Lab Med: CMP and Electrolytes Flashcards

1
Q

Which tests monitor renal function?

A

BUN

Cr

BUN/Cr ratio

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2
Q

Which tests measure electrolytes and pH?

A

Na

K

Cl

CO2

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3
Q

What are considered the liver tests?

A

ALT

AST

ALP

Total Bili

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4
Q

Which tests monitor synthetic function of the liver?

A

albumin

platelets

PT/INR

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5
Q

A basic metabolic panel consists of what labs?

A

glucose

BUN, Cr, BUN/Cr ratio

Na, K, Cl

CO2

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6
Q

What is the most common acute cause of hyperglycemia?

A

Physiologic stress (trauma, illness, infx, burn, surgery, etc)

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7
Q

Which endocrine disorders can cause hyperglycemia?

A

Cushings, Acromegaly

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8
Q

Cushings causes hyperglycemia through what mechanism?

A

excess cortisol production results in increased glucagon release

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9
Q

Acromegaly causes hyperglycemia through what mechanism?

A

increased HGH is secreted, which causes increased glucagon release

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10
Q

What drug class can cause hyperglycemia?

A

steroids

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11
Q

What are three common causes of hypoglycemia?

A

insulin OD

starvation

Addision’s, Hypopituitarianism

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12
Q

Which electrolytes rise with kidney dysfunction?

A

K, PO4, Mg

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13
Q

Urea is formed in the ______ and excreted by the ______

A

formed in liver

excreted by kidneys

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14
Q

This test is an indirect measurement of the liver’s metabolic function and the excretory function of the kidney

A

BUN

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15
Q

Severe primary liver diseases have what effect on BUN?

A

decreased BUN due to decreased urea synthesis

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16
Q

Primary renal diseases do what to BUN?

A

increase BUN secondary to reduced urea excretion

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17
Q

Dehydration does what to BUN?

A

concentrates BUN, increases serum BUN

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18
Q

how does an upper GI bleed lead to increased BUN?

A

blood overloads gut with protein

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19
Q

What conditions lead to increased BUN?

A

primary renal diseases

dehydration

UGIB

high protein diet

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20
Q

What conditions lead to a decreased BUN?

A

Severe primary liver diseases

overhydration

low protein diet

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21
Q

What makes creatinine a specific measure of renal function?

A

creatinine is excreted 100% by the kidneys

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22
Q

Cr can be used as an approximation of what physiologic process?

A

GFR

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23
Q

Describe the relationship between GFR and Cr

A

inverse

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24
Q

What is the main cause of increased Cr?

A

AKI

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25
Q

list your DDx for increased Cr…

A

AKI

CKD

Rhabdo

Dehydration

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26
Q

list your DDx for decreased Cr

A

debilitation

muscular dystrophy

myasthenia gravis

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27
Q

An acute kidney injury results in a rapid _____ in GFR

A

AKI = rapid decrease of GFR

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28
Q

Bun/Cr ratio is helpful in determining what?

A

cause of AKI

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29
Q

A BUN/Cr of 20:1 or higher indicates…

A

prerenal AKI

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30
Q

A BUN/Cr of 10:1 indicates

A

intrinsic renal AKI

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31
Q

The following would classify as what type of AKI?

hypovolemia
CHF
vascular resistance changes

A

prerenal

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32
Q

What is the main cause of intrinsic AKI?

A

acute tubular necrosis from IV contrast

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33
Q

The following would classify as what type of AKI?

ureteral stones
bladder outlet obstruction
BPH
Urethral Stricture

A

postrenal

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34
Q

Hyper/hypochloremia usually accompanies a shift in what two measures?

A

sodium and bicarb

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35
Q

CO2 is an indirect measure of…

A

HCO3/bicarb

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36
Q

What regulates HCO3 retention or secretion?

A

kidneys

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37
Q

The following conditions affect what… albumin or globulin?

liver disease
edematous states
protein losing conditions
nutrition status

A

albumin

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38
Q

The following conditions affect what… albumin or globulin?

immune disorder
cancer

A

globulin

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39
Q

By what mechanism does albumin keep fluid within the vascular space?

A

maintains osmotic pressure

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40
Q

A patient presents with increased albumin… what can you immediately include in your DDx?

A

dehydration

41
Q

When albumin is low, what happens to globulin and why?

A

elevated to maintain normal total protein

42
Q

What is the MC cause of hypoalbuminemia?

A

liver disease

43
Q

What is the complete list of DDx for hypoalbuminemia?

A

Liver disease

Crohns/celiac/protein losing enteropathies

nephrotic syndrome/protein losing nephropathies

burn

malnutrition/malabsorption

inflammatory disease

44
Q

what is the cause of edema in nephrotic syndrome?

A

decreased albumin causes decreased osmotic pressure

45
Q

Patients presenting with normal total protein with hypoalbuminemia and increased globulin should be considered for what conditions?

A

chronic liver disease

collagen vascular diseasae/lupus

46
Q

patients with increased total protein with increased globulin fraction should be considered for…

A

multiple myeloma

47
Q

what two diagnostics indicate multiple myeloma?

A

M-spike

bence jones proteinuria

48
Q

what are the transaminases?

A

ASP

ALT

49
Q

Which liver tests measure injury to hepatocytes?

A

AST, ALT

50
Q

which liver tests measure injury to the bile ducts/bile flow?

A

ALP, total bili

51
Q

Which is more specific to the liver, AST or ALT?

A

ALT

52
Q

Where is ALP found?

A

liver, biliary tract, bone

53
Q

if a patient presents with increased ALP in the presence of otherwise normal labs, what should you suspect?

