Clinical Mysteries • Electrolytes
The Weakness After Diuresis
The presentation
After aggressive diuresis, a heart-failure patient developed weakness, cramps and ectopy.
The first explanation was plausible, but the pattern did not fully fit. A deliberate second look focused on physiology, medication/exposure history, serial observations and the clue that the initial diagnosis could not explain.
The turn
Potassium replacement alone failed until magnesium was corrected.
Diagnosis
Hypokalaemia with hypomagnesaemia
Why this case matters
Refractory hypokalaemia often has a magnesium story.
Take-home message: When the clinical course contradicts the working diagnosis, stop escalating the same treatment and rebuild the problem from first principles.