A 26-year-old recent immigrant from Brazil presents to the hospital with a subacute, worsening paraparesis. The patient had worked in the lumber industry deep in the Amazon jungle. MRI of the spinal cord is abnormal and a biopsy reveals widespread granulomas. In the midst of one granuloma is an ovoid mass with a spine extending from one side. The pathologist interprets this as a parasitic ovum. If the pathologist is correct, which of the following is the most likely cause of the lesion?

a. Taenia solium

b. Entamoeba histolytica

c. Schistosoma mansoni

d. Schistosoma japonicum

e. Treponema pallidum

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; Schistosoma mansoni.[3]

T. pallidum may produce a granulomatous lesion (gumma) in the spinal cord, but this young man has an ovum in the granuloma, which suggests the much more common transverse myelitis attributable to schistosomiasis. Both S. mansoni and S. japonicum embolize eggs to the CNS, but it is S. mansoni that is endemic in Puerto Rico and in locations in South America and that embolizes to the lumbar spinal cord. This patient should be treated with an antischistosomal agent such as praziquantel. Even with treatment, the reversal of disability produced by this spinal cord injury is usually negligible.