They come from opposite coasts, but their symptoms are too similar to ignore. Can you find the common thread in these cases?
The 7-year-old boy in Virginia: 2-day history of headache, fever, lethargy, decreased activity and maculopapular rash. Petechiae were noted on sites of previously noted papules.
Patient history: Immunizations current; lives in the city but was camping in the mountains with family 2 weeks ago.
Physical examination: Lethargic/toxic; erythematous macules and papules on wrists, ankles, palms, soles.
Pt #2, a 2-year-old, presented with fever and rash while on vacation in San Diego, CA. Note peripheral distribution of rash.
It is essential to obtain a travel history, particularly because ticks that carry RMSF aren't present in California. These parents traveled from their home in Kansas two days ago. So, RMSF has to be high on our list of possibilities.
Choices: Rocky Mountain Spotted Fever, meningococcemia, coxsackievirus A-16, ehrlichiosis. A decision at this point could be life-saving.
RMSF: Etiologic agent:
. Seasonal prevalence: Spring and Summer. Most prevalent among: children aged 5-9 years. Reported in nearly all states, but Oklahoma, the Carolinas, and Tennessee have ~48% of cases.
Incubation period, 3-12 d; undifferentiated febrile illness, myalgias, headache; rash is major diagnostic sign.
RMSF: High index of suspicion. Four-fold rise in antibody titer; immunofluorescent antibody test; complement fixation; low sodium, low platelets, normal or low WBC.
Early treatment critical
; mortality rate for those treated within first 5 days is 6.5% vs 22.9% after 5 days. Doxycyline, tetracycline, chloramphenicol.
Differential diagnosis: consider petechial rashes and their unique distribution (peripheral in RMSF) and those with unique laboratory results (hyponatremia in RMSF).
Dr. Jonathan Schneider has juxtaposed 2 cases of febrile rash in young boys who live in very different geogrpahic regions. He has a good teaching reason for his choices, as you'll find out as you click through the case above.Â Â Â Â Â Internet ResourcesMedscape - Rocky Mountain spotted fever (updated December 2014) http://emedicine.medscape.com/article/228042-overviewCDC Rocky Mountain Spotted Fever (updated 2013)http://www.cdc.gov/rmsf/CDC handout on tickborne diseaseshttp://www.cdc.gov/lyme/resources/tickbornediseases.pdfMedscape â Tick Borne Diseaseshttp://emedicine.medscape.com/article/786652-overviewFÂ Journal ReferencesDrage LA. Life-threatening rashes: dermatologic signs of four infectious diseases. Mayo Clin Proc. 1999;74:68-72.Thorner AR, Walker DH, Petri WA Jr. Rocky mountain spotted fever. Clin Infect Dis. 1998;27:1353-9; quiz 1360Cale DF, McCarthy MW.Â Treatment of Rocky Mountain spotted fever in children.Â Ann Pharmacother. Â Â Â 1997;31:492-494.Silber JL. Rocky Mountain spotted fever. Clin Dermatol. 1996;1:245-58.Walker DH. Rocky Mountain spotted fever: a seasonal alert.Â Clin Infect Dis. 1995;20:1111-7.Dumler JS, Walker DH.Â Diagnostic tests for Rocky Mountain spotted fever and other rickettsial diseases.Dermatol Clin. 1994;12:25-36.Myers SA, Sexton DJ.Â Dermatologic manifestationsÂ of arthropod-borne diseases.Â Infect Dis Clin North Am. 1994;8:689-712.Belman AL. Tick-borne diseases. Semin Pediatr Neurol, 1999;6:249-66.Â