Therapeutics 4 - Acute and Chronic Kidney Disease

tylerwise's version from 2015-05-04 02:12

Acute Kidney Injury

Question Answer
Clinical definition of AKIGFR decrease > 25% or 1.5-fold increase in SCr
Urine output < 0.5 mL/kg/hr
How is AKI Classified?RIFLE and AKIN
RIFLE categoriesRisk
>SCr increase of 1.5-fold or GFR decrease of >25%
>Urine output of <0.5 mL/kg/hr for 6 hours

>SCr increase of 2-fold or GFR decrease of >50%
>Urine output of <0.5 mL/kg/hr for 6 hours

>SCr increase of 3-fold or GFR decrease of >75%
>Urine output of <0.3 mL/kg/hr or anuria for 12 hours

>Persistent acute renal failure = complete loss of function (RRT) for >4 weeks

>RRT > 3 months
AKIN categoriesStage 1
>SCr increase of 0.3 mg/dL or 1.5-2 fold
>Urine output of <0.5 mL/kg/hr for 6 hours

Stage 2
>SCr increase of 2-3 fold
>Urine output of <0.5 mL/kg/hr for 12 hours

Stage 3
>SCr increase of >3-fold or need for RRT
>Urine output of <0.3 mL/kg/hr or anuria for 12 hours
Anuria definitionUrine output < 50 mL/day
Oliguria definitionUrine output < 500 mL/day
Non-oliguric definitionUrine output > 500 mL/day
Prerenal AKIAssociated with decreased renal perfusion in presence of normal kidney
Usually due to volume depletion/dehydration
Intrinsic AKIAssociated with kidney damage
Postrenal AKIKidney is initially undamaged
Usually caused by bladder outlet/ureteral/renal pelvis or tubular obstructions
Urine sediment findingsPrerenal: hyaline casts; may be normal
Intrinsic: granular casts; cellular debris
Postrenal: cellular debris
Urinary RBC findingsPrerenal: none
Intrinsic: 2-4+
Postrenal: variable
Urinary WBC findingsPrerenal: none
Intrinsic: 2-4+
Postrenal: 1+
Urine sodium findingsPrerenal: <20
Intrinsic: >40
Postrenal: >40
FENa findingsPrerenal: <1
Intrinsic: >2
Postrenal: variable
Urine/serum osmolality findingsPrerenal: >1.5
Intrinsic: <1.3
Postrenal: <1.5
UrineCr/SCr findingsPrerenal: >40:1
Intrinsic: <20:1
Postrenal: <20:1
BUN/SCr findingsPrerenal: >20 (<1:12.4)
Intrinsic: 15 (1:16)
Postrenal: 15 (1:16)
Urine-specific gravity findingsPrerenal: >1.018
Intrinsic: <1.012
Postrenal: variable
Risk factors of AKIUnderlying CKD
Age > 65 years
Multisystem organ failure
Chronic diseases
Bone marrow or organ transplantation
NSAID contribution to AKINSAIDs inhibit prostaglandins which normally cause vasodilation of the afferent arterioles
Vasoconstriction occurs, causing a decrease in GFR
ACE-I/ARB contribution to AKIACE-I/ARB block activity of AngII which normally causes vasoconstriction of the efferent arterioles
Vasodilation occurs, causing a decrease in GFR
Prevention of AKI1) Hydration
2) Antioxidants (N-acetylcysteine reserved for contrast-induced nephrotoxicity)
3) Glycemic control
4) Withdrawal of causative agents
Treatment of AKI1) Remove offending agents or adjust doses for renal function
2) If dehydrated, infuse IV NS boluses
3) Blood products if a result of anemia (Hgb <7 or <9 and symptomatic)
4) Supportive care (electrolyte and nutritional abnormalities (hyperkalemia!!!)
5) Use of loops may be beneficial in non-oliguric
6) RRT (dialysis) may be necessary

Chronic Kidney Disease

Question Answer
Classifications of CKDStage 1: Kidney damage with GFR >90 mL/min/1.72m^2
Stage 2: Mild reduction in GFR (60-89 mL/min/1.72m^2)
Stage 3: Moderate reduction in GFR (30-59 mL/min/1.72m^2)
Stage 4: Severe reduction in GFR (15-29 mL/min/1.72m^2)
Stage 5: Kidney failure (GFR <15 mL/min/1.72m^2 or dialysis)
Risk factors of CKDSystemic inflammation
Complications of CKDFluid and electrolyte abnormalities (hyperkalemia and hyperphosphatemia)
CKD-related mineral and bone disorder and renal osteodystrophy
Metabolic acidosis (generally in Stage 5 disease)
Hypertension goals in CKDPre-dialysis BP of <140/90
Post-dialysis BP of <130/80
Hypertension treatments and rationaleACE-Is or ARBs
>Renal protective: prevent arterial remodeling and stiffening and possess sympathetic activity in Stages 4 and 5 disease

>Only use if benefit (non-oliguria) exists
Hyperphosphatemia treatmentsPhosphate binders (calcium acetate/carbonate, lanthanum, sevelamer)
Avoid calcium products if hypercalcemia exists)
Hypocalcemia treatmentsCalcium supplementation with or without calcitriol
Anemia treatmentsIron supplementation (PO only for Stages 1-3; IV for Stages 4-5)
ESA if Hgb <10 (target goal is 11-12)
Vitamin D deficiency treatmentsStages 1-3: any OTC vitamin D
Stages 4-5: calcitriol
Elevated PTH treatmentsCinacalcet (Sensipar) and vitamin D supplementation
>Except when serum calcium < 8.4mg/dL)

Monitoring Parameters

Question Answer
Fluid I/OsEvery shift
Patient weightDaily
HemodynamicsEvery shift
Blood chemistriesDaily
Nutritional regimenDaily
Blood glucoseAt least daily
Drug serum concentrationsAfter regimen changes and after RRT has been instituted
Urinalysis (CrCl and FENa)Every measured urine collection