Sick-Day Insulin Prescription for a 19-Year-Old with Type 1 Diabetes and Chest Infection

Patient B-217, a 19-year-old woman, presents with a two-day history of fever, productive cough with green sputum and right-sided chest pain. She has type 1 diabetes mellitus diagnosed at age 12, treated with a basal-bolus regimen. Her usual doses are insulin glargine 20 units once daily at bedtime and insulin lispro with meals: 8 units at breakfast, 6 units at lunch and 8 units at dinner. She weighs 70 kg and has no known drug allergies. On examination, she is alert, flushed, and clinically dehydrated. Temperature is 38.4°C, pulse 110 beats per minute, blood pressure 110/70 mmHg, respiratory rate 22 breaths per minute, oxygen saturation 96% on room air. Chest examination reveals right basal crackles. Investigations: blood glucose 16.0 mmol/L, blood ketones 0.7 mmol/L (normal less than 0.6), serum creatinine 0.8 mg/dL, eGFR 90 mL/min, serum sodium 132 mmol/L, potassium 4.5 mmol/L, white cell count 18.0 x 10^9/L, C-reactive protein 120 mg/L. Chest X-ray shows right lower lobe consolidation. Her morning capillary glucose readings over the past three days have been between 14 and 18 mmol/L. She is not pregnant. Prescribe the insulin regimen for the next 24 hours, including basal and prandial doses, with any adjustments you consider necessary for sick-day rules.