Urine Flashcards

1
Q

What is the normal urine volume?

A

1 to 2 Liters

intake of water - insensible losses = urine output

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2
Q

What are signs of impaired dilution?

A

impaired dilution = impaired water excretion = water retention = hyponatremia

can be associated with low urine

high urine OSM (ADH present)

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3
Q

What is a normal specific gravity?

A

1.005 to 1.035

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4
Q

What are the categorical values for proteinuria?

A

1+ = 30 mg/dL

2+ = 100 mg/dL

3+ = 500 mg/dL

4+ = >2000 mg/dL

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5
Q

In the setting of metabolic acidemia, what should high urine pH raise suspicion for?

A

renal tubular acidosis

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6
Q

What is the maximal tubular reabsorption of glucose?

A

300 mg/dL

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7
Q

What is the urine anion gap in gap acidosis?

A

Urine K + Urine Na + Urine NH4 = Urine Cl + excreted anions (ex. ketoacids)

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8
Q

What pathological process would give a dipstick positive urine with no RBCs on microscopy?

A

rhabdomyolysis, hemolysis, and dilute urine

low specific gravity

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9
Q

What are the causes for hematuria?

A

GU cause

contamination

if RBC casts, proteinuria, or dysmorphic RBCs are present, suggests glomerulonephritis

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10
Q

causes of leukocyturia

A

contamination

infection (vaginitis, urethritis, bladder, kidney)

inflammation of the kidney or bladder - interstitial cystitis, interstitial nephritis, eosinophils classically associated, though evidence does not support

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11
Q

What do nitrites in the urine indicate?

A

some bacteria convert nitrates to nitrites

can be detected on dipstick

may be colonization or infection

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12
Q

hyaline cast

A

found in normal urine

can also found in people who are dehydrated

fomred due to slow flow of urine

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13
Q

What happens to the tubular cells in the case of AKI, morphologically?

A

proximal tubular cells lose their brush borders, undergo swelling, and blebbing of microvilli during injury, leading to cast formation

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14
Q

pigmented cast

A

suggests ATN or rhabdomyolysis

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15
Q

white cell cast

A

allergic interstitial nephritis

pyelonephritis

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16
Q

fatty cast

A

often can see maltese crosses

suggests nephrotic syndrome

17
Q

maltese crosses

A

dead renal tubular epithelial cell filled with cholesterold from the lipiduria that occurs with nephrotic syndrome

18
Q

urine indices for obstruction

A

300-500 U Osm

>40 UNa

>1 FE Na

don’t rely on indices to diagnose, better to image or use a foley catheter

19
Q

What is the difference between prerenal and ATN?

A

depends on whether or not the tubules are working

in ATN, tubules are not functional, so spilling sodium (FE Na > 1 and UNa > 40)

can’t concentrate or dilute in ATN (UOsm < 350)

20
Q

What are the urine indices for prerenal injury?

A

U Osm > 500

U Na < 20

FE Na < 1

21
Q

What are the indices for AGN, and what features help diagnose it?

A

U Osm 300-500+

U Na < 40

Fe Na < 1

also presence of hematuria, proteinuria, and casts

22
Q

What are the values for high and low potassium?

A

< 20 mEq/day is low - serum potassium is likely low

> 40 mEq/day is high - serum potassium is likely high

23
Q

normal urine creatinine

A

15-20 mg/kg per day in females

20-25 mg/kg/day in males

24
Q

normal urine sodium

A

100-260 mEq/24 hours (varies on intake)

25
Q

normal urine potassium

A

25-125 mmol/24 hours (variable)

26
Q

normal urine chloride

A

100-250 mmol/24 (variable)

27
Q

When is a urine chloride measurement useful?

A

non-gap metabolic acidosis

metabolic alkalosis

28
Q

What are the cuases of saline resistance metabolic alkalosis (U Cl > 20)?

A

alkali ingestion

adrenal excess - hyperaldosteronism, Cushing’s Disease, meds (steroids)

Bartter’s syndrome

Gitelman’s syndrome

Liddle’s syndrome

Licorice

“Refeeding” alkalosis

29
Q

What are the causes of saline responsive metablic alkalosis (U Cl <10)

A

GI loss - vomiting, diarrhea (with Cl-), and adenoma

post hypercapnia

diuretics

30
Q

What does specific gravity measure and what SG is isosthenuria?

A

measures how concentrated the urine is

isosthenuria occurs at 1.012

lower means dilure, and higher means concentrated

each unit of specific gravity approximates 1150 (range of urine Osm)/28 (range of urine Osm)

31
Q

What is the calculation of urine osmols from specific gravity?

A

40 Osm per 0.001 unit of specific gravity