MedCosmos Surgery
Surgery Lecture Notes, Books, MCQ and Good Articles
Friday, September 5, 2008
General Surgery MCQ
1. Skeletal muscle breakdown produces predominantly liberation of
which two amino acids?
A. Lysine.
B. Tyrosine.
C. Alanine.
D. Glutamine.
E. Arginine.
Answer: CD
DISCUSSION: Alanine is released from skeletal muscle and extracted
by the liver, where it is converted to new glucose. Glutamine is also
released from muscle and participates in renal acid-base homeostasis
and serves as fuel for rapidly growing cells such as enterocytes,
stimulated macrophages, and fibroblasts. Together, these two amino
acids account for approximately two thirds of the nitrogen released
from skeletal muscle.
2. In “catabolic” surgical patients, which of the following changes in
body composition do not occur?
A. Lean body mass increases.
B. Total body water increases.
C. Adipose tissue decreases.
D. Body weight decreases.
Answer: A
DISCUSSION: Lean body mass represents the body compartment that
contains protein. Because critical illness stimulates proteolysis and
increased excretion of body nitrogen, this compartment is
consistently reduced, not increased. The change in body composition
is associated with a loss of body weight, an increase in total body
water, and a decrease in body fat.
,3. The hormonal alterations that follow operation and injury favor
accelerated gluconeogenesis. This new glucose is consumed by which
of the following tissues?
A. Central nervous system.
B. Skeletal muscle.
C. Bone.
D. Kidney.
E. Tissue in the healing wound.
Answer: ADE
DISCUSSION: Glucose is produced in increased amounts to satisfy the
fuel requirements of the healing wound. In addition, nerve tissue and
the renal medulla also utilize this substrate. Skeletal muscle primarily
utilizes fatty acids, and bone utilizes mineral substrate.
4. Cytokines are endogenous signals that stimulate:
A. Local cell proliferation within the wound.
B. The central nervous system to initiate fever.
C. The production of “acute-phase proteins.”
D. Hypoferremia.
E. Septic shock.
Answer:ABCD
DISCUSSION: Although cytokines exert primarily autocrine and
paracrine effects, they may also cause systemic effects.
5. The characteristic changes that follow a major operation or
moderate to severe injury do not include the following:
A. Hypermetabolism.
B. Fever.
C. Tachypnea.
D. Hyperphagia.
E. Negative nitrogen balance.
Answer: D
DISCUSSION: The characteristic metabolic response to injury includes
hypermetabolism, fever, accelerated gluconeogenesis, and increased
proteolysis (creating a negative nitrogen balance). Food intake is
generally impossible because of abdominal injury or ileus. With time,
food intake increases, but the patient generally experiences anorexia,
not hyperphagia.
6. Shock can best be defined as:
A. Hypotension.
,B. Hypoperfusion of tissues.
C. Hypoxemia.
D. All of the above.
Answer: B
DISCUSSION: Shock, no matter what the cause, is a syndrome
associated with tissue hypoperfusion. Tissue hypoperfusion leads to
tissue hypoxia, which may or may not be due to hypoxemia.
Hypotension is a late sign of shock and, therefore, is not a good
clinical indicator of the presence of tissue hypoperfusion.
7. Which of the following statements about continuous cardiac output
monitoring are true?
A. Continuous cardiac output monitoring may unmask events not
detected by intermittent cardiac output measurements.
B. Continuous cardiac output monitoring by the thermodilution
method requires continuous infusion of fluid injectate at a constant
rate and temperature.
C. The major advantage of the Fick method over the thermodilution
method of calculating cardiac output is that it is noninvasive, requiring
only the determination of oxygen consumption by respiratory gas
analysis.
D. The technique of thoracic electrical bioimpedance utilizes sensors
to determine stroke volume by detecting changes in resistance to a
small, applied alternating current.
Answer: AD
DISCUSSION: Various techniques are available to measure cardiac
output continuously. The advantages of continuous cardiac output
monitoring, as compared with intermittent methods, are (1)
previously undetected events may be unmasked; (2) more prompt
recognition of adverse events may be achieved; and (3) earlier
therapeutic intervention may be possible. Continuous cardiac output
monitoring using the thermodilution method appears to be as
accurate as the “standard” intermittent bolus method, but it does not
require fluid injectates. In this method, a modified pulmonary artery
catheter incorporating a thermal filament heats blood in the right
ventricle at pulsed intervals, and a distal thermistor detects the
temperature change, which can be related mathematically to cardiac
output. The Fick method combines respiratory gas analysis with
oximetery to determine oxygen consumption (V(overdot)O 2) and to
estimate mixed venous and arterial oxygen content differences,
respectively. Cardiac output (CO) is then determined from the
formula: CO = V(overdot)O 2/ {C(a-v)O 2 × 10} @ V(overdot)O 2/ {SaO 2
- SvO 2) × (Hb) × (1.39) × 10}. Thoracic electrical bioimpedance is a
technique by which the resistance to a small-amplitude alternating
, current (i.e., the impedance) is measured using various electrodes.
