2450 renal failure (wk5) Flashcards
7 major funx of kidneys that are altered in renal fail
4 regulations, activation, excrete/secrete
- regulation of fluid balance
- regulation of electrolyte balance
- regulation of acid-base balance
- excretion of metabolic waste products & foreign chemicals
- activation of vita. D
- secretion of erythropoietin
- regulation of systemic BP
important factors in renal activation of vitamin D, secretion of erythropoietin,
- affects Ca+ absorp. in gut & reabsorb. in nephron
2. erythropoietin is a cytokine that regulates RBC produxn. and longevity
how do the kidneys regulate systemic BP
1 fluid balance (RAAS)
2. renal prostaglandins; cox 1 housekeeping are natriuretic & block Na+ & H2O cause vasodilation
cox -2 inflammatory, reabsorption
7 general assessments based on renal funx
- urine output pattern
- serum electrolytes
- acid-base status
- BUN creatinine levels
- S/S of hyperPO4-/hypoCa+
- CBC- Hgb, Hct, RBC
- blood pressure
how many nephrons needed to work to achieve kidney’s funx?
at what point will renal funx not be sustained?
what else occurs?
- 2 million
- renal funx sustained until 75% nephronal damage
- compensatory hypertrophy
3 facts about ARF or AKI
Acute Renal Fail, Acute Kidney Injury
- usually associated with acute injury or illness
- reversible if underlying etiologies corrected and renal hypoperfusion not prolonged
- usually affects all nephrons about equally
3 etiologies of ARF
- acute ischemic event or loss of renal perfusion (MI, bleeding, surgery, clot)
- acute nephrotoxic injury w/damage to renal tubules (drug bugs chemicals)
- obstruction to urine flow (rare)
3 facts about CRF or CKD
Chronic Renal Failure or Kidney Disease
- gradual onset & progression
- generally irreversible
- attack localized groups of nephrons, causing other nephrons to compensate
5 etiologies of CRF
- tubulointerstitial dz
- glomerulonephropathies
- renal vascular d/o
- nephrotic syndrome
- renal cancer
what is tubulointerstitial dz and how does it affect renal funx
spaces b/w kidney tubules become inflamed. This inflammation can affect kidney funx by affecting ability to filter waste
1 final pathway in end-stage renal fail
2 progression
3. 2 d/o’s that cause interstitial nephritis
- chronic hypoxia b/c of decreased nourishment,
2 tubulointerstitial damage progresses & is associated with loss of peritubular capillaries which leads to apoptosis - lupus or NSAID hypersensitivity
what does glomerulonephropathies or glomerulonephritis result from and what happens
- most result from immune dysregulation mediated by type 2 (cell lysis) or Type 3 (immune complex deposition) hypersensitivity rxns.
- damage to glomerulus results in changes in GFR & capillary wall structures which cause proteinuria & hematuria (ex: rusty pipes)
- diffuse (rather than local) lesions result in renal failure
3 renal vasc. d/o
HTN, stenosis (narrowing), atherosclerosis (plaque & thickens vessels)
- where does nephrosis start
- what it affects
- how
- who
- dz’s
- usually starts in glomerulus
- affects all of the kidney
- is the excretion of 3.5g or more of protein in the urine per day (characteristic of glomerular dz
- more common in children than adults
- DM, systemic lupus erythematosus, malignancies
- cancer associated with CRF
- who
- prognosis
- adrenocarcinomas that arise from tubular epithelium in the cortex (PCT DCT)
- seen more in males, 50-60yo, black ppl, smokers obese
- less than 50% w/o metastasis, 2% w/ metastasis
4 stages of CRF
- diminished renal reserve
- renal insufficiency
- end-stage renal dz (ESRD)
- uremic syndrome
diminished renal reserve in CRF 1 Nephron loss 2. lab data 3. creatinine clearance 4. symptoms
- 50%
- serum creatinine doubles from baseline
- decreases to 1/2 norm. (norm~125mL/min down to 60-70)
- none
renal insufficiency in CRF 1 Nephron loss 2. lab data 3. creatinine clearance 4. symptoms
- 75%
- serum CR x4
- 40-50
- HTN, anemia, bone dz (s/s begin)
ESRD in CRF 1 Nephron loss 2. lab data 3. creatinine clearance 4. symptoms
- 90%
- serum electrolyte, & acid base alterations Serum CR > or = to 10X
- 10-15
- metab acidosis, increase of K+ Na+ h2o retention (require dialysis or transplant)
uremic syndrome 1 Nephron loss 2. lab data 3. creatinine clearance 4. symptoms
- > or= 90%
- findings reflect multiorgan involve.
