A patient presents with recurrent episodes of sudden, severe vertigo lasting hours, accompanied by nausea, vomiting, and nystagmus. Vestibular function tests demonstrate unilateral weakness. Which of the following conditions is most likely responsible for this presentation?

Correct Answer: A

Rationale: The patient's presentation of recurrent episodes of sudden, severe vertigo lasting hours with nausea, vomiting, and nystagmus, along with unilateral weakness on vestibular function tests, is most consistent with vestibular neuritis. Vestibular neuritis is characterized by inflammation of the vestibular nerve leading to sudden onset vertigo that can last for hours to days. It is often associated with nausea, vomiting, and nystagmus. Unilateral weakness on vestibular function tests indicates dysfunction of one vestibular system. Differential diagnosis for this type of presentation includes other conditions such as Meniere's disease, BPPV, and acoustic neuroma. However, the combination of symptoms and unilateral vestibular weakness makes vestibular neuritis the most likely diagnosis in this case.

Correct Answer: A

Rationale: The presentation described is consistent with anterior uveitis. Anterior uveitis involves inflammation of the iris and ciliary body. Patients typically present with symptoms such as redness, pain, photophobia, and blurred vision. The slit-lamp examination findings of ciliary injection (redness and dilation of blood vessels in the iris and ciliary body), corneal edema, and a mid-dilated pupil with a fixed reaction to light (due to ciliary muscle spasm causing decreased accommodation) are characteristic of anterior uveitis. This condition is often idiopathic but can be associated with various systemic diseases like ankylosing spondylitis, inflammatory bowel disease, and other autoimmune disorders. Treatment involves addressing the inflammation with topical corticosteroids and, in some cases, cycloplegic agents to reduce pain and inflammation.

Correct Answer: B

Rationale: The pharynx is the structure responsible for transporting food from the oral cavity to the esophagus during swallowing. When food is chewed and mixed with saliva in the oral cavity, it forms a bolus that is propelled to the pharynx by the tongue. The pharynx serves as a common passageway for both air and food, allowing the bolus to pass into the esophagus while preventing it from entering the trachea. The epiglottis, although important in preventing food from entering the airway, is not directly involved in the transportation of food from the oral cavity to the esophagus.

Correct Answer: B

Rationale: Attrition is the dental condition characterized by the abnormal wearing away of tooth structure due to factors such as bruxism (grinding or clenching of teeth) or acidic erosion. Bruxism can cause tooth-to-tooth contact that leads to the wearing down of the tooth enamel and eventually can affect deeper layers of the tooth. Acidic erosion, on the other hand, is caused by the direct contact of teeth with acidic substances, which can lead to the gradual loss of tooth structure over time. Dental caries refers to tooth decay caused by bacteria, abrasion involves wearing away of tooth structure due to external factors like improper brushing habits, and erosion specifically relates to the loss of tooth structure caused by acidic substances.

Correct Answer: D

Rationale: Erosion is the dental condition characterized by the destruction of tooth structure due to exposure to acidic substances, such as gastric acid from conditions like gastroesophageal reflux disease (GERD) or acidic beverages like sodas and citrus fruits. This acidic attack softens and wears away the enamel, leading to the erosion of tooth structure. Unlike dental caries, which is caused by bacteria producing acid from sugars in the mouth, erosion is primarily a result of external acidic sources. Attrition refers to the wear of tooth structure from tooth-to-tooth contact, and abrasion refers to the wear of tooth structure due to forces like brushing too hard or using abrasive toothpaste.