Diabetic Nephropathy

Question 1

Definition of diabetic nephropathy

Answer 1

Diabetic kidney disease is defined as albuminuria and progressive reduction in estimated glomerular filtration rate in the setting of diabetes, and is usually associated with retinopathy

Question 2

Aetiology of diabetic nephropathy

Answer 2

• Is multifactorial, but the most important factors are the:
◦ Extent and duration of hyperglycaemia
◦ Hypertension
Other risk factors are:
‣ Smoking
‣ Obesity
‣ Physical inactivity
‣ Dyslipidaemia
‣ Proteinuria
‣ Family history

Question 3

Pathophysiology of diabetic nephropathy

Answer 3

• The hyperglycaemia and hypertension can result in glomerular hypertension.
• This would then progress into proteinuria
• Then glomerular and intertidal fibrosis
• The GFR would then decline
• This can then progress to renal failure (commonest cause of end-stage renal failure) There is also an associated increased risk of CVD

• Also, the Renin-Angiotensin System goes into overdrive, resulting in vasoconstriction and increase BP

Question 4

History and Examination for diabetic nephropathy

Answer 4

• Microalbuminuria: Is the EARLIEST hallmark of diabetic nephropathy. Needs 2 positive tests

• Likely to have hypertension and signs of retinopathy (poor vision etc)
• Advanced disease leads to peripheral oedema

Question 5

Investigations for diabetic nephropathy

Answer 5

• Urinalysis: proteinuria indicates nephropathy is present
• Urine albumin to creatinine ratio (ACR): needs 2 positive tests. Albuminuria is the first clinical sign of diabetic nephropathy. Microalbuminuria is enough to diagnose (moderately increased albuminuria)
• Serum creatinine with eGFR

Question 6

Treatment of diabetic nephropathy

Answer 6

1) Tighter glycaemic control: For Type1D, ensure they are taking adequate insulin. For Type2D, ensure metformin (contraindicated with an eGFR <30mmol is being taken and preferably a SGLT2 inhibitor alongside this

+ ACEi/ARB even if normotensive as soon as patient has Microalbuminuria: Treat blood pressure ASAP to slow the progression of the nephropathy

+ Lifestyle modification: smoking cessation, nutrition advice, physical exercise. Consider statins

+ Non steroidal mineralcorticoid receptor antagonist: Give if Type2D as it demonstrates positive kidney and cardiovascular outcomes in patients with CKD. Finerenone

Question 7

Prevention and prognosis of diabetic nephropathy

Answer 7

Maintaining good glycaemic and BP control reduces the risk of diabetic complications
Can also reduce rate of progression
Avoid NSAIDs and nephrotoxic drugs

Associated with worsening proteinuria, unless the hyperglycaemia and hypertension are promptly treated

Question 8

Complications of diabetic nephropathy

Answer 8

• End stage renal disease
• Hyperkalaemia: associated with renal failure (failure to excrete potassium and acidosis leading to potassium leaving cells)
• CVD: Kidney disease predisposes to CVD
• Other diabetic complications
• Anaemia
• Bone disease: CKD can often develop secondary hyperparathyroidism due to vitamin D deficiency