United State Medical Licensing Examination (Step 1) Set 13

Physical examination reveals severe laryngeal edema resulting in a marked hoarseness when the 17- year- old girl attempts to speak. Also, her lips and tongue show significant swelling. Which of the following chemicals most likely caused this edematous swelling?

In February, three patients from a nursing home in East Dallas develop an abrupt onset of a febrile upper respiratory tract illness. They have received no immunizations in the last year. Culture of the nasopharynx of one patient shows influenza A virus. To prevent further cases within the next two weeks, which of the following should be administered?

Which of the following statements best describes interferon's suspected mode of action in producing resistance to viral infection?

A 25-year-old man with acquired immune deficiency disease (AIDS) has malabsorption, chronic abdominal pain, low-grade fever, and nonbloody diarrhea. In fecal smears, large numbers of oocysts containing four sporozoites were observed. Which of the following organisms is most likely the etiological agent?

A 38-year-old sexually-active woman developed symptoms of lower abdominal pain with adjacent tenderness. No gram-negative cocci were observed or isolated. The obligate intracellular organism causing the infection is unable to perform which of the following metabolic functions?

Severe septic infections caused by bacteriapossessing capsules often occur following splenectomy. Which of the following statements most accurately explains why this medical complication is able to occur?

A 37-year-old man was immunologically competent but presented to his physician with malaise, fever, lethargy, and back pain. Examination also revealed vertebral osteomyelitis, splenomegaly, and hepatomegaly. He was a PPD-negative farm worker who consumed unpasteurized goat milk. Which of the organisms listed below is the mostlikely etiological agent?

A 45-year-old man was admitted to the hospital because of fever, shortness of breath, and weight loss with edema in the lower limbs. Examination revealed cardiomegaly and arrhythmias, and a diagnosis of myocarditis was made. Bacterial blood cultures were negative. Which of the following organisms is most likely responsible for this illness?

A 5-month-old baby presents to the local community clinic with noted oral candidiasis, chronic diarrhea, extensive diaper rash, and an overall failure to thrive. Previously this infant has been seen for multiple severe, recurrent infections from viruses, fungi, bacteria, and protozoa. Chest x-ray reveals an absent thymic shadow. Which of the following immunodeficiencies best explains this baby's recurrent infections?

Which of the following can most likely restore the immunological competency of this 5-month-old baby?