urine Flashcards
what is turbidity of urine
“cloudiness” of urine
list the components of a urine dipstick
- pH
- specific gravity
- glucose
- keytones
- protein
- blood
- nitrite
- leukocyte esterase
- biliruben
- urobilinogen
urine pH has what relationship to serum pH
parallels
which value is described as acidic pH? alkaline pH?
- acidic: 4.5-5.5
- alkaline: 6.5-8
- a pH out of these ranges is not possible; pH > 8 indicates overgrowth of urease producing bacteria
List some causes of alkaline urine
- urea-splitting organisms
- standing urine
- fruit/vegetables
- metabolic or respiratory alkalosis
- meds
List some causes of acidic urine
- large intake of meat
- cranberries, plums, prunes
- metabolic or respiratory acidosis
- meds
urine will have what specific gravity compared to water
- specific gravity of water = 1
- urine will have higher specific gravity due to dissolves substances, primarily urea, sodium, and chloride
- the more concentrated, the higher the specific gravity
with kidney disease, the ability to concentrate the urine may be lost and the specific gravity may become fixed at what value? why this value? what is this called?
- 1.010
- SG at the initial plasma filtrate at the glomerulus
- isosthenuria
what is oliguria in terms of urine volume
< 500 cc/24 hrs
what is anuria in terms of urine volume
< 100 cc/ 24 hours
when plasma glucose is above what, the renal threshold is exceeded and patient will spill glucose into urine
150-180 mg/dl
false negatives of glucose urine dipstick can be caused by
- ascorbic acid
- aspirin
what are products of incomplete fat metabolism occurring when carbohydrate stores are diminished
keytones
presence of keytones in urine may indicate what
- acidosis
- DKA
- rapid weight loss
- fasting
- starvation
- pregnancy
Normal urinary protein excretion should be < 150 mg/24 hours .list the breakdown of what protein is excreted in the urine
- 30% albumin
- 30% globulins (iron/oxygen binding proteins)
- 40% tamm-horsefall protein
how does specific gravity alter dipstick result of protein
- high specific gravity: may show higher protein level
- low specific gravity: may show lower protein level
urine dipstick may be falsely positive for protein if
- high alkaline urine
- high specific gravity
- pyridium present
moderately increased albumin in urine is a prognostic indicator for kidney disease in what conditions?
- Diabetes
- HTN
- cardiovascular disease
- post-streptococcal glomerular nephritis
- ** this test refers to urinary excretion of albumin that is below the detection capability of urine dipstick but above upper limit of normal for healthy individuals
what tests are done to assess for moderately increased albumin
- 24 hour urine collection
- urinary albumin/creatinine ratio (most practical)
- normal: < 30 mg albumin/gram urinary creatinine
- microalbuminuria: 30-300 mg/g creatinine
dipstick detects presence of RBCs or hemoglobin from RBCs
lysed
urine dipstick can have fast negative for blood due to
ascorbic acid
urine nitriate test detects
- bacteria that are capable of reducing nitrates to nitrite
- 50% sensitive in Dx UTI
urine dipstick can have false negatives for nitrite due to
- urine in bladder for < 4 hours
- patient’s diet is deficient in nitrates
- bacteria which do have necessary enzymes
urine dipstick can have false positives for leukocyte esterase from
- vaginal contamination
- trichomonads
function of leukocyte esterase
- detects leukocytes in urine, can detect lysed WBCs
what is biliruben
- product of RBC breakdown carried to liver in unconjugated form (indirect)
- conjugated in the liver (direct)
route of biliruben once it is conjugated
- excreted from liver via bile duct
- goes into small intestine and is converted by bacterial flora to urobilinogen
biliruben and urobilinogen are both normally excreted where
- stool
- thus dipstick is normally negative for both of these
urine turns what color in the presence of biliruben
brown
biliary obstruction can cause which to appear in urine: bilirubin or urobilinogen
bilirubin
hemolytic disease can cause which to appear in urine: bilirubin or urobilinogen
urobilinogen
microscopic UA is done to view the urinary
sediment
WBC and RBC are reported as the number per
high power field
casts are reported as the number per
low power field
what type of cell in urine appears as refractile disks with hypertonicity of the urine, and have a “crenated” shrunken appearance
RBC
what number of RBCs in the urine is abnormal
> 3
causes of hematuria by in age 0-20 yo
- glomerulonephritis
- UTI
- congenital anomaly
causes of hematuria by in age 20-40
- UTI
- calculi
- bladder CA
causes of hematuria by in age 40-60
