A woman in her 50s with a history of gastric bypass surgery presented for evaluation of fatigue. She was found to have iron deficiency anemia. Intravenous iron treatments led to a hematologic response, albeit with minimal improvement in fatigue. Following restoration of iron stores, she developed polycythemia, with a hemoglobin level of 16 g/dL (to convert to g/L, multply by 10.0) and hematocrit level of 50.6%. She denied dyspnea, wheezing, snoring, witnessed apneas during sleep, aquagenic pruritus (itching after contact with warm water), or erythromelalgia (painful erythema of the palms or soles). She had no history of cigarette smoking, high altitude or carbon monoxide exposure, or cardiopulmonary disease. Obstructive sleep apnea (OSA) questionnaire scores were low. On examination, vital signs were normal and body mass index (calculated as weight in kilograms divided by height in meters squared) was 25.3. She had facial ruddiness, palmar erythema, and clear lungs, but no cyanosis or clubbing of her digits. White blood cell and platelet counts were normal. Serum erythropoietin (EPO) level was 6 mU/mL (normal range, 3-18 mU/mL). Testing results for JAK2 V617F, JAK2 exon 12 mutations, and hereditary erythrocytosis genes (EPO receptor, hypoxia-inducible factor 2α, proline hydroxylase domain-2, and von Hippel Lindau gene mutations) were negative. Carboxyhemoglobin, hemoglobin electrophoresis, and P₅₀ hemoglobin-oxygen dissociation curve were normal. Total testosterone level was minimally elevated at 54 ng/dL (normal range, 2-45 ng/dL; to convert to nmol/L, multiply by 0.0347). Abdominal and pelvic imaging showed uterine fibroids, but a gynecologic evaluation found these to be clinically insignificant. Bone marrow biopsy results showed no morphologic features of myeloproliferative neoplasm. A sleep study, surprisingly, revealed OSA. After starting nocturnal positive airway pressure therapy, her fatigue markedly improved, and her polycythemia completely resolved.

一名50多岁，有胃旁路手术史的女性出现，用于评估疲劳。发现她患有缺铁性贫血。静脉铁剂治疗可导致血液学反应，尽管对疲劳的改善很小。恢复铁存储后，她发展为红细胞增多症，血红蛋白水平为16 g / dL（转换为g / L，多为10.0），血细胞比容水平为50.6％。她否认呼吸困难，喘息，打，睡眠中出现呼吸暂停，水生性瘙痒（接触温水后瘙痒）或红斑性肌痛（手掌或足底疼痛性红斑）。她没有吸烟，高空或一氧化碳暴露或心肺疾病的病史。阻塞性睡眠呼吸暂停（OSA）问卷得分较低。经检查，生命体征正常，体重指数（以体重（公斤）除以身高（米）计算）为25.3。她有面部红润，手掌红斑和清晰的肺部，但没有发osis或指状肿块。白细胞和血小板计数正常。血清促红细胞生成素（EPO）水平为6 mU / mL（正常范围为3-18 mU / mL）。的测试结果JAK2 V617F，JAK2外显子12突变和遗传性红细胞增多症基因（EPO受体，缺氧诱导因子2α，脯氨酸羟化酶结构域2和von Hippel Lindau基因突变）均为阴性。羧基血红蛋白，血红蛋白电泳和P ₅₀血红蛋白-氧解离曲线正常。总睾丸激素水平最低增至54 ng / dL（正常范围为2-45 ng / dL；转换为nmol / L，乘以0.0347）。腹部和骨盆成像显示子宫肌瘤，但经妇科评估发现它们在临床上无意义。骨髓活检结果未显示骨髓增生性肿瘤的形态学特征。令人惊讶的是，一项睡眠研究发现了OSA。开始夜间进行气道正压通气治疗后，她的疲劳明显改善，并且红细胞增多症完全消退。