Shock: Pathophysiology and Forms

Question 1

Which of the following best defines shock?
A. A state of persistent hypotension
B. A reduction in circulating blood volume
C. Inadequate tissue perfusion leading to cellular hypoxia
D. Failure of the heart to pump blood

Answer 1

C. Inadequate tissue perfusion leading to cellular hypoxia

Rationale: Shock is fundamentally defined by inadequate tissue perfusion and oxygen delivery, not hypotension alone.

Question 2

Which variable most directly determines oxygen delivery (DO₂) to tissues?
A. Systemic vascular resistance
B. Cardiac output and arterial oxygen content
C. Mean arterial pressure alone
D. Hemoglobin level alone

Answer 2

B. Cardiac output and arterial oxygen content

Rationale: DO₂ depends on cardiac output × arterial oxygen content, making both circulation and oxygen-carrying capacity essential.

Question 3

Which metabolic change occurs earliest at the cellular level in shock?
A. Apoptosis
B. Anaerobic metabolism
C. Coagulation activation
D. Cytokine exhaustion

Answer 3

B. Anaerobic metabolism

Rationale: Reduced oxygen delivery causes an early shift to anaerobic metabolism, leading to lactate production.

Question 4

The primary cause of lactic acidosis in shock is:
A. Renal failure
B. Hepatic dysfunction
C. Anaerobic glycolysis
D. Respiratory alkalosis

Answer 4

C. Anaerobic glycolysis

Question 5

Which compensatory response is mediated by the sympathetic nervous system during early shock?
A. Bradycardia
B. Vasodilation
C. Tachycardia and vasoconstriction
D. Decreased catecholamine release

Answer 5

C. Tachycardia and vasoconstriction

Rationale: Sympathetic activation increases heart rate and peripheral vasoconstriction to maintain perfusion.

Question 6

Which hormone system is activated to conserve sodium and water during shock?

Answer 6

Renin–angiotensin–aldosterone system

RAAS activation promotes vasoconstriction and fluid retention.

Question 7

Which mechanism explains persistent tissue hypoxia despite normal blood pressure?
A. Reduced hemoglobin concentration
B. Microcirculatory dysfunction
C. Increased preload
D. Bradycardia

Answer 7

B. Microcirculatory dysfunction

Rationale: Shock involves microvascular failure, preventing effective oxygen extraction even when macrocirculation appears adequate.

Question 8

Which ion pump failure is central to cellular injury in shock?
A. Ca²⁺ ATPase
B. Na⁺/K⁺ ATPase
C. H⁺ pump
D. Cl⁻ channel

Answer 8

B. Na⁺/K⁺ ATPase

Rationale: ATP depletion causes Na⁺/K⁺ pump failure, leading to cellular swelling and death.

Question 9

Which inflammatory mediator is most responsible for vasodilation in septic shock?
A. Histamine
B. Nitric oxide
C. Thromboxane A₂
D. Endothelin

Answer 9

B. Nitric oxide
Rationale: Excess nitric oxide causes profound vasodilation and low SVR.

Question 10

Which organ is most sensitive to hypoperfusion in early shock?
A. Liver
B. Brain
C. Skin
D. Kidneys

Answer 10

D. Kidneys

Rationale: The kidneys have high metabolic demand and limited tolerance to ischemia, making oliguria an early sign.

Question 11

Which stage of shock is characterized by failure to respond to therapy?
A. Compensated
B. Decompensated
C. Progressive
D. Irreversible

Answer 11

D. Irreversible
Rationale: In irreversible shock, widespread cellular death prevents recovery.

Question 12

Which feature best distinguishes distributive shock from other types?
A. Decreased preload
B. Increased SVR
C. Pathologic vasodilation
D. Myocardial failure

Answer 12

C. Pathologic vasodilation

Rationale: Distributive shock is marked by loss of vascular tone.

