Shock MCQs Part 3 – Hard USMLE-Level Cases
This section focuses on advanced shock physiology and clinical reasoning. Designed for medical students preparing for USMLE, finals, and ICU/emergency rotations.
📌 Advanced Concepts
- Shock = imbalance between oxygen delivery (DO2) and consumption (VO2)
- Lactate elevation = anaerobic metabolism marker
- MAP = CO × SVR
- Early septic shock → high CO, low SVR
- Late septic shock → low CO, multi-organ failure
🧠 Hard MCQs
1. A patient in ICU has low MAP, high lactate, and high SVR. Most likely shock?
A) Septic early
B) Septic late
C) Hypovolemic
D) Neurogenic
High SVR = compensatory vasoconstriction due to low volume
2. Which shock shows low SVR with high cardiac output early?
A) Cardiogenic
B) Septic
C) Hypovolemic
D) Obstructive
3. Patient with tension pneumothorax develops shock. Mechanism?
A) Pump failure
B) Vasodilation
C) Reduced venous return
D) Myocardial infarction
4. Which parameter is decreased in all types of shock?
A) SVR
B) Tissue perfusion
C) Heart rate
D) Blood pressure always normal
5. Which shock type is associated with bradycardia?
A) Septic
B) Neurogenic
C) Hypovolemic
D) Cardiogenic
6. In cardiogenic shock, which compensatory mechanism is activated?
A) Decreased SVR
B) Increased SVR
C) No change
D) Vasodilation
7. Most sensitive early marker of shock?
A) Blood pressure
B) Heart rate
C) Serum lactate
D) Urine output
8. A patient with septic shock receives fluids but remains hypotensive. Next step?
A) Stop fluids
B) Start vasopressors
C) Give diuretics
D) Observe only
9. Shock index is defined as?
A) HR / SBP
B) SBP / HR
C) MAP / HR
D) HR × RR
10. Shock index > 1 indicates?
A) Normal state
B) Severe shock
C) Hypertension
D) Bradycardia
📊 Clinical Summary
✔ Lactate = severity marker
✔ SVR changes depend on type
✔ MAP is key resuscitation target
🧠 Final Challenge
👉 Answer: Hypovolemic shock 😏