A 28-year-old woman from Delhi presents with a 3-week history of polyuria, polydipsia, and weight loss of 4 kg. She reports recent onset of fatigue and blurred vision. On examination, she appears lean (BMI 19 kg/m²), and her breath has a fruity odour. Laboratory investigations show: fasting blood glucose 320 mg/dL, venous pH 7.28, HCO₃⁻ 12 mEq/L, serum ketones positive, and C-peptide 0.3 ng/mL (normal: 0.8–3.1). Anti-GAD and anti-IA2 antibodies are positive. What is the most appropriate initial management?

Explanation

## Clinical Diagnosis: Type 1 Diabetes Mellitus with Diabetic Ketoacidosis (DKA) ### Key Diagnostic Features | Feature | Finding | Significance | |---------|---------|---------------| | **Age & BMI** | 28 years, BMI 19 | Lean phenotype typical of T1DM | | **Presentation** | Acute onset (3 weeks) | Rapid β-cell destruction | | **Metabolic derangement** | pH 7.28, HCO₃⁻ 12 | Metabolic acidosis (DKA) | | **Serum ketones** | Positive | Ketone body accumulation | | **C-peptide** | 0.3 ng/mL (low) | Severe β-cell dysfunction | | **Autoantibodies** | Anti-GAD, anti-IA2 positive | Autoimmune destruction confirmed | **Key Point:** The combination of acute presentation, low C-peptide, positive autoantibodies, and DKA is pathognomonic for Type 1 diabetes. ### Management Algorithm for DKA ```mermaid flowchart TD A[Type 1 DM + DKA]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No| C[IV fluids 0.9% NaCl]:::action B -->|Yes| C C --> D[Insulin infusion 0.1 U/kg/hr]:::action D --> E[Monitor K+, pH, HCO3-]:::action E --> F[Transition to SC insulin when stable]:::action F --> G[Long-term basal-bolus regimen]:::outcome ``` ### Why IV Insulin Is Mandatory Here 1. **DKA requires rapid insulin:** Venous pH 7.28 and positive serum ketones indicate severe metabolic derangement requiring IV insulin infusion (0.1 U/kg/hr), not oral agents. 2. **Fluid deficit:** Polyuria + 3-week illness suggests significant volume depletion requiring IV 0.9% NaCl before insulin. 3. **Electrolyte risk:** Insulin shifts K⁺ intracellularly; baseline serum K⁺ must be checked and monitored closely. 4. **Transition phase:** Once pH > 7.3, HCO₃⁻ > 18, and patient can eat, switch to subcutaneous basal-bolus insulin (e.g., NPH/regular or long-acting analogue + rapid-acting bolus). **Clinical Pearl:** Never start oral agents in DKA—they are ineffective in severe acidosis and delay life-saving IV insulin. **High-Yield:** Type 1 diabetes diagnosis is confirmed by: (a) acute presentation, (b) low/absent C-peptide, (c) positive autoantibodies (GAD, IA2, ZnT8), and (d) absence of insulin resistance features. ### Long-Term Management (After Stabilization) - **Basal-bolus insulin:** NPH once or twice daily + rapid-acting insulin with meals, OR long-acting analogue (glargine/degludec) + rapid-acting bolus. - **Target HbA₁c:** < 7% (individualize based on hypoglycemia risk). - **Screening:** Annual microalbuminuria, lipid panel, ophthalmology, foot examination. - **Counselling:** Carbohydrate counting, sick-day management, hypoglycemia recognition.