Endocrine Abstracts

Background: We present an unusual case of Hyperosmolar Hyperglycaemic State (HHS). A 9 year old girl with complex neurodisability due to HIE, presented with HHS twice within one year. Despite this, she has not yet developed diabetes mellitus and moreover, a raised HbA1c has since normalised.

Clinical presentation: In January 2022 she presented with lethargy and increased wet nappies. She had had two recent minor illnesses and had an acutely infected scalp wound on examination. She was severely dehydrated with a weight loss of 1.7 kg (<0.4th centile). Her GCS was 9/15. Her capillary blood glucose (BG) was 39.4 mmol/L and ketones 0.9 mmol/L. A venous blood gas showed pH 7.32 and bicarbonate 28.7 mmol/L. Initial investigations demonstrated elevated serum osmolality (418 mOsm/kg), severe hypernatraemia (sodium >180 mmol/L) and an AKI. In December 2022 she had been unwell with a diarrhoeal illness and became severely dehydrated. She developed a LRTI, later confirmed Influenza A, and had a respiratory arrest at home requiring CPR and intubation. On attendance her BG was >29 mmol/L and serum sodium 177 mmol/L with mild ketonaemia.

Management: On both occasions she was admitted to PICU for IV fluid and electrolyte management as per ACDC/BSPED HHS guideline with gradual normalisation of her sodium and glucose. Subcutaneous insulin was administered on her first episode only. Further investigations included a satisfactory urine osmolality, negative pancreatic autoantibodies and slightly high C-peptide and Insulin when normoglycaemic. Her HbA1c was 38 mmol/mol during her first episode but 46 mmol/mol on her second. This was repeated post discharge and had fallen to 31 mmol/mol. Her outpatient plan is to performs twice weekly BG monitoring with increased frequency during periods of illness and to seek medical review if hyperglycaemic.

Discussion: HHS is a triad of severe hyperglycaemia >33.3 mmol/L, increased serum osmolality >320 mOsm/kg and severe dehydration without marked ketoacidosis. HHS can be triggered by illness and is known to occur in children with diabetes mellitus, this may be undiagnosed before presentation. This case is of particular interest as it is still not clear whether she is progressing towards a diagnosis of Type 1 or 2 diabetes eighteen months post her first presentation of HHS.