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Tick-Borne Diseases, Rocky Mountain Spotted Fever: Treatment & Medication

Author: Allon Amitai, MD, International Emergency Medicine Fellow, Rhode Island Hospital; Consulting Staff, Memorial Hospital of Rhode Island; Doctoring Preceptor, Brown University Medical School
Coauthor(s): Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Contributor Information and Disclosures

Updated: Jan 15, 2008

Treatment

Prehospital Care

Deliver supportive care, including airway support and intravenous fluids, as determined by severity of the patient's condition.

Emergency Department Care

  • Intravenous hydration if hypotension or prerenal azotemia is present
  • Supplemental oxygen and endotracheal (ET) intubation for airway protection and ventilatory support, as indicated
  • Packed red blood cells (pRBCs) for anemia or severe life-threatening GI bleeding
  • Platelet transfusion for severe thrombocytopenia with active bleeding
  • Hemodialysis for oliguric or anuric acute tubular necrosis
  • Pulmonary artery catheter placement for judicious fluid replacement in patients with hypovolemia and ARDS

Consultations

Because the differential diagnosis includes many rare diseases, consultations from a dermatologist and/or infectious diseases subspecialists may be needed.

Medication

Tetracyclines are the drugs of choice (DOC) for Rocky Mountain spotted fever (RMSF). Despite the risk of teeth staining, tetracycline is now preferred over chloramphenicol for children younger than 9 years. In the review by Holman et al of 6388 cases of RMSF reported between 1981 and 1998, patients treated with chloramphenicol only had an odds ratio for mortality of 5.5, after adjustment for other risk factors.9  

Doxycycline therapy also treats Lyme disease, ehrlichiosis, and relapsing fever—entities often clinically confused with RMSF.

No human data exist to support use of fluoroquinolones in RMSF. Penicillin, cephalosporins, erythromycin, aminoglycoside, and trimethoprim and sulfamethoxazole are not effective against rickettsia.

Antibiotics usually are administered for 7 days or until the patient is afebrile for 2 days.

Antibiotics

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.


Doxycycline (Bio-Tab, Doryx, Vibramycin)

Classically the DOC for adults and children >9 y. Now recommended by the CDC for children <9 y as well, given better efficacy in treating this potentially life-threatening disease. No risk of aplastic anemia exists. Because it binds less strongly to calcium than does tetracycline, it is considered less likely to stain teeth.

Adult

200 mg PO/IV divided bid

Pediatric

<100 lb: 2 mg/lb PO/IV divided bid
>100 lb: 200 mg PO/IV divided bid

Bioavailability decreases with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate; tetracyclines can increase hypoprothrombinemic effects of anticoagulants; tetracyclines can decrease effects of oral contraceptives, causing breakthrough bleeding and increased risk of pregnancy

Documented hypersensitivity; severe hepatic dysfunction

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Photosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in renal impairment; consider drug serum level determinations in prolonged therapy; tetracycline use during tooth development (last one half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconilike syndrome may occur with outdated tetracyclines


Chloramphenicol (Chloromycetin)

Recommended by the CDC as an alternate drug for the treatment of pregnant women to avoid the risks of tooth and bone malformations. No longer routinely recommended for children because of reduced effectiveness and deleterious side effects.
If administered on an outpatient basis, 30% of patients subsequently will require hospitalization, compared to 11% of patients treated with tetracyclines.