- = or < 10-15
- pigmentation pruritis uremic frost uremic pericarditis
describe normal urine output pattern
kidneys maintain body h2o homeostasis & norm. osmolality by adjusting concentration/dilution of urine. urine osmolality (200-1400 osmolality)
3 alterations to Urine output, & associated risks
- anuria
- oliguria (risk for excess fluid volume)
- polyuria (deficient fluid volume)
clinical manifestation of hypervolemia (EFV)
- generalized edema=anasarca
- pulmonary edema
- concentrated urine
- less than 30mL of urine output/hr
clinical manifestations of hypovolemia (DFV)
- increased output
- decrease in BP
- dry mucus membranes, poor turgor
- dilute urine (low specific gravity)
3 methods of normal electrolyte balance regulation
3 earliest detectable most harmful electrolyte imbalances
- diffusion, osmosis, & active transport of electrolytes at nephronal level
- hyperK+, hypoCa+, hyperPO4-
What happens is Renal failure related hyperkalemia & manifestations & most important
- nephron’s inability to secrete K+ ion
- N/V/D fatigue
- EKG changes, tall T waves (indicated possible ischemia), wide QRS waves (indic. slow ventricular activation), disappearing P waves (loss of atrial contraction)–> can be life threatening arrhythmias Y brady<3
etiology of renal failure related hypoCa+ & hyperPO4-
hypoCa+: kidney’s inability to activate vitamin D
hyperPO4-: kidney’s failure to excrete phosphate, excess PO4- binds to Ca+, eventually metastatic calicifications are risk & cause organ dysfunx–> <3, lungs, kidneys
clinical manifestations (3) of hypocalcemia/hyperphophatemia
- neuromusc. excitability (tetany->chvostek/trousseau; adult form of rickets)
- bleeding d/o’s
how do they kidneys maintain acid-base balance & etiology in renal failure
- secretion of H+ from tubular cells into urine & reabsorption of bicarbonate HCO3-
- inability to excrete acids & reabsorb bicarbonate which cause metabolic acidosis
etiology of HTN in renal fail
- decreased renal perfussion sensed in juxtaglomerular apparatus ->stimulates RAAS (angiotensin 2 vasoconstrict -> increase BP, aldosterone Na+ & h2o retention -> increase blood volume)
- decrease GFR -> decrease h2o excretion=h2o retention ->BP increase
- decrease renal produxn of prostaglandins -> increase BP
RBC Hgb Hct norm. & altered funx
- normal: renal secretion of erythropoietin in response to hypoxemia, stimulates RBC produxn in bone marrow & prolong life of existing RBC
- alteration: renal inability to secrete erythropoietin -> low RBC, Hgb, Hct -> symptomatic anemia (fatigue, SOB, palor, palpitations)
normal funx of renal elimination of toxins and waste
renal excretion of nitrogenous waste, toxins, & waste products from blood & body
in altered renal elimination of toxins & waste, what are 2 commonly measured nitrogenous waste products normal ranges
- urea: waste of protein metab., filtered in the glomerulus & reabsorbed @ several different sites along nephron (BUN=8-20)
- creatinine: waste of muscle metabolism, amt produced per day is proportional to body’s muscle mass & occurs @ constant rates (.6-1.2)
define azotemia & 2 examples of non-renal etiology
high levels of blood urea nitrogen
high protein diet & starvation (muscle waste product)
describe Cr & GFR correlation
- increase Cr= Decrease GFR
2. decrease in GFR = decrease in Cr clearance
pathophysiology of prerenal failure (acute)
- decreased renal blood flow (RBF)
- renal adaptation to decreased RBF
- result: concentrated urine, high BUN, no change in creatinine (creatinine is never reabsorbed)
etiology of decreased RBF in acute prerenal fail
- decreased renal cellular metab & tubular transport systems (starves renal cell = no funx)
- decrease driving force for glomerular filtration = decrease in hydrostatic pressure
how does renal adaptation to decrease in RBF occur
- autoregulation (can occur when sys BP b/w 80-180 to maintain norm GFR, if < 80 AKI risk)
- stimulation of RAAS
causes of high BUN
- increased Na+ reabsorption
- increased h2o reabsorption
- decreased urine flow rate through nephron
2 pathophysiology for postrenal failure
- complete bilateral obstruction -> anuria
2. unilateral obstruction -> oliguria
etiology for anuria caused by bilateral obstruction
- urine accumulates-> increase pressure in collecting system & back into nephron
- Na+, h2o, urea reabsorbed
- increased hydrostatic pressure in Bowman’s capsule -> increased force oppose filtration -> decreased GFR
what happens if bilateral obstruction is prolonged
- tubular dilation & damage
- interstitial compression
- decreased renal tubular funx ->intrarenal failure
what happens in unilateral obstruction
same a bilat obstruct just progresses @ slower rate & hypertrophy of unobstructed kidney
2 dz of Acute intrarenal failure
- ischemic acute tubular necrosis
2. nephrotoxic acture tubular necrosis
2 causes of ischemic acute tubular necrosis
may be a reperfusion injury (release of free radicals)
- renal vascontriction d/t: persistent stimulation of RAAS related to decreased renal perfusion & decreased renal prostaglandin produxn b/c of overwhelmed autoregulation mechanisms to counteract RAAS
- tubular injury & dysfunction
etiology of tubular injury & dysfunx
- damage to renal tubule cell=basement membrane
- renal tubule cell membrane disrupted -> loss of renal tubule cell funx
- increased tubule permeability
what happens when renal tubule is too permable
- tubular fluid & protein leak back in to interstitium ->cause inflammation
2, casts form and found in urine - some nephrons may collapse
3 steps in nephrotoxic acute tubular necrosis
- injury to renal tubule cell (inside nephron) drugs bugs or chemicals
- epithelial cells of nephron affected 1st -> microvilli slough off, casts formed -> decrease nephron funx
- oliguria- nonoliguria and even polyuria occur
4 phases of ARF
- beginning
- duration
- s/s
- onset/ initiating phase (begins with acute renal injury lasts 24-48hrs until oliguric phase low urine output rising BUN)
- oliguric phase (begins 1-2 days after trauma/illness lasts for 1-3 wks) marked loss of nephron funx need to replace renal funx during this phase
- diuresis phase (begins 2-4 weeks after trauma/ischemia, last 1-2 wks if underlying caused removed) nephrons healing but may be unable to concentrate urine
- recovery phase (3-12 months for full recovery), 30% never recover
2 facts about diuresis phase (skip, & careful)
- PTs w/ nephrotoxic injury d/t drugs or toxins may skip oliguric phase & go straight to diuresis phase
- careful fluid & electrolyte monitoring & replacement is essential
Treatment for Acute intrarenal failure
- rest kidney (dialysis)
- treat underlying cause
- replace lost renal funx until renal funx returned (blood transfusion electrolytes)