A 23-year-old man is brought to the emergency department due to generalized weakness and abdominal pain. One week earlier, he began a diet challenge that involved a "juice cleanse" and exclusive consumption of raw vegetables. He does not use tobacco, alcohol, or illicit drugs. The patient's mother has hypothyroidism and his father died of lung cancer. Temperature is 37.8 C (100 F), blood pressure is 110/70 mm Hg, pulse is 110/min, and respirations are 27/min. The oral mucosa is dry. Laboratory results are as follows:
| Sodium | 132 mEq/L |
| Potassium | 5.4 mEq/L |
| Chloride | 96 mEq/L |
| Bicarbonate | 12 mEq/L |
| Creatinine | 1.8 mg/dL |
| Glucose | 375 mg/dL |
Which of the following is the most likely cause of the increased potassium level in this patient?
Show Explanatory Sources
This young patient with marked hyperglycemia (glucose >300 mg/dL), anion gap metabolic acidosis, dehydration (eg, dry mucous membranes, tachycardia), and abdominal pain has diabetic ketoacidosis (DKA), indicating a new diagnosis of type 1 diabetes mellitus. Calorie and carbohydrate restriction can cause ketosis and precipitate DKA in patients with type 1 diabetes mellitus.
Most patients with DKA have normal or elevated serum potassium values on laboratory testing, but actually have a total body potassium deficit. The overall potassium deficit is due to urinary potassium losses from osmotic diuresis, elimination of ketoacid anions as potassium salts (seen only in DKA), and secondary hyperaldosteronism resulting from volume contraction, which leads to potassium excretion and reabsorption of sodium in the distal renal tubule (Choices B, D, and E). Despite this deficit, normal or elevated laboratory potassium measurements occur due to:
Administration of insulin during treatment drives potassium into cells and can rapidly lead to hypokalemia. For this reason, potassium should be monitored closely and added to intravenous fluids whenever serum potassium is <5.3 mEq/L.
(Choice A) Although vegetables and juices can contain high levels of potassium, this patient's anion gap metabolic acidosis and hyperglycemia point to hyperosmolarity and insulin deficiency as more likely causes of the laboratory findings.
(Choice F) Acute onset of abdominal pain and elevated creatinine can be seen in hemolytic uremic syndrome or thrombotic thrombocytopenic purpura, conditions associated with intravascular hemolysis and hyperkalemia (due to destruction of red blood cells). However, this patient's severe hyperglycemia (blood glucose >300 mg/dL) and anion gap acidosis suggest DKA.
Educational objective:
Diabetic ketoacidosis causes osmotic diuresis and secondary hyperaldosteronism, leading to urinary potassium loss and a total body potassium deficit. However, laboratory potassium values are often normal or elevated. This finding is due to hyperosmolarity, which draws water and potassium into the extracellular space, and insulin deficiency, which impairs cellular uptake of potassium.