Interactive diabetes case 15: A 74-year-old patient with type 2 diabetes and recurrent hyperkalemia – C2

ANSWER — 

Correct.

Increases in the doses of insulin are necessary for the management of the patient's uncontrolled diabetes but not sufficient at this time to produce a meaningful decrease in the serum potassium level.

The patient needs additional therapy to break the pattern of recurrent hyperkalemia, which can no longer be attributed to hyperglycemia-induced hyperkalemia, to medications, or to impaired kidney function at the current levels of serum creatinine.

The patient now has the typical profile of a patient with hyporeninemic hypoaldosteronism (type 4 renal tubular acidosis [RTA]): over 50 years of age with diabetic nephropathy and mild to moderate impaired kidney function. The blood glucose levels are not sufficiently elevated to explain the hyperkalemia, she is no longer on medications that cause hyperkalemia, and she is following a low potassium diet. It is time to initiate fludrocortisone.

Four days later, the serum potassium level is 5.1 mEq/L. It falls progressively to 4.2 mEq/L over the next six weeks and remains normal thereafter. Concurrently, the blood urea nitrogen (BUN) falls to 35 mg/dL and the serum creatinine level to 1.3 mEq/L.

Evaluation and management of this patient is discussed further separately. (See "Interactive diabetes case 15: A 74-year-old patient with type 2 diabetes and recurrent hyperkalemia – Comment".)