A patient presents with recurrent episodes of throat pain, odynophagia, and fever. Physical examination reveals tonsillar enlargement with yellow-white exudates and tender cervical lymphadenopathy. Which of the following organisms is most likely responsible for this presentation?

Correct Answer: C

Rationale: The correct answer is C: Group A beta-hemolytic Streptococcus (GAS). GAS is the most likely organism responsible for this presentation, known as acute bacterial tonsillitis. GAS commonly causes symptoms such as throat pain, odynophagia, fever, tonsillar enlargement with exudates, and cervical lymphadenopathy. Streptococcal pharyngitis is a common bacterial infection of the throat caused by GAS. The other options are less likely as Streptococcus pneumoniae typically causes pneumonia and Haemophilus influenzae is associated with respiratory tract infections. Epstein-Barr virus (EBV) commonly causes infectious mononucleosis, which presents with different symptoms than those described in the question.

Correct Answer: A

Rationale: The correct answer is A: Anterior uveitis. This condition presents with redness, pain, and photophobia due to inflammation of the uveal tract. Ciliary injection, corneal edema, and mid-dilated pupil with fixed reaction to light are classic signs of anterior uveitis. The other choices can be ruled out based on specific findings: B: Acute angle-closure glaucoma would present with a high intraocular pressure, not fixed dilated pupil. C: Endophthalmitis typically presents with severe pain, hypopyon, and vitreous inflammation. D: Corneal abrasion would not cause ciliary injection or fixed dilated pupil.

Correct Answer: A

Rationale: The correct answer is A: Central retinal artery occlusion. This condition presents with sudden-onset, painless vision loss, cherry-red spot at the macula due to lack of blood flow, and attenuated retinal vessels. The cherry-red spot is due to the transparency of the fovea when there is ischemia in the surrounding retina. Central retinal vein occlusion (B) presents with sudden vision loss accompanied by retinal hemorrhages and dilated tortuous veins. Retinal detachment (C) typically presents with sudden flashes, floaters, and a curtain-like visual field defect. Acute angle-closure glaucoma (D) presents with severe eye pain, blurred vision, halos around lights, and a fixed mid-dilated pupil.

Correct Answer: D

Rationale: The correct answer is D: Teeth. Teeth are responsible for the initial mechanical breakdown of food during mastication. Step 1: Teeth use their hard surfaces to chew and grind food into smaller pieces. Step 2: This process increases the surface area of the food, making it easier for digestive enzymes to break down. Step 3: The tongue aids in moving the food around the mouth but does not break down the food mechanically. Pharynx is responsible for swallowing, not mastication. Salivary glands produce saliva that helps in the lubrication and digestion of food, but they do not directly participate in the mechanical breakdown of food.

Correct Answer: C

Rationale: The correct answer is C: Pancreas. The pancreas is responsible for producing digestive enzymes and bicarbonate-rich pancreatic juice. It secretes enzymes like amylase, lipase, and protease to break down carbohydrates, fats, and proteins in the small intestine. The bicarbonate-rich juice helps neutralize stomach acid. The liver (A) produces bile stored in the gallbladder (B), which aids in fat digestion. The spleen (D) is involved in immune function and blood filtration, not digestive enzyme production.