine for hemostasis during general anesthesia are equally safe.

Methemoglobinemia is a rare autosomal recessive genetic disease caused by disruptive mutations in the CYB5R3 gene (MIM: 250800). Herein, a novel mutation is reported in an Iranian patient affected with methemoglobinemia type II. In this case study, the patient is precisely described according to the thoroughly carried-out examinations and workups. In so doing, the peripheral blood sample was collected to evaluate the methemoglobin level and NADH-CYB5R3 activity test. Moreover, whole-exome sequencing (WES) was recruited to identify the mutation leading to this disorder. Subsequently, Sanger sequencing was employed to confirm the detected mutation. Magnetic Resonance Imaging was also performed to explore the structure of the brain. As identified by the blood test, the methemoglobin level increased up to 25%, and the NADH-CYB5R3 enzyme activity showed to be 13.8 IU/g of Hb. A novel homozygous mutation in CYB5R3 (NM_001171661: g.23435C>T, c.181C>T, p.R61X, rs1210302322) was identified as the cause of the Methemoglobinemia type II in the proband. This nonsense mutation alters arginine to the stop codon at position 61 of protein in the FAD-binding domain that results in a truncated protein. The MRI revealed brain atrophy and corpus calusom hypoplasticity. It was established that this variation can lead to Methemoglobinemia. The proband demonstrates Methemoglobinemia type II phenotype such as cyanosis, severe mental retardation, microcephaly, as well as developmental delay. The brain MRI revealed brain atrophy and corpus calusom hypoplasticity.The cyanosis symptom is managed by daily ascorbic acid uptake.

Recurring annual asthma or asthma-like outbreak in Ahvaz City, Iran, has become a serious public health problem. A toxic gas, a chemical compound, or an allergen with unknown nature and mechanism leads to severe asthma outbreaks each year. Bronchospasm, cough, dyspnea, chest tightness, and wheezing are the main symptoms of these attacks. Oxygen and anti-asthma therapy are effective treatments in outbreak management. Based on our findings, it is hypothesized that vast amounts of ammonium nitrate used in agriculture underlay high concentrations of nitrate. This substance is transported by PM10 and is the main cause of the respiratory outbreak. The concentration of nitrate was determined by the ion chromatography method in dust samples during 2015-2016. Using spectroscopic methods, the effect of nitrate ions on hemoglobin oxidation and methemoglobin formation was studied. Our results indicate that the concentration of ammonium nitrate in dust collected from indoor spaces is five times higher than the levels allowed amount in airborne pollutants. Our findings also indicate that this concentration of nitrate in the bloodstream can instantly increase methemoglobin percent to 18% with symptomatic consequences. The exact mechanism proposed by this study is that inhaled nitrate or nitric acid finally increases the nitrate in the circulation of affected individuals. Hemoglobin oxidation and methemoglobin formation are the subsequent events leading to methemoglobinemia with asthma-like reactions seen in Ahvaz respiratory syndrome. Restricting or even prohibiting ammonium nitrate application in agriculture seems to be an urgent measure to stop Ahvaz's recurring respiratory syndrome.

Methemoglobinemia is a rare disease characterized by the elevated levels of methemoglobin in the blood. It may be congenital or acquired. Co-trimoxazole is an antibiotic that belongs to the sulfone group. Sulfone group drugs may produce drug-induced acquired methemoglobinemia. Methemoglobin is an oxidized form of hemoglobin that has an increased affinity to oxygen and a reduced ability to release oxygen to tissues. High levels of methemoglobin in red blood cells cause tissue hypoxia. This disorder may present with several symptoms such as cyanosis, fatigue, dyspnea, and headache. Because it is a rare cause of cyanosis and hypoxemia, the diagnosis of methemoglobinemia is often delayed. We herein discuss a five-year-old boy with steroid-resistant nephrotic syndrome who presented with exertional dyspnea and cyanosis and was later diagnosed as a case of co-trimoxazole-induced methemoglobinemia.

Substituted urea herbicide is widely used in the agricultural industry and is accessible to most people around the globe. Accidental or deliberate poisoning is an anticipated complication of these agrochemical products.

We present a 15-year-old girl following deliberate self-ingestion of substituted urea herbicide (Diuron). She was diagnosed with Diuron induced methemoglobinemia and treated with intra venous methylene blue. Later she developed hemolytic anemia and needed 3 units of blood transfusions. Her haemolysis was thought to be due to methylene blue with concomitant Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency as no other possible cause was found for haemolysis. But on follow-up visits, G6PD deficiency was excluded by screening test and enzyme level assay.

Heamolytic anemia is a possible rare complication that should be anticipated in patients presented with the significant amount of substituted urea herbicide poisoning. Studies have found the possibility of reactive oxygen species accumulation in cells leading to oxidative damage. But we were unable to find any reported cases of haemolysis in humans. We postulate that the inhibition of NADPH production like G6PD deficiency may be the key mechanism that causes haemolysis in humans by creating an acquired G6PD deficiency status in red blood cells. However, further studies are needed to identify the exact mechanism of hemolysis in humans.

