Diabetic Nephropathy

Overview – Diabetic Nephropathy

Diabetic nephropathy is a progressive kidney condition caused by chronic hyperglycaemia in patients with type 1 or type 2 diabetes. It is the leading cause of end-stage renal failure (ESRF) worldwide. Diabetic nephropathy results from long-term damage to glomeruli and renal microvasculature, leading to albuminuria, proteinuria, and eventually a decline in glomerular filtration rate (GFR). Early detection and management are crucial to prevent progression to irreversible kidney failure.

Definition

• Diabetic nephropathy is a form of chronic kidney disease caused by diabetes mellitus.
• It involves progressive glomerular and tubular damage due to prolonged hyperglycaemia.

Aetiology

• Type 1 Diabetes Mellitus
• Type 2 Diabetes Mellitus

Pathophysiology

• Chronic hyperglycaemia → glycosuria → metabolic and structural kidney changes:
  • Glycosylation of proteins in basement membrane → hyaline arteriosclerosis
  • Glomerular hypertension → initially increased GFR
  • Thickened glomerular basement membrane + podocyte injury → compromised filtration barrier
  • Tubular and interstitial fibrosis → nephron dropout
  • Later stage: GFR declines due to progressive glomerular damage

Clinical Features

• Often asymptomatic in early stages
• Albuminuria (micro → macro)
• Proteinuria (may reach nephrotic range)
• No haematuria
• Up to 50% of diabetics with nephropathy may present with nephrotic syndrome

Investigations

• Albuminuria detection:
  • Microalbuminuria = early marker
  • 24-hour urinary albumin or spot urine albumin:creatinine ratio

Management

• Tight glycaemic control: slows progression
• ACE inhibitors (first-line):
  • Dilate efferent arteriole → reduce intraglomerular pressure
• Lifestyle modifications:
  • Salt restriction
  • Weight management
  • Blood pressure control (target <130/80 mmHg)

Complications

• Progressive chronic kidney disease
• End-stage renal failure (ESRF)
  • Occurs in ~30% of diabetic patients
• Cardiovascular disease risk also elevated

Differential Diagnosis

• Hypertensive nephrosclerosis
• Minimal change disease
• Focal segmental glomerulosclerosis
• Amyloidosis
• IgA nephropathy

Summary – Diabetic Nephropathy

Diabetic nephropathy is a chronic complication of both type 1 and type 2 diabetes, caused by prolonged hyperglycaemia leading to glomerular damage, albuminuria, and progressive renal dysfunction. It may be asymptomatic early on, but without intervention, it can progress to nephrotic syndrome and end-stage renal failure. ACE inhibitors and strict glycaemic control are the cornerstones of management. For a broader context, see our Renal Overview page.