CMP Flashcards
1
Q
What is in a basic metabolic panel
A
- glucose
- BUN
- creatinine
- BUN/creatinine ratio
- Na
- K
- Cl
- CO2
2
Q
A comprehensive metabolic panel includes the BMP plus
A
- total protein
- albumin
- Ca
- alk phos
- ALT
- AST
- total bilirubin
3
Q
shorthand fishbone diagram
A
4
Q
What does the Blood Urea Nitrogen (BUN) lab value signify
A
- Urea formed in liver -> byproduct of protein metabolism
- deposited in blood and transported to kidney (excretion)
- directly related to liver and kidney function
5
Q
critical value for BUN
A
BUN > 100 mg/dl
6
Q
azotemia
A
retention of nitrogenous waste
- will see an increase in BUN and creatinine
7
Q
how can renal disease impact BUN levels
A
- renal disease -> inadequate urea excretion
- inadequate urea excretion = increased BUN concentration
- *unilateral kidney disease -> compensation
- may not see rise in BUN
8
Q
how can excess protein intake effect BUN
A
increase BUN
9
Q
how can hydration status affect BUN levels
A
- dehydration = increased BUN
- overhydration = decreased BUN
10
Q
what BUN levels are expected in combined liver and renal disease
A
- WNL
- kidneys are not excreting as much but liver is not making as much
11
Q
How is creatinine formed
A
- catabolic product on creatine phosphate (used in skeletal muscle contraction)
- daily production and levels related to muscle mass
12
Q
explain how creatinine levels vary diurnal and postprandial
A
- Lowest point: 7 am
- Peak point: 7 pm
- eating a high protein meal will cause increase
13
Q
critical value of creatinine
A
> 4 mg/dL
14
Q
creatinine is a marker for which organ’s function
A
- directly proportional to renal function
- excreted entirely by kidneys
- approximation of GFR
15
Q
what does elevated creatinine serum concentration mean
A
- serum concentration tends to rise later -> suggests chronicity of renal disease
16
Q
serum creatinine levels are influenced by what
A
- muscle mass and protein intake
- more muscle mass -> elevated creatinine
17
Q
what is the function of BUN/Cr ratio
A
- measurement of kidney and liver function
- increased ratio = decrease in the flow of blood to the kidneys
18
Q
what are some conditions that can cause increased BUN/Cr ratio
A
- renal hypoperfusion
- GI bleed
- high protein diet
- sepsis/hypermetabolic state
- drugs
19
Q
what are some conditions that can cause decreased BUN/Cr ratio
A
- malnutrition
- low protein diet
- ketoacidosis
- drugs
20
Q
a serum creatinine increase greater than over baseline indicates an acute kidney injury
A
- > or = 0.5 mg/dL
- >50% over baseline
21
Q
signs of acute kidney injury
A
- rapid deterioration of GFR
- decrease in urine output
- accumulation of nitrogenous wastes
- urea and Cr (azotemia)
22
Q
an elevated BUN/Cr ratio greater than (20:1) is associated with what
A
- Prerenal Azotemia
- causing reduced renal perfusion
- Azotemia is an elevation of blood urea nitrogen (BUN) and serum creatinine levels.
23
Q
what are some causes of Prerenal Azotemia
A
- reduced renal perfusion
- hypovolemia
- shock
- burns
- dehydration
- CHF (low CO)
- MI
- excessive protein ingestion
- sepsis
24
Q
treatment of Prerenal Azotemia
A
- restore intravascular volume
- fluids
- reduce or d/c diuretics
- monitor BUN/Cr
25
an elevated BUN/Cr ratio (10:1) is associated with what
Intrinsic renal azotemia
26
list some causes of Intrinsic renal azotemia
* acute tubular necrosis: most common cause
* nephrotoxins
* NSAIDS, aminoglycosides
* Glomerulonephritis
27
Name some causes of Postrenal Azotemia
* BUN/Cr ratio variable
* causes: obstruction to urine flow
* ureter and renal pelvis: blood clot, stones
* bladder
* malignancy
* urethral stricture
28
function of Chloride
* extracellular anion
* maintains electrical neutrality
* water moves with sodium and chloride
* buffer to assist in acid-base balance
* as CO2+ and H+ rise -\> Cl- shifts into cells
29
critical value of Chloride
* \< 80 mEq/L
* \> 115 mEq/L
30
will you often see changes in chloride levels on its own?
