Quiz 2: CMP Flashcards
What is the second most frequently used test?
CMP
When you think CMP you should think:
renal function, liver function, side effects/toxicities
What’s in a CMP?
Sodium, potassium, chloride, CO2, anion gap, glucose, BUN, creatinine, calcium, bilirubin, total protein, albumin, alkaline phosphatase, Aspartate aminotransferase (AST), alanine aminotransferase (ALT)
What part of the CMP is used to monitor electrolyte function and abnormalities?
sodium, potassium, chloride, CO2, anion gap, calcium
What part of the CMP is used to monitor renal function?
BUN and creatinine
What part of the CMP is used to monitor liver function?
bilirubin, alkaline phosphatase, AST, ALT
What part of the CMP is used to monitor proteins?
albumin, total protein
What part of the CMP is used for diabetes monitoring?
Glucose level
What are the two types of body fluid?
extracellular fluid (interstitial fluid, plasma) and intracellular fluid
The ICF is predominately?
potassium
The ECF is predominately?
Sodium
What is the major determinate of ECF osmolality (tonicity)
Sodium
How does the body maintain sodium homeostasis?
regulating water intake or excretion in the kidneys
Where do we find sodium receptors?
carotids, kidneys, or hypothalamus
How does sodium regulation occur?
multiple hormones, including aldosterone and naturietic hormone, but primarily anti-diuretic hormone (ADH)
Where is ADH produced?
hypothalamus
Where is ADH released?
pituitary
What is another name for ADH?
vasopressin
ADH functions to increase?
renal free water reabsorption
When there is an increase in renal free water reabsorption via ADH, it results in?
less diuresis
Diuresis =
making more urine
What two inputs result in the release of ADH?
1) osmoreceptors detect increased osmotic pressure 2) baroreceptors detect decreased blood pressure
What is the ultimate outcome of ADH release?
increased BP and increased blood volume
Describe the path of sodium regulation beginning with plasma water increases:
1) plasma water increases 2) sodium and osmolality decreases 3) ADH secretion decreases 4) collecting renal tubule becomes impermeable to water so water is not reabsorbed
Decreasing ADH increases?
urination (diuresis)
Describe the path of sodium regulation beginning with plasma water decreases:
1) plasma water decreases 2) sodium and osmolality increases 3) ADH secretion increases 4) collecting renal tubule reabsorbs more water
Increasing ADH decrease?
diuresis
Hypernatremia occurs in?
unreplaced water loss
Who is susceptible to hypernatremia?
Elderly patients with impaired mental faculties and may have diminished thirst stimulation, patients not given free access to water, given hypertonic saline solutions
Is hyponatremia from decreased oral intake of sodium common?
No, but can result from inadequate sodium IV fluids, especially if those fluids given to patient with GI loss of sodium
What medication can cause hyponatremia?
Thiazide diuretics used in the treatment of hypertension
Name two thiazide diuretics?
hydrochlorothiazide, chlorthalidone
Aside from medications, what else can cause hyponatremia?
Renal insufficiency–impaired free water excretion, retention of ingested water
Where are potassium levels higher? intracellular concentrations or serum potassium?
Intracellular concentration
When you draw blood you are assessing what potassium level?
Serum potassium (much lower)
Potassium gradient across cells influences?
muscle and nerve excitability
Changes in serum potassium can have major effects on?
muscle contractility, especially cardiac muscles
What can falsely elevate lab potassium levels?
opening/closing hand during blood draw or hemolysis of specimen
Causes of increased potassium:
increased dietary or IV intake, ACE inhibitors (pril), crush injuries or infection
Causes of decreased potassium:
fluid and electrolyte loss, diuretics (hydrochlorothiazide, chlorthalidone), deficient dietary or IV intake
Glucose reading gives measurement of quantity of glucose in?
serum
What cells secrete insulin?
cells in the Islet of Langerhans in the pancreas
What increases glucose readings?
diabetes, acute stress response, pancreatitis, corticosteroid therapy
What decreases glucose readings?
Insulinoma, insulin overdose, starvation
What is the main filtering structure of the kidney?
glomerulus
Glomerular filtration rate:
number of milliliters of body fluid cleared by the kidneys per unit of time
BUN stands for?
blood urea nitrogen
Urea formation occurs primarily in the?
liver
Urea formation occurs as a result of?
catabolism of protein into amino acids, which forms free ammonia in the process
Ammonia molecules combine to form?
urea
Approximately x% of urea is reabsorbed in renal tubule and the rest is excreted in urine?
50%
BUN reflects the X and X?
metabolic functioning of the liver, excretory function of the kidneys
Increased BUN levels:
high protein diets, GI bleeding, dehydration
Decreased BUN levels
low protein diets, starvation, overhydration
Creatinine is byproduct of?
catabolism of creatine phosphate
Creatinine is filtered by?
glomerulus of kidney
Creatinine is secreted by the kidneys at what rate?
constant
Since creatinine is excreted entirely by the kidneys, it’s not affected by
liver function
Which is more accurate at estimating kidney function: BUN or creatinine?
creatinine
Generally, creatinine levels are X in absence of disease and with stable muscle mass and consistent dietary intake
Constant
Production of creatinine is dependent on?
muscle mass
When does creatinine tend to increase in the process of renal disease? Why?
