A previously healthy 8-year-old boy has a 3-week history of low-grade fever of unknown source, fatigue, weight loss, myalgia, and headaches. On repeated examinations during this time, he is found to have developed a heart murmur, petechiae, and mild splenomegaly. Which of the following is the most likely diagnosis?
a. Rheumatic fever
b. Kawasaki disease
c. Scarlet fever
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.
The correct answer is d; Endocarditis.
The presentation of infective endocarditis can be quite variable, ranging from prolonged fever with few other symptoms to an acute and severe course with early toxicity. A high index of suspicion is necessary to make the diagnosis quickly. Identification of the causative organism (frequently Streptococcus sp. or Staphylococcus sp.) through multiple blood cultures is imperative for appropriate treatment. Echocardiography may identify valvular vegetations and can be predictive of impending embolic events. Treatment usually consists of 4 to 6 weeks of appropriate antimicrobial therapy. Bed rest should be instituted only for heart failure. Antimicrobial prophylaxis prior to and after dental cleaning is indicated. The child is older than typical for Kawasaki disease (80% will present under the age of 5 years), and the history is not consistent with the diagnosis.
Scarlet fever is typically self-limited and would not be consistent with the 3-week time course. Tuberculosis can certainly cause prolonged low-grade fever, but cardiac involvement is unusual, consisting of pericarditis; thus a friction rub would be the typical exam finding. Patients usually exhibit typical signs and symptoms seasonally, most often during the winter, with symptoms remitting in the spring. Hypersomnia and hyperphagia (atypical signs of a depression) are classically seen with this disorder. Light therapy and serotonergic agents (typically SSRIs) are the treatments of choice for this disorder.