**Core Concept**
A cholesteatoma in a patient with chronic suppurative otitis media (CSOM) can lead to complications, including erosion of the ossicles, labyrinthitis, and vertigo. The presence of a cholesteatoma necessitates surgical intervention to prevent further complications and ensure proper drainage of the ear.

**Why the Correct Answer is Right**
Immediate mastoid exploration is the treatment of choice for a patient with CSOM and a cholesteatoma presenting with vertigo. This procedure allows for the removal of the cholesteatoma, repair of any damage to the middle ear, and relief of any compression on the labyrinth. The surgeon can also inspect the mastoid for any other signs of disease and perform a tympanoplasty to replace the damaged ossicles. This approach is essential to prevent further complications, such as hearing loss, facial paralysis, or meningitis.

**Why Each Wrong Option is Incorrect**

**Option A:** Antibiotics and labyrinthine sedative may provide temporary relief from symptoms, but they do not address the underlying cause of the vertigo, which is the cholesteatoma. This option is inadequate as a treatment for a patient with a cholesteatoma.

**Option B:** Myringoplasty is a surgical procedure to repair the tympanic membrane, but it is not sufficient for a patient with a cholesteatoma and vertigo. Myringoplasty alone does not address the complications caused by the cholesteatoma.

**Option D:** Labyrinthectomy is a procedure to destroy the labyrinth, but it is not the treatment of choice for a patient with a cholesteatoma and vertigo. Labyrinthectomy is typically considered for patients with severe labyrinthitis or Meniere's disease, not for patients with a cholesteatoma.

**Clinical Pearl / High-Yield Fact**
A cholesteatoma can erode the ossicles, leading to conductive hearing loss, and can also cause vertigo by compressing the labyrinth. It is essential to diagnose and treat a cholesteatoma promptly to prevent these complications.

**✓ Correct Answer: C. Immediate mastoid exploration. Immediate mastoid exploration allows for the removal of the cholesteatoma, repair of any damage to the middle ear, and relief of any compression on the labyrinth.**