STEP 1 — MCQs (NO answers here)

MCQ 1 — Core Definition

Shock is best defined as:

a. Any drop in blood pressure below normal

b. A state where diminished cardiac output or effective circulating volume impairs tissue perfusion and causes cellular hypoxia

c. A condition of acute heart failure only

d. A state where only CNS perfusion is affected

e. A form of irreversible necrosis

MCQ 2 — Reversibility

In early shock:

a. Cellular injury is irreversible

b. Cellular injury is reversible

c. Necrosis is established in all tissues

d. Only brain injury is reversible

e. Mitochondria are destroyed immediately

MCQ 3 — Outcomes of Prolonged Shock

Prolonged, uncorrected shock typically leads to:

a. Complete recovery without damage

b. Irreversible tissue injury and often death

c. Only neurological dysfunction

d. Only reversible myocardial changes

e. Hypertension

MCQ 4 — Situations That Can Lead to Shock

Shock may complicate all of the following EXCEPT:

a. Severe hemorrhage

b. Extensive trauma or burns

c. Myocardial infarction

d. Pulmonary embolism

e. Mild, self-limited viral URTI in a healthy adult

MCQ 5 — Big Three Categories

The three major categories of shock described in this section are:

a. Cardiogenic, hypovolemic, obstructive

b. Cardiogenic, hypovolemic, septic

c. Neurogenic, anaphylactic, septic

d. Cardiogenic, distributive, neurogenic

e. Hypovolemic, septic, anaphylactic

MCQ 6 — Cardiogenic Shock: Mechanism

Cardiogenic shock is primarily due to:

a. Loss of vascular tone

b. Severe hypovolemia only

c. Low cardiac output due to myocardial pump failure

d. Excessive vasodilation with normal pump function

e. Massive fluid loss from burns

MCQ 7 — Causes of Cardiogenic Shock

Which of the following is NOT a typical cause of cardiogenic shock?

a. Myocardial infarction

b. Ventricular arrhythmia

c. Cardiac tamponade

d. Massive pulmonary embolism causing outflow obstruction

e. Severe diarrhea with massive fluid loss

MCQ 8 — Hypovolemic Shock: Mechanism

Hypovolemic shock results from:

a. Low cardiac output due to loss of blood or plasma volume

b. Myocardial pump failure only

c. Widespread vasodilation from inflammatory mediators

d. Obstruction of pulmonary artery only

e. Failure of the autonomic nervous system

MCQ 9 — Causes of Hypovolemic Shock

Which is the BEST example of a cause of hypovolemic shock?

a. Massive myocardial infarction

b. Massive pulmonary embolism

c. Severe burns with major fluid loss

d. Ventricular fibrillation

e. Anesthesia-induced vasodilation

MCQ 10 — Septic Shock: Trigger

Septic shock is primarily:

a. Due to pure blood loss

b. Triggered by microbial infections and associated with systemic inflammatory response syndrome

c. Due only to IgE-mediated hypersensitivity

d. Due only to spinal cord injury

e. Due to pure mechanical obstruction of flow

MCQ 11 — SIRS and Septic Shock

Which statement about septic shock/SIRS is TRUE?

a. SIRS only occurs in bacterial sepsis

b. SIRS can be triggered by burns, trauma, and pancreatitis in addition to infections

c. SIRS does not involve inflammatory mediators

d. Septic shock is unrelated to SIRS

e. SIRS always leads to cardiogenic shock, not septic shock

MCQ 12 — Core Hemodynamic Problems in Septic Shock

The cardinal cardiovascular abnormalities of septic shock include:

a. Arterial vasoconstriction and reduced venous pooling

b. Arterial vasodilation, increased vascular leakage, venous blood pooling

c. Pure hypovolemia without vascular effect

d. Myocardial infarction only

e. Increased systemic vascular resistance and hypertension

MCQ 13 — Final Pathway in Septic Shock

These septic shock–related changes (vasodilation, leakage, pooling) ultimately cause:

a. Tissue hyperperfusion and alkalosis

b. Tissue hypoperfusion, cellular hypoxia, metabolic derangements, organ dysfunction/failure

c. Only fever and rash without organ damage

d. Hypertension with preserved organ function

e. Isolated CNS changes with preserved peripheral perfusion

MCQ 14 — Neurogenic Shock

Neurogenic shock is most accurately described as:

a. Shock due to loss of vascular tone associated with anesthesia or spinal cord injury

b. Shock due to myocardial infarction

c. Shock due to IgE-mediated reaction

d. Shock due to bacterial toxins only

e. Shock due to hemorrhage

MCQ 15 — Anaphylactic Shock

Anaphylactic shock is caused by:

a. Systemic vasoconstriction and decreased permeability

b. IgG-mediated immune complex formation

c. IgE-mediated hypersensitivity reaction causing systemic vasodilation and increased vascular permeability

d. Autoimmune attack on myocardium only

e. Direct bacterial invasion of vessels

STEP 2 — ANSWERS + SHORT EXPLANATIONS

MCQ 1 — b

Shock = diminished cardiac output or effective circulating volume → impaired tissue perfusion → cellular hypoxia.

