Renal Fxn Test Flashcards
1
Q
Screening for CKD
A
- Over 60- everyone w/o risk factors
- Dm, HTN, fmHx of kidney disease
- High risk groups: screening includes
- Serum Cr lelves with estimation of GFR using CKD-EPI
- Urine albumin to creatinine ratio
- UA
- High risk groups: screening includes
2
Q
Kidney Damage
A
- two main markers = albumin and eGFR
- Use eGFR from CPK-EPI equation
- eGFR = best overall marker of kidney function
- Use albumin- look for albuminuria
- Spilling of proteins
3
Q
estimated glomerular filtration rate (eGFR)
A
- calculated using isotope dilution mass spectrometry-trceable serum creatinine measurements and pts’ age, gender, race.
- uses gender, age, weight, and race + serum creatinine
- serum creatinine can be within range but the eGFR will tell you if the kidneys are actually working and determine what stage of kidney damage is prevent
- It declines with advancing age, will inc with body mass, and less in women
- Ideally: normal range > 90 ml/min/1.73 m2
- Low creatinine and high eGFR = good
- High creatinine and low eGFR = bad
- A pt can have kidney disease with a normal eGFR if he has evidence of other kidney damage such as hematuria, structural abnorms, albuminuria
- Presence of albuminuria aka spilling of excess albumin in urine = definite marker of renal disease regardless of eGFR (early and sensitive marker of kidney diseases)
- uses gender, age, weight, and race + serum creatinine
4
Q
creatinine (Cr)
A
- metabolite of creatine, a major muscle constituent (exogenous substance)
- in a healthy person, daily Cr production is relatively constant and determined by skeletal muscle mass
- measured to judge how well glomeruli are filtering
- a substance from the plasma that is entirely filtered at glomeruli and not reabsorbed back into bloodstream or secreted later in the tubule
- Creatinine Clearance:
- Rough measurement of GFR, with a timed urine collection (usually 24 hours) and a blood sample taken to measure plasma creatinine taken at end of that time period
- Time consuming and expensive
- Tends to OVERestimate the GFR
- Rough measurement of GFR, with a timed urine collection (usually 24 hours) and a blood sample taken to measure plasma creatinine taken at end of that time period
5
Q
blood urea nitrogen (BUN)
A
- Urea is major waste product of protein metabolism/catabolism (liver)
- Reflects dietary intake of protein and protein catabolic rate
- BUN is completely filtered by glomerulus
- Not as accurate as Cr because a lot of BUN can be absorbed to make it a less helpful marker for pure kidney dz
- Reabsorbed when kidneys are trying to hold onto volume (low volume state)
- Not as accurate as Cr because a lot of BUN can be absorbed to make it a less helpful marker for pure kidney dz
- Normal Range 6- 20 mg/dL
- Uremia: describes azotemia (high levels of nitrogen compounds in blood) so severe to produce symptoms
- Clinical syndrome associated with electrolyte, and hormone imbalances and metabolic abnormalities, which develop in parallel with deterioration of renal function- common with CKD
- Symptoms: Fatigue, N/V, anorexia, weight loss, muscle cramps, mental status changes
- Can occur in AKI if there is a rapid drop
6
Q
BUN / Cr ratio
A
- Steady state ratio 10-20:1
- Elevated BUN/Cr ratio indicates a pre-renal problem
- Kidney is trying to hold onto solute to hold onto water
- Could be due to:
- Decreased effective circulating volume
- Dehydration/volume depletion
- CHF
- Sodium avid states so BUN avid states
- Increased urea production
- Inc dietary protein intake
- GI hemorrhage
- Sepsis/catabolic states
- Decreased effective circulating volume
- Normal/depressed ratio could be renal or post-renal
7
Q
Albuminuria
A
- Persistent increased protein in urine (at least two positive ACR tests over 3 or more months)
- Indicated of kidney damage sufficient to make the dx of CKD
8
Q
Spot Urine albumin/creatinine ratio (ACR)
A
-
detect elevated protein
- Corrects for variations in urinary concentration due to hydration
- Fever, menstrual bleeding, UTI, fever, exercise can inc ACR
- Preferred test to detect albuminuria
- < 30 mg albumin per g of creatinine is normal
- urine for microalbumin: 30-300 mg albumin per g of creatinine is termed moderately increased
- aka microalbuminuria
- Macroalbuminuria: > 300 mg albumin
- Gold standard for urine = 24 hour collection
9
Q
Define Acute Kidney Injury (AKI)
A
- AKI: abrupt decrease in glomerular filtration rate sufficient to promote retention of nitrogenous waste products
- MC in hospitalized patients!
- BUN and Cr
- Sudden drop in kidney function
- Hospital conditions normally
- Complications: progression to severe kidney filature, need for RRT, CKD, death
- If you lost all kidney function overnight, your Cr would rapidly rise/elevate each day.
10
Q
DDX of AKI: three categories
A
- Pre-renal
- renal
- post-renal
11
Q
Pre-renal AKI
A
- the result of a decrease in renal blood flow and perfusion of the kidney… BEFORE kidneys
- Poor perfusion
- The kidneys sense not enough volume so their BUN will rise and Cr will rise
- MCC community-acquired AKI
- MCC of hospital acquired AKI
- What can cause:
- Poor CO so dec volume … CHF
- Tx: with tx CHF
- Hypotension
- Dehydration/volume depletion
- TX: with saline/fluids
- Poor CO so dec volume … CHF
- Dx: at first, aki is just a combo of symptoms creating aki syndrome….
- You can use crcl to look and see if creatinine serum rises in comparison to baseline
- >1.5 times baseline = stage 1
- >2 times baseline = stage 2
- >3 times baseline = stage 3
12
Q
Renal AKI
A
- the result of disease affecting one of the renal parenchymal compartments… KIDNEY
- cellular damage
- Problem with kidney’s themselves
- What can cause:
-
Glomerulonephritis
- RBC and protein inc
-
Interstitial nephritis
- RBC and WBC inc - eosinophils
-
Acute tubular necrosis: MCC
- Renal tubular cells that have been damaged/sloffed off
- Nephrotoxic medications can cause or ischemia
-
Glomerulonephritis
- Dx: do a UA
13
Q
Post-renal AKI
A
- the result of obstruction to urinary flow anywhere along the urinary tract starting from the renal calyces/pelves or the ureters, bladder, or urethra.,…. JUST OUTSIDE/AFTER KIDNEY
- obstruction
- Kidneys themselves can be healthy but there is obstruction in urine drainage causing pressure in tubules that can cause damage
- MC in elderly men with prostatic hyperplasia, bladder dysfunction
- Dx: Imaging / US of kidneys
14
Q
Prerenal and postrenal AKI
A
- See “bland urine”
- Not a direct kidney problem
15
Q
24 hour urine
A
- Used to calculate CrCl
- Pt collects all urine voided in 24 hours and has serum creatinine drawn at the end of collection
- Pregnancy, extremes of age and wt, amputees bodybuilders used
- Make sure they void at start time and discard that urine
- Keep refridgerated
- Void at end time and include that urine
- Not common anymore
18
Q
CKD staging
A
19
Q
CKD w/ action plan
A
21
Q
Normal Vs. Dz kidney
A
22
Q
CKD complications
A
