**Core Concept**
The sudden onset of altered sensorium in a 2-year-old child, accompanied by elevated blood pressure (hypertension), suggests a possible hypertensive emergency. This condition is characterized by a sudden, significant increase in blood pressure that can lead to end-organ damage, including neurological impairment.

**Why the Correct Answer is Right**
The child's presentation is consistent with a diagnosis of **Hypertensive Emergency**, specifically **Refractory Cerebral Edema**. The elevated blood pressure and altered sensorium indicate that the child's brain is under pressure, leading to swelling and impaired function. The pathophysiology involves the rupture of small blood vessels in the brain, causing bleeding and edema.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because **Hypertensive Crisis** is a broader term that encompasses both hypertensive emergencies and urgencies. While the child's presentation suggests a hypertensive emergency, the term "crisis" does not accurately describe the severity of the condition.

**Option B:** This option is incorrect because **Acute Cerebral Hemorrhage** is a specific type of stroke that involves bleeding in the brain, but it does not account for the child's altered sensorium and hypertension.

**Option C:** This option is incorrect because **Meningitis** is an infection of the meninges, which can cause altered sensorium, but it is not typically associated with hypertension.

**Option D:** This option is incorrect because **Encephalitis** is an inflammation of the brain, which can cause altered sensorium, but it is not typically associated with hypertension.

**Clinical Pearl / High-Yield Fact**
In children, hypertensive emergencies are often caused by **Renal Parenchymal Disease**, such as renal artery stenosis or renovascular hypertension. It's essential to consider this diagnosis in children presenting with hypertension and altered sensorium.

**Correct Answer: B. Acute Cerebral Hemorrhage**