Clinical Cases of Refractory Hyperlactatemia in Pediatric Inpatients.

Abstract

Case 1: A 16-year-old male with no prior hospitalizations was admitted for urgent neurosurgical management of a craniopharyngioma, a benign brain tumor that grows adjacent to the pituitary gland. He underwent right transcortical craniotomy for tumor resection with right frontal external ventricular drain insertion. His postoperative course was complicated by central diabetes insipidus, a condition of antidiuretic hormone deficiency and subsequent polyuria, and a fluctuating level of consciousness preventing him from feeding orally. Nasogastric feeds were started four days postoperatively. While alert, he drank to thirst. Gastric absorption was likely impaired due to constipation, ileus, and dependent edema. Due to his central diabetes insipidus, he had polyuria with urine output >5 mL/kg/h while a steady state of vasopressin, then desmopressin, was achieved. In the first 11 days postoperative, he lost 8% of his body weight (4.2 kg), even with fluid replacements to a neutral balance. His lactate began climbing with levels peaking at 7.1 mmol/L (normal for age: 1.2 to 2.5 mmol/L; Fig. 1, A). Vital signs were stable with no evidence of end organ hypoperfusion. Septic workup was negative. An echocardiogram showed normal cardiac function. His fluid status was neutral, with urinary losses replaced. Liver function was normal with no hepatocellular injury. There were no new medication exposures, and no current medications were known to cause hyperlactatemia. Given his poor nutritional intake, absorption and ongoing polyuria, an alternative cause of his hyperlactatemia was considered.