Diabetic Nephropathy Flashcards
What factors lead to diabetic nephropathy?
- Increased glomerular hydrostatic pressure caused by HTN
- Activation of RAS (renin angiotensin system) which causes vasoconstriction of the efferent arterioles (as well as all over the body)
- Ischaemia of the nephron, resulting in atrophy and destruction
Why does vasoconstriction of efferent arteriole have an affect?
It causes the blood to back up in the glomerulus, increasing hydrostatic pressure.
Why does the RAS get overactivated in DM?
Hyperglycaemia in the kidney causes activation of the RAS
What does long term high hydrostatic intraglomerular pressure cause?
Pressure (Baro) trauma to the kidneys which affects the mesangial cells
What do mesangial cells do in response to high pressure?
Release cytokine
Release free radicals
Undergo mesangial expansion
How does mesangial expansion have an effect on the kidneys?
The mesangium pushes on the capillaries, decreasing surface area, thickening the basement membrane and causing the podocytes to become more separated.
Why does the nephron become ischaemic?
RAS activation causes less blood to exit via efferent arteriole. This causes less blood to flow through into the intratubular arteriole which supplies the nephron.
What are the stages of diabetic nephropathy?
- Increase in GFR
- Detectable proteinuria
- Microhaematuria
- Compensation of GFR by other nephrons for those nephrons that have died
- Kidney failure
Why do you get increased GFR at the start of diabetic nephropathy?
Due to increase in hydrostatic pressure in Bowman’s space
Why do you get proteinuria in diabetic nephropathy?
The hydrostatic pressure causes the podocytes to space out which allows protein into the urine, most commonly albumin.
Why do you get microhaematuria in diabetic nephropathy?
The nephrons start to die from lack of blood supply from the intratubular arteriole
What consequences can kidney failure cause?
Anaemia (low EPO)
Metabolic salt imbalances
Heart arrhythmias
Why do you get arrhythmias in CKD?
Uraemia causes reduced potassium which affects the repolarisation and causes oxidative stress
How do we prevent diabetic nephropathy?
Treat the hypertension! ACE-i, ARB CCB Diuretic Try to keep it below 140/90
Treat the hyperglycaemia and control the diabetes!
