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Acute pyelonephritis (p.12-13)
- Acute inflammatory condition involving kidney and renal pelvis caused by bacterial infectionManifestation of UTI
- Usually involves infection originating in lower urinary tract
- - cystitis, protatitis, urethritis
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What factors contribute to acute pyelonephritis? (p.12-13)
- Organisms likely to cause:
- - E. coli (most common)
- - Proteus klebsiella
- - Enterobacter
- - Pseudomonas
- Often result of manipulation of urinary tract:
- - catheterization
- - cystoscopy
- Routes for bacteria to reach kidneys:
- - bloodstream
- - lower urinary tract
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What are the clinical manifestations of acute pyelonephritis? (p.13)
- Onset of pain at costovertebral angle
- Signs of systemic infection - fever, chills, malaise
- Can be self-limiting
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Azotemia
- Substantial rise in plasma concentration of non-protein nitrogenous compounds
- Urea
- Creatinine
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Prerenal ARF (azotemia)
- Result of decreased blood flow
- - inadequate perfusion
- - decreased glomerular filtration in presence of otherwise normal renal function
- No parenchymal damage
- Reversible - if renal blood flow quickly restored and cardiac output normal
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Causes of prerenal ARF
- Systemic hypotension or hypovolemia
- - decreased cardiac output (CHF)
- - burns, trauma (hemorrhage)
- - dehydration
- - bacterial sepsis
- - bilateral renal stenosis
- - any situation resulting in shock --> renal hypoperfusion
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Postrenal ARF (azotemia)
- 5% of cases of ARF
- Usually result of obstruction of urethra, bladder neck, bilateral ureters, or unilateral ureters in patient with one functioning kidney
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Causes of Postrenal ARF
- Benign prostatic hypertrophy
- Blood clots
- Tumors
- Renal calculi
- Foley catheter obstruction
- Urethral strictures
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Intrarenal ARF
- Result from any lesion in any part of the kidney, including:
- - glomeruli (progressive glomerulonephritis)
- - blood vessels (malignant hypertension)
- - DIC
- - HUS
- - tubules and interstitium - acute tubular necrosis, allergic acute interstitial nephritis
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Cause of intrarenal ARF?
- Most common cause = Acute Tubular Necrosis (ATN)
- Either ischemic or nephrotoxic
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Differentiate between prerenal and intrarenal ARF in terms of parenchymal damage.
- Prerenal = no parenchymal damage
- Intrarenal = + parenchymal damage
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How will urine lab values differ between prerenal & intrarenal ARF?
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Acute Tubular Necrosis (ATN) (p.16-17)
- Acute injury of renal tubules
- Result in acute suppression of renal function
- - decreased GFR
- - oliguria (<400 mL/day)
- - anuria
- - increased BUN and serum creatinine levels (azotemia)
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Ischemic ATN
- Segmental necrosis
- + basement membrane rupture
- Injury to renal tubules
- Impaired Na+, Cl-, and fluid reabsorption
- Little urine produced - unconcentrated (isotonic), increased Na+ concentration (>40 mEq/L)
- Ischemia >60 minutes = irreversible
- Occurs as response to shock or dehydration
- - decreased renal blood flow
- - reduced GFR
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Nephrotoxic ATN
- No rupture of basement membrane
- Reversible if treated quickly
- Repair process not long because basement membrane still intact
- Caused by many poisons, heavy metals, numerous drugs
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In ARF, the oliguric phase is represented by approximately how much urine output? (p.16)
- <400 mL/day
- (< 0.5 mL/kg/hr)
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