A patient presents with grouped vesicles on an erythematous base, affecting the lips and perioral region. The patient reports a history of similar episodes triggered by sunlight exposure and stress. Which of the following conditions is most likely responsible for this presentation?

Correct Answer: A

Rationale: The patient's presentation with grouped vesicles on an erythematous base affecting the lips and perioral region, triggered by sunlight exposure and stress, is classic for herpes simplex labialis, commonly known as cold sores. Herpes simplex virus type 1 (HSV-1) is responsible for cold sores and is highly contagious. Recurrent episodes can be triggered by factors like UV exposure, stress, illness, and hormonal changes. Symptoms typically start with tingling or burning sensations before progressing to grouped vesicles that rupture, forming crusts. Treatment may involve antiviral medications to reduce the severity and duration of symptoms. Perioral dermatitis typically presents with papules and pustules around the mouth, while angular cheilitis involves fissures and inflammation at the corners of the mouth. Allergic contact dermatitis would present with erythema, pruritus, and possibly vesicles in

Correct Answer: B

Rationale: The patient's symptoms of unilateral nasal congestion, facial pain, and purulent nasal discharge with tenderness over the affected sinus are suggestive of acute sinusitis. Acute sinusitis is typically caused by a viral or bacterial infection leading to inflammation and swelling of the sinus mucosa, resulting in the characteristic symptoms described. The tenderness over the affected sinus indicates inflammation in that area. Allergic rhinitis typically presents with bilateral nasal congestion, clear nasal discharge, and itching, rather than facial pain and purulent discharge. Nasal polyps are associated with chronic conditions and usually lead to more gradual onset of symptoms. A deviated nasal septum may contribute to chronic sinus issues but typically does not present with acute symptoms of infection like purulent discharge and facial pain.

Correct Answer: A

Rationale: The patient's sudden onset of severe vertigo, nausea, vomiting, and nystagmus following a recent upper respiratory tract infection is consistent with vestibular neuritis. Vestibular neuritis is characterized by acute onset vertigo, often severe, which is typically associated with nausea, vomiting, and nystagmus. The condition is thought to be caused by inflammation of the vestibular nerve, often viral in nature, which can occur following an upper respiratory tract infection. This inflammation leads to dysfunction of the vestibular system in the inner ear, resulting in the symptoms described. Benign paroxysmal positional vertigo (BPPV), characterized by brief episodes of vertigo triggered by specific head movements, is less likely in this case given the sudden onset of symptoms not triggered by head movements. Meniere's disease is characterized by recurrent episodes of vertigo accompanied by hearing loss, tinnitus, and a feeling of fullness

Correct Answer: A

Rationale: The described presentation of a painless, slowly enlarging mass in the right neck just above the clavicle, along with the cytology findings of clusters of polygonal cells with clear cytoplasm and centrally located nuclei, is classic for parathyroid adenoma. Parathyroid adenomas are benign tumors arising from one of the parathyroid glands, which are typically located in the neck region close to the thyroid gland. The clear cytoplasm and centrally located nuclei of the cells are characteristic histological features of parathyroid adenomas. This condition can often lead to hyperparathyroidism, characterized by increased levels of parathyroid hormone (PTH) and hypercalcemia. Treatment involves surgical removal of the adenoma.

Correct Answer: C

Rationale: The described clinical presentation of a yellowish-white spot on the cornea with a ring of inflammation, along with branching, filamentous opacities extending from the corneal lesion, is highly suggestive of fungal keratitis. Fungal keratitis is commonly caused by filamentous fungi such as Fusarium and Aspergillus species. The characteristic finding of branching, filamentous opacities seen on slit-lamp examination is classic for fungal infections of the cornea. It is important to promptly diagnose and treat fungal keratitis since delayed or inadequate management can result in vision-threatening complications.