Question 13

Which coagulation abnormality may occur in severe shock?
A. Hyperfibrinogenemia
B. Polycythemia
C. Disseminated intravascular coagulation
D. Thrombocytosis

Answer 13

C. Disseminated intravascular coagulation

Rationale: Inflammatory activation of coagulation may lead to DIC.

Question 14

Which statement about shock is MOST accurate?
A. Hypotension is required for diagnosis
B. Shock is purely a cardiovascular disorder
C. Shock is a systemic disease involving inflammation
D. Shock always presents with cold skin

Answer 14

C. Shock is a systemic disease involving inflammation

Rationale: Shock is a systemic, immuno-inflammatory process, not merely circulatory failure.

Question 14

Which factor primarily determines preload?
A. Arterial resistance
B. Venous return
C. Heart rate
D. Afterload

Answer 14

B. Venous return

Rationale: Preload reflects ventricular filling, which depends on venous return.

Question 15

A trauma patient with massive hemorrhage develops tachycardia and cold clammy skin. Which shock type is present?
A. Septic
B. Cardiogenic
C. Hypovolemic
D. Neurogenic

Answer 15

C. Hypovolemic

Rationale: Blood loss causes reduced preload and CO → hypovolemic shock.

Question 16

Warm, flushed skin with bounding pulses is MOST consistent with:
A. Hypovolemic shock
B. Early septic shock
C. Cardiogenic shock
D. Obstructive shock

Answer 16

B. Early septic shock

Rationale: Early septic shock presents with vasodilation and high CO.

Question 16

A patient with acute myocardial infarction develops pulmonary edema and hypotension. Which mechanism explains the shock?
A. Vasodilation
B. Reduced preload
C. Pump failure
D. Cytokine storm

Answer 16

C. Pump failure
Rationale: Myocardial dysfunction leads to cardiogenic shock.

Question 17

A hypotensive patient with bradycardia after a cervical spine injury is in which type of shock?
A. Septic
B. Cardiogenic
C. Neurogenic
D. Hypovolemic

Answer 17

Answer: C
Rationale: Loss of sympathetic tone causes hypotension with bradycardia.

Question 17

Elevated jugular venous pressure with hypotension and muffled heart sounds suggests:
A. Massive pulmonary embolism
B. Cardiac tamponade
C. Hypovolemia
D. Septic shock

Answer 17

B. Cardiac tamponade

Rationale: Beck’s triad indicates obstructive shock due to tamponade.

Question 17

Why may blood pressure be normal in early septic shock?
A. Increased SVR
B. Increased preload
C. Increased cardiac output
D. Reduced oxygen consumption

Answer 17

C. Increased cardiac output
Rationale: Early sepsis is a high-output, low-SVR state.

Question 17

Which finding best indicates inadequate tissue perfusion despite normal blood pressure?
A. Normal urine output
B. Elevated serum lactate
C. Bounding pulses
D. Wide pulse pressure

Answer 17

B. Elevated serum lactate
Rationale: Elevated lactate reflects cellular hypoxia.

Question 18

Which shock type is primarily associated with decreased SVR?
A. Hypovolemic
B. Cardiogenic
C. Septic
D. Obstructive

Answer 18

C. Septic

Rationale: Septic shock causes vasoplegia.

Question 19

Which mechanism contributes MOST to ARDS in shock?
A. Alveolar hemorrhage
B. Endothelial injury and capillary leak
C. Bronchospasm
D. Atelectasis

Answer 19

B. Endothelial injury and capillary leak

Rationale: Inflammatory injury increases alveolar–capillary permeability.