- UTI
- bladder CA
- calculi
causes of hematuria by in age > 60 in males
- BPH
- bladder, prostate, or kidney CA
- UTI
causes of hematuria by in age > 60 in females
- UTI
- bladder or kidney CA
centrifuge shows sediment red urine, then red or brown urine is caused by
hematuria
centrifuge shows supernatant red urine, then red or brown urine is caused by
- unknown, do dipstick heme
- if negative:
- beets, phenazopyridine
- if positive
- myoglobin
- hemoglobin
- if negative:
how can you differentiate between myoglobin and hemoglobin as cause of red, brown urine
-
plasma color (centrifuge a blood sample)
- clear: myoglobinuria
- red: hemoglobinuria => hemolysis
what cells in urine have lobed nuclei and refractile cytoplasmic granules
WBCs
what value of WBC in urine is suspicious for UTI
10-20 WBCs/HPF
- >20WBC usually indicates UTI
bacteria is reported as what in urine microscopy
0-4+
what can happen to bacteria count if urine collection stands out for a period of time without being refrigerated
more bacteria will grow
what are oval fat bodies
- degenerated tubular cells containing abundant lipid
- indicative of glomerular disease
what exhibit “maltese cross” configuration by polarized light microscopy
oval fat bodies
squamous epithelial cells in urine indicate
- contaminated specimen
- skin or external urethral origin
where are urine casts formed
only in the distal convoluted tubule
what are hyaline casts. what are they indicative of
- pale and slightly refractile, are common findings in normal urine
- composed of tamm-horsfall protein secreted by tubule cells
RBC casts are indicative of
glomerulonephritis or vasculitis
WBC casts are indicative of
acute pyelonephritis
renal tubular cell casts are indicative of
injury to the tubular epithelium
what are granular/waxy casts
broken down tubule cast
uric acid crystals in urine are seen with
- acidic urine
- secondary to hyperuricemia
cystine crystals in urine are seen with
- cystinuria
- rare genetic cause of kidney stones
struvite crystals in urine are seen with
- alkaline urine
- secondary to infection by urease-producing bacteria
calcium oxylate crystals in urine are seen with
- independent of pH
- cause kidney stones
- monohydrate/dihydrate
what is the most reliable method for determining if infection exists
urine culture
- >100,000 coloinies is consistent with infection
elevated potassium may be caused by what 4 things
- false elevation
- inadequate excretion by kidneys
- redistribution from ICF to ECF
- excess administrations
what is pseudohyperkalemia
- artificatually high K+ due to
- hemolysis due to poor venipuncture tenchinque
- should recheck K+ value
what are some causes of inadequate excretion of K+
- renal failure
- medications that inhibit K+ excretion
- aldosterone antagonists
- K+ sparing diuretics
- ACE-I/ARB
- hypoaldosteronism
- adrenal insufficiency
- congenital adrenal hyperplasia
- NSAIDs
what are some causes of redistribution of K+
- tissue damage
- acidosis (decrease in H+ raises serum K+)
- decreased insulin
what are the clinical features of hyperkalemia
- generally occur > 7
- A FACT
- Arrhythmias
- Flaccid paralysis
- Ascending muscle weakness
- Conduction abnormalities
- T waves (peaked)
treatment options for rapid correction of hyperkalemia
- IV calcium chloride
- maneuvers to shift K+ from ECF to ICF
- sodium bicarb
- D50W + insulin IV
treatment options for slow correction of hyperkalemia
- loop or thiazide diuretics
- hemodialysis
causes of hypokalemia
- inadequate intake
- GI tract loss
- renal loss
- redistribution from ECF to ICF
causes of inadequate K+ intake
- meds that promote K+ los
- thiazide, loop diuretics
what form of GI loss causes hypokalemia
- upper GI
- vomiting, NG suction
- causes metabolic alkalosis which promotes renal potassium loss
causes of hypokalemia due to renal loss
- diuretics
- bicarb excretion
- mineralocorticoid excess
- hyperaldosteronism
- cushings syndrome
causes of hypokalemia due to redistribution from ECF to ICF
- metabolic alkalosis
- insulin administration
- B-adrenergic agonists (albuterol) induce cellular uptake of K+ and promote insulin secretion
- hypokalemic periodic paralysis
clinical features of hypokalemia
- YOU CRAMP
- hYpOkalemia U waves
- Cramping
- Respiratory failure, Rhabdomyolysis
- Anorexia, N/V
- Muscle weakness
- Paralysis
if potassium is low, what lab value should be checked
- magnesium
- hypomagnesemia will cause potassium excretion
urine potassium < 20 meq/d suggests
- extrarenal/redistribution
urine potassium > 20 meq/d suggests
renal losses
rapid correction of hypokalemia
- cardiac monitor
- IV potassium chloride
- check K+ every 2-4 hours