* no
* usually part of Na or bicarbonate shifts
* part of anion gap calculation
* (Na+ -(HCO3- + Cl-))
31
what proteins make up Total protein? Function of total protein
* Total protein = albumin + globulin + prealbumin
* most significant component contributing to osmotic pressure in vascular space
* keeps fluid in vascular space
32
what is albumin formed? what is its half-life
* formed in liver
* half-life 12-18 days
33
albumin makes up what percentage of total protein
60%
34
name some conditions that can decrease albumin levels
* burns
* malnourished
* liver diseae
* third spacing : lost into extravascular space
35
why is prealbumin measured
* **early indicator** of nutritional status
* distinct maker for protein synthesis
* _3 day half life_
* synthesis increases within _48 hours_ of appropriate nutritional support
36
Acute-phase proteins
class of proteins whose plasma concentrations increase (positive acute-phase proteins) or decrease (negative acute-phase proteins) in response to inflammation.
Ex:
* prealbumin: negative
* CRP: positive
37
Where are globulins formed? Function?
* mostly made in bone marrow and lymph tissue
* building blocks for
* Antibodies
* transport
38
what are the three groups of globulins
* alpha
* beta
* gamma
* gammaglobulins = immunoglobulins
39
normal albulin/globulin ratio? What does a lower ratio indicate?
* normally exceeds 1.0
* lesser ratios indicate albumin level affected
40
function of serum protein electrophoresis
* separates serum components based on electrical charge
* ex: multiple myeloma
* SPEP demonstrates: M-spike (spike in beta or gamma globulin)
41
What does **total calcium** measure?
* Total Ca = free (ionized) + protein bound
* measure albumin simultaneously
* absorbed through GI tract (influenced by vit D)
* stored in bone
* excreted by kidney
42
it is important to monitor total calcium in patients with
* renal failure
* hyperparathyroidism
* malignancies
43
critical value of total calcium
* \< 6.0 mg/dl
* \> 13 mg/dl
44
describe calcium distribution in the body
* 99% bone
* 0.8-1.0% in cells
* 0.1-0.2% in ECF
* 40% is protein bound (albumin)
45
serum calcium is dependent on what two things
* parathyroid hormone
* secretion -\> increase in serum Ca
* vitamin D
46
serum calcium elevated x 3 is associated with what three conditions
1. Hyperparathyroidism
1. most common: increased GI absorption, descreased excretion, increased bone reabsorption
2. Malignancy: 2nd most common
1. tumor metastasis to bone causing Ca reabsorption into blood
3. chronic renal failure
4. excessive vit D
5. granulomatous infections
47
causes of hypercalcemia: CHIMPANZEES
* Calcium supplementation
* Hyperparathyroidism
* Iatrogenic
* Multiple myeloma, medication
* Parathyroid hyperplasia or adenoma
* Alcohol
* Neoplasm
* Zollinger Ellison syndrome
* Excessive Vit D
* Excessive Vit A
* Sarcoidosis
48
clinical presentation
* muscle weakness, loss of muscle tone, lethargy, coma
* HTN, EKG abnormalities (short QT interval)
* polyuria, increased thirst, kidney stones
* anorexia, N/V, constipation
hypercalcemia
49
what are some conditions associated with hypocalcemia
* **hypoalbuminemia**
* **large blood transfusion**
* citrate addictives -\> bind free calcium
* **intestinal malabsorption**
* vit D deficiency
* **renal failure**: excessive loss of Ca
* **alkalosis**: protein binding to Ca
* **acute pancreatitis**: saponification of fat (fatty acid binds to Ca)
* **hypomagnesemia**
* magnesium defiency inhibits PTH
50
what equation can be used to determine actual total Ca levels when albumin levels are high or low
* = measured total calcium + 0.8 (4.0 - serum albumin)
51
clinical presentation
* (increased excitability): paresthesia, muscle cramps
* hyperactive reflexes
* positive Chvostek and Trousseau signs
* tetany
* hypotension, EKG changes (prolonged QT interval); arrhythmias
hypocalcemia
CATS go numb"- Convulsions, Arrhythmias, Tetany and numbness/parasthesias in hands, feet, around mouth and lips
52
what is tetany
* lowered threshold for muscular excitability
* involuntary sustained contractions
* contractions of hands and feet -\> carpopedal spasms
53
Chvostek's sign
* tapping facial nerve against bone just in front of ear results in contraction of facial muscles
* tetany
54
Trousseau's sign
* occluding brachial artery for 3 minutes with BP cuff induces carpal spasms
* tetany
55
treatment for severe (symptomatic) hypocalcemia
* 100-300 mg elemental calcium