Adult

500 mg IV divided qid for 7 d

Pediatric

Not recommended

Concurrently with barbiturates, chloramphenicol serum levels may decrease while barbiturate levels may increase causing toxicity; manifestations of hypoglycemia may occur with sulfonylureas; rifampin may reduce serum chloramphenicol levels, presumably through hepatic enzyme induction; may increase effects of anticoagulants; may increase serum hydantoin levels, possibly resulting in toxicity; chloramphenicol levels may be increased or decreased

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Use only for indicated infections, or as prophylaxis for bacterial infections; serious and fatal blood dyscrasias (aplastic anemia, hypoplastic anemia, thrombocytopenia, granulocytopenia) can occur; evaluate baseline and perform periodic blood studies approximately every 2 d while in therapy; discontinue upon appearance of reticulocytopenia, leukopenia, thrombocytopenia, anemia or findings attributable to chloramphenicol; adjust dose in liver or kidney dysfunction; caution in pregnancy at term or during labor because of potential toxic effects on fetus (gray syndrome)

More on Tick-Borne Diseases, Rocky Mountain Spotted Fever

Overview: Tick-Borne Diseases, Rocky Mountain Spotted Fever
Differential Diagnoses & Workup: Tick-Borne Diseases, Rocky Mountain Spotted Fever
Treatment & Medication: Tick-Borne Diseases, Rocky Mountain Spotted Fever
Follow-up: Tick-Borne Diseases, Rocky Mountain Spotted Fever
References
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References

  1. Marshall GS, Stout GG, Jacobs RF. Antibodies reactive to Rickettsia rickettsii among children living in the southeast and south central regions of the United States. Arch Pediatr Adolesc Med. May 2003;157(5):443-8. [Medline].

  2. Chapman AS, Murphy SM, Demma LJ, Holman RC, Curns AT, McQuiston JH. Rocky mountain spotted fever in the United States, 1997-2002. Ann N Y Acad Sci. Oct 2006;1078:154-5. [Medline].

  3. Lacz NL, Schwartz RA, Kapila R. Rocky Mountain spotted fever. J Eur Acad Dermatol Venereol. Apr 2006;20(4):411-7. [Medline].

  4. Dalton MJ, Clarke MJ, Holman RC, et al. National surveillance for Rocky Mountain spotted fever, 1981-1992: epidemiologic summary and evaluation of risk factors for fatal outcome. Am J Trop Med Hyg. May 1995;52(5):405-13. [Medline].

  5. Archibald LK, Sexton DJ. Long-term sequelae of Rocky Mountain spotted fever. Clin Infect Dis. May 1995;20(5):1122-5. [Medline].

  6. Demma LJ, Holman RC, Mikosz CA, Curns AT, Swerdlow DL, Paisano EL. Rocky mountain spotted fever hospitalizations among American Indians. Am J Trop Med Hyg. Sep 2006;75(3):537-41. [Medline].

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Further Reading

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Keywords

RMSF, Rickettsia rickettsii, American dog tick, Dermacentor variabilis, D variabilis, Rocky Mountain wood tick, Dermacentor andersoni, D andersoni, myalgias, petechial rash, spotted fevers, encephalitis, confusion, lethargy, stupor, delirium, seizures, coma, Rocky Mountain spotless fever, jaundice, ataxia, cranialnerve palsies, hearing loss, meningismus, photophobia, severe vertigo, dysarthria, aphasia, hemiplegia, paraplegia, complete paralysis, nystagmus, hyperreflexia, spasticity, fasciculations, neurogenic bladder, pulmonary edema, heme-positive stools, Rhipicephalus sanguineus, Amblyomma cajennense

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Contributor Information and Disclosures

Author

Allon Amitai, MD, International Emergency Medicine Fellow, Rhode Island Hospital; Consulting Staff, Memorial Hospital of Rhode Island; Doctoring Preceptor, Brown University Medical School
Allon Amitai, MD is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Richard Sinert, DO is a member of the following medical societies: American College of Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Peter MC DeBlieux, MD, Professor of Clinical Medicine and Pediatrics, Section of Pulmonary and Critical Care Medicine, Program Director, Department of Emergency Medicine, Louisiana State University Health Sciences Center
Peter MC DeBlieux, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, Radiological Society of North America, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Jon Mark Hirshon, MD, MPH, Associate Professor, Department of Emergency Medicine, University of Maryland School of Medicine
Jon Mark Hirshon, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Public Health Association, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: eMedicine.com, Inc. Consulting fee Consulting

 
 
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