## **Core Concept**
Unilateral sensorineural hearing loss refers to a condition where there is damage to the inner ear or the auditory nerve pathways, leading to hearing loss in one ear. This type of hearing loss can result from various causes, including infections, trauma, tumors, or vascular events affecting the auditory system.

## **Why the Correct Answer is Right**
The correct answer, **C. Acoustic neuroma**, is right because acoustic neuroma, also known as vestibular schwannoma, is a benign tumor that grows on the vestibular nerve, which is responsible for balance. As the tumor grows, it can compress the adjacent cochlear nerve, leading to unilateral sensorineural hearing loss. This condition is a classic cause of unilateral sensorineural hearing loss and tinnitus.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain viral infections can cause sensorineural hearing loss, they more commonly cause bilateral hearing loss or are associated with other symptoms.
- **Option B:** Meniere's disease typically presents with episodic vertigo, tinnitus, hearing loss (usually low-frequency sensorineural hearing loss), and aural fullness. It can affect one ear initially but often becomes bilateral over time.
- **Option D:** Ototoxicity usually results in bilateral sensorineural hearing loss due to the systemic administration of ototoxic drugs, though the hearing loss may not be perfectly symmetrical.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that unilateral sensorineural hearing loss, particularly when sudden in onset or progressive, warrants an MRI to rule out retrocochlear pathology, such as **acoustic neuroma**. Early detection of such conditions can significantly impact management and outcomes.

## **Correct Answer:** C. Acoustic neuroma