Idiopathic Ketotic Hypoglycemia (IKH)

Idiopathic Ketotic Hypoglycemia (IKH), also known as ‘accelerated starvation’ is the common cause of clinically significant non-diabetic hypoglycemia among children between 1 and 5 years of age.[1] Originally described by Colle and Ulstrom in 1964, IKH is defined by periodic episodes of hypoglycemia, associated with ketonuria, in an otherwise healthy child, usually occurring after food deprivation.[2] The hypoglycemia is associated with raised ketone bodies and free fatty acids with suppressed insulin levels.[3] The most likely cause is an imbalance in the suppression of glucose utilization by ketone bodies and a limited rate of hepatic glucose production.[4] Diagnosis requires exclusion of other causes of hypoglycemia, particularly GH deficiency, hypopituitarism, adrenocorticotropic hormone (ACTH) unresponsiveness, and glycogen synthase deficiency, all of which may have similar presentations. Here we report a child presented to us for dental extractions under general anaesthesia.
An eight-year-old boy, weighing 35 kg, known case of IKH for past 5 years and asthma since childhood, was
scheduled for extraction of multiple decayed teeth as a day case surgery. The IKH was diagnosed in 2011 when the child presented with nausea, vomiting and fatigue at the age of 4 years. He had delayed milestones, a slow learner and concentration deficit during studies. His lab work-up revealed severe acidosis (pH 7.06-7.25 on serial ABG’s), low bicarbonate levels a, urinary ketones >7.8 mmol/l, Lactic acid 8.1-4.2 and blood sugars <43 g/dl. The child had episodes of hypoglycemia with lactic acidosis thrice in 2012 and twice in 2013. His DNA testing revealed no known deleterious mutations. This metabolic derangement was labeled as ketotic hypoglycemia with lactic acidosis. Child was kept on special dietary supplement i.e., FantoMalt that contains Carbohydrate 96 grams and no protein & fat (Fig. 1a).
The child visited the preoperative anaesthesia clinic and after reviewing his case in consultation with Pediatric team, family is advised not to proceed as day case procedure because the child required intravenous fluid replacement and biochemical monitoring, so admitted one day prior to the surgery.[5] Since admission, the child was kept on intravenous maintenance fluid i.e., half strength dextrose saline + 25 % dextrose water (Fig.
1b) and his blood glucose was monitored every 4 hourly along with urinary ketones and lactic acid once nothing per oral (NPO). The relevant investigations were Hb - 2.7 g/dl, Hct - 40.2%, Na - 139 mmol/l, K - 5.3 mmol/l, Bicarbonate - 25.6mmol/l, glucose – 95 g/dl and lactic acid - 4.8 mmol/l. As fasting for surgery and anaesthesia is inevitable, every effort was made in planning and scheduling to perform surgical procedure right after six hours of
NPO.
Another concern is use of muscle relaxant for endotracheal intubation. The child was asthmatic, so we could not use atracurium as it causes histamine release. His serum K+ was 5.3 slightly raised, we avoided succinylcholine because it causes hyperkalemia. Rocuronium has variable effect and sometimes its duration is more than an hour in our experience. After application of standard ASA monitoring (ECG, NIBP, SPO2, ETCO2), we use the same intravenous line (24 G) for induction of anaesthesia. We decided to avoid any muscle relaxant and proceed with short acting narcotic fentanyl 3 μg/kg, propofol 2 mg/kg and sevoflurane 4-6% in 100% oxygen. The child was intubated using cuffed Ring, Adair and Elwyn (RAE) size 6.0 mm endotracheal tube. The same maintenance fluid was continued in intraoperative period. Blood glucose was monitored intraoperatively and postoperatively (112 & 95 g/dl). Surgery went uneventful, remained hemodynamically stable and his biochemical and metabolic profile were also normal post operatively.
In conclusion, children with metabolic disorders presenting for anaesthesia and surgery can be best managed by optimizing their requirements with close liaison between all caring teams.