Differential diagnosis for chronic hypokalaemia.

Doctors will often see patients with chronic hypokalaemia, frequently this is secondary to gastrointestinal losses, diuretics or renal disease. However, in this case report we review a rarer cause of chronic hypokalaemia-Gitelman syndrome (GS).GS is an uncommon genetic disorder which causes primary renal tubular hypokalaemic metabolic alkalosis with secondary hypomagnesaemia and hypocalciuria. Although rare, it is important to remember GS when considering differential diagnoses for chronic hypokalaemia. We report the case of a woman who presented to the ophthalmology department with sclerochoroidal calcification. An ophthalmologist was reviewing the medical literature, which prompted them to investigate for GS. A diagnosis was formed at that time based on the blood and urine chemistry results. However, later we were able to offer the patient genetic testing, which confirmed our provisional diagnosis. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.