# A 7-year-old child is brought to the emergency department with a 3-day history of fever, headache, and muscle aches after returning from a camping trip in North Carolina. Which assessment finding would be most characteristic of Rocky Mountain spotted fever? > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=542289 > language: ko > subject: Child Health ## 문제 A 7-year-old child is brought to the emergency department with a 3-day history of fever, headache, and muscle aches after returning from a camping trip in North Carolina. Which assessment finding would be most characteristic of Rocky Mountain spotted fever? ## 보기 1. Koplik spots on the buccal mucosa 2. Petechial rash beginning on wrists and ankles **✔ 정답** 3. Vesicular lesions in various stages of healing 4. Erythema migrans with central clearing **정답: 2** ## 해설 Rocky Mountain spotted fever is characterized by a petechial rash starting on wrists and ankles, spreading centrally. Koplik spots are seen in measles, vesicular lesions in chickenpox, and erythema migrans in Lyme disease. ## 심화 해설 Core Clinical Presentation of Rocky Mountain Spotted Fever (RMSF) The question describes a classic epidemiological scenario for Rocky Mountain spotted fever (RMSF): a child with a febrile illness following a tick exposure in an endemic area (North Carolina). The causative agent is *Rickettsia rickettsii*, an intracellular coccobacillus transmitted by a tick vector [1]. The pathophysiological hallmark of this infection is a small-vessel vasculitis caused by the organism's invasion of endothelial cells, leading to increased vascular permeability and microhemorrhages. This mechanism directly explains the characteristic rash. The classic triad of symptoms for RMSF includes fever, headache, and a rash [1]. The rash is the most distinctive feature for diagnosis. It typically begins as a maculopapular eruption, but the finding most characteristic of the disease is its evolution into a petechial rash that starts on the extremities. The distribution is centripetal, meaning it appears first on the wrists and ankles and then spreads proximally to the trunk [1]. This pattern reflects the vasculitic damage occurring in the small peripheral vessels, which are affected early in the disease course. Let's analyze why the other options are incorrect by linking them to their respective pathophysiologies and classic presentations: - **Option 1 (Koplik spots):** These are small, white spots on the buccal mucosa and are pathognomonic for rubeola (measles). They appear before the characteristic maculopapular rash of measles, which typically begins on the face and spreads downward, not on the extremities. - **Option 3 (Vesicular lesions in various stages):** This description is classic for varicella (chickenpox). The lesions progress from macules to papules, vesicles, and finally crusts, with lesions in different stages present simultaneously. The rash usually starts on the trunk and face, not the distal extremities. - **Option 4 (Erythema migrans):** This is the hallmark of early localized Lyme disease, caused by *Borrelia burgdorferi* [2]. It is an expanding, erythematous, annular rash with central clearing that occurs at the site of a tick bite. It is not petechial and does not have the distal-extremity distribution pattern of RMSF. Therefore, recognizing the petechial rash beginning on the wrists and ankles in the context of fever, headache, and a history of tick exposure is critical for the early identification of RMSF. This assessment finding directly reflects the underlying vasculitic process of the infection and is the most specific cue among the options provided [1]. References (research sources) - [1]An Abnormal Presentation of Rocky Mountain Spotted Fever: A Case Report.Case reportNelson JJ, Buchmiller K, Valentine MJ, Lakshmanan K, Kayastha A, Dhingra JS, Fisher RG, Parry CA, Konrad AK, Mughal A, Kirila CE. (2024) · DOI: 10.7759/cureus.57319 - [2]Tick-borne infections in children in North America.Research articleTaylor-Salmon E, Shapiro ED. (2024) · DOI: 10.1097/mop.0000000000001326 ## 임상 시나리오 Rocky Mountain Spotted Fever Rash IdentificationDistinguishing the centripetal petechial rash from other exanthems The classic triad of Rocky Mountain spotted fever (RMSF) is fever, headache, and rash. The rash evolves from a maculopapular eruption to a petechial rash due to underlying small-vessel vasculitis. The most characteristic feature is its centripetal distribution: it begins on the wrists and ankles and then spreads proximally to the trunk. Palms and soles are often involved. CautionThe rash may not appear until day 3-5 of illness. Do not delay empiric doxycycline treatment pending its appearance in a clinically compatible febrile illness with tick exposure, as delayed therapy increases mortality. ## 핵심 개념 - **Rocky Mountain spotted fever (RMSF)** — A tick-borne illness caused by Rickettsia rickettsii, characterized by small-vessel vasculitis leading to fever, headache, and a petechial rash. - **Petechial rash** — Small, non-blanching red or purple spots on the skin caused by minor bleeding from broken capillary blood vessels, a hallmark of RMSF vasculitis. - **Centripetal rash distribution** — A rash pattern that begins on the extremities (wrists/ankles) and spreads toward the trunk, classic for RMSF. - **Rickettsia rickettsii** — An obligate intracellular coccobacillus that invades endothelial cells, causing the vasculitis seen in RMSF. ## 같은 주제 문제 - [A 10-year-old child presents to the emergency department with a 4-day history of fever, he…](https://mymerci.kr/pages/nclex_q.php?qn_id=542290) - [A 7-year-old child is brought to the emergency department with a 4-day history of fever, h…](https://mymerci.kr/pages/nclex_q.php?qn_id=542291) - [A 10-year-old child is diagnosed with Rocky Mountain spotted fever after developing a char…](https://mymerci.kr/pages/nclex_q.php?qn_id=542292) - [A nurse is caring for a 7-year-old child diagnosed with Rocky Mountain spotted fever (RMSF…](https://mymerci.kr/pages/nclex_q.php?qn_id=542293) - [A 10-year-old child is admitted to the pediatric unit with a diagnosis of Rocky Mountain s…](https://mymerci.kr/pages/nclex_q.php?qn_id=542294) --- More free questions: [기출문제](https://mymerci.kr/) _학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._