A 35-year-old post-operative patient becomes restless. On examination, he has dilated pupils, tachycardia, and hypertension. Which is the most likely cause?

Correct option is A

Acute pain activates the sympathetic nervous system, leading to pupil dilation, tachycardia, hypertension, and anxiety. These are classic features of unrelieved severe pain.
Explanation of options: (a) ✔ Correct; acute pain causes adrenergic stimulation, explaining all findings. (b) ✘ Opioid overdose causes pinpoint pupils and bradycardia, opposite to this case. (c) ✘ Hypoglycemia may cause sweating, tremors, seizures, but not dilated pupils with hypertension. (d) ✘ Hypovolemia causes hypotension and tachycardia, not hypertension.