Orange juice overdose - a quirky case history of potentially fatal hyperkalemia

The notion that orange juice may be harmful to health seems counterintuitive if not bizarre, but as a recently published case history reveals, orange juice contains significant amounts of potassium and ingestion of large quantities of orange juice can lead to hyperkalemia of sufficient severity to threaten life. 

Over a period of a few days the 51-year old subject of this case history developed muscle weakness that progressed to flaccid paralysis in all four limbs requiring urgent hospital referral. Admission laboratory testing revealed severe hyperkalemia, serum potassium 9.0 mmol/L, a level associated with high risk of life threatening cardiac arrhythmias and sudden cardiac arrest. 

Emergency treatment was successful with return of serum potassium to a normal value of 5.0 mmol/L within a few hours. Neuromuscular function was restored over the same time period. 

In the absence of renal insufficiency (the most common pathological cause of hyperkalemia) and with exclusion of endocrine causes, this episode of hyperkalemia was finally attributed to excessive ingestion of orange juice when the patient admitted drinking 2.5 litres of orange juice (potassium concentration 450 mg/l) every day for the preceding three weeks to quench thirst during a spell of hot weather. 

Despite significant variation in dietary intake of potassium, plasma concentration is normally maintained within narrow well-defined limits (3.5–5.2 mmol/L). This control is due principally to the kidneys ability to continuously adjust the amount of potassium lost from the body in urine. 

Increased urinary excretion of potassium usually protects against a rise in plasma potassium concentration following high potassium intake, so that increased dietary potassium is a rare cause of hyperkalemia in those with normal renal function.