Jan17 M1-Hematuria, Urinalysis, Proteinuria Flashcards
3 reasons to evaluate urine
- hematuria or proteinuria found incidentally
- high Cr
- systemic disease to check for renal involvement
8 common urine tests
UA (dipstick) U microscopy U culture U electrolytes U Cr, albumin and protein 24 hr protein 24 hr urine CrCl over 24 hr urine (need blood Cr too)
normal urine pH
5 to 6.5
U pH, glucosuria, ketones and nitrites used and seen in what
pH: for RTA
glucosuria: unc diabetic, SGLT2 inh, proximal (type 2) RTA
ketones: DKA
nitrites: bacteria (they do nitrate to nitrite)
U WBC seen in what
infection or acute interstital nephritis
dipstick detects what level of proteinuria and normal disptick proteinuria result
above 0.3g/L. normal is negative
Hb dipstick detects what and why need further investigation
-Hgb w/ 1-2 RBCs per high power field
-myoglobin
-free Hb
need microscopy to check if really RBC in there (might me myoglobin from muscle injury)
significant hematuria def
3 or more RBCs per hpf
things to check for hematuria on microscopy
- amount
- shape of RBCs
- casts (RBC, WBC, mixed)
hematuria on microscopy: what points to a kidney problem
dysmorphic RBCs
RBC casts
acanthocytes (glomerulus)
GN on U micro
dysmorphic RBCs, casts (any or mixed)
normal looking RBC in the urine point to what
malignancy, stones, infection, PCKD
workup for hematuria (gross) of unclear etiology
- bloodwork (CBC, Cr, lytes)
- UA and micro
- U culture
- U spot protein/Cr ratio
- US
how blood test can reinforce a glomerular disease dx
if Cr is high
what proteins are normally filtered at the glomerulus
small amount of albumin and LMW proteins
how filtered proteins are handled by the nephron
most of albumin is reabso at the PCT (intact or degraded)
daily protein qt excreted and albumin in that
150 mg. 5 mg is albumin
4 mechanisms of proteinuria
- functional
- overproduction
- tubular protein loss
- glomerular protein loss
functional proteinuria def
fever, exercise, CHF, orthostatic
overproduction proteinuria def
protein produced in another part of the body excreted by the kidney
example of overprod proteinuria
free light chains (LMW prots made by plasma cells), typically in myeloma
myeloma free light chains effect on kidney
direct tubular toxicity and formation of casts causing tubular obstruction
tubular proteinuria def
impaired reabso of prots along the tubule
ex of disease where get tubular proteinuria and cause
Fanconi syndrome (PCT prob). chemo is the cause
glomerular proteinuria def
loss of negative charge on GBM, pore size prob
nephrotic (MCD, FSGS, MN, diabetic renal disease)
criteria for nephrotic syndrome
3.5+ g/day proteinuria (alone)
criteria for mixed nephrotic nephritic
3.5+ g/day proteinuria + dysmorphic hematuria and RBC/cellular casts
proteinuria (so above 150mg/day) but less 1g a day means what
tubular (failure to reabso) or hemodynamic (hypertensive nephrosclerosis for ex)
proteinuria 1-2.9 g/day meaning
kidney disease for sure but is either glomerular, tubular or overprod proteinuria
proteinuria more 3g a day meaning
glomerular (ex. MCD)
how to qtfy proteinuria (3)
- UA
- urine albumin/Cr or protein/Cr ratio (spot)
- 24 hr urine collection
how to calculate albumin/Cr ratio
albumin conc in mg/Cr conc in g (or in mmol)
normal albumin/Cr ratio men and women
women: 0-2.7 mg/mmol
men: 0-1.9 mg/mmol
how to convert U alb/Cr ratio from mg/mmol to ALBUMIN g/day (not proteins g/day..)
divide by 100
2.7mg/mmol max in women is therefore 0.027g albumin/day so 27mg.
how to convert alb/Cr ratio from mg/mmol to mg of albumin/g
multiply by 10.
2 mg/mmol is 20 mg/g
two factors in CKD staging
- GFR
- albuminuria
3 categories of albuminuria and values
- normal to mild elevation: less 3mg/mmol or less 30 mg/g
- moderately increased: 3-30 mg/mmol or 30-300 mg/g
- severly increased: over 30 mg/mmol or over 300 mg/g
4 indications for biopsy
- proteinuria +1g/day
- proteinuria + hematuria or casts
- systemic disease
- AKI/CKD unexplained on imaging
why would you not biopsy a diabetic with proteinuria
it is part of the normal progression of the disease. diabetic nephropathy.
most common tests ordered to screen for kidney disease
UA, U micro and U alb/Cr ratio
thing that is widely used to follow and prognosticate patients with kidney disease
spot albumin/Cr ratio