The impedance change induced by each cardiac ejection is a function
of the stroke volume, which then can be used to calculate the cardiac
output.
8. Which of the following statements regarding cytokines is incorrect?
A. Cytokines act directly on target cells and may potentiate the actions
of one another.
B. Interleukin 1 (IL-1) is a major proinflammatory mediator with
multiple effects, including regulation of skeletal muscle proteolysis in
patients with sepsis or significant injury.
C. Platelet-activating factor (PAF) is a major cytokine that results in
platelet aggregation, bronchoconstriction, and increased vascular
permeability.
D. Tumor necrosis factor alpha (TNF-a), despite its short plasma
half-life, appears to be a principal mediator in the evolution of sepsis
and the multiple organ dysfunction syndrome because of its multiple
actions and the secondary cascades that it stimulates.
Answer: C
DISCUSSION: Cytokines are soluble peptide molecules that are
synthesized and secreted by a number of cell types in response to
injury, inflammation, and infection. Cytokines, which include the
interleukins, tumor necrosis factor, colony-stimulating factors, and the
interferons, comprise only one category of inflammatory mediators
involved in the host response. Endotoxin, complement fragments,
eicosanoids, kinins, nitric oxide, oxidants, and PAF are noncytokine
mediators that also have important roles in the systemic
inflammatory response. IL-1 and TNF-a, like other cytokines, have
multiple effects on target cells and potentiate the actions of other
mediators to produce an amplified inflammatory response. TNF-a is
thought to play a central role in the stress response, particularly in
response to endotoxemia.
9. True statements concerning hypoadrenal shock include which of
the following?
A. Adrenocortical insufficiency may manifest itself as severe shock
refractory to volume and pressor therapy.
B. The presence of hyperglycemia and hypotension may suggest the
diagnosis of shock due to adrenocortical insufficiency.
C. Hydrocortisone does not interfere with the serum cortisol assay
and should be given to hemodynamically unstable patients suspected
of having hypoadrenal shock.
D. The rapid adrenocorticotropic hormone (ACTH) stimulation test
should be performed to help establish the diagnosis of acute
Surgery Lecture Notes, Books, MCQ and Good Articles
Friday, September 5, 2008
General Surgery MCQ
1. Skeletal muscle breakdown produces predominantly liberation of
which two amino acids?
A. Lysine.
B. Tyrosine.
C. Alanine.
D. Glutamine.
E. Arginine.
Answer: CD
DISCUSSION: Alanine is released from skeletal muscle and extracted
by the liver, where it is converted to new glucose. Glutamine is also
released from muscle and participates in renal acid-base homeostasis
and serves as fuel for rapidly growing cells such as enterocytes,
stimulated macrophages, and fibroblasts. Together, these two amino
acids account for approximately two thirds of the nitrogen released
from skeletal muscle.
2. In “catabolic” surgical patients, which of the following changes in
body composition do not occur?
A. Lean body mass increases.
B. Total body water increases.
C. Adipose tissue decreases.
D. Body weight decreases.
Answer: A
DISCUSSION: Lean body mass represents the body compartment that
contains protein. Because critical illness stimulates proteolysis and
increased excretion of body nitrogen, this compartment is
consistently reduced, not increased. The change in body composition
is associated with a loss of body weight, an increase in total body
water, and a decrease in body fat.
,3. The hormonal alterations that follow operation and injury favor
accelerated gluconeogenesis. This new glucose is consumed by which
of the following tissues?
A. Central nervous system.
B. Skeletal muscle.
C. Bone.
D. Kidney.
E. Tissue in the healing wound.
Answer: ADE
DISCUSSION: Glucose is produced in increased amounts to satisfy the
fuel requirements of the healing wound. In addition, nerve tissue and
the renal medulla also utilize this substrate. Skeletal muscle primarily
utilizes fatty acids, and bone utilizes mineral substrate.
4. Cytokines are endogenous signals that stimulate:
A. Local cell proliferation within the wound.
B. The central nervous system to initiate fever.
C. The production of “acute-phase proteins.”
D. Hypoferremia.
E. Septic shock.
Answer:ABCD
DISCUSSION: Although cytokines exert primarily autocrine and
paracrine effects, they may also cause systemic effects.
