✅ Model Answer:
• Diagnosis: Diabetic ketoacidosis (DKA) — hyperglycemia (450 mg/dL), ketosis (serum ketones positive, urine ketones 3+), metabolic acidosis (pH 7.15), polyuria, polydipsia, weight loss, Kussmaul breathing. New-onset Type 1 Diabetes Mellitus.
• Any other test: HbA1c, C-peptide, autoimmune antibodies (GAD, IA-2, ZnT8), blood cultures, serum electrolytes (already done), renal function tests, ECG.
• What to do next: IV fluids (0.9% saline bolus followed by maintenance), insulin infusion (0.1 U/kg/hour), monitor potassium closely (replace if low), frequent glucose and pH monitoring. ICU admission if severe.
• Follow-up plan: Transition to subcutaneous insulin when acidosis resolved and oral intake tolerated. Diabetes education (insulin administration, glucose monitoring, sick day rules). Endocrinology follow-up.

✅ Model Answer:
• ISPAD criteria for DKA:
- Hyperglycemia: Blood glucose >200 mg/dL (11 mmol/L)
- Ketosis: Ketones in blood (β-hydroxybutyrate >3 mmol/L) or urine (≥2+)
- Metabolic acidosis: Venous pH <7.3 or bicarbonate <15 mEq/L
• Severity grading:
- Mild: pH 7.2-7.3, bicarbonate 10-15
- Moderate: pH 7.1-7.2, bicarbonate 5-10
- Severe: pH <7.1, bicarbonate <5

✅ Model Answer:
• Pathophysiology: Absolute insulin deficiency (due to autoimmune destruction of pancreatic β-cells) →
- Hyperglycemia: Increased glucose production (gluconeogenesis, glycogenolysis) and decreased peripheral utilization
- Ketosis: Lipolysis → free fatty acids → ketone bodies (β-hydroxybutyrate, acetoacetate)
- Acidosis: Accumulation of ketones → metabolic acidosis
- Osmotic diuresis: Hyperglycemia → glucosuria → osmotic diuresis → dehydration, electrolyte loss
- Kussmaul breathing: Respiratory compensation for metabolic acidosis

✅ Model Answer:
• Common precipitating factors:
- New-onset Type 1 Diabetes (most common in children)
- Missed insulin doses (omission or underdosing)
- Infection (viral, bacterial, UTI, pneumonia)
- Stress (emotional stress, trauma, surgery)
- Pump failure (insulin pump malfunction)
- Intercurrent illness (fever, gastroenteritis)
- Medications (corticosteroids, sympathomimetics)
- Poor compliance (adolescents)

✅ Model Answer:
• Fluid therapy:
- 0.9% saline bolus: 10-20 mL/kg over 30-60 minutes (if shock or severe dehydration)
- Maintenance fluids: 0.9% saline or 0.45% saline + KCl (if K+ >3.3 mEq/L)
- Calculate deficit: 5-10% dehydration, replace over 24-48 hours
- Monitor urine output
• Insulin therapy:
- Insulin infusion: 0.1 U/kg/hour IV (regular insulin)
- Start after fluid bolus (not before, to avoid hypokalemia)
- Goal: Decrease glucose by 50-100 mg/dL/hour
- When glucose <250 mg/dL: Add D10% to IV fluids
- Transition to SC insulin when pH >7.3, bicarbonate >15, and oral intake tolerated

✅ Model Answer:
• Potassium (K+):
- Initial serum K+ may be normal/elevated (due to shift from intracellular to extracellular)
- Total body K+ is depleted → K+ will drop with insulin therapy
- Replace K+ (20-40 mEq/L in IV fluids) if K+ <5.5 mEq/L and urine output adequate
- Monitor ECG for arrhythmias
• Sodium (Na+):
- Hyponatremia is common (dilutional, corrected by hyperglycemia)
- Corrected Na+ = measured Na+ + 0.016 × (glucose - 100)
- Hypertonic saline may be needed if severe hyponatremia or neurological symptoms
• Phosphate:
- May need replacement if phosphate <1 mmol/L (rarely required)

✅ Model Answer:
• Complications:
- Cerebral edema — most serious complication, leading cause of death in DKA
- Hypokalemia — cardiac arrhythmias, respiratory muscle weakness
- Hypoglycemia — due to insulin therapy
- Hypophosphatemia — respiratory muscle weakness
- Acute kidney injury (prerenal azotemia)
- Aspiration pneumonia
- Thrombosis (hypercoagulable state)
- Cerebral venous thrombosis
- Sepsis (if underlying infection)
- Cerebral herniation (from cerebral edema)

✅ Model Answer:
• Long-term management:
- Insulin therapy: Basal-bolus regimen (multiple daily injections or insulin pump)
- Blood glucose monitoring: Regular SMBG or CGM (continuous glucose monitoring)
- Diet and nutrition: Carbohydrate counting, balanced diet
- Exercise: Regular physical activity
- Diabetes education: Insulin administration, hypoglycemia management, sick day rules
- Psychosocial support
• Prognosis:
- Lifelong disease — requires chronic management
- Good glycemic control reduces risk of long-term complications
- Complications: Retinopathy, nephropathy, neuropathy, cardiovascular disease
- Regular follow-up with endocrinology, ophthalmology, nephrology
- HbA1c target: <7.5% (pediatric)