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Diabetic nephropathy
Diabetic nephropathy

Diabetic nephropathy

Diabetic nephropathy also referred to as diabetic kidney disease (DKD) refers to the renal consequences and manifestations of diabetes. It usually is with long-standing diabetes (>10 years).

Pathophysiology

It is dependant on the extent and duration of hyperglycaemia and hypertension present in the patient and is accelerated with smoking, obesity, physical inactivity, dyslipidaemia, high protein and fat diets.

Metabolic changes such as hyperglycaemia and hyperlipidaemia are responsible. Haemodynamic alterations such as hypertension and glomerular hypertension are also important in the disease aetiology

Hyperglycaemia increases growth factors, RAAS activation and production of AGEs and free radicals. All of these factors result in inflammation, endothelial dysfunction and oxidative stress. Oxidative stress particularly consumes a lot of nitric oxide which increases glomerular capillary pressure → endothelial injury → further inflammation and the cycle continues to progress the disease.

Ultimately the outcome is impaired filtration (albuminuria) and reduced eGFR. There are typically an absence of signs/symptoms of primary causes of kidney damage.

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⚠️ Risk factors

  • Hyperglycaemia
  • Hypertension
  • Obesity
  • Smoking
  • Family history of kidney disease or hypertension

😷 Presentation

DKD another silent disease. It presents clinically with albuminuria and reduced eGFR.

  1. Oedema
  2. Fatigue
  3. Anorexia

Other diabetic complications such as:

  • Neuropathy
  • Retinopathy
  • Claudication - pain in the lower extremities and absence of peripheral pulses.
  • Foot changes - ulceration and Charcot foot etc.

🔍 Investigations

🥇
First-line investigations:
  1. Urinalysis - showing proteinuria.
  2. Albumin:creatinine ratio (ACR) - albumin is usually filtered, however, when there is damage to the kidney it becomes more permeable to large proteins such as albumin and we get albuminuria.
    1. <3mg/mmol - microalbuminuria (A1)
    2. 3-29mg/mmol - moderate albuminuria (A2)
    3. >30mg/mmol - severe albuminuria (A3)
  3. Serum creatinine and eGFR - eGFR is calculated using age, race, sex.
🔪
Imaging:
  • Kidney USS may be needed to exclude other diagnosis

👀 Screening

All diabetic patients are invited for annual screening of their ACR using an early morning specimen. An ACR >2.5mg/mmol is indicative of microalbuminuria.

🧰 Management

💊
DKD management:
  • Glycaemic control and hypertensive control are the mainstays of DKD management:
  • Lifestyle modifications should also be advised, such as:
    • Restriction of dietary protein
    • Restriction of sodium <2g daily
    • Reduce hyperlipidaemia through diet and statins
    • BP target of <130/80mmHg

Pharmacological management:

  1. 🥇 ACE inhibitor or angiotensin-II receptor antagonist - if the ACR is ≥3 or more.
  2. 🥈 SGLT2 inhibitors - if the ACR is 30 or more (considered in those with an ACR of 3-30 mg/mmol).
  3. Statins - this will be used in most cases as the patients tend to have dyslipidaemia as well.