eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Rocky Mountain Spotted Fever: Differential Diagnoses & Workup

Author: Nicholas John Bennett, MB, BCh, PhD, Fellow in Pediatric Infectious Disease, Department of Pediatrics, State University of New York Upstate Medical University
Coauthor(s): Joseph Domachowske, MD, Professor of Pediatrics, Microbiology and Immunology, Department of Pediatrics, Division of Infectious Diseases, State University of New York-Upstate Medical University; Walid Abuhammour, MD, FAAP, Associate Professor of Pediatrics, Michigan State University; Director of Pediatric Infectious Disease, Department of Pediatrics, Hurley Medical Center
Contributor Information and Disclosures

Updated: Sep 10, 2009

Differential Diagnoses

Ehrlichiosis
Leptospirosis
Meningococcal Infections
Rickettsial Infection
Syphilis

Other Problems to Be Considered

Typhoid fever
Atypical measles
Hypersensitivity reactions to drugs
Murine typhus
Rickettsial pox

Workup

Laboratory Studies

  • Laboratory findings may be nonspecific in Rocky Mountain spotted fever (RMSF).
    • The total leukocyte count may be normal, elevated, or decreased but usually shows a left shift.
    • Mild anemia and thrombocytopenia of less than 150 X 109/L (<150 X 103/µL) occur in approximately one third of patients.
    • Severe thrombocytopenia of less than 20 X 109 L (<20 X 103 µL) occurs in approximately 10% of patients.
    • Hyponatremia (<130 mEq/L) is noted in 20% of patients.
    • The serum alanine aminotransferase level is usually increased.
    • Serum albumin values may be low.
    • The BUN level is increased.
    • Results of cerebrospinal fluid (CSF) analysis are generally normal. However, mild pleocytosis may be present, and approximately 50% of patients have a predominance of polymorphonuclear cells. An elevated CSF protein level may also be observed.
  • Serologic assays to detect anti– R rickettsii immunoglobulin G (IgG) antibodies are usually performed for definitive diagnosis. Testing of acute-phase and convalescent-phase sera is recommended to demonstrate a 4-fold or higher increase in the titer.
  • Enzyme immunoassays (EIAs) and immunoglobulin M (IgM) antibody-capture immunoassays are new serologic tests that potentially allow for early diagnosis.
  • In research laboratories, isolation of rickettsiae from tissues or direct detection of rickettsiae in tissues by means of direct immunofluorescence is used to confirm the diagnosis.
  • Polymerase chain reaction tests have been developed but are not widely available.

More on Rocky Mountain Spotted Fever

Overview: Rocky Mountain Spotted Fever
Differential Diagnoses & Workup: Rocky Mountain Spotted Fever
Treatment & Medication: Rocky Mountain Spotted Fever
Follow-up: Rocky Mountain Spotted Fever
Multimedia: Rocky Mountain Spotted Fever
References
[ CLOSE WINDOW ]

References

  1. Chapman AS, Bakken JS, Folk SM, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever, ehrlichioses, and anaplasmosis--United States: a practical guide for physicians and other health-care and public health professionals. MMWR Recomm Rep. Mar 31 2006;55(RR-4):1-27. [Medline]. [Full Text].

  2. Holman RC, McQuiston JH, Haberling DL, Cheek JE. Increasing incidence of Rocky Mountain spotted fever among the American Indian population in the United States. Am J Trop Med Hyg. Apr 2009;80(4):601-5. [Medline].

  3. Adjemian JZ, Krebs J, Mandel E, McQuiston J. Spatial clustering by disease severity among reported Rocky Mountain spotted fever cases in the United States, 2001-2005. Am J Trop Med Hyg. Jan 2009;80(1):72-7. [Medline].

  4. [Guideline] Chapman AS, Bakken JS, Folk SM, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever, ehrlichioses, and anaplasmosis--United States: a practical guide for physicians and other health-care and public health professionals. MMWR Recomm Rep. Mar 31 2006;55:1-27. [Medline]. [Full Text].

  5. Cale DF, McCarthy MW. Treatment of Rocky Mountain spotted fever in children. Ann Pharmacother. Apr 1997;31(4):492-4. [Medline].

  6. Abramson JS, Givner LB. Rocky Mountain spotted fever. Pediatr Infect Dis J. Jun 1999;18(6):539-40. [Medline].

  7. American Academy of Pediatrics Committee on Infectious Diseases. Rocky Mountain spotted fever. In: Red Book. 27th Ed. Elk Grove Village, IL: AAP; 2006:570-2.

  8. Azad AF, Beard CB. Rickettsial pathogens and their arthropod vectors. Emerg Infect Dis. Apr-Jun 1998;4(2):179-86. [Medline].

  9. Kostman JR. Laboratory diagnosis of rickettsial diseases. Clin Dermatol. May-Jun 1996;14(3):301-6. [Medline].

  10. Thorner AR, Walker DH, Petri WA. Rocky mountain spotted fever. Clin Infect Dis. Dec 1998;27(6):1353-9; quiz 1360. [Medline].

[ CLOSE WINDOW ]

Further Reading

[ CLOSE WINDOW ]

Keywords

Rocky Mountain spotted fever, RMSF, tick-borne disease, Rickettsia rickettsii, R rickettsii, black measles, Lyme disease, vasculitis, edema of the medulla oblongata, rickettsial disease, glucose-6-phosphate dehydrogenase, G-6-PD deficiency, conjunctival hyperemia, photophobia, hepatomegaly, splenomegaly, meningoencephalitis, meningismus

[ CLOSE WINDOW ]

Contributor Information and Disclosures

Author

Nicholas John Bennett, MB, BCh, PhD, Fellow in Pediatric Infectious Disease, Department of Pediatrics, State University of New York Upstate Medical University
Nicholas John Bennett, MB, BCh, PhD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Pediatrics
Disclosure: Nothing to disclose.

Coauthor(s)

Joseph Domachowske, MD, Professor of Pediatrics, Microbiology and Immunology, Department of Pediatrics, Division of Infectious Diseases, State University of New York-Upstate Medical University
Joseph Domachowske, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Walid Abuhammour, MD, FAAP, Associate Professor of Pediatrics, Michigan State University; Director of Pediatric Infectious Disease, Department of Pediatrics, Hurley Medical Center
Walid Abuhammour, MD, FAAP is a member of the following medical societies: American Medical Association and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

Medical Editor

José Rafael Romero, MD, Director of Pediatric Infectious Diseases Fellowship Program, Associate Professor, Department of Pediatrics, Combined Division of Pediatric Infectious Diseases, Creighton University/University of Nebraska Medical Center
José Rafael Romero, MD is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, New York Academy of Sciences, and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Larry I Lutwick, MD, Professor of Medicine, State University of New York, Downstate Medical School; Director, Infectious Diseases, Veterans Affairs New York Harbor Health Care System, Brooklyn Campus
Larry I Lutwick, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; sanofi pasteur Honoraria Speaking and teaching; Baxter Healthcare Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
HONcode

We subscribe to the
HONcode principles of the
Health On the Net Foundation

All material on this website is protected by copyright, Copyright© 1994- by Medscape.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.