A 4-year-old boy was admitted to the hospital last night with the complaint of “difficulty breathing.” He has no past history of lung infection, no recent travel, and no day-care exposure; he does, however, have an annoying tendency to eat dirt. In the emergency center he was noted to be wheezing and to have hepatomegaly. He is able to talk, relaying his concern about his 6-week-old Chihuahua being left alone at home. Laboratory studies revealed marked eosinophilia (60% eosinophils). Which of the following tests is most likely to produce a specific diagnosis?
a. Tuberculin skin test
b. Histoplasmin test
c. ELISA for Toxocara
d. Silver stain of gastric aspirate
e. Stool examination for ova and parasites
the answer is below…
The United States Medical Licensing Examination, or USMLE for short, is a three-part licensing examination that is required in order to receive a license to practice medicine within the United States.
The USMLE assesses a physician’s ability to apply knowledge, concepts, and principles, and to determine fundamental patient-centered skills that are important in health and disease and that constitute the basis of safe and effective patient care.Examination committees composed of medical educators and clinicians from across the United States and its territories prepare the examination materials each year.
This exam is designed by the Federation of State Medical Boards and the National Board of Medical Examiners to determine whether or not an individual understands and can apply the knowledge necessary to practice medicine safely and intelligently.
The USMLE is actually comprised of three different exams that are referred to as steps, which examine the individual’s knowledge of specific topics related to the field of medicine such as basic science, medical knowledge, medical skills, clinical science, and the application of all of these skills and areas of knowledge in the medical field.
All three steps of the USMLE include a series of computerized multiple-choice questions, but the format of the exam and the information covered in each multiple-choice section is different for each step of the USMLE. The USMLE Step II also has a clinical skills portion that examines an individual’s ability to work with real patients and the USMLE Step III has a computerized patient simulation portion in addition to the multiple-choice section of the exam. In order for an individual to receive a license to practice medicine, the individual must pass all three steps of the USMLE. Medical doctors with an M.D. degree are required to pass this examination before being permitted to practice medicine in the United States of America
The correct answer is c; ELISA for Toxocara.
The presentation described is characteristic of visceral larva migrans from infestation with a common parasite of dogs, Toxocara canis. Dirt-eating children ingest the infectious ova. The larvae penetrate the intestine and migrate to visceral sites, such as the liver, lung, and brain, but do not return to the intestine, so the stools do not contain the ova or parasites. The diagnosis can be made by a specific enzyme-linked immunosorbent assay (ELISA) for Toxocara.