WBR265
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Pulmonology, SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 4-year old male was brought to the emergency room by his mother with complaints of fever, cough, runny nose and rash. The mother reports that the rash began on the forehead and moved downwards. Past medical history is unremarkable. Physical examination revealed post-auricular lymphadenopathy. What is the likely causative organism?]] |
| Answer A | AnswerA::HHV-6 |
| Answer A Explanation | AnswerAExp::Rncorrect. HHV-6 causes Roseola, a macular rash over the body that appears after several days of high fever and it usually affects infants. |
| Answer B | AnswerB::Varicella zoster virus |
| Answer B Explanation | AnswerBExp::Incorrect. Varicella zoster virus causes chicken pox in which the rash begins from the trunk, spreads to the face and extremities. |
| Answer C | AnswerC::Mumps virus |
| Answer C Explanation | AnswerCExp::Incorrect. Mumps virus causes Mumps, which presents with no rash but with parotitis, meningitis (orchitis or oophoritis in young adults). |
| Answer D | AnswerD::Rubella virus |
| Answer D Explanation | AnswerDExp::Correct- See explanation |
| Answer E | AnswerE::Measles virus |
| Answer E Explanation | AnswerEExp::Incorrect. Measles virus causes measles or Rubeola. The rash in measles is preceded by cough, coryza, conjunctivitis and blue-white (Koplik) spots on the buccal mucosa. |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::This is a case of German measles caused by the Rubella virus. The primary symptom of rubella virus infection is the appearance of a rash (exanthem) on the face which spreads to the trunk and limbs and usually fades after three days. Other symptoms include low grade fever, swollen glands (post-cervical/post-auricular lymphadenopathy), joint pains, headache, conjunctivitis. The swollen glands or lymph nodes can persist for up to a week and the fever rarely rises above 38 oC (100.4 oF). The rash disappears after a few days with no staining or peeling of the skin. A characteristic clinical presentation of Rubella virus infection is the post-auricular lymphadenopathy.
Educational Objective Rubella virus causes German measles with the clinical presentation of post-auricular lymphadenopathy and rash. Reference: First AID for the USMLE Step 1, 2011 Pg 180 |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |