consequence of impaired kidney func
concept of CKD
what does CKD mean for patient?
renal function: 3 functions of the kidneys
- Homeostasis; regulates and maintains.
- > elimination of waste
- > water homeostasis
- > acid base homeostasis; need to pass enough H+ ions to prevent acidosis
- > electrolyte homeostasis
- > BP control
- Excretion of drugs and drug metabolites
- Metabolic/ Endocrine -> synthesis of hormones
what 3 hormones synthesised in kidney?
Vitamin D, Erythipoietin, Renin
what electrolytes does kidney control (homeostasis)?
K, Phosphate, Ca
How would you measure kidney function?
- what influences this?
serum creatinine (traditional measure) - influenced by gender, ethnicity, age, body mass, diet, excercise
relationship on graph between plasma conc and GFR?
- as kidney function declines, the creatinine levels increase (GFR increases)
- not sensitive to small changes
- non-linear relationship to kidney function
- doesn’t take long-term changes into account
How would you estimate the GFR?
- calculate from creatinine, age, gender, ethnicity
- better reflection of kidney function
- best measure for use in stable renal function
Is CKD irreversible or reversible?
irreversible and tends to progress
Stages of CKD?
CKD 1-5
CKD 5- worst, shows kidney failure of levels of 0-15 eGFR
CKD 4- Severe decrease in GFR ; 15-29; feeling tired and insulin doses and drug tablets
CKD 3- moderate CKD; 30-59
CKD2- kidney damage but mild; 60-89
CKD 1- kidney damage but normal GFR; >90
What occurs with CKD 5?
- end stage renal failure
- insufficient renal function to sustain life/health
- death
- there are renal replacement therapies are essential to prevent progression of kidney failure
3 possible treatments for CKD5?
end stage renal failure
- > haemodialysis
- > peritoneal dialysis
- > kidney transplantation
Who has CKD?
- common
- most of it unrecognised
- diabetes and renovascular disease lead to CKD and most common
- more common with older age
What are the risk factors for CKD?
- increased age
- hypertension (highest risk)
- diabetes
- smoking
- poor education
- drugs (NSAIDs)
6 possible Causes of CKD
- systemic diseases; diabetes, hypertension, atherosclerotic disease !!!
- immune mediated diseases; IPA nephropathy
- infectious diseases; HIV, HBV, HCV, TB
- genetic diseases; polycystic kidneys
- arterial disease; atherosclerosis
- obstruction; tumours, stones, fibrosis
With chronic glomerulonephritis, what happens to the glomeruli and tubules?
sclerosed glomeruli and atrophied tubules
What is the pathology of CKD? 3 steps
- thickening of BM; cap walls become weak, bleed and leak protein; slow blood flow
- mesangial expansion
- > hyperglycaemia stimulates increased matrix production by mesengial cells
- > stimulation of TGF-beta release
- glomerulosclerosis
- > due to intraglomerular hypertension or ischaemic damage
- high levels of sugarcane also make vessels to become narrow and clogged
Explain the vascular disease- renal artery stenosis
- low blood flow
- consequence of poor diet and diabetes
- both or one of the arteries leading to the kidneys becomes narrowed
- cant use an ACE inhibitor
- we want to constrict the afferent arterial to maintain BP and glomerular pressure
List the complications of CKD
- anaemia
- hypertension
- disturbed calcium
- CVD
- Bone disease
- immune suppression
- bleeding tendency
- treatment complications
4 types of obstructions that may occur?
stones
benign prostate
tumours: intrinsic/ extrinsic
fibrosis: narrow blood vessels
obstructio may cause hydronephrosis, what is it?
enlargement + swelling of kidney as build up of urine
why is anaemia a complication of CKD
lack of erythrop. production, loss of Fe absorption -> Fe deficiency
hyeprtension in CKD caused by result of?
RAAS system inactivation problem-
if not able to pass fluids properly -> urine poorly func kidneys = inc BP
What does the failure of fluid homeostasis lead to? (2)
inability to concentrate urine
- > loss of diurnal rhythm of urine excretion
- > limited rate of water excretion
- osmotic diuresis of surviving glomeruli
inability to excrete water load
- > dilutational hyponatraemia
- > oedema
- > hypertension
What is the treatment for fluid overload?
- diuretics (remove as much urine as possible, using working parts of kidney)
- salt restriction
- fluid restriction
if doesnt work then dialysis and transplant
