A 12-year-old boy is brought back to the emergency department (ED) by his mother due to worsening symptoms. The boy was evaluated in the ED yesterday for 3 days of fever, abdominal pain, generalized body aches, and headache. Evaluation revealed no significant abnormalities at that time, and the boy was sent home and advised to take ibuprofen. However, overnight he developed confusion and worsened abdominal pain. The patient lives near a lake surrounded by woods and often plays there with his friends. Temperature is 39 C (102.2 F), blood pressure is 90/60 mm Hg, pulse is 120/min, and respirations are 20/min. There is no neck stiffness or lymphadenopathy. Oropharynx is clear. A maculopapular rash is now present on the arms and legs. There is nonspecific generalized abdominal tenderness with no rebound or rigidity. Neurologic examination is nonfocal. Laboratory results are as follows: CT scan of the abdomen shows no abnormalities. What is the most appropriate next step in management?

Question

A 12-year-old boy is brought back to the emergency department (ED) by his mother due to worsening symptoms.  The boy was evaluated in the ED yesterday for 3 days of fever, abdominal pain, generalized body aches, and headache.  Evaluation revealed no significant abnormalities at that time, and the boy was sent home and advised to take ibuprofen.  However, overnight he developed confusion and worsened abdominal pain.  The patient lives near a lake surrounded by woods and often plays there with his friends.  Temperature is 39 C (102.2 F), blood pressure is 90/60 mm Hg, pulse is 120/min, and respirations are 20/min.  There is no neck stiffness or lymphadenopathy.  Oropharynx is clear.  A maculopapular rash is now present on the arms and legs.  There is nonspecific generalized abdominal tenderness with no rebound or rigidity.  Neurologic examination is nonfocal.  Laboratory results are as follows:  CT scan of the abdomen shows no abnormalities.  What is the most appropriate next step in management?

Quizplus · Accepted Answer

11ec25c8_d5ec_1af4_bc81_ed94513993f6_MD0003_00 This boy with several days of constitutional symptoms now has a maculopapular rash on his arms and legs, thrombocytopenia, and elevated transaminase levels, raising strong suspicion for Rocky Mountain spotted fever (RMSF). RMSF is a tickborne illness caused by the gram-negative, obligate intracellular pathogen Rickettsia rickettsii. Cases arise throughout the United States and are particularly common in those individuals exposed to grassy, wooded areas during the summer months. Many patients do not recall a preceding tick bite. Manifestations begin with 3-4 days of nonspecific findings (eg, fever, myalgia, malaise) followed by the development of a characteristic rash. The rash often starts as maculopapular lesions on the ankles and wrists and spreads toward the center of the body; it progresses to petechial lesions over time and usually involves the palms and soles. Children often have severe abdominal pain as part of the illness, which may cause practitioners to incorrectly assume appendicitis or bowel obstruction. Laboratory evaluation classically shows thrombocytopenia due to intravascular platelet destruction; elevated aminotransferase levels may be present due to hepatic endothelial vascular injury. Untreated RMSF can progress to vascular collapse and death. Therefore, patients with suspected RMSF should be treated empirically with doxycycline. This drug is recommended in all patients, including in children, in whom the risk of dental staining is minimal with the short courses (eg, 5-7 days) used for RMSF. Diagnostic confirmation is generally made retrospectively with serology. (Choice A) Amoxicillin can be used to treat Lyme disease, which often causes constitutional symptoms and rash a week or two after inoculation. However, the rash is a spreading annular lesion (erythema migrans), not a maculopapular lesion on the extremities. Thrombocytopenia and transaminitis would be atypical. (Choice C) Laparoscopy is an invasive procedure; it would not be indicated at this time given the negative abdominal CT. (Choice D) Prednisone can treat immune thrombocytopenia, which is typically marked by asymptomatic mild/moderate thrombocytopenia. The presence of transaminitis, rash, and constitutional symptoms makes RMSF far more likely. (Choice E) Serum ceruloplasmin level can help diagnose Wilson disease, a genetic disorder of copper transport. Although patients often present with hepatic damage and abdominal pain, thrombocytopenia and a maculopapular rash would be atypical. (Choice F) Stool ova and parasite can identify Entamoeba histolytica, which can cause abdominal pain, fever, and liver disease. However, most patients have bloody stools; a maculopapular rash would also be atypical. Educational objective: Rocky Mountain spotted fever typically presents with 3-4 days of nonspecific symptoms followed by a characteristic rash. The rash often begins as maculopapular lesions on the wrists and ankles, involves the palms/soles, and then spreads centrally; it usually evolves to petechial lesions over time. Thrombocytopenia, elevated aminotransferases, and hyponatremia are important laboratory clues. Empiric doxycycline should be initiated while awaiting confirmation with serology.

A 12-Year-Old Boy Is Brought Back to the Emergency Department