26th April 2024

A 55-year-old woman presents with a three-month history of increased thirst, frequent urination, and unexplained weight loss of 5 kg.

A 55-year-old woman presents with a three-month history of increased thirst, frequent urination, and unexplained weight loss of 5 kg. She also mentions feeling more tired than usual. On examination, she appears generally well but slightly dehydrated. Her BMI is 29 kg/m².

Investigations:

Fasting plasma glucose: 8.5 mmol/L (3.9–5.6)

HbA1c: 9.0% (Normal <5.7%)

C-peptide level: 1.2 ng/mL (Normal range 1.1–4.4 ng/mL)

Autoantibodies (including GAD, IA-2): Negative

Serum ketones: Negative

Which is the most likely diagnosis?