A 46-year-old woman with metastatic breast cancer develops distended neck veins, muffled heart sounds, systolic blood pressure of 78 mmHg, pulsus paradoxus of 20 mmHg, and tachycardia. Which category of shock does this represent?
- A Distributive shock
- B Cardiogenic shock
- C Obstructive shock ✓
- D Hypovolaemic shock
Correct answer: C. Obstructive shock
Explanation
Beck triad of hypotension, muffled heart sounds, and distended neck veins with a large pulsus paradoxus indicates cardiac tamponade from malignant pericardial effusion. Tamponade is classified as obstructive shock because extrinsic compression prevents ventricular filling, giving low preload and low output despite an intact pump. Cardiogenic shock implies intrinsic pump failure such as infarction, which would not show exaggerated pulsus paradoxus.
Reference: Schwartz's Principles of Surgery, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.