SM 194: Urine Flashcards
What are the normal components of urine? Specific gravity, pH, protein
Specific Gravity: 1.000-1.030
pH: 5-8
Protein: negative-trace
Leukocyturia (meaning, sign of what)
WBC in urine
indicates: possible contamination during collection, infection (UTI, bladder, vaginitis), inflammation of kidney or bladder (interstitial cystitis/nephritis)
Nitrates in Urine (meaning)
presence of bacteria that convert nitrates to nitrites
may show colonization, infection or contamination
Dipstick Proteins (what is measured, determinations of amount detected, most common cause, clinical vs. nephrotic range)
Only measures negatively-charged proteins (ie Albumin)
Only detects concentrations (not true amount, depends on urine volume)
Most common cause: DIABETES
Clinical albuminuria = >300mg/day or 0.3 a/cr urine spot
Nephrotic Range: >3g/day proteinuria
Hematuria DDx
Can be seen grossly or on microscope
Rhabdomyolysis, GU cancer, contamination, infection, or glomerular cause (nephritic syndrome)
Glycosuria DDx
Urine Glucose = Serum Glu - Max Glu Reabsorption
Urine Glu can exceed Plasma Conc if ADH present
Ketones DDx and Bilirubin DDx
Ketones: Diabetic Ketoacidosis or starvation (poor oral intake)
Bilirubin: Liver disease
How to use urinalysis to differentiate between types of AKI
prerenal: Urine OsM > 500 (high), Urine Na < 20, FeNa < 1 (low) - signifies volume depletion and Na retention working
intrinsic: Urine OsM < 350 (normal/low), Urine Na > 40, FeNa > 1 - shows kidneys are not able to concentrate urine or reabsorb Na!
Postrenal: obstruction, but functional kidneys
DDx of Pigmented Casts
DDx of RBC Casts
DDx of WBC Casts
Pigmented: dark coarse granules = due to Intrinsic AKI (Tubular Interstitial Disease, ATN)
RBC: Nephritic Syndrome
WBC: Intrinsic AKI (Allergic Interstitial Nephritis, Pyelonephritis)
