Anion gap metabolic acidosis on continuous renal replacement therapy: Are you missing something

Introduction: Anion gap metabolic acidosis is a common metabolic abnormality seen in the clinical practice. Causes includes Lactic acidosis, Ketoacidosis, Renal failure, volatile acid toxicity and salicylate poisoing. Ketoacidosis is due to decreased glucose and insulin availability leading to starvation ketosis and diabetic ketoacidosis respectively. Ketoacidosis is uncommonly seen in patients on prolonged continuous renal replacement therapy. We present 2 cases at Grady Hospital admitted with Acute hypoxic Respiratory Failure due to COVID 19 pneumonia, developed euglycemic ketoacidosis on Continuous Renal Replacement Therapy Case Description: case 1: 73 male with the history of HTN, DM, CKD III admitted for acute hypoxic respiratory failure due to COVID 19 pneumonia. He was intubated on admission day 9. Course got complicated by hypotension during intubation leading to Acute Renal Failure on day 11. Patient was started on Renal Replacement Therapy on day 12 due to volume overload and acidosis. Day 19, Anion gap worsened and betahydroxybutyrate was elevated. Patient was started on insulin drip with resolution of acidosis on day 20. Case 2: 48 yo male with the history of HTN, DM II, CKD stage III admitted for Altered mental status, hypertensive emergency and cough. He was diagnosed with COVID 19 Pneumonia. Patient had non oliguric acute kidney injury on admission. Hospital day 11, patient was oliguric, volume overloaded and hyperkalemia prompted Renal replacement therapy initiation. Day 14, Anion gap worsened and betahydroxybutyrate was elevated. Tube feed were initiated and Dialysate prescription was reduced leading to resolution of anion gap on day 12. Discussion: Diabetic ketoacidosis is a medical emergency commonly in patients with Type I DM but also in Type II DM patients as well. It occurs due to decrease insulin concentration or increase insulin resistance with or without decreased glucose availability leading to release of counterregulatory hormone and fatty acid metabolism producing ketoacids. Diagnostic criteria include pH 250 mg/dl and positive serum +/-Urine ketones. Euglycemic DKA is a subtype of DKA with serum glucose of <200 mg/dl. Incidence of Euglycemic DKA varies from 2.6-3.2%. Continuous renal replacement therapy is an under-recognized cause of Euglycemic DKA in patients with Diabetes Mellitus.