Two Very Sick Kids on Two Opposite Coasts

Two children sick with febrile rashes, one is in Virginia, the other is in southern California.

Choices: Rocky Mountain Spotted Fever, meningococcemia, coxsackievirus A-16, ehrlichi

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.

7-year-old patient from Virginia lies exhausted; papules and petechiae as shown.

Pt #2, a 2-year-old, presented with fever and rash while on vacation in San Diego, CA. Note peripheral distribution of rash.

Choices: Rocky Mountain Spotted Fever, meningococcemia, coxsackievirus A-16, ehrlichiosis.

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.

Answer: Rocky Mountain Spotted Fever

RMSF: Etiologic agent:

Rickettsia rickettsii

. 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).

Fever without rash? Consider erlichiosis. History of tick bite/exposure, low WBC, low platelets, mild elevation of liver function tests without icterus.