Endocrine Abstracts

Background: We present a teenager with type 1 diabetes who sustained a substantial weight loss of 20 kg over 15 months. He had minimal insulin requirements with an extraordinarily low HbA1c.

Presentation: During his presentation with excessive weight loss, he had blood tests which revealed pre-renal failure, following which he was admitted for rehydration and assessment. Apparently he was consuming fluid in excess of 2 l/day. Ultrasound of kidneys was normal. A discussion regarding healthy weight and exercise ensued with the dietitian. A referral to Child and Adolescent Mental Health Service (CAMHS) was made to consider a possibility of anorexia. The teenager had a pre-morbid history of obsessive compulsive behaviour. However, the diagnosis was disregarded and he was discharged by CAMHS.

Early morning paired serum and urine tests were done to rule out diabetes insipidus as a cause for polydipsia.

He continued to lose weight and was supported by the dietitian. His HbA1c was as low as 34 mmol/mol and he denied manipulating insulin. He was having disabling hypoglycemia on insulin requirements of <10 units/day. Autoantibodies were positive and he had minimal urine C-peptide at 3 years into diagnosis to suggest type 1 diabetes.

In due course, he broke down and confessed to throwing food away and having a low carbohydrate diet to explain low insulin requirements. Subsequently, with support from CAMHS and the diabetes team, his weight has improved and insulin requirements have standardised.

Discussion: Eating disorders are very common in type 1 diabetes due to a constant focus on food and carbohydrates to match the insulin.

Control would usually deteriorate with eating disorders and these children are at an increased risk of developing microvascular complications.

This case was unusual due to the very low insulin requirements and possible co-existing honeymoon period to explain the low HbA1c.