Necrotizing enterocolitis in a 850 gram infant receiving sorbitol-free sodium polystyrene sulfonate (Kayexalate): clinical and histopathologic findings.

We report a 27-week, 850 g infant with severe Streptococcus group B sepsis and life-threatening hyperkalemia due to progressive anuria. On the fourth day of life, after he failed treatment with diuretics, salbutamol, insulin, calcium gluconate and sodium bicarbonate, he was treated with sorbitol-free Kayexalate enemas. Potassium level slowly decreased from 9.2 mmol/l to normal level along with a recovery of normal urine output. On the 11th day of life, clinical and radiological signs of a perforated necrotizing enterocolitis (NEC) occurred and the patient required surgical intestinal resection. Histologic examination of the ileum specimen revealed areas of necrosis with fibrosis and giant cell reaction to a nonpolarizable material consistent with sodium polystyrene sulfonate. Usually, Kayexalate is suspended in hyperosmolar sorbitol solutions and the elevated osmolarity seems to be responsible for hemorrhagic colitis, transmural necrosis and definitely NEC. Our case report shows that Kayexalate per se, and not necessarily suspended in sorbitol, can lead to gastrointestinal tract complications and NEC in preterm infants.