A 24-year-old man sustains a fall from height. He has flaccid paralysis below the T6 level, BP 80/50 mmHg, heart rate 52/min, and warm dry skin. Intravenous fluid boluses produce no significant rise in blood pressure. The most likely mechanism of his hypotension is:

• A Mechanical obstruction of right ventricular filling
• B Acute blood loss into the thoracic cavity
• C Systemic release of inflammatory mediators reducing afterload
• D Loss of sympathetic vasomotor tone with unopposed vagal activity ✓

Explanation

Injury to the cervical or upper thoracic cord interrupts descending sympathetic fibres, causing loss of arteriolar tone (warm skin), venous pooling, and loss of cardiac accelerator fibres, hence bradycardia. Haemorrhagic shock would produce tachycardia and cool clammy skin, and septic shock requires an infectious source, so options B and C fail on the heart rate alone.

Reference: Schwartz's Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.