A

bone pathology

54
Q

What is on your list of DDx for AST/ALT > ALP?

A

liver drug toxicity

viral hepatitis

alcoholic and non-alcoholic liver disease

cirrhosis

infiltrative liver disease, tumor

genetic liver disorder

biliary cholestasis (obstruction)

55
Q

What is the list of DDx for elevated ALP?

A

biliary obstruction

hepatitis, cirrhosis, infiltrative liver disease

drug toxicity

56
Q

What is a common cause for increased ALP in children and adolescents?

A

physiologic growth

57
Q

What are the broad two reasons for extrahepatic ALP elevation?

A

high bone turnover

3rd trimester pregnancy

58
Q

what test can be ordered to distinguish between liver and bone etiology for isolated ALP elevation?

A

ALP isoenzymes

59
Q

increased unconjugated bili is caused by…

A

hemolysis

HF

Gilbert syndrome

60
Q

increased conjugated bili is caused by…

A

hepatitis

drugs

TB/liver infiltration

biliary obstruction

61
Q

Calcium has an inverse relationship with…

A

phosphorus

62
Q

of the 1% of calcium not in bone, what percent is free/ionized?

A

50%

63
Q

of the 1% of calcium not in bone, what percent is bound to albumin?

A

40%

64
Q

this form of calcium is free to participate in cellular function, and is the most accurate measurement of serum calcium…

A

ionized Ca

65
Q

When serum albumin is low, what should you expect calcium level to be?

A

low

66
Q

PTH is stimulated by falling blood Ca levels. PTH secretion from the parathyroid has what effects?

A

stimulates Ca release from bone

increases Ca uptake in kidneys and GI

67
Q

Calcitonin is stimulated by rising blood Ca levels. When it is released by the thyroid, calcitonin has what effect?

A

stimulates ca deposition in bone

reduces GI and Kidney uptake of Ca

68
Q

What is responsible for 90% of cases of hypercalcemia?

A

hyperparathyroidism and malignancy

69
Q

A patient presents with the following S/S… what is this suspicious for?

  • decreased neuromuscular function
  • shortened QT
  • Nephrolithiasis, polyuria, polydipsia
  • constipation
A

Hypercalcemia

70
Q

How do you manage hypercalcemia?

A

tx underlying cause

volume expansion

calcitonin, bisphosphates

71
Q

What is the most common cause of hypocalcemia?

A

hypoalbuminemia

72
Q

when you see hypoalbuminemia, what should you do to dx hypocalcemia

A

calculate corrected Ca

73
Q

when should you check serum ionized calcium

A

only if dx of hypocalcemia is in doubt after calculating corrected Ca

74
Q

What causes hypocalcemia from large blood transfusions

A

chelation of calcium to citrate additives

75
Q

Hypomagnesemia causes hypocalcemia because…

A

Mg deficiency inhibits PTH activity

76
Q

Renal failure causes hypocalcemia through what mechanism?

A

phosphorus retention leads to reciprocal loss of Ca

77
Q

A patient presents with the following… what do you suspect?

parasthesias

hyperactive DTRs

Carpopedal spasm

Chvosteks sign

Trousseau sign

prolonged QT

A

Hypocalcemia

78
Q

The tapping of facial nerve resulting in contraction of facial muscles is known as…

A

chvostek’s sign

79
Q

occlusion of brachial artery for 3 minutes inducing carpal spasm is known as…

A

trousseau’s sign

80
Q

How do you manage mild hypocalcemia?

Severe?

A

mild: oral calcium +/- Vitamin D

Severe: IV Calcium gluconate

81
Q

What is the most important regulator of serum phosphate?

A

kidneys

82
Q

Phosphate has an inverse relationship with what electrolyte?

A

calcium

83
Q

What is the most common reason for hyperphosphatemia?

A

renal failure

84
Q

What is the full list of DDx for hyperphosphatemia

A

renal failure

hypoparathyroidism

hypocalcemia

exogenous phosphate

85
Q

What is the number one reason for hypophosphatemia?

A

malnutrition/malabsorption

86
Q

Cellular shift is when a mediator drives electrolytes into a cell. What are two common causes of cellular shift derived hypophosphatemia?

A

insulin

refeeding syndrome

87
Q

hypophosphatemia can be caused by…

A

malnutrition/malabsorption

hyperparathyroidism

chronic alcoholism

severe vomiting/diarrhea

cellular shift

88
Q

Severe hypophosphatemia manifests with what sxs?

A

muscle weakness

rhabdo

seizures

89
Q

how do you treat hyperphosphatemia

A

treat underlying cause

90
Q

how is hypophosphatemia treated?

A

treat underlying cause

phosphate repletion as appropriate

91
Q

magnesium levels are intimately tied to which electrolytes?

A

calcium and potassium

92
Q

hypomagnesemia can contribute to what two conditions?

A

refractory hypocalcemia and hypokalemia

93
Q

What are the two most common causes of hypermagnesemia?

A

renal insufficiency

large Mg load

94
Q

The following can do what to magnesium levels?

Malnutrition/absorption

severe diarrhea

alcoholism

cellular shift

A

cause hypomagnesemia

95
Q

Hypermagnesemia presents with…

A

decreased DTRs

Bradycardia

Hypotension

96
Q

Hypomagnesemia presents with…

A

tetany

cardiac arrhythmias/torsades

97
Q

How should hypermagnesemia be treated?

A

stop magnesium containing meds

isotonic fluids and loop diuretics

dialysis

IV calcium

98
Q

How should hypomagnesemia be treated?

A

asymptomatic: oral Mg
symptomatic: IV Mg