Question 19

Which laboratory finding is expected in prolonged shock? A. Respiratory alkalosis B. Metabolic acidosis C. Hypokalemia D. Hypoglycemia

Answer 19

B. Metabolic acidosis Rationale: Lactic acid accumulation causes metabolic acidosis.

Question 19

A patient remains hypotensive despite fluids and vasopressors. This indicates: A. Compensated shock B. Early shock C. Irreversible shock D. Neurogenic shock

Answer 19

C. Irreversible shock Rationale: Failure to respond suggests irreversible shock.

Question 19

Which shock type commonly involves a mixed pathophysiology in trauma patients? A. Septic B. Neurogenic C. Traumatic D. Cardiogenic

Answer 19

C. Traumatic Rationale: Trauma often causes hypovolemic ± obstructive shock.

Question 20

Why does oliguria occur early in shock? A. ADH suppression B. Reduced renal perfusion C. Increased GFR D. Tubular obstruction

Answer 20

B. Reduced renal perfusion Rationale: Kidneys receive reduced blood flow during shock.

Question 20

Which factor worsens organ failure even after resuscitation? A. Hypothermia B. Microthrombi formation C. Hypertension D. Bradycardia

Answer 20

B. Microthrombi formation Rationale: Microvascular thrombosis impairs tissue perfusion.

Question 21

Which shock type has the HIGHEST preload? A. Hypovolemic B. Septic C. Cardiogenic D. Neurogenic

Answer 21

C. Cardiogenic Rationale: Pump failure leads to blood backing up into the heart.

Question 22

A patient with tension pneumothorax develops shock due to: A. Reduced oxygen content B. Myocardial ischemia C. Impaired venous return D. Cytokine release

Answer 22

C. Impaired venous return Rationale: Increased intrathoracic pressure obstructs venous return.

Question 23

Which immune response contributes to late immunosuppression in shock? A. Neutrophil activation B. Lymphocyte apoptosis C. Complement activation D. Cytokine surge

Answer 23

B. Lymphocyte apoptosis Rationale: Immune exhaustion occurs due to lymphocyte loss.

Question 23

Which sign indicates progression from compensated to decompensated shock? A. Tachycardia B. Narrow pulse pressure C. Hypotension D. Cool extremities

Answer 23

C. Hypotension Rationale: Hypotension indicates failure of compensation.

Question 24

Why is early recognition of shock critical? A. Shock is always reversible B. Cellular injury becomes irreversible with time C. Hypotension develops late D. Inflammation cannot be controlled

Answer 24

B. Cellular injury becomes irreversible with time Rationale: Delayed treatment leads to irreversible cellular damage.

Question 25

Which shock state is most associated with DIC (Disseminated Intravascular Coagulation)? A. Neurogenic B. Septic C. Hypovolemic D. Obstructive

Answer 25

B. Septic Rationale: Severe sepsis strongly activates coagulation pathways.

Question 26

Which parameter best reflects effective resuscitation? A. Blood pressure B. Heart rate C. Lactate clearance D. Skin temperature

Answer 26

C. Lactate clearance Rationale: Lactate clearance reflects improved cellular oxygenation.

Question 27

Why is hypotension a late finding in shock? A. Early myocardial failure B. Early vasodilation C. Effective compensatory mechanisms D. Reduced preload

Answer 27

C. Effective compensatory mechanisms Rationale: Compensatory mechanisms initially maintain BP.

Question 28

Which shock form involves loss of vascular tone without hypovolemia? A. Septic B. Cardiogenic C. Hypovolemic D. Obstructive

Answer 28

Answer: A Rationale: Septic shock causes vasodilation without volume loss initially.

Question 29

A patient with septic shock has a normal mean arterial pressure after aggressive fluid resuscitation and vasopressors. However, serum lactate remains elevated and urine output is declining. Which pathophysiologic abnormality BEST accounts for this dissociation between macrocirculation and cellular perfusion? A. Downregulation of β-adrenergic receptors B. Impaired mitochondrial oxygen utilization (cytopathic hypoxia) C. Reduced arterial oxygen content D. Persistent activation of the renin–angiotensin–aldosterone system

Answer 29

Answer: B Rationale: In advanced shock, particularly septic shock, mitochondrial dysfunction prevents effective use of delivered oxygen (cytopathic hypoxia). Thus, oxygen delivery and blood pressure may appear adequate, yet cells cannot generate ATP, resulting in persistent lactic acidosis and organ dysfunction.