5. The characteristic changes that follow a major operation or
moderate to severe injury do not include the following:
A. Hypermetabolism.
B. Fever.
C. Tachypnea.
D. Hyperphagia.
E. Negative nitrogen balance.
Answer: D
DISCUSSION: The characteristic metabolic response to injury includes
hypermetabolism, fever, accelerated gluconeogenesis, and increased
proteolysis (creating a negative nitrogen balance). Food intake is
generally impossible because of abdominal injury or ileus. With time,
food intake increases, but the patient generally experiences anorexia,
not hyperphagia.
6. Shock can best be defined as:
A. Hypotension.
,B. Hypoperfusion of tissues.
C. Hypoxemia.
D. All of the above.
Answer: B
DISCUSSION: Shock, no matter what the cause, is a syndrome
associated with tissue hypoperfusion. Tissue hypoperfusion leads to
tissue hypoxia, which may or may not be due to hypoxemia.
Hypotension is a late sign of shock and, therefore, is not a good
clinical indicator of the presence of tissue hypoperfusion.
7. Which of the following statements about continuous cardiac output
monitoring are true?
A. Continuous cardiac output monitoring may unmask events not
detected by intermittent cardiac output measurements.
B. Continuous cardiac output monitoring by the thermodilution
method requires continuous infusion of fluid injectate at a constant
rate and temperature.
C. The major advantage of the Fick method over the thermodilution
method of calculating cardiac output is that it is noninvasive, requiring
only the determination of oxygen consumption by respiratory gas
analysis.
D. The technique of thoracic electrical bioimpedance utilizes sensors
to determine stroke volume by detecting changes in resistance to a
small, applied alternating current.
Answer: AD
DISCUSSION: Various techniques are available to measure cardiac
output continuously. The advantages of continuous cardiac output
monitoring, as compared with intermittent methods, are (1)
previously undetected events may be unmasked; (2) more prompt
recognition of adverse events may be achieved; and (3) earlier
therapeutic intervention may be possible. Continuous cardiac output
monitoring using the thermodilution method appears to be as
accurate as the “standard” intermittent bolus method, but it does not
require fluid injectates. In this method, a modified pulmonary artery
catheter incorporating a thermal filament heats blood in the right
ventricle at pulsed intervals, and a distal thermistor detects the
temperature change, which can be related mathematically to cardiac
output. The Fick method combines respiratory gas analysis with
oximetery to determine oxygen consumption (V(overdot)O 2) and to
estimate mixed venous and arterial oxygen content differences,
respectively. Cardiac output (CO) is then determined from the
formula: CO = V(overdot)O 2/ {C(a-v)O 2 × 10} @ V(overdot)O 2/ {SaO 2
- SvO 2) × (Hb) × (1.39) × 10}. Thoracic electrical bioimpedance is a
technique by which the resistance to a small-amplitude alternating
, current (i.e., the impedance) is measured using various electrodes.
The impedance change induced by each cardiac ejection is a function
of the stroke volume, which then can be used to calculate the cardiac
output.
8. Which of the following statements regarding cytokines is incorrect?
A. Cytokines act directly on target cells and may potentiate the actions
of one another.
B. Interleukin 1 (IL-1) is a major proinflammatory mediator with
multiple effects, including regulation of skeletal muscle proteolysis in
patients with sepsis or significant injury.
C. Platelet-activating factor (PAF) is a major cytokine that results in
platelet aggregation, bronchoconstriction, and increased vascular
permeability.
D. Tumor necrosis factor alpha (TNF-a), despite its short plasma
half-life, appears to be a principal mediator in the evolution of sepsis
and the multiple organ dysfunction syndrome because of its multiple
actions and the secondary cascades that it stimulates.
Answer: C
DISCUSSION: Cytokines are soluble peptide molecules that are
synthesized and secreted by a number of cell types in response to
injury, inflammation, and infection. Cytokines, which include the
interleukins, tumor necrosis factor, colony-stimulating factors, and the
interferons, comprise only one category of inflammatory mediators
involved in the host response. Endotoxin, complement fragments,
eicosanoids, kinins, nitric oxide, oxidants, and PAF are noncytokine
mediators that also have important roles in the systemic
inflammatory response. IL-1 and TNF-a, like other cytokines, have
multiple effects on target cells and potentiate the actions of other
mediators to produce an amplified inflammatory response. TNF-a is
thought to play a central role in the stress response, particularly in
response to endotoxemia.
9. True statements concerning hypoadrenal shock include which of
the following?
A. Adrenocortical insufficiency may manifest itself as severe shock
refractory to volume and pressor therapy.
B. The presence of hyperglycemia and hypotension may suggest the
diagnosis of shock due to adrenocortical insufficiency.
C. Hydrocortisone does not interfere with the serum cortisol assay
and should be given to hemodynamically unstable patients suspected
of having hypoadrenal shock.
D. The rapid adrenocorticotropic hormone (ACTH) stimulation test
should be performed to help establish the diagnosis of acute
