Patient with DKA

Madam PG is a 29 year old young woman with poorly controlled diabetes on oral hypoglycaemic agents for the past 2 years, who also has history of peptic ulcer disease and 2 recent admissions for diabetic ketoacidosis. She presented on the 21^st of March 2011 with nausea and vomiting for 2 days associated with epigastric pain. During this period she was unable to tolerate orally and had not been able to take her medication. She had no symptoms suggestive of a respiratory or urinary tract infection. On admission she was moderately dehydrated and lethargic however she was not in respiratory distress. Her capillary blood glucose reading was 23.6 mmol/L and her vital signs were as follows: BP: 130/80, pulse: 110, temperature: 37.2C, respiratory rate : 20 and SPO2: 100% on room air. Her venous blood gases showed metabolic acidosis, her serum ketone level was 5.8 mmol/L and ketones were also detected in her urine. She was also noted to have a thyroid enlargement however she was clinically euthyroid. In the ward, she was treated with an intravenous insulin infusion, initiated at 6 units per hour (0.1units/kg/hour), and rehydrating fluids both of which were adjusted according to her blood glucose level. Potassium supplementation (1g/hr of KCL in each alternate bottle of fluid) was commenced on day 2 of admission when her K⁺ levels dropped from 4.5 mmol/L to 3.6 mmol/L. On day 5 of admission her general condition improved and she was no longer acidotic (VBG: no acidosis, serum ketones: 0). She was started on of s/c actrapid insulin in place of IV insulin and was discharged well on the 27^th of March 2011 with s/c mixtard insulin and T. Metformin.

Issues in this case

From her diagnosis 2 years ago, Madam PG has been labeled as a type 2 diabetic. However, because of her young age, frequent episodes of DKA, poor diabetic control with OHAs as well as the associated clinical finding of a goiter, could Madam PG be a Type 1 diabetic instead? During clerking, it was also revealed that her mother was also diagnosed with type 2 diabetes at a relatively young age (in her early 30s), another fact in favour of type 1 DM. In the ward, the managing doctors considered ordering a C-Peptide measurement for her. However, it was not done as the rationale was that, whether she has type 1 or type 2 diabetes will not change the subsequent management because she will be started on insulin following this admission. Should more have been done for her in terms of diagnosis of type 1 DM? Would an autoimmune screen be necessary as she also has a thyroid enlargement?