A patient presents with recurrent episodes of vertigo, nausea, and nystagmus, often triggered by head movements. Dix-Hallpike maneuver elicits positional vertigo and rotary nystagmus. Which of the following conditions is most likely responsible for this presentation?

Correct Answer: B

Rationale: The patient's presentation with recurrent episodes of vertigo, nausea, and nystagmus triggered by head movements, along with a positive Dix-Hallpike maneuver eliciting positional vertigo and rotary nystagmus, is classic for Benign Paroxysmal Positional Vertigo (BPPV). BPPV is the most common cause of vertigo due to a mechanical problem in the inner ear. In BPPV, brief episodes of vertigo are typically triggered by specific head movements, such as rolling over in bed or looking up. The characteristic rotary nystagmus observed in BPPV is consistent with the brief, intense episodes of vertigo that patients experience. The Dix-Hallpike maneuver, commonly used to diagnose BPPV, involves moving the patient from sitting to a supine head-hanging position and can induce vertigo and nystagmus in affected

Correct Answer: D

Rationale: The presentation described is characteristic of a parathyroid adenoma. Parathyroid adenomas are benign neoplasms that can present as painless, well-defined nodules usually located in the lower pole of the thyroid gland or in close proximity, such as the lateral aspect of the neck above the clavicle. Fine-needle aspiration cytology of a parathyroid adenoma typically reveals polygonal cells with abundant granular cytoplasm, often referred to as chief cells. This is key in differentiating it from other conditions mentioned in the question.

Correct Answer: C

Rationale: The description provided is classical for fungal keratitis. Fungal keratitis typically presents with a yellowish-white spot on the cornea, often surrounded by a ring of inflammation. Branching, filamentous opacities extending from the corneal lesion are commonly seen on slit-lamp examination in cases of fungal keratitis. This condition is often associated with risk factors such as trauma with organic material or contact lens wear. Prompt diagnosis and treatment with antifungal agents are crucial in managing fungal keratitis to prevent potential complications.

Correct Answer: A

Rationale: The presentation described in the question is most consistent with anterior uveitis. Anterior uveitis, also known as iritis, is characterized by redness, pain, and photophobia in the affected eye. Slit-lamp examination typically reveals ciliary injection (reddening of the conjunctiva and episclera), corneal edema, and a mid-dilated pupil with a fixed reaction to light (miosis). This occurs due to inflammation within the anterior chamber of the eye involving the iris and ciliary body.

Correct Answer: C

Rationale: A dental abscess is characterized by a localized collection of pus that results from a bacterial infection of the tooth pulp, leading to swelling, pain, and inflammation. The infection typically occurs when bacteria enter the tooth through a cavity, crack, or other dental injury. The abscess can cause significant pain and discomfort and must be treated promptly by a dentist to prevent further complications. Dental caries refer to tooth decay or cavities that result from the breakdown of tooth structure by acids produced by bacteria. Periodontitis is a severe gum infection that damages the soft tissue and destroys the bone that supports the teeth. Oral candidiasis is a fungal infection that affects the mouth and throat.