Which of the following are manifestations of Cushing syndrome?
- A. Truncal obesity with thin extremities.
- B. Enlargement of face, hands, and feet.
- C. Cachexia.
- D. Thick scalp hair.
Correct Answer: A
Rationale: Truncal obesity with thin extremities is a classic manifestation of Cushing syndrome due to the redistribution of fat. Enlargement of face, hands, and feet is seen in conditions like acromegaly, not Cushing syndrome. Cachexia is a state of severe weight loss and muscle wasting, typically seen in conditions like cancer or advanced infections. Thick scalp hair is not typically associated with Cushing syndrome.
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Which of the following patients are at higher risk for developing oral cancer?
- A. A female who has taken oral contraceptives for the last 4 years
- B. Both an adult male with a history of alcoholism and a middle-aged male who smokes a pipe
- C. An adult female who eats spicy foods regularly
- D. An older adult female who chews gum frequently
Correct Answer: B
Rationale: The correct answer is 'Both an adult male with a history of alcoholism and a middle-aged male who smokes a pipe.' Alcohol consumption and tobacco use, such as smoking a pipe, are well-known risk factors for developing oral cancer. These two factors significantly increase the likelihood of developing oral cancer compared to the other choices. Taking oral contraceptives, eating spicy foods regularly, and chewing gum frequently are not established risk factors for oral cancer, making them less likely to lead to the development of this type of cancer.
Women who have breast cancer due to a BRCA1 gene mutation are usually:
- A. positive for human epidermal growth factor receptor 1 and 2.
- B. negative for estrogen receptor.
- C. positive for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.
- D. negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.
Correct Answer: D
Rationale: Women with breast cancer due to a BRCA1 gene mutation commonly have a triple-negative breast cancer subtype, which means they are negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). This subtype tends to be more aggressive and harder to treat. Choice A is incorrect as they are typically negative for HER2. Choice B is incorrect because they are usually negative for estrogen receptor. Choice C is incorrect as they are usually negative for progesterone receptor and HER2.
In which disorder does a Staphylococcus aureus organism produce a toxin leading to exfoliation and large blister formation?
- A. Herpes simplex I virus
- B. Herpes simplex II virus
- C. Necrotizing fasciitis
- D. Cellulitis
Correct Answer: B
Rationale: The correct answer is 'Herpes simplex I virus.' This disorder is known as Staphylococcal scalded skin syndrome (SSSS), where a Staphylococcus aureus organism produces an exfoliative toxin leading to skin exfoliation and large blister formation. Choices B, C, and D are incorrect. Herpes simplex viruses (I and II) cause different types of skin lesions and do not lead to exfoliation and blister formation. Necrotizing fasciitis is a severe soft tissue infection, while cellulitis is a bacterial skin infection that does not typically involve exfoliation and blister formation like in SSSS.
Which of the following is a common cause of mechanical small intestine obstruction?
- A. Infection
- B. Postoperative adhesions
- C. Tumors
- D. Foreign body
Correct Answer: B
Rationale: Postoperative adhesions are a common cause of mechanical small intestine obstruction. Adhesions can form after abdominal surgery, causing bands of scar tissue that may twist or pull the intestines, leading to obstruction. This is a more common cause compared to infection, tumors, or foreign bodies. Infection may lead to inflammation but is not a typical cause of mechanical obstruction. Tumors and foreign bodies can cause blockages but are less common than postoperative adhesions.
Why does multiple sclerosis manifest as asymmetrical and in different parts of the body?
- A. Autoreactive lymphocytes are causing diffuse patchy damage to the myelin sheath in the central nervous system.
- B. Acetylcholine receptors are destroyed by immunoglobulin G.
- C. Autoreactive T lymphocytes cause progressive loss of neurons in the substantia nigra.
- D. Cortical motor cells degenerate.
Correct Answer: C
Rationale: Multiple sclerosis is characterized by the immune system mistakenly attacking the myelin sheath in the central nervous system. This results in the formation of lesions that can occur in different parts of the central nervous system, leading to varied symptoms depending on the location of the damage. Choice A is the correct answer because it accurately describes the pathophysiology of multiple sclerosis. Choices B, C, and D are incorrect because they describe mechanisms or locations that are not associated with the pathogenesis of multiple sclerosis.