It should be noted that using oxidants such as methylene blue in patients with G6PD deficiency may cause severe hemolytic crisis.5 and 6 There are two forms of methemoglobinemia, congenital and acquired forms. Diaphorase-I deficiency, hemoglobin variants (Hgb H, Hgb M) and G6PD deficiency are major causes of congenital form.1 Environmental exposure and toxins are acquired causes of the disorder. Nitrates, chlorates, aniline are agents which may lead to methemoglobinemia.7 In a retrospective study 138 cases of acquired methemoglobinemia were selleck examined and etiologic agents were found to be dapsone in 42%, benzocaine

in 4%, primaquine in 4% of the patients. A known side effect of dapsone therapy is methemoglobinemia during its usage in autoimmune diseases and prophylaxis against Pneumocystis pneumonia (PCP) caused by Pneumocystis jirovecii. In another study performed on 242 cases of methemoglobinemia related with anesthesia and benzocaine found to be responsible in 60% of the cases.8 In our case there was no history of drug use or environmental exposure, and the most significant complaint was shortness of breath induced by exercise. Considering that the patient’s brother also died

with similar complaints at the age of fifteen, strengthening the idea that methemoglobinemia Autophagy inhibitor cost is congenital in this patient. The diagnosis and treatment of bronchial asthma by previous physicians, may be explained with insufficient investigation of the complaints, findings and history. After exposure to fenasetin and sulfanamid a rare disorder, sulfhemoglobinemia, may occur which can be clinically confused with methemoglobinemia. The distinction can be made by non-responsiveness of sulfhemoglobinemia to treatment with methylene blue. Additionally, the definitive diagnosis can be made by spectrometric examination.9 Administration of 1–2 mg/kg IV methylene blue and oral vitamin C have great help for the treatment of methemoglobinemia. N-acetylcysteine, cimetidine and ketokanazol all are experimental but promising treatments in methemoglobinemia yet. Exchange transfusion is

an alternative treatment in patients who are refractory to methylene blue.10 We met a similar methemoglobinemia case in the literature who was treated as asthma previously. Because cyanosis and shortness of breath complaints were constant despite the asthma therapy, the patient was detected and homozygous type 1b5r deficiency was found in the patient. The authors stated that the patient was freed from unnecessary treatment and the use of unnecessary drugs.11 Existence of dyspnea, hypoxemia and cyanosis in a patient firstly signs heart diseases (atrial septal defect, ventricular septal defect, etc.) and lung diseases (pulmonary embolism, etc.). Therefore evaluation of these diseases is a normal procedure.