Week 5 Flashcards
(82 cards)
What drugs vasoconstrict the afferent arteriole? What does this cause?
NSAIDs e.g. naproxen.
Causes decreased glomerular filtration rate.
What drugs vasodilator the afferent arteriole? What does this cause?
ANP
Prostaglandins
Increases glomerular filtration rate.
What drugs vasoconstrict the efferent arteriole? What does this cause?
Angiotensin II
ANP
Noradrenaline
Causes an increase in glomerular filtration.
What drugs vasodilator the efferent arteriole? What does this cause?
ACEI
ARB
Causes a decrease in glomerular filtration rate.
What is renal osteodystrophy?
When the kidneys become damaged in chronic kidney disease- it means they hydrolysing vitamin D to its active form. This means that calcium isn’t absorbed from the gut to replace that lost from the bone. This causes weak bones.
Acute kidney injury can be…
Pre, intra or post renal.
Causes of pre-renal AKI?
Due to hypoperfusion of the kidney e.g. from renal artery stenosis, hypovolaemia due to diarrhoea, sepsis causing hypovolaemia, hypotension due to cardiac causes e.g. MI.
What would happen if AKI wasn’t treated?
It would mean the kidney would undergo acute tubular necrosis due to lack of oxygen.
How would you diagnose AKI?
Ultrasound is needed to check for obstruction and to check the size of the kidneys (to check for acute exacerbation of chronic kidney disease which will mean the kidneys are often smaller)
What would you do if the ultrasound reveals no apparent cause of hypoperfusion of the kidneys and they appear to be normal size?
Urgent renal biopsy
What is the treatment for hyperkalaemia?
Calcium gluconate 10% 10mls IV- cardioprotective against arrhythmias.
10 units of act rapid insulin and 50mls of glucose 50%IV- insulin causes potassium to move into cells and glucose prevents the subsequent hypoglycaemia it would cause.
2.5mg of salbutamol. Beta agonists cause pottasium uptake in cells.
Will the acute treatment of hyperkalaemia suffice?
Patient is most likely to need heamo-dialysis as the acute treatment is only temporary.
What are the stages of chronic kidney disease?
Stage 1- GFR normal- >90. Has to have evidence of kidney damage.
Stage 2- GFR 60-90. Need evidence of kidney damage.
Stage 3- GFR 30-59.
Stage 4- GFR of 15-30
Stage 5- GFR of less than 15 OR on renal replacement therapy.
Pathogenesis of diabetic nephropathy
High blood glucose causes release of vasoactive mediators that dilate the afferent arteriole increasing GFR. Also causes a release of growth factors causing renal hypertrophy and mesangial expansion.
This causes nodule formation and diffuse glomerulosclerosis.
This causes inflammation, proteinuria (due to GBM thickening and podocyte dysfunction) and tubulointerstitial fibrosis.
How would you diagnose diabetic nephropathy?
History of DM
Albuminuria/proteinuria
Presence of other diabetic problems (if they have retinopathy they are likely to have issues with their kidney)
Renal impairment (late finding)
Describe the 3 stages of diabetic nephropathy
Stage 1: Pre - renal hypertrophy -GFR increases Stage 2: Incipient - microalbuminuria -hypertension Stage 3: Overt -proteinuria -nephrotic syndrome -mesangial nodules (Kimmel-steil wilson lesions) -tubulointerstitial fibrosis
How would you prevent and manage diabetic nephropathy?
Prevention- good glycaemic control
Antihypertensive therapy- tight BP control (< 130/80) using ACE inhibitors and ARBs
Lipid control.
How do you slow the progression of diabetic nephropathy?
Reduce proteinuria.
What is ischaemic neuropathy?
Refers to the reduced GFR associated with reduced renal blood flow beyond the level of auto regulatory compensation.
Over time- can lead to renal atrophy and progressive CKD.
What can cause ischaemic neuropathy?
Essential hypertension
Secondary hypertension- due to atherosclerosis in the renal arteries causing stenosis
Or fibromuscular dysplagia
What occurs if the renal is under-perfused?
It activates a series of hormonal and neuronal responses resulting in an increase in systemic bp.
This is due to the increased blood pressure trying to overcome the blockage and perfuse the kidneys. It compensates a bit. When you then treat the high blood pressure- the kidneys become even more under-refused hence the AKI.
Who gets atherosclerotic renal vascular (renal artery stenosis) disease?
Older patients (greater than 50)
Males affected more than females
Usually unilateral
Clinical presentation of renal vascular disease?
Renovascular hypertension AKI after treatment for hypertension CDK with diffuse vascular disease Flash pulmonary oedema Abdominal bruits.
What investigation would you use to look into renal artery stenosis?
Renal artery US Renal artery duplex studies CT angiography MR angiography Conventional angiography