Question 30

Shock caused by a large tension pneumothorax is categorized as A. Trauma shock B. Vasodilatory shock C. Cardiogenic shock D. Obstructive shock

Answer 30

D. Obstructive shock

Question 31

What is true about baroreceptors? A. Volume receptors can be activated in hemorrhage with reduction in le atrial pressure. B. Receptors in the aortic arch and carotid bodies inhibit the autonomic nervous system (ANS) when stretched. C. When baroreceptors are stretched, they induced increased ANS output and produce constriction of peripheral vessels. D. None of the above

Answer 31

B. Receptors in the aortic arch and carotid bodies inhibit the autonomic nervous system (ANS) when stretched.

Question 32

3. Chemoreceptors in the aorta and carotid bodies do NO sense which o the ollowing? A. Changes in O2 tension B. H+ ion concentration C. HCO3- concentration D. Carbon dioxide (CO2) levels

Answer 32

C. HCO3- concentration

Question 33

Neurogenic shock is characterized by the presence o A. Cool, moist skin B. Increased cardiac output C. Decreased peripheral vascular resistance D. Decreased blood volume

Answer 33

C. Decreased peripheral vascular resistance

Question 34

When a patient with hemorrhagic shock is resuscitated using an intravenous colloid solution rather than lactated Ringer solution, all of the following statements are true EXCEPT A. Circulating levels of immunoglobulins are decreased. B. Colloid solutions may bind to the ionized raction of serum calcium. C. Endogenous production of albumin is decreased. D. Extracellular fluid volume deficit is restored.

Answer 34

D. Extracellular fluid volume deficit is restored.

Question 35

In hemorrhage, larger arterioles vasoconstrict in response to the sympathetic nervous system. Which categories of shock are associated with vasodilation of larger arterioles? A. Septic shock B. Cardiogenic shock C. Neurogenic shock D. A & C

Answer 35

D. A & C

Question 36

Which o the ollowing is true about antidiuretic hormone (ADH) production in injured patients? A. ADH acts as a potent mesenteric vasoconstrictor. B. ADH levels all to normal within 2 to 3 days o the initial insult. C. ADH decreases hepatic gluconeogenesis. D. ADH secretion is mediated by the renin-angiotensin system.

Answer 36

A. ADH acts as a potent mesenteric vasoconstrictor.

Question 37

Which o ollowing occur as a result of epinephrine and norepinephrine? A. Hepatic glycogenolysis B. Hypoglycemia C. Insulin sensitivity D. Lipogenesis

Answer 37

A. Hepatic glycogenolysis

Question 38

A patient has a blood pressure of 70/50 mm Hg and a serum lactate level of 30 mg/100 mL (normal: 6–16). His cardiac output is 1.9 L/min, and his central venous pressure is 2 cm H2O. The most likely diagnosis is A. Congestive heart failure B. Cardiac tamponade C. Hypovolemic shock D. Septic shock

Answer 38

C. Hypovolemic shock

Question 39

Which cytokine is anti-inflammatory and increases after shock and trauma? A. Interleukin (IL)-1 B. IL-2 C. IL-6 D. IL-10

Answer 39

D. IL-10

Question 39

Tumor necrosis factor-alpha (TNF-α) A. Can be released as a response to bacteria or endotoxin B. Increased more in trauma than septic patients C. Induces procoagulant activity and peripheral vasoconstriction D. Contributes to anemia of chronic illness

Answer 39

A. Can be released as a response to bacteria or endotoxin

Question 40

A 70-kg male patient presents to ED following a stab wound to the abdomen. He is hypotensive, markedly tachycardic, and appears confused. What percent of blood volume has he lost? A. 5% B. 15% C. 35% D. 55%

Answer 40

D. 55%

Question 41

Vasodilatory shock A. Is characterized by failure of vascular smooth muscle to constrict due to low levels of catecholamines B. Leads to suppression of the renin-angiotensin system C. Can also be caused by carbon monoxide poisoning D. Is similar to early cardiogenic shock

