Objective : A 27 year old male presented with a 10 years history of Type 1 diabetes. He was keen to come off insulin to continue to work as a front line fire fighter as an employers’ mandatory requirement.
He was diagnosed when he presented to a remote hospital with generalized illness. He could not recollect the events and had no access to his medical records. He was free of complications of diabetes & was maintained on 10 units BID of Lispro mix 50 insulin.
He never had Diabetic Ketoacidosis (DKA) and indeed was able to miss insulin for 2-3 days without any consequences. Occasionally he would experience hypoglycemia particularly after exertion. Maternal grandmother had type 2 diabetes treated with oral agents.
His BMI was 24 kg/m2 with body weight of 67 Kg. Glycemic control was good as demonstrated by Hba1c of 6.9%.
Methods : In order to determine pancreatic endocrine function, we measured basal plasma insulin, c- peptide, & glucose followed by a carbohydrate rich meal. Serial measurements were taken every 30 minutes up to three hours. Insulin was omitted for 24 hours prior to and during the test.
Results : Results confirmed endogenous insulin secretion with significant rise in plasma insulin and c-peptide levels. Maternal HBA1c was checked and type 2 diabetes was diagnosed with HBA1c of 7.4 %. With three generations affected by diabetes, his monogenic screen was done and was negative. GADA, IA-2A were weakly positive with strongly positive Zn transporter 8 antibodies confirming auto-immunity.
He was admitted for a week to withhold insulin under observation. He remained well & we monitored capillary glucose, venous PH and urine ketones twice daily. He remained free of ketones with normal PH and with maximal glucose excursion of 15 mmol/L.
Discussion : Several histological studies have shown existence of insulin producing beta cells in long standing type 1 diabetes patients. Possible explanation for this phenomenon of retention of beta cell function could be attributed to “burnt out” auto immunity, less intense auto immunity or even beta cells being able to regenerate or circumvent immune attack. There is some evidence albeit weaker that DPP-4 inhibitors can preserve beta cell mass in type 1 diabetes leading to maintenance / enhancement of c-peptide levels.
Conclusion : Our case serves a reminder that proportion of patients with chronic auto immune type 1 diabetes are micro secretors of insulin even after a decade of diagnosis which is sufficient to avoid lipolysis and ketosis. He is now managing diabetes with Sitagliptin 50mg daily for last 2 months with normoglycaemia and without any episodes of DKA.
Muhammad Butt– Consultant Endocrinologist, King Faisal Specialist Hospital and research Hospital / AlFaisal University Riyadh Saudi Arabia, Riyadh, Saudi Arabia
Lama Amer– Fellow Endocrinology, King Faisal Specialist Hospital and research Hospital Riyadh Saudi Arabia
Muhammad Riazuddin– Consultant Medicine, Riyadh, Saudi Arabia
Tarek Elsayed– Assistant consultant Endocrinologist, King Faisal Specialist Hospital and research Hospital Riyadh Saudi Arabia
King Faisal Specialist Hospital and research Hospital / AlFaisal University Riyadh Saudi Arabia
Riyadh, Saudi Arabia
King Faisal Specialist Hospital and research Hospital Riyadh Saudi Arabia