A 19-year-old college student, Todd, is brought to your clinic by his mother. She is concerned that there is something seriously wrong with him. She states for the past 6 months his behavior has become peculiar and he has flunked out of college. Todd denies any recent illness or injuries. His past medical history is remarkable only for a broken foot. His parents are both healthy. He has a paternal uncle who had similar symptoms in college. The patient admits to smoking cigarettes and drinking alcohol. He also admits to marijuana use but none in the last week. He denies using any other substances. He denies any feelings of depression or anxiety. While speaking with Todd and his mother you do a complete physical examination, which is essentially normal. When you question him on how he is feeling, he says that he is very worried that Microsoft has stolen his software for creating a better browser. He tells you he has seen a black van in his neighborhood at night and he is sure that it is full of computer tech workers stealing his work through special gamma waves. You ask him why he believes they are trying to steal his programs. He replies that the technicians have been telepathing their intents directly into his head. He says he hears these conversations at night so he knows this is happening. Todd's mother then tells you, "See, I told you . . . he's crazy. What do I do about it?" While arranging for a psychiatry consult, what psychotic disorder do you think Todd has?

Correct Answer: D

Rationale: The correct answer is D: Schizophrenia. Todd presents with a history of peculiar behavior, academic decline, paranoid delusions, and auditory hallucinations. These are classic symptoms of schizophrenia, a chronic and severe mental disorder. Schizoaffective disorder (A) involves a mix of schizophrenia symptoms and mood disturbances, but Todd does not exhibit significant mood symptoms. Psychotic disorder due to a medical illness (B) would require evidence of a medical condition causing Todd's symptoms, which is not present. Substance-induced psychotic disorder (C) would require Todd's symptoms to be solely due to substance use, but his symptoms persist despite marijuana abstinence. Therefore, based on Todd's symptoms and history, the most likely diagnosis is schizophrenia.

Correct Answer: C

Rationale: The correct answer is C: Psoriasis. The key clinical features described, such as pruritic rash with scabbing, crusting, silvery scale, and nail pitting, are classic signs of psoriasis. The presence of small "pits" in the nails, known as nail pitting, is a common finding in psoriasis. The worsening of symptoms in winter and improvement with sun exposure is also typical of psoriasis. Eczema (choice A) typically presents with red, inflamed, and weeping skin lesions. Pityriasis rosea (choice B) presents with a herald patch followed by smaller similar lesions. Tinea infection (choice D) presents with scaling, redness, and itching but does not typically cause nail pitting. In this case, the combination of symptoms and nail pitting point to psoriasis as the most likely diagnosis.

Correct Answer: C

Rationale: The correct answer is C: Hordeolum. A hordeolum, also known as a stye, presents as a red raised tender area at the margin of the eyelid. In this case, the absence of tearing upon palpation of the lesion suggests it is localized to the eyelid itself. Dacryocystitis (choice A) involves the lacrimal sac and would present with tearing. A chalazion (choice B) is a painless nodule on the eyelid, unlike the tender lesion described here. Xanthelasma (choice D) is characterized by yellowish plaques on the eyelids, not a red raised tender area.

Correct Answer: B

Rationale: The correct term for the phenomenon described is "Consensual reaction" (Choice B). This occurs because the optic nerves from both eyes are connected, causing stimulation of one eye to result in a simultaneous response in the other eye due to the consensual pupillary reflex. The other choices are incorrect because: A: Direct reaction refers to the pupil directly exposed to light contracting. C: Near reaction refers to the pupillary response when focusing on a near object. D: Accommodation refers to the ability of the eye to adjust focus for near and far objects, not pupil constriction.

Correct Answer: C

Rationale: The correct answer is C: Efferent nerve damage on the right. When both pupils dilate but only the right pupil constricts briskly in response to light, it indicates a problem with the efferent pathway controlling the right eye's pupillary constriction. This suggests damage to the parasympathetic fibers of the oculomotor nerve (CN III) that innervate the pupillary sphincter muscle. Choices A and B (optic nerve damage) do not involve pupil constriction. Choice D (efferent nerve damage on the left) would not explain the brisk constriction in the right eye.