L16: Renal+Urology diagnostics Flashcards
acute kidney injury staging is based on
GFR
Creatinine
Urine output
Normal serume creatinine
.5-1.2
Serum creatinine measures
Measures renal function
Know baseline, may be normal even with poor renal function
From catabolism in skeletal muscle and dietary meat intake→ released into circulation at constant rate→ stable plasma concentration→ freely filtered by glomerulus and excreted by the kidneys
serum creatinine
normal BUN
10-20
Product of protein catabolism excreted by kidneys
BUN
Increased BUN
dehydration, GI bleed, use of steroids or tetracyclines
marker for volume status
BUN/Creatinine ration
Normal GFR values
Males: 130 mL/min/1.73 m2
Females: 120 mL/min/1.73 m2
Stage 1 CKD
Kidney damage with normal or increased GFR>90
Stage 2 CKD
Kidney damage with normal or decreased GFR 60-89
Stage 3 CKD
Moderately decreased GFR 30-59
Stage 4 CKD
Severely decreased GFR 15-29
Stage 5 CKD
Kidney failure <15
Stage 5D CKD
Kidney failure with dialysis, no GFR
GFR is used to
Track disease progression/regression
Dosing of medications
Sex/race/body habitus dependent
improves estimates of GFR
Cystatin C
Sum of filtration rates of all functioning nephrons→ rough measure of number of functioning nephrons
Cannot be measured directly: Modification of Diet in Renal disease equation
GFR
One of the first signs of kidney disease and should not be ignored
protein on urinalysis
How to obtain Creatinine clearance
By 24-hour-urine collection, Cockcroft-Gault formula
Uses of Creatinine clearance
Approximates GFR: choosing/dosing medications
blood on urinalysis may indicate
Calculi glomerular damage neoplasm acute tubular necrosis trauma infection
Prostate Specific Antigen uses
Glycoprotein found in prostatic lumen
Not recommended in men >70
Screening for early detection of prostate cancer, monitor disease after treatment
Normal Prostate Specific Antigen antigen values
<4ng/mL
increased Prostate Specific Antigen may indicate
prostate cancer
BPH, prostatitis
following prostate manipulation: ultrasound, biopsy
If you suspect
Systemic lupus erythematosus, order
ANA double stranded DNA antibody levels
If you suspect Granulomatosis with Polyangiitis, order
C-ANCA and P-ANCA
If you suspect Goodpasture syndrome, order
Anti-GBM antibodies
If you suspect Glomerulonephritis, order ______ to narrow down the cause
Hep B and C
HIV
Venereal disease research laboratory (VDRL) serology
Serum complement
If you suspect Post-streptococcal glomerulonephritis, order
Antistreptolysin O
If you suspect Multiple myeloma, order
Serum and urine protein electrophoresis (SPEP, UPEP)
Possible causes of RBC casts
Glomerulonephritis
Vasculitis
Possible causes of WBC casts
Tubulointerstitial disease
Acute pyelonephritis
Glomerular disorders
Possible cause of epithelia cell casts
Acute tubular necrosis
uric acid crystals are
radiolucent on Xray, won’t show up
struvite crystals are made of
magnesium ammonium phosphate
Hyaline casts indicate
dehydration
Better quantitative measurement for proteinuria or GFR determination
24 hour urine collection
To find bench jones proteins in multiple myeloma
Urine protein immunoelectrophoresis (UPEP)
Urine eosinophils are seen in
*Acute interstitial nephritis* Transplant rejection pyelonephritis prostatitis cystitis atheroembolic disease rapidly progressive glomerulonephritis
Microalbumin on urine study
The earliest clinically detectable sign of diabetic nephropathy or kidney damage
Xrays will miss
Smaller stones
uric acid stones (radiolucent)
stones overlying bony structure
How is a kidney, ureters, and bladder film (KUB) taken
supine and upright positions
Test of choice to exclude urinary tract obstruction
Renal ultrasonography
Stones that are visible on KUB film
Calcification in the urinary tract:
Calcium containing, struvite, cystine stones
staghorn means
nephrolithiasis involving renal pelvis and extending into >2 calyces
Other things that can be seen on KUB film
Prostatic calculi Bladder distention Pancreatic calculi Calcified arteries Calcification in biliary tract Bowel gas pattern Free air secondary to ruptured viscus Calcified prostate: the whole prostate is opaque
Renal ultrasonography vs CT
U/S is less sensitive that CT in initially detecting a renal mass, but doesn’t use contrast
test to evaluate renal vascular flow
renal doppler ultrasonoography
May be seen on renal ultrasonography
Obstruction
Nephrolithiasis: appear white
Severity and length of ureteral strictures
Renal cysts (appear black) and masses (grayish tissue color)
Hydronephrosis
Renal or perinephric abscess
Atrophic kidneys
Ureteral diverticuli
Pyelonephritis: hypodense mass with internal echoes
can be seen on renal doppler ultrasonography
Renal vein thrombosis Renal infarction Renal artery stenosis Intrarenal vascular disease Arteriosclerosis
test of choice for nephrolithiasis
non-contrast CT
-can see stones not visible on KUB
On contrast CT, a stone looks like
stone in kidney prevents contrast from being normally excreted, dilated ureter
CT angiography can show
renal artery stenosis
renal vein thrombosis
Uses for CT
Distinguish benign vs malignant cysts
Evaluate and stage renal cell carcinoma
Bilateral pyelonephritis: triangular hypodense streaks spreading from pelvis to cortex: “stranding”
gold standard for Renal vein thrombosis
MRI
MRA can show
Renal artery stenosis
contraindications to MRI
Gadolinium in GFR<30 (chronic renal failure) or acute renal failure of any severity
→ nephrogenic systemic fibrosis
Shows size and shape of kidneys, ureters, bladder
Contrast in injected, then x-rays taken
Excretory function: time it takes for contrast to pass
Not frequently used due to contrast dye
Intravenous pyelogram
Intravenous pyelogram can show
Stones: seen obstructing the flow of contrast in the lumen of the ureter
Obstruction
Renal angiography uses
Pre-operative mapping of renal vasculature (main use)
Stenosis→ angioplasty and stenting
Fibromuscular dysplasia “sting of pearls”
Renal biopsy is used for diagnosis of
Unexplained acute renal failure Nephrotic syndrome Acute nephritis syndrome Renal mass Assessment for rejection following transplant
Bladder filled with contrast→ take x-rays
Can be done while voiding
Better for primary bladder conditions than intravenous pyelogram
Cystourethrogram
Cystourethrogram can show
Vesicoureteral reflux
Distortion of the bladder
Fistula
Perforation
Thin fiber-optic tube (flexible vs. rigid) passed through a hollow sheath into the urethra and advanced into the bladder
cytoscopy
Cytoscopy complications
Post-procedure hematuria: expected, passes within 3 voids
sepsis
hemorrhage
perforation of the bladder
post-procedure dysuria
Urogynecologic malignancies that can be assessed with cytoscopy
Incontinence with irritative voiding symptoms Sterile hematuria/pyuria Recurrent infection Urethral diverticula Fistulas
Intrinsic bladder diseases that can be assesed with cytoscopy
Interstitial cystitis
Bladder tumors, stones, or scarring
Uses of testicular ultrasound
testicular/scrotal size, pain, masses
Testicular torsion (Doppler)
Location of undescended testes
How is a prostate ultrasound and biopsy performed, and on whom
transrectally
high PSA to detect prostate cancer
