Severe Hyperkalemia Related to Excessive Tomato Juice Ingestion in Presence of Neobladder

Hyperkalemia and other metabolic abnormalities are wellknown sequelae of urinary intestinal diversion.1 Potassium overload has also been reported in patients with renal insufficiency who consume excessive juices.2 A case of potentially life threatening hyperkalemia is described in a man who consumed excessive tomato juice while recovering from cystoprostatectomy and urinary diversion. CASE REPORT A 68-year-old man was discharged home after undergoing cystectomy and creation of an orthotopic ileal (Studer) neobladder. He asked for approval to continue recovery from the operation on a moored oceangoing boat. The boat was air conditioned and had “the comforts of home,” so approval was given provided he maintained adequate fluid intake and avoided the summer heat. No specific oral intake guidelines were given, but he was instructed that the urine should remain clear as an indicator of adequate hydration. Despite physiological diaphoresis due to the September heat, he maintained adequate fluid intake to achieve that goal. Two weeks later the patient reported progressive asthenia, pruritis and anorexia. He was admitted to the local hospital after serum laboratory tests demonstrated potassium 8.5, sodium 127, bicarbonate 28, chloride 98, blood urea nitrogen 137 and creatinine 3.1. Electrocardiogram was normal with no QRS widening. Abdominal computerized tomography showed no hydronephrosis, minimal residual volume in the neobladder and no abnormal fluid collections. He was admitted to the intensive care unit with the diagnosis of hyperkalemia secondary to prerenal azotemia. Sodium polystyrene sulfonate was administered rectally, and serum potassium and creatinine normalized within 12 hours using an intravenous drip of insulin, bicarbonate and 50% dextrose solution. With the exception of the recent operation, the patient denied all known risk factors, including significant intake of foods (ie bananas, oranges, etc) known to have high potassium concentration. However, he volunteered that the primary source of fluid (“at least 12 to 15 glasses a day”) during the recovery period was tomato juice. No other sources of hyperkalemia were identified. Following dietary reeducation and recovery from the acute illness all symptoms remain resolved and the patient remains clinically free of disease 12 months postoperatively. All laboratory values remain normal except blood urea nitrogen, which is steady in the 30 to 40 range. DISCUSSION A MEDLINE search revealed no published reports of hyperkalemia related to the ingestion of tomato juice. Patients with normal renal function should be able to maintain electrolyte homeostasis within wide-ranging intakes. However, those with urinary intestinal diversion reabsorb urinary potassium through the ileal wall.1 Tomato juice has a high concentration of potassium at 12 to 35 mEq per 100 ml.3 It appears that the combination of high potassium intake with reabsorption through the neobladder and dehydration led to dangerous serum levels in this patient. The absence of recurrence simply with dietary reeducation confirms this etiology. Physicians caring for patients with urinary diversion should be aware that ingestion of excessive amounts of tomato juice can be an uncommon risk factor for the development of severe hyperkalemia.