Increases in creatinine tend to occur later in renal disease because some of the creatinine secreted is secreted by the renal tubules (as much as 10-20%)
A doubling in serum creatinine generally reflects a x% decrease in GFR
50%
Diets high in X can increase serum creatinine
meat
Creatinine increase:
disorders of renal function, urinary tract obstruction, diabetic nephropathy, rhabdomyolysis, gigantism/acromegaly
Creatinine decrease:
debilitation, decreased muscle mass
Why does a urinary tract obstruction cause increased creatinine levels?
urine starts to backflow and damages kidneys over time.
What is rhabdomyolysis?
severe muscle breakdown which releases toxins, gets filtered through kidneys, damages them
Why does gigantism/acromegaly cause increased creatinine levels?
a lot more muscle mass
Why might creatinine look normally in an elderly patient with kidney damage?
Low muscle mass
Where is calcium more abundant? ICF or ECF?
ECF
Calcium is involved in? 4 things
muscle contraction, cardiac function, neural transmission, clotting cascade
Calcium exists in three forms:
protein-bound (mostly albumin, but also alpha, beta 1&2, gamma globin), complex (with phosphate, citrate, bicarbonate, sulfate), ionized (free calcium)
What % of protein is bound to protein?
40%
Calcium levels are regulated by?
Parathyroid hormone (PTH) and calcitonin
Where is PTH secreted from?
Parathyroid glands
Where are parathyroid glands located?
On the thyroid gland
Calcitonin is produced by?
thyroid gland
As calcium levels decrease, what happens to PTH?
PTH is released and calcium is reabsorbed by the kidneys, released from bone and absorption from GI tract increased
If calcium levels increase too much, what is released?
calcitonin
If patient has elevated calcium, it is recommended to?
order additional tests: ionized calcium, PTH, albumin levels
What is the second most common cause of hypercalcemia?
malignancy (bone metastasis, and cancer produces at PTH-like substance)
Ionized calcium is not impacted by?
albumin levels
Increased calcium:
hyperparathyroidism, vitamin D intoxication, tumors, acromegaly
Decreased calcium:
hypoparathyroidism, vitamin D deficiency, hypoalbuminemia, malabsorption
Vitamin D promotes
absorption of calcium
Bilirubin is formed by?
the breakdown of red blood cells
The breakdown of RBC occurs mostly in the?
spleen and reticuloendothelial system
When RBCs are broken down, they form:
heme + globin
Heme is catabolized and forms
biliverdin, which then becomes bilirubin
Unconjugated bilirubin becomes conjugated once in the ?
liver
Bilirubin becomes conjugated with x to become conjugated bilirubin
glycuronide
In order to determine the cause of the elevated bilirubin, we need to measure?
direct (conjugated) and indirect (unconjugated) bilirubin
Total bilirubin =
direct + indirect
If the defect occurs prior to conjugation with glycuronide, then
unconjugated hyperbilirubinemia results
Jaundice occurs when bilirubin levels are
too high
Jaundice can occur when total serum bilirubin exceeds?
2.5 mg/dL
Why do newborns experience jaundice?
their liver may not have adequate levels of conjugating enzymes so bilirubin remains unconjugated
Which bilirubin has the ability to pass through the blood-brain barrier?
unconjugated bilirubin
If unconjugated bilirbuin levels are too high, what can result?
mental retardation and encephalopathy
What level of bilirubin is critical?
> 15 mg/dL
Causes of indirect (unconjugated) hyperbilirubinemia
hepatocellular dysfunction (hepatitis, cirrhosis, neonatal hyperbilirubinemia), any disease process that increases RBC destruction (transfusion reaction, sickle cell anemia, hemolytic anemia), many medications
Causes of direct (conjugated) hyperbilirubinemia
gallstones, obstruction of extrahepatic ducts by tumor or other cause, liver metastases (obstruction)
Unconjugated (indirect) bilirubin is normally what percent of total bilirubin?
70-85%
Conjugated (direct) bilirubin is normally what % of total bilirubin?
15-30%
If indirect bilirubin is greater than X% think liver injury, RBC hemolysis, medications:
85%
If direct bilirubin is greater than x% think obstructive cause:
50%
Serum protein reflects the:
synthesis and maintenance of the total amount of protein in the circulation
The main components of the serum protein are:
Albumin and globulins
What is the most abundant serum protein?
albumin
What percent of the serum protein is albumin?
