A 10-month-old boy, recently arrived from Guyana, has a 5-h history of crying, with intermittent drawing up of his knees to his chest. On the way to the emergency room he passes a loose, bloody stool. He has had no vomiting and has refused his bottle since the crying began. Physical examination is noteworthy for an irritable infant whose abdomen is very difficult to examine because of constant crying. His temperature is 38.8°C (101.8°F). The rectal ampulla is empty, but there is some gross blood on the examining finger. Which of the following studies would be most helpful study in the immediate management of this patient?

a. Stool culture

b. Examination of the stool for ova and parasites

c. An air-contrast enema

d. Examination of the blood smear

e. Coagulation studies

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; An air-contrast enema.[2]

The usual presentation of intussusception is that of an infant between 4 and 10 months of age who has a sudden onset of intermittent colicky abdominal pain. The child can appear normal when the pain abates, but as it recurs with increasing frequency, the child can begin to vomit and become progressively more obtunded. The passage of stool containing blood and mucus, and resembling currant jelly, is often observed. Early examination of the abdomen can be unremarkable, but as the problem persists, a sausage-shaped mass in the right upper quadrant is frequently palpated. A contrast enema examination under fluoroscopic control can be therapeutic as well as diagnostic when the hydrostatic effects of the column of air serve to reduce the intussusception. Early diagnosis prevents bowel ischemia. The cause of most intussusceptions is unknown, but a Meckel’s diverticulum or polyp can serve as a lead point.