Answer 41

C. Can also be caused by carbon monoxide poisoning

Question 42

A patient in septic shock remains hypotensive despite adequate fluid resuscitation and initiation of norepinephrine. What is often given to patients with hypotension refractory to norepinephrine? A. Dopamine B. Arginine vasopressin C. Dobutamine D. Milrinone

Answer 42

B. Arginine vasopressin

Question 43

Tight glucose management in critically ill and septic patients A. Requires insulin to keep serum glucose <140 B. Has no effect on mortality C. Has no effect on ventilator support D. Decreases length o antibiotic therapy

Answer 43

D. Decreases length of antibiotic therapy

Question 44

Cardiogenic shock A. Is most commonly caused by exacerbation of congestive heart failure. B. Cardiogenic shock following an acute myocardial infarction is typically present on admission. C. Cardiogenic shock occurs in 5 to 10% of acute MIs. D. Is characterized by hypotension, reduced cardiac index, and reduced pulmonary artery wedge pressure.

Answer 44

C. Cardiogenic shock occurs in 5 to 10% of acute MIs.

Question 45

All of the ollowing result from the placement of an intra-aortic balloon pump in a patient with acute myocardial failure EXCEPT A. Reduction of systolic afterload B. Increased cardiac output C. Increased myocardial O2 demand D. Increased diastolic perfusion pressure

Answer 45

C. Increased myocardial O2 demand

Question 45

Which constellation of clinical findings is suggestive of cardiac tamponade? A. Hypotension, wide pulse pressure, tachycardia B. Tachycardia, hypotension, jugular venous distension C. Hypotension, wide pulse pressure, jugular venous distension D. Hypotension, muffled heart tones, jugular venous distension

Answer 45

D. Hypotension, muffled heart tones, jugular venous distension

Question 46

A 43-year-old man is struck by a motor vehicle while crossing the street; he arrives in the ED hypotensive, bradycardic, and unable to move his extremities. What is the most likely cause of his hypotension? A. Hypovolemic shock B. Obstructive shock C. Neurogenic shock D. Vasodilatory shock

Answer 46

C. Neurogenic shock

Question 47

Corticosteroids in the treatment of septic shock A. Improves rates of shock reversal in patients requiring vasopressors B. Improves mortality in patients with relative adrenal insufficiency C. Is contraindicated in patients with positive bacterial blood cultures D. None of the above

Answer 47

B. Improves mortality in patients with relative adrenal insufficiency

Question 48

21. What is FALSE about serum lactate? A. Generated from pyruvate in the setting of insufficient O2 B. Metabolized by the liver and kidneys. C. Is an indirect measure of the magnitude and severity of shock. D. The time to peak lactate from admission predicts rates of survival.

Answer 48

D. The time to peak lactate from admission predicts rates of survival.

Question 49

Phases of Shock

Answer 49

1. Compensated 2. Decompensated - Inadequate tissue perfusion 3. Irreversible Shock

Question 49

Inflammatory mediators of shock

Answer 49

Anti-Inflammatory- IL-4, 10, 13; Prostaglandin E2, TGFB Pro-Inflammatory- IL-1,2,6,8, Interferon, TNF, PAF

Question 50

Compensated Phase Mechanisms

Answer 50

Compensated - Sympathetic Vasocontrictor System - Baroreceptor System - CNS Ischemic Response Neurohormonal Mechanism - Catecholamines - RAAS

Question 51

Decompensated Phase Mechanisms

Answer 51

1. Cardiac Depression 2. Vasomotor Failure 3. Vessel Dysfunction 4. Toxin Release 5. Glucose Metabolism Dysfunction

Question 52

Irreversible Phase Mechanisms

Answer 52

1. Depletion of High Energy Phosphates 2. Cellular Injury Features: Blood Pressure - unresponsive Cardiac Output- Critically impaired Tissue Perfusion- Irreversibly damaged Cell Metabolism - Failure of OXPHOS