Excessive watermelon consumption caused severe hyperkalemia
Some popular foods, such as bananas, tomatoes and potatoes, can cause hyperkalemia if overeaten, which is a generally known fact. However, the similar harm of watermelon is often overlooked - and it can be deadly. This is the conclusion reached by US medics who told of three patients with severe hyperkalemia.
Medics at St. Vincent's Hospital in Worcester, Massachusetts, USA, described three cases of severe hyperkalemia - an increase in blood potassium concentration caused by overeating watermelons. This potentially life-threatening electrolyte imbalance, associated with reduced renal excretion of potassium or its abnormal release from cells, requires emergency medical attention.
Among other things, patients may complain of weakness, muscle paralysis, shortness of breath, cardiac dysfunction, and nausea. As a result, there is a risk of arrhythmic abnormalities including sinus bradycardia, ventricular tachycardia, ventricular fibrillation and asystole manifested by fainting, hemodynamic instability or sudden cardiac death. The report is published in the journal Annals of Internal Medicine.
Watermelon is a favorite berry, a gourd crop of the pumpkin family. In summer, it is actively eaten in Russia: for example, as of 2023, the average Russian eats about 6.5 kilograms of watermelons annually. They contain many useful elements: vitamin A, B vitamins, vitamin C, folic acid and antioxidants.
However, at the same time, watermelon is an unrecognized source of potassium in food: in two slices of this berry (1/8 of the fruit) - approximately 16.4 millimoles of potassium, or 640 milligrams. Its excess - hyperkalemia - can aggravate people with chronic kidney disease.
According to various estimates, the mortality rate from untreated severe hyperkalemia, which is defined as a blood potassium level of more than 6.0 millimoles per liter, exceeds 30%. In the risk group - patients with chronic kidney disease of the third and fourth stages, diabetes mellitus, heart failure, as well as those who take certain drugs: in particular, inhibitors of the renin-angiotensin-aldosterone system (RAAS) and mineralocorticoid receptor antagonists (diuretic). If the cause of hyperkalemia is recognized in time, treatment can be initiated and relapses can be avoided.
Americans, about whom the authors of the new study reported, came to the doctors after excessive consumption of watermelon and severe hyperkalemia developed against this background. Two were hospitalized in the intensive care unit, another person was observed on an outpatient basis in a dialysis clinic in Worcester.
The first patient, a 56-year-old man with type 2 diabetes and stage 4 chronic kidney disease, collapsed at home. He was found to have sinus bradycardia (slowed heart rate); his pulse was 20 beats per minute and his blood pressure was 62/32 millimeters of mercury. The blood potassium level was seven millimoles per liter; creatinine, an important indicator of kidney function, was 262.5 micromoles per liter.
The man admitted that he had been eating watermelon at night for the past two months. The patient was prescribed lisinopril, calcium gluconate, insulin, albuterol and sodium polystyrene sulfonate.
The second case: a 72-year-old man with a history of ischemic cardiomyopathy and an implantable cardioverter-defibrillator (a small electronic device connected to the heart) was admitted after AICD shock, i.e., activation-induced cell death. On examination, his blood pressure was 176/90 millimeters of mercury column and his heart rate was 66 beats per minute. On examination, physicians found no significant abnormalities, but laboratory tests showed elevated potassium (6.6 millimoles per liter) and creatinine (142.3 micromoles per liter).
The patient was prescribed an antihypertensive drug called valsartan, given insulin and dextrose (D-glucose), furosemide, and albuterol inhalations. Potassium levels eventually normalized. The man confirmed that he had been drinking two glasses of watermelon juice a day for about a month.
Finally, the third case is a 36-year-old woman with terminal renal failure on hemodialysis. The patient underwent tests every month, at the end of one of which she was diagnosed with asymptomatic hyperkalemia. Her potassium levels were as high as 7.4 millimoles per liter. The cause turned out to be due to eating large amounts of watermelon daily for three weeks.
"The minimum daily potassium intake for [healthy] adults is estimated to be about 1,600 milligrams (40 millimoles), and the World Health Organization's recommendation is a daily dose of 3,510 milligrams (90 millimoles). It's important to remember that watermelon - although not typically considered a high-potassium food - contains approximately 320 milligrams, or eight millimoles, of potassium in a slice. For patients with impaired kidney function, such a load can be life-threatening," the medics concluded.