Cloned from: Renal Diagnostics



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Urinalysis
  • general exam of urine to determine baseline information or provide data to establish a tenative diagnosis and dtermine if other studies are needed
  • try to obtain first urine of morning and examine within 1 hr
Creatinine Clearance
  • creatinine is a waste prosduct of protein breakdown (primariily body muscle mass), clearance aproximates GFR
  • normal 85-135 ml/min
  • collect 24 ghr specimen, discard first and start time, finish 24hr with a final urination
Composite urine Collection
  • collection of urine from 2-24 hrs to measure lytes, glucose, protein, ketosteroids, catecholamines, creatinine, and minerals
  • discard first urine and start time, finish time with urination, keep sample cool or add presevatives
Urine Culture
  • clean catch and midstream
  • done to confim suspected UTI and Id causative organism
  • < 10,000 organisms/ml indicates no infection
  • 10,000-100,000 not diagnostic, needs to be repeated
  • > 100,000 organisms/ml indicates infection
  • use sterile container, cleanse area, start urinating and collect from mid stream
Concentration Test
  • evaluates renal concentration ability as measured by specific gravity
  • normal SG: 1.020-1.035
  • fast in evening, collect samples at 3 hourly intervals in morning
Residual Urine
  • determines amount of urine left in bladder after urinating
  • normal ≤ 50ml
  • catheterize pt immediately after urinating or use US
Protein Determiniation
  • Dipstick: detects protein in urine (primarily albumin)
  • Quantitative test for protein: 12-24 hr collection
  • done via either dipstick or 24 hr collection
Urine cytology
  • urine can be used to id abnormal cellular structures from bladder cancer or to monitor progress of bladder cancer
  • do not use first mornings urine
  • analyze within one hour
BUN
  • most commonly used to ID renal problems
  • concentration of urea in blood is regulated by rate at which the kidneys excrete urea
  • normal 10-30 mg/dl
  • nonrenal factors can increase (infections, GI bleeding, trauma, athletic activity, excessive muscle breakdown, corticosteroids)
Creatinine
  • more reliable than BUN at determining renal function
  • Creatinine is the end product of muscle and protein metabolism and is liberated at a constant rate
  • normal is 0.5-1.5, higher in men
BUN/Cr ratio
  • normal ratio is 10:1
Uric Acid
  • screening test for disorders of purine metabolism, but can indicate kidney disease as well
  • values depend on renal functin, purine metabolism, and dietary purine intake
Sodium (Na+)
  • normal 135-145 mEq/L
  • main extracellular lyte determining blood volume
  • usualy stays in range until late stages of kidney failure
Potassium (K+)
  • normal 3.5-5 mEq/L
  • K+ levels are one of the first to become abnormal in kidney disease
Calcium (Ca+)
  • normal 9-11 mg/dl
  • main mineral in bone
  • aids in muscle contraction, neurotransmission, and clotting
  • in renal disese, deccreased Ca reabsorption leads to renal osteodystrophy
Phosphorus
  • Normal 2.8-4.5
  • inveresely related to Ca balance
  • eleveated in renal disease because the kidney is the primary excretory organ
KUB (Kidneys, ureters, bladder)
  • x-ray of abdomen and pelvis
  • delineates size, shape, and position of kidneys
  • radiopaque stones and foreign bodies can also be seen
  • pt may need bowel prep (if ordered)
Intravenous Pyelogram (IVP)
  • x-ray exam of urinary tract after injuction of IV contrast
  • presence, position, size, and shape of kidneys, ureters, and bladder can be evaluated
  • cysts, tumors, lesions, and obstructions cause a distortion in the normal appearance of these structures
  • should not be done on pts with decreased renal function d/t nephrotoxicity
  • pt NPO 8 hrs prior, give cathartic/enemea to empty colon of feces and gas, assess for iodine sensitivity
  • force fluid post procedure to flush contrast media
Antegrade Pyelogram (nephrostogram)
  • x-ray to evaluate the upper urinary tract when there is an allergy to contrast media, decreased renal function, or inability to place a uretreral catheter
Nephrotomogram
  • an x-ray with rotating tubes
  • delineates kidneys at different levels
  • multiple exposures to visualize specific sections after injection of IV contrast
Retrograde Pyelogram
  • x-ray of the urinary tract after injection of contrast into the kidney
  • may be done if IVP does not visulize the urinary tract, if the pt is allergic to contrast material, or if pt has decreased renal function
  • a cystoscope is inserted all the way to the renal pelvis and dye is injected
Renal ateriogram (angiogram)
  • used to visualize renal blood vessels
  • can assist in diagnosing renal stenosis, missing or extra vessels, and renovascular htn
  • included in the work up of a possible donor
  • a catheter is inserted through the femoral artery up the aorta at the level of the kidneys
Renal Ultrasound
  • used to detect renal or perirenal masses, in the differential diagnosis of renal cysts and solid masses, and in identification of obstructions
  • normal US procedure
CT Scan
  • provides excellent visualization of the kidneys
  • kidney size can be evaluated
  • tumors, abcesses, suprarenal masses, and obstructions can be detected
  • better than US at distinguishing subtle differences of density
  • IV contrast can help differentiate masses
MRI
  • useful for visualization of kidneys
  • not proven useful for detecting urinary calculi or calcified tumors
Magnetic Resonance angiography
  • allows visualization of renal vasculature
  • does not require femoral puncture
Cystogram
  • used to visualize bladder and evaluate vesicoureteral reflux
  • also used to evaluate pts with neurogenic bladder and recurrent UTIs
  • can delineate abnormalities of the bladder such as diverticula, calculi, and tumors
  • contrast is instilled via cystoscope or catheter
Urethrogram
  • retrograde injection of contrast into the urethra to identify strctures, diverticula, or other urethral pathologic conditions
  • done before catheterization if urethral trauma is suspected
Voiding Cystourethrogram (VCUG)
  • study of the bladder opening and urethra
  • bladder is filled with contrast material and fluoroscopic films taken
  • more films taken after urination to assess residual urine
  • can detect abnormalities of lower urinary tract, urethral stenosis, bladder neck obstructions, and prostatic enlargement
Loopogram
  • used to detect obstructions, anastomotic leaks, stones, reflux, and other uropathologic features when pt has a urinary pouch or ileal conduit
  • risk for absoprtion of contrast material d/t diverisons created with the bowel
Renal Scan
  • evaluates anatomic structures, perfusion, and function of kidneys
  • isotopes are injected IV and probes placed over kidneys
  • distribution of radiation is scanned and mapped over kidney
  • allows assesment of blood flow, glomerular function, tubular function, and urinary excretion
  • abcesses, cysts, and tumors appear as cold spots d/t presence of non-functioning tissue
Renal Biopsy
  • done to obtain renal tissue to determine type of renal disease or to follow process of renal disease
  • done as a percutaneous insertion into lower lobe of kidney under US or CT guidance
  • contraindications: bleeding disorders, single kidney, uncontrolled HTN
Cystoscopy
  • used to inspect the interior of the bladder with a cystoscope
  • used to insert ureteral catheters, remove calculi, obtain biopsy specimens and treat bleeding lesions
  • done in lithotomy under general or local
  • complications: urinary retention, urinary tract hemorrhage, bladder infection, or perforation of the bladder
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