A 70 year old patient with benign prostatic hyperplasia underwent transuretheral resection of prostate under spinal anaesthesia. One hour later, he developed vomiting and altered sensorium. Which of the following is the most probable cause?
**Core Concept**
Spinal anesthesia can cause sympathetic blockade, leading to vasodilation and a subsequent decrease in blood pressure. This can precipitate a decrease in blood flow to the gastrointestinal tract, leading to nausea and vomiting.
**Why the Correct Answer is Right**
The most probable cause of the patient's symptoms is **hypotension** due to spinal anesthesia. The sympathetic blockade caused by the spinal anesthesia leads to vasodilation and a decrease in blood pressure, which can cause a decrease in blood flow to the gastrointestinal tract. This is known as **gastrointestinal hypoperfusion**. The decrease in blood flow to the gastrointestinal tract can cause nausea and vomiting, as well as altered sensorium due to the decreased blood flow to the brain.
**Why Each Wrong Option is Incorrect**
**Option A:** **Anaphylaxis** is unlikely in this scenario as there is no mention of any allergic reaction. Anaphylaxis is a severe, life-threatening allergic reaction that requires immediate treatment.
**Option B:** **Benign prostatic hyperplasia** is a condition that can cause urinary retention and other symptoms, but it is not directly related to the patient's current symptoms of vomiting and altered sensorium.
**Option C:** **Transuretheral resection of prostate** is a surgical procedure that can cause bleeding and other complications, but it is not directly related to the patient's current symptoms.
**Clinical Pearl / High-Yield Fact**
Spinal anesthesia can cause hypotension due to sympathetic blockade, which can lead to gastrointestinal hypoperfusion and subsequent nausea and vomiting.
**Correct Answer: C. Hypotension**