* calcium chloride or D5W
56
treatment for mild hypocalcemia
* oral calcium + vit D
* calcium carbonate (tums) = no vit D
* calcium citrate = contains Vit D
57
function of magnesium
* bound to ATP
* organs and neuromuscular tissue depend on Mg
* intimately tied to potassium and calcium to maintain neutral intracellular charge
58
magnesium is present in what types of food
* green veggies
* grains
* nuts
* meats
* seafood
* \*25-65% is absorbed
59
how is magnesium regulated by the kidneys
* Mg reabsorption decreased if
* serum level of Mg is elevated
* serum level of Ca is elevated
* Mg reabsorption decreased by loop diuretics
60
Name some conditions that commonly cause increased levels of magnesium
* **renal insufficiency**
* addison's disease
* hypothyroidism
* ingestion of Mg-containing compoungs
* antacids, laxatives
61
clinical presentation
* hyperactive reflexes, paresthesias, muscle weakness and tremors, tetany with + chvostek and + trousseau signs
* prolonged PR and QT intervals
* widening of QRS
**Hypomagnesemia**
* neuromuscular effects (similar to hypocalcemia)
* \*\*clinically, more common and significant than hypermagnesemia
62
treatment of hypomagnesemia
* oral replacement
* magnesium oxide (400 mg tabs)
* use cation in patients with renal disease
* IV replacement
* magnesium sulfate infusion followed by additional infusion over 3-7 days
* follow blood levels and DTR's
63
how does low Mg+ affect calcium and potassium levels
* hypomagnesemia -\> hypocalcemia
* low PTH levels
* impairs ability of kidney to conserve K+
64
clinical presentation
* hyporeflexia
* muscle weakness; respiratory paralysis
* confusion
* hypotension
* cardiac arrhythmias
hypermagnesemia
65
phosphate levels are determined by
* calcium metabolism
* Phosphorous is combined with calcium in skeleton
* PTH
* renal excretion
* intestinal absorption (small bowel)
66
what is the critical value of phosphate (inorganic phosphate is measured)
\< 1 mg/dL
67
what effect does antacids have on phosphate absorption
* dietary phosphate is absorbed in small intestine and decreased with antacids (opposite of Ca)
68
relationship between phosphate and calcium
* INVERSE
* PTH decreases phosphate reabsorption by the kidneys
69
what can cause phosphate elevation
* treatment of DKA
* alcohol withdrawal
* hypoparathyroidism
70
alkaline phosphate has the highest concentrations where in the body
* liver
* in kupffer cells
* biliary tract epithelium
* excreted in bile
* bone
71
causes of elevated alkaline phosphatase
* extrahepatic and intrahepatic obstructive biliary disease and cirrhosis
* new bone growth : high in adolescents
* osteoblastic metastatic tumors
72
where is alanine aminotransferase (ALT) found in body?
* predominately in liver
* injury/disease to liver -\> release of ALT
73
AST:ALT ratio \< 1 indicates what
* \< 1 indicates viral hepatitis
* \> 1 indicates hepatocellular disease other than viral hepatitis
* \*\*less accurate if AST exceeds 10 x normal value
74
AST is released by liver with hepatocellular injury. elevation occurs how long after cell injury
* elevation occurs 8 hrs after injury
* peak: 24-36 hours
75
AST levels 20 x normal value indicates
acute hepatitis
76
AST levels 10 x normal indicates
* acute extrahepatic obstruction (i.e. gallstones)
77
how is biliruben formed
* breakdown of RBC
* hemoglobin released from RBC and broken down into heme and globulin
* heme transformed into biliruben
78
critical value of total biliruben
* total = unconjugated (indirect) + conjugated (direct)
* critical value= \> 12 mg/dL
79
differentiate between indirect and direct biliruben
* indirect = unconjugated
* normally makes up 70-85% of total bili
* heme -\> biliruben
* direct = conjugated
* indirect bili is conjugated in liver
* excreted from liver into hepatic ducts, common bile duct, and bowel
80
a total serum bili exceeding what value will present with jaundice
2.5 mg/dl
81
what conditions would lead to elevated levels of unconjugated and conjugated biliruben
* elevated unconjugated
* hepatocellular dysfunction (hepatitis, RBC hemolysis)
* elevated conjugated
* extrahepatic obstruction (gallstones, tumor)
82
cause of physiologic jaundice of newborn
* newborn liver is immature
* not enough conjugating enzymes
* high circulating blood level of unconjugated bili
* can pass blood-brain barrier -\> brain
* encephalopathy (kernicterus)
83
critical value of unconjugated bili
\>15 mg/dL