This is a retrospective study to investigate the effects of Carboxyhemoglobin (COHb) and Methemoglobin (MetHb) levels in the diagnosis and prognosis of Pulmonary Thromboembolism (PTE). Cases that were confirmed with PTE diagnosis using CT Pulmonary Angiography (CTPA) or Ventilation/Perfusion Scintigraphy were accepted as pulmonary embolism. And patients which were excluded using the same methods were accepted as the control group. Patients with carbon monoxide poisoning, Chronic Obstructive Pulmonary Disease (COPD), sepsis, pneumonia, asthma, idiopathic pulmonary fibrosis, bronchiectasis, decompensated cardiac failure or those who used drugs that cause methemoglobinemia (sulphanomides, dapson, phenacetin, primacine,benzocaine) were not included in the study. In our study, 462 patients were examined with an initial PTE diagnosis. Among these patients, 107 patients who met the inclusion criteria were included in the study. The mean age of all patients was 56.44 ±17.3 years (21-86) and the mean age of patients with PTE diagnosis was 55.3 years and the mean age of excluded patients was 59 years (p:0.27). When the blood gas parameters of both groups were compared, COHb levels in the groups with PTE diagnosis were statistically significantly higher (p=0.001), and the PO2 levels in the group excluded for PTE diagnosis were statistically significantly higher (p=0.028). In our study, six of our patients (8.1%) died in the early stages because of PTE. In our study, COHb level was found to be statistically significant in the group with PTE. However, this value was not higher than the normal COHb level in the blood. We found that MetHb and COHb levels were not statistically significant in the prognosis of PTE.

One of the complications of nitroglycerin infusion during surgery is methemoglobinemia. The aim of this study was to investigate the prevalence of methemoglobinemia and its association with nitroglycerin infusion for the treatment of hypertension during general anesthesia. Patients received nitroglycerin infusion at a dose of 2 μ/kg/min. The aim of controlling blood pressure was to set the blood pressure at 20% of the patient’s baseline. Then, the amount of methemoglobin was recorded at 15-minute intervals. Backward stepwise logistic regression test was used to determine the factors affecting methemoglobinemia. Based on the criterion of methemoglobin level above 2%, the prevalence of pathologic methemoglobinemia was 56.6%. After adjusting for confounding variables in the final model, the total prescribed dose was the only factor affecting pathologic methemoglobinemia. For the first time, we showed that more than half of the patients undergoing surgery suffered from methemoglobin level above 2% after prescribing nitroglycerin, and the only predictor of abnormal methemoglobin level was the rate of nitroglycerin prescription. Anesthesiologists are recommended to be more careful about the speed of nitroglycerin infusion, and if the patient needs higher doses, patient care for the early detection of methemoglobinemia should be the priority.

The aim of present work was to evaluate the drinking water quality from various regions including both urban and rural areas of Hamadan Province, western Iran. In this cross-sectional descriptive study, the samples were collected for a periods of 12 months between January 25, 2014 and January 25, 2015 from frequently used household taps as well as from municipal and communal water supplies. The main parameters investigated were nitrate, fluoride, pH, turbidity and chlorine. The maximum and minimum values for nitrate concentrations were measured as 140.80 mg/l and 1.56 mg/l, respectively. Nitrate and fluoride content of samples were higher in wet season than in dry season and their concentration was higher in rural areas rather to urban areas. On average, fluoride contents in both urban and rural areas were well compliance with the WHO guidelines. The pH of all samples of the study regions was in the ranges of 6.25 to 8.41 that were in the standard ranges. Twenty three percent of total samples were exceeded Iranian standards of one NTU for turbidity. The groundwater of the study area is presently having not serious health risks. However, regarding that disinfection efficiency adversely is affected by turbidity, particular attention and more programs for regular monitoring has to be done, which will not always be done in all regions.

Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin. Prilocaine which is one of the oxidizing local anaesthetics is widely used in many local procedures. The first choice of treatment of complications due to the use of these local anaesthetics is methylene blue, while ascorbic acid is the alternative choice. The side effects of metilen blue restrict its usage in some special conditions. Ascorbic acid is a good alternative drug with limited experience in methemoglobinemia. We present a case of a methemoglobinemia treated with ascorbic acid successfully to emphasize the use of ascorbic acid as an alternative method..

Subclinical methemoglobinemia (MetHb) is an occult disease. Clinical diagnosis is difficult. Acquired MetHb is a most common presentation in practice, and its detection help to improve health status of involved individuals. Healthcare professionals enumerate as one of the at risk groups against adverse health effects. All the participations were hospital healthcare professionals and to follow designed criteria to the study. A total of 117 healthcare professionals fulfilled the criteria of study. Mean age was 39±9 SD years, ranged 20-60 years. Female sex included 52%. Frequency of MetHb was detected in 6% of population. Of them, 71% were male. All the subjects were diagnosed with MetHb located at the poor-ventilated workplaces. There were significant differences between MetHb and carboxyhemoglobin levels (P<0.001). Subclinical MetHb was meaningful in the target of population. It may be originated due to ambient air pollution. There was high-frequency levels of involvement in men had. Evaluation the causal factors are an impact that will require the future studies.

Congenital methemoglobinemia is a rare cause of cyanosis. We report a case of a girl, 17 years old with peripheral cyanosis and normal cardio-pulmonary system. She was diagnosed as a case of methemoglobinemia based on findings of polycythemia and HbM band on hemoglobin electrophoresis. We emphasize the importance of this rare entity in the differential diagnosis of cyanosis.