A 34-year-old man comes to the emergency department due to skin rash that he noticed this morning on his arms and legs. He has also had fever and headache for 3 days. The patient had a root canal 2 weeks ago with mild post-procedure pain and gum swelling. Medical history is otherwise noncontributory. He is an avid biker who enjoys spending time outdoors. The patient does not use alcohol or tobacco. He has a male partner with whom he has been in a stable relationship for the last 2 years.
Temperature is 39.7 C (103.5 F), blood pressure is 122/70 mm Hg, and pulse is 114/min and regular. No lymph node enlargement is present. There is no sinus tenderness to palpation. The lungs are clear to auscultation. There are no heart murmurs. The abdomen is soft and nontender, and the tip of the spleen is not palpated. Maculopapular rash with petechiae is present on the arms and legs. There are no meningeal signs.
Laboratory results are as follows:
Two blood smears are negative for potential blood-borne pathogens.
Which of the following is the most appropriate next step in management of this patient?

Question

A 34-year-old man comes to the emergency department due to skin rash that he noticed this morning on his arms and legs.  He has also had fever and headache for 3 days.  The patient had a root canal 2 weeks ago with mild post-procedure pain and gum swelling.  Medical history is otherwise noncontributory.  He is an avid biker who enjoys spending time outdoors.  The patient does not use alcohol or tobacco.  He has a male partner with whom he has been in a stable relationship for the last 2 years.
Temperature is 39.7 C (103.5 F), blood pressure is 122/70 mm Hg, and pulse is 114/min and regular.  No lymph node enlargement is present.  There is no sinus tenderness to palpation.  The lungs are clear to auscultation.  There are no heart murmurs.  The abdomen is soft and nontender, and the tip of the spleen is not palpated.  Maculopapular rash with petechiae is present on the arms and legs.  There are no meningeal signs.
Laboratory results are as follows:
 Two blood smears are negative for potential blood-borne pathogens.
Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_9640_5a1d_853d_cdcf56805cc7_MD0002_00 This patient's high fever, headache, and extremity rash raise suspicion for Rocky Mountain spotted fever (RMSF). RMSF is a potentially lethal tick-borne illness due to Rickettsia rickettsii. Although RMSF can occur throughout the United States, it is most common in the southeastern region. Peak incidence is in the spring and summer. Manifestations usually begin with nonspecific symptoms (eg, fever, severe headache, malaise, myalgias, arthralgias) followed 3-5 days later by a maculopapular rash that becomes petechial over time. The rash typically starts on the ankles and wrists and spreads centrally to the trunk and peripherally to the palms and soles. Hyponatremia, thrombocytopenia, and elevated serum transaminases are important diagnostic clues. Identifying potential cases of RMSF is often challenging due to the following: Approximately 35% of patients have no knowledge of tick bite (as in this case)Only 15% of patients have a rash at presentationA minority (~10%) never develop a rash ("spotless" RMSF) Approximately 35% of patients have no knowledge of tick bite (as in this case) Only 15% of patients have a rash at presentation A minority (~10%) never develop a rash ("spotless" RMSF) Because of these difficulties, empiric first-line treatment with doxycycline is typically administered to patients who develop a nonspecific febrile illness in the spring and summer if they are from an endemic area and have had known or possible tick exposure. Early treatment is crucial as antibiotic initiation ≥5 days after symptom onset is associated with much higher risk of morbidity (eg, encephalitis, gangrene of the digits) and death. The diagnosis is usually confirmed several days later with serology or skin biopsy (after the rash appears). (Choice B) Meningococcemia can also cause headache, fever, and a petechial rash, but most cases come to clinical attention <22 hours after symptom onset and are also associated with confusion and meningeal signs (eg, nuchal rigidity). If early meningococcemia cannot be differentiated from RMSF, patients sometimes require a combination of empiric ceftriaxone and doxycycline while awaiting cerebrospinal fluid results. (Choice C) Mononucleosis can cause high fever and a rash (usually after antibiotic administration), but patients also typically have sore throat, lymphadenopathy, malaise, and/or splenomegaly. (Choice D) Secondary syphilis can also cause a maculopapular rash that involves the palms and soles but is not usually associated with high fevers. Patients who may have secondary syphilis but are at risk for RMSF should be treated with doxycycline while syphilis serology is pending. (Choice E) Infective endocarditis can cause high fever and skin manifestations (eg, Janeway lesions, Osler nodes), but a maculopapular rash on the bilateral extremities would be atypical. Educational objective: Rocky Mountain spotted fever is a tick-borne rickettsial illness that causes nonspecific symptoms followed by a maculopapular rash 3-5 days later. The rash typically starts on the ankles and wrists and spreads centrally to the trunk and peripherally to the palms and soles. Empiric therapy with doxycycline should be started as soon as possible to decrease morbidity and mortality. __________ References: Rocky Mountain spotted fever. (http://www.ncbi.nlm.nih.gov/pubmed/11982306) Rocky Mountain spotted fever. (http://www.ncbi.nlm.nih.gov/pubmed/17961858)

A 34-Year-Old Man Comes to the Emergency Department Due to Skin