Repeated USMLE Questions Step 1- Review- 56

Q- Exposure to which one of the following substances is considered a risk factor for developing hepatic angiosarcoma?

A- Aromatic hydrocarbons

B- Benzene

C- Nitrosamines

D- Vinyl chloride

D- Vinyl chloride- Chronic exposure to VC which is used in plastic industry can lead to developing hepatic angiosarcoma. Aromatic hydrocarbons are risk factor for bronchogenic carcinoma. Benzenes is risk factor for leukemia while exposure to nitrosamines is a risk factor for gastric cancer.

Q- Infection with which one of the following organisms may lead to spastic paralysis through blocking the release of GABA and glycine?

A- Bacillus anthracis

B- Clostridium botulinum

C- Clostridium tetani

D- Enterotoxigenic E. Coli

C- Clostridium tetani- It releases a neurotoxin that causes the above condition. Bacillus anthracis and Enterotoxigenic E coli may increase cellular fluid loss leading to edema and diarrhea through their exotoxins. C. botulinum causes flaccid paralysis by blocking the release of acetylcholine.

Q- In cases of Tetralogy of Fallot with pulmonary atresia, the patients benefit from maintaining patency of ductus arteriosus. Which of the following drugs can be used to maintain ductal patency?

A- Betamethasone

B- Epinephrine

C- Indomethacin

D- Prostaglandin E1

D- Prostaglandin E1- Prostaglandin E1 such as alprostadil is the only one on the list that maintains patent ductus arteriosus. Indomethacin induces closing it. A and B don’t have any rule in that.

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