Life-threatening hypokalaemia on a low-carbohydrate diet associated with previously undiagnosed primary hyperaldosteronism [corrected].
BACKGROUND
Low-carbohydrate diets are popular and fashionable for weight loss despite lack of evidence about long-term effects. Many individuals attempting to lose weight have hypertension, especially those with diabetes, and the prevalence of hyperaldosteronism among hypertensive patients is higher than previously recognized. We present a patient with Type 2 diabetes and previously undiagnosed hyperaldosteronism who developed life-threatening hypokalaemia while following a low-carbohydrate diet.


METHODS
A 60-year-old man with diet-treated Type 2 diabetes and hypertension presented with generalized muscle weakness and serum potassium of 1.9 mmol/l. He had succeeded in losing three and a half stones during the previous 4 months by adhering strictly to a low-carbohydrate diet. HbA(1c) was 4.8% and plasma aldosterone:renin ratios were elevated suggestive of increased aldosterone secretion. On a low-calorie mixed diet serum potassium levels were maintained in the low-normal range over the following 165 days. The adrenals were normal on CT scanning and blood pressure responded dramatically to the addition of spironolactone on day 212 (125/83 mmHg).


CONCLUSIONS
The prevalence of primary hyperaldosteronism in the hypertensive population, based on elevation of plasma renin:aldosterone ratio, is approximately 6%. The majority of these people are normokalaemic and remain undiagnosed. However, when carbohydrate intake is restricted such individuals are at increased risk of potentially life-threatening metabolic derangements.
Advani
A
A
Department of Diabetes and Metabolism, Medical School, William Leech Building, 1 Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Andrew.Advani@ncl.ac.uk
Taylor
R
R
D000450:Aldosterone / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D004038:Diet, Reducing / Q000009:adverse effects*; D004040:Dietary Carbohydrates / Q000009:adverse effects*; D006801:Humans; D006994:Hypoaldosteronism / Q000097:blood / Q000188:drug therapy / Q000209:etiology*; D007008:Hypokalemia / Q000188:drug therapy / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D000451:Mineralocorticoid Receptor Antagonists / Q000627:therapeutic use; D012083:Renin / Q000097:blood; D013148:Spironolactone / Q000627:therapeutic use; D016896:Treatment Outcome
D004040:Dietary Carbohydrates; D000451:Mineralocorticoid Receptor Antagonists; D013148:Spironolactone; D000450:Aldosterone; D012083:Renin