60%
Globulins are composed of:
a1, a2, B, and y globulins
Almost all of the serum proteins are composed in the:
liver
In healthy kidney tissue, most filtered protein is:
reabsorbed by the renal tubules
In renal disease, the glomerulus becomes less able to filter proteins and overwhelms the ability of the renal tubules to reabsorb proteins, results in
loss of protein in urine
Patients with low serum protein should have?
a urinalysis to check for protein in the urine
Hyperproteinemia:
dehydration (increased concentration of proteins), malignancy (overproduction of immunoglobulins), infection (overproduction of immunoglobulins)
Hypoproteinemia:
hepatic failure or disease, malnutrition states, malabsorption states, renal failure or disease
Where is albumin synthesized?
liver
What are the functions of albumin?
important regulator of osmotic balance between intravascular and interstitial spaces (albumin “pulls” water into circulatory system), act as transporter for many things
Half life of albumin:
12-18 days
The long half life of albumin makes it a poor indicator of?
nutritional status (prealbumin is better), liver disease (won’t manifest until later)
Disease that cause damage to the kidney result in what to albumin?
Increased albumin levels in urine, because it impairs kidney’s ability to reabsorb albumin
Hyperalbuminemia:
dehydration
Hypoalbuminemia
malnutrition, pregnancy, hepatic disease/failure, renal damage
Life enzyme tests include:
ALP, AST, ALT
Liver function tests abnormalities can be caused by:
injury to hepatocytes from alcohol, fatty deposits in liver, viruses (such as hepatitis)
Alkaline phosphatase is essential for?
bone mineralization
Highest concentrations of alkaline phosphatase are found?
in liver, biliary tract, bone
Alkaline phosphatase functions better at what pH levels?
higher
Alkaline phosphatase plays an import role in detection of?
bone and liver disorders
ALP is present in what cells in the liver and biliary tract?
Kupffer cells
ALP is secreted into:
bile
ALP increases in: (liver)
cirrhosis, obstruction of the biliary tract, liver tumors, drugs that are toxic to liver
ALP decreases in: (liver)
malnutritional states
ALP is elevated in: (bones)
cancers that metastasize to the bone, primary cancer of the bone, post-fracture, hyperparathyroidism, growing children
AST is an enzyme found in:
highly metabolic tissue within the body, such as heart, liver, skeletal muscle
Cell inflammation, injury and death =
increased AST
AST elevated in:
liver disease, tumors involving liver, infectious mononucleosis, skeletal muscle disease or trauma
Elevation of the ALT points to the liver as the source instead of RBC hemolysis in the x patient?
Jaundiced
ALT is found primarily in the:
liver, but can be found in smaller amounts in other tissue
If liver damage occurs, then ALT is found?
in circulation
Is ALT or AST more specific for liver?
ALT (think LLLLLL for liver)
ALT increased in :
hepatitis (major increase), hepatotoxic drugs (moderate increase), cirrhosis (moderate increase), myositis (mild increase), MI (mild increase)
If AST or ALT are 3x normal think:
bad habits (obesity, alcohol), toxicity (tylenol), illness or injury to liver
AST: ALT ratio >1:
alcoholic cirrhosis (frequently >2), metastatic tumor of the liver
AST: ALT ratio <1:
viral hepatitis, mononucleosis
What is the basic metabolic panel?
includes 7 or 8 tests included in the CMP
What’s special about BUN/Creatinine ratio?
Not included in CMP, but can be manually calculated
If both the BUN and Creatinine are normal is it necessary to calculate ratio?
nO
Azotemia:
increase in nitrogen containing compounds in blood
Pre-renal:
results from abnormalities in systemic circulation that decrease blood flow to the kidney (diabetes, ischemia)
Intra-renal
results from abnormalities within the kidneys themselves (PKD)
Post-renal
results from obstruction of collecting system of kidneys (kidney stone)
Pre-renal BUN/Cr ratio:
greater or equal to 20:1
Pre-renal conditions:
volume depletion of any cause (dehydration), sepsis, hypotension, CHF
Intrarenal BUN/Cr ratio:
less than or equal to 10:1
Intra-Renal conditions:
Any disease affecting the renal parenchyma, such as glomerulonephritis
Post-renal BUN/cr ratio:
Early: greater than or equal to 20:1
Late: less than or equal to 10:1
Post renal conditions:
urinary tract obstruction, nephrolithiasis, prostatic hyperplasia, metastatic disease
Why do is there a change in post-renal ratios depending on early/late?
If you have an obstruction, it’s probably okay at first but then will result in backflow of urine damaging kidneys.
GGT =
Gamma-glutamyl transpeptidase
GGT is involved in:
amino acid transport
GGT is present in many tissues including,
kidneys, pancreas, liver, spleen, heart, brain, seminal vesicles
Why is a CMP-GGT test useful?
It’s not expressed in bone, but ALP is. If ALP is elevated, order GGT test to further differentiate as liver and kidneys
Increased GGT
hepatitis, cirrhosis, alcoholic liver disease, liver cancer/metastasis