MCQ 2 — b

Initially, injury is reversible; with prolonged shock it becomes irreversible.

MCQ 3 — b

Prolonged, uncorrected shock → irreversible tissue injury and often fatal.

MCQ 4 — e

Shock: hemorrhage, trauma, burns, MI, PE, sepsis; a mild URTI in a healthy adult does not usually cause shock.

MCQ 5 — b

Three main categories: cardiogenic, hypovolemic, septic.

MCQ 6 — c

Cardiogenic shock: low cardiac output from myocardial pump failure.

MCQ 7 — e

Severe diarrhea with fluid loss → hypovolemic, not cardiogenic. Others are classic cardiogenic causes (MI, arrhythmia, tamponade, massive PE).

MCQ 8 — a

Hypovolemic shock: low cardiac output due to loss of blood or plasma volume.

MCQ 9 — c

Severe burns → massive fluid loss → hypovolemic shock.

MCQ 10 — b

Septic shock: triggered by microbial infections and linked to SIRS.

MCQ 11 — b

SIRS may be triggered by infections, burns, trauma, pancreatitis, etc.

MCQ 12 — b

Septic shock: arterial vasodilation, vascular leakage, venous pooling.

MCQ 13 — b

These lead to tissue hypoperfusion, cellular hypoxia, metabolic derangements, organ dysfunction/failure, and death if severe and persistent.

MCQ 14 — a

Neurogenic shock: loss of vascular tone due to anesthesia or spinal cord injury.

MCQ 15 — c

Anaphylactic shock: IgE-mediated hypersensitivity → systemic vasodilation + increased vascular permeability.

STEP 3 — HIGH-YIELD NOTES (EXAM-READY)

1. Core Definition of Shock

• Shock =
• State where diminished cardiac output OR reduced effective circulating blood volume
• → Impaired tissue perfusion
• → Cellular hypoxia.
• Early phase:
• Cellular injury reversible.
• Prolonged shock:
• Irreversible tissue injury, organ failure, often fatal.

2. Clinical Contexts Where Shock Appears

Shock commonly complicates:

• Severe hemorrhage
• Extensive trauma or burns
• Myocardial infarction
• Pulmonary embolism
• Microbial sepsis

Think: big systemic insults → reduced effective perfusion → shock.

3. Major Categories of Shock

A. Cardiogenic Shock

• Mechanism:
• Low cardiac output due to myocardial pump failure.
• Causes:
• Myocardial damage:
• Acute myocardial infarction.
• Ventricular arrhythmias:
• e.g., VT/VF interfering with effective stroke volume.
• Extrinsic cardiac compression:
• Cardiac tamponade (fluid in pericardial sac compressing heart).
• Outflow obstruction:
• e.g., massive pulmonary embolism blocking right ventricular outflow.

Bottom line: heart can’t pump → low CO → systemic hypoperfusion.

B. Hypovolemic Shock

• Mechanism:
• Low cardiac output due to loss of blood or plasma volume.
• Causes:
• Hemorrhage (trauma, GI bleed, obstetric bleed).
• Plasma/fluid loss:
• Severe burns (massive plasma leakage).
• Severe dehydration, vomiting, diarrhea (conceptually similar).

Key point: pump may be OK, but not enough volume to pump.

C. Septic Shock

• Trigger:
• Microbial infections (bacteria, fungi) → severe SIRS.
• SIRS can also be triggered by non-infectious insults:
• Burns
• Trauma
• Pancreatitis
• Common pathogenic mechanism:
• Massive outpouring of inflammatory mediators from innate and adaptive immune cells.
• Main cardiovascular effects:
1. Arterial vasodilation
2. Increased vascular permeability → leakage
3. Venous blood pooling
• Consequences:
• Tissue hypoperfusion
• Cellular hypoxia
• Metabolic derangements
• Organ dysfunction, and if severe/persistent → organ failure and death.

4. Other Important Types of Shock

A. Neurogenic Shock

• Mechanism:
• Loss of vascular tone.
• Typical settings:
• Anesthesia
• Spinal cord injury
• Pathophysiology:
• Sudden loss of sympathetic tone → vasodilation, drop in systemic vascular resistance, hypotension, hypoperfusion.

B. Anaphylactic Shock

• Mechanism:
• IgE-mediated hypersensitivity reaction.
• Triggers:
• Drugs, insect stings, foods, etc.
• Effects:
• Systemic vasodilation
• Increased vascular permeability
• Result:
• Reduced effective circulating volume
• Hypotension, tissue hypoperfusion, possible airway compromise.

5. Ultra-High-Yield One-Liners

• “Shock = impaired perfusion + cellular hypoxia due to low CO or low effective volume.”
• “Early shock: reversible; prolonged shock: irreversible organ damage.”
• “Cardiogenic = pump failure; Hypovolemic = volume loss; Septic = inflammatory vasodilation + leak + pooling.”
• “Septic shock is just SIRS on overdrive from infections (or similar insults).”
• “Neurogenic: loss of vascular tone (anesthesia, spinal injury).”
• “Anaphylactic: IgE-mediated, systemic vasodilation and vascular leak.”