Elevated salivary potassium in paediatric CKD patients, a novel excretion pathway

Background. Hyperkalaemia is one of the complications of chronic renal failure. Gastrointestinal excretion and cellular uptake are two adaptive mechanisms for extra-renal potassium (K) disposal in these patients. The salivary glands' secretion system can actively excrete K into the oral cavity.Methods. We examined salivary K levels in four groups of paediatric chronic kidney disease (CKD) patients: 25 pre-dialytic (PreD) patients, 18 patients on maintenance dialysis (D), and 31 transplanted patients with a functioning graft (T), compared with 32 healthy children (C).Results. Salivary K levels were significantly higher in the D and PreD groups than the C group (P = 0.03 and P = 0.0004, respectively). Interestingly, a significant negative correlation was found between glomerular filtration rate and salivary K in PreD and T patients.Conclusions. We suggest an extension of the gastrointestinal adaptive K pathway via salivary gland secretion in patients suffering from hyperkalaemia.