NEET PG High-Yield: Diabetes Mellitus (DM)
A chronic metabolic disorder characterized by hyperglycemia due to absolute or relative insulin deficiency or resistance.
Diagnostic Criteria (ADA)
| Parameter | Diabetes Threshold |
|---|---|
| Fasting Plasma Glucose | ≥ 126 mg/dL (7.0 mmol/L) |
| 2-hour Plasma Glucose (OGTT) | ≥ 200 mg/dL (11.1 mmol/L) |
| HbA1c | ≥ 6.5% |
Clinical Classification
- Type 1 DM: Autoimmune destruction of pancreatic $\beta$-cells (absolute insulin deficiency).
- Type 2 DM: Progressive insulin secretory defect on the background of insulin resistance.
- Gestational DM: Diabetes diagnosed in the second or third trimester of pregnancy.
High-Yield NEET PG Pearls:
- Complications: Microvascular (Retinopathy, Nephropathy, Neuropathy) and Macrovascular (CHD, Stroke, PAD).
- First-line Therapy: Metformin is the preferred initial pharmacologic agent for Type 2 DM.
- Screening: In India, screening is recommended for all adults ≥ 30 years (or earlier if high-risk, e.g., obesity/family history).
- Prevention: Lifestyle modifications (weight loss and physical activity) are highly effective in delaying Type 2 DM onset.