Cruz António José, Castro Alexandra
Serviço de Medicina Interna, Centro Hospitalar de Entre o Douro e Vouga-Hospital de São Sebastião, Santa Maria da Feira, Portugal.
BMJ Case Rep. 2013 Jan 22;2013:bcr2012007929. doi: 10.1136/bcr-2012-007929.
A 32-year-old woman with no significant medical history was sent to our consultation due to hypokalaemia (<3.0 mmol/l). Her main complaints were longstanding polyuria and nocturia. Physical examination was normal. Basic investigations showed normal renal function, low serum potassium (2.7 mmol/l) and magnesium (0.79 mmol/l), metabolic alkalosis (pH 7.54; bicarbonate 32.5 mmol/l), elevated urinary potassium (185 mmol/24 h) and normal urinary calcium (246 mg/24 h). Thiazide test revealed blunted response. Chronic vomiting and the abuse of diuretics were excluded. Genetic tests for SLC12A3 gene mutation described in Gitelman syndrome (GS) came negative. CLCNKB gene mutation analysis present in both GS and Bartter (BS) type 3 syndromes was positive. The patient is now being treated with potassium and magnesium oral supplements, ramipril and spironolactone with stable near-normal potassium and magnesium levels. This article presents the case of a patient with hypokalaemia caused by CLCNKB gene mutation hard to categorise as GS or BS type 3.
一名32岁无重大病史的女性因低钾血症（<3.0 mmol/l）前来我们科室咨询。她的主要症状是长期多尿和夜尿。体格检查正常。基本检查显示肾功能正常、血清钾（2.7 mmol/l）和镁（0.79 mmol/l）偏低、代谢性碱中毒（pH 7.54；碳酸氢盐32.5 mmol/l）、尿钾升高（185 mmol/24 h）以及尿钙正常（246 mg/24 h）。噻嗪类试验显示反应减弱。排除了慢性呕吐和利尿剂滥用。吉特曼综合征（GS）中描述的SLC12A3基因突变的基因检测结果为阴性。GS和巴特综合征（BS）3型综合征中均存在的CLCNKB基因突变分析结果为阳性。该患者目前正在接受钾和镁口服补充剂、雷米普利和螺内酯治疗，钾和镁水平接近正常且稳定。本文介绍了一例由CLCNKB基因突变导致低钾血症的患者，该病例难以归类为GS或BS 3型。
