Acute Renal Failure also called
Acute Kidney Injury
-Rapid decrease in kidney function which causes collection of metabolic wastes in the body
3 types of AKI
- prerenal
- intrarenal
- postrenal
prerenal AKI
-caused by reduced blow flow to the kidney
Intrarenal AKI
-causes damage to what three areas
- caused by infections such as pyelonephritis, GN which caused damage to the glomeruli and interstitial tissue and tubules
postrenal AKI
- 2 causes
-caused by an obstruction of urine flow bc of stones or BPH- begnin prostatic hyperplasia
generalized possible caused of AKI
- reduced blood flow like hypovolemic shock
- toxins
- infections
- UT obstruction
Explain the process of kidney dysfunction
pressure in the kidney tubules intrarenal pressure exceeds glomerular pressure GFR stops and nitrogen wastes begin to collect in the blood (BUN and creatinine)
so when yup have the constant high BUN and Creatine this is kidney dysfunction
phaes of AKI
- onset
- oliguric
- diuretic
- recovery
how does the reduced blood flow to the kidney impact AKI
- kidney compensates for the low perfusion of the kidneys
-and compensates by constricting the renal blood vessels
activating RAAS and releasing ADH
-inc blood volume to the kidney
-they reduce urine volume-oliguric phase
-Azotemia- retention and buildup of nitrogen waste in the blood
-nephron cell injury occurs due to lack of 02 (ischemia and reduced blood flow)
-toxins case blood vessel constriction and reduce the kidney blood flow
Chronic Renal Failure
- Progressive, irreversible disorder where kidney function does not recover
causes of Chronic Renal Failure
- HTN- end organ damage of the kidney
- DM- macrovascular changes of the kidney
- Acute Renal Failure- if left untreated
- Lupus
- PKD
- GN
How is Chronic Renal Failure Staged
- based on the levels of GFR the lower the GFR the worse the kidney failure IS
What happens to CRF
-it becomes end stage kidney disease person dies
what kidney changes do we see in someone who has chronic kidney disease
- the healthy nephrons become larger and try to work harder
- GFR is going well until the 3/4 of the kidney function is lost then it becomes so low
- abnormal urine production begins-poor water excretion
what metabolic changes do we see in someone who has CKD
- urea and creatinine excretion are disrupted when the kidneys don’t work
- when the kidneys are not working the creatnine levels increase in the blood
- urea levels in the blood also inc for urea if kidneys don’t work
where do creatine come from
protein from skeletal muscle
when is urea made?
protein metabolism
what happens to Na levels during early and late CKD
- in early: there are not enough nephrons to absorb the Na and there is polyuria so alot of the Na is being pee-ed out
- in Late CKD- there is oliguria and Na is kept in causing too much Na in the blood
Potassium changes and CKD
in late stages there is going to hyperkalemia bc the kidneys dont work and none is being excreted
this causes fatal EKG changes and dyrthythmias
acid base changes in CKD
- in the easrly stages the nephrons that are working are removing H so there is not much difference
- in the late stages- the kidneys cannot excrete the H so its acidic and Ammonia production is decreased. the kidneys also cannot reabsorb the HCO3 which makes reduced levels of bicarb
Phosphate CKD
Ca
phosphate retention
vit d is not being activated
normally the kidneys would remove the excess phosphate and the PTH would control the P in the blood by causing tubular excretion of P
so low Ca and high P levels
the low Ca levels tell the PTH to take Ca out of the Bone (bone reabsorbtion) and this causes weak bones
renal osteodystrophies
bone metabolism cause by CKD bc of the low Ca levels in the blood ad the high P levels
HTN in CKD
-Na inc
-fluid overload
-dysfunction of RAAS
this is serve and worsens the kidney function
causes heart damage and enlargement
hyperlipidema
changes in fat metabolism that increase LDL, Triglycerides, in risk for artherosclerosis and DM
