| Disease/Syndrome |
Rocky Mountain spotted fever |
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| Category |
Infection, Occupational |
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| Acute/Chronic |
Acute-Severe |
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| Synonyms |
North American tick typhus; New World spotted fever; Tickborne typhus fever; Sao Paulo fever; Rickettsia rickettsii infection |
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| Biomedical References |
Search PubMed |
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| Comments |
FINDINGS: A maculopapular rash is usually seen on the third to fifth day of the illness. The rash appears first on the extremities and includes the palms and soles. A majority of patients develop a petechial rash on or after the sixth day. [CCDM, p. 459-61] Common findings after the initial flu-like syndrome include conjunctival injection, stiff neck, nausea/vomiting, abdominal pain, hepatomegaly, splenomegaly, and hypotension. Pneumonitis (cough, rales, and pulmonary infiltrates) occurs in about 17% to 30% of patients. Encephalitis with confusion, lethargy, and delirium occur in over 25% of patients. Patients may also have ataxia, seizures, and coma. The CSF shows evidence of meningitis. Severe hemorrhage occurs "very infrequently." Laboratory abnormalities include abnormal liver and kidney function tests, hyponatremia (56% to 91% of patients), proteinuria, microscopic hematuria, mild thrombocytopenia, and increased bands (immature neutrophils). Over 30% of patients have elevated bilirubin levels, and jaundice is sign of fulminant disease. Acute renal failure following hypotension is also common. Myocarditis is a rare complication. [ID, p. 1473-80] Other findings are lymphadenopathy (27%), diarrhea, (20%), and anemia (5%-24%). In 1/3 of cases, CSF shows increased leukocytes with a predominance of either lymphocytes or neutrophils. [PPID, p. 2290] EPIDEMIOLOGY: The tick must be attached for at least 4-6 hours for infection to occur, but cases have been reported from breaks in the skin contaminated by crushed ticks or tick feces. The natural animal reservoirs are ticks. Dogs and rodents may become infected. [CCDM] Goats, sheep, and rabbits are also reservoirs. [PPID, p. 3632] |
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| Latency/Incubation |
3 days to 2 weeks |
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| Diagnostic |
Paired sera; Skin biopsy; [CCDM] DFA of skin biopsy: about 70% sensitive and 100% specific; IgM appears by day 3-8, peaks at 1 month, and lasts 3-4 months; [Wallach, p. 949-50] Do not delay treatment decisions while waiting for lab confirmation. [CDC] |
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| ICD-9 Code |
082.0 |
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| Effective Antimicrobics |
Yes |
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| Scope |
Canada, USA, Mexico, Panama, Costa Rica, Columbia, Brazil, and Argentina; |
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| Reference Link |
CDC - Rocky mountain spotted fever |
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| Related Information in Haz-Map |
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| Symptoms/Findings |
Symptoms/Findings associated with this disease:
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| Job Tasks |
High risk job tasks associated with this disease:
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