eMedicine Specialties > Emergency Medicine > Infectious Diseases

Rabies: Differential Diagnoses & Workup

Author: Mark A Merlin, DO, EMT-P, FACEP, Assistant Professor, EMS Medical Director, Department of Emergency Medicine, University of Medicine and Dentistry-Robert Wood Johnson Medical School; Medical Director, New Jersey EMS/Disaster Medicine Fellowship, New Jersey EMS Physician Response Program, New Jersey EMS Task Force; Chair of New Jersey Mobile Intensive Care Unit Advisory Council, New Jersey Department of Health and Senior Services
Coauthor(s): Peter W Pryor II, MD, MPH, Fellow in Emergency Medical Services/Disaster Medicine, Attending Physician, Department of Emergency Medicine, Robert Wood Johnson University Hospital, University of Medicine and Dentistry of New Jersey; John Bertolini, MD, Chair, Department of Emergency Medicine, Union Hospital; Raffi Kapitanyan, MD, Assistant Professor, Assistant Professor of Emergency Medicine, Emergency Medicine, Robert Wood Johnson University Hospital/UMDNJ
Contributor Information and Disclosures

Updated: May 11, 2009

Differential Diagnoses

Encephalitis
Herpes Simplex
Herpes Simplex Encephalitis

Other Problems to Be Considered

Any rapidly progressing encephalitis

Workup

Laboratory Studies

  • Cerebrospinal fluid
    • The patient's CSF may be normal, but the protein level usually is elevated, and cases of mildly increased CSF white blood cell (WBC) and red blood cell (RBC) counts have been reported.
    • The CSF protein level may be normal or moderately elevated.
    • The rabies virus may be isolated from saliva, CSF, serum, or nuchal skin samples.
    • A lumbar puncture can provide diagnosis with a rabies-neutralizing antibody titer higher than 5 in the serum or CSF of unvaccinated people (may be negative for 7 d after clinical illness has begun).
  • In humans, detection of direct fluorescent antibody from the brain or nerves surrounding hair follicles in the nape of the neck assists in the definitive diagnosis.
  • Diagnosis can be determined by isolating the rabies virus from saliva, CSF, or CNS tissue.

Imaging Studies

  • Head CT scan findings are normal.

Other Tests

  • In animals, the postmortem examination shows characteristic Negri bodies in the hippocampus and Purkinje cells of the cerebellum. These are found in 70-80% of cases along with perivascular inflammation of gray matter.
Hematoxylin and eosin stain of Negri body in a ra...

Hematoxylin and eosin stain of Negri body in a rabies-infected neuron. Courtesy of the US Centers for Disease Control and Prevention.

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Hematoxylin and eosin stain of Negri body in a ra...

Hematoxylin and eosin stain of Negri body in a rabies-infected neuron. Courtesy of the US Centers for Disease Control and Prevention.


Procedures

More on Rabies

Overview: Rabies
Differential Diagnoses & Workup: Rabies
Treatment & Medication: Rabies
Follow-up: Rabies
Multimedia: Rabies
References
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References

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Further Reading

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Keywords

rabies, animal bite, treatment, symptoms, causes, human rabies, rabies vaccine, hydrophobia, mad dog disease, bat rabies, avian rabies, paralytic rabies, dumb rabies, furious rabies, rabies virus, rhabdovirus, Rhabdoviridae, Lyssavirus, human rabies immune globulin, rabies vaccination, postexposure prophylaxis for rabies 

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Contributor Information and Disclosures

Author

Mark A Merlin, DO, EMT-P, FACEP, Assistant Professor, EMS Medical Director, Department of Emergency Medicine, University of Medicine and Dentistry-Robert Wood Johnson Medical School; Medical Director, New Jersey EMS/Disaster Medicine Fellowship, New Jersey EMS Physician Response Program, New Jersey EMS Task Force; Chair of New Jersey Mobile Intensive Care Unit Advisory Council, New Jersey Department of Health and Senior Services
Mark A Merlin, DO, EMT-P, FACEP is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American Medical Association, and American Osteopathic Association
Disclosure: Nothing to disclose.

Coauthor(s)

Peter W Pryor II, MD, MPH, Fellow in Emergency Medical Services/Disaster Medicine, Attending Physician, Department of Emergency Medicine, Robert Wood Johnson University Hospital, University of Medicine and Dentistry of New Jersey
Disclosure: Nothing to disclose.

John Bertolini, MD, Chair, Department of Emergency Medicine, Union Hospital
John Bertolini, MD is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

Raffi Kapitanyan, MD, Assistant Professor, Assistant Professor of Emergency Medicine, Emergency Medicine, Robert Wood Johnson University Hospital/UMDNJ
Raffi Kapitanyan, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Robert L Norris, MD, Associate Professor, Department of Surgery; Chief, Division of Emergency Medicine, Stanford University Medical Center
Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, California Medical Association, International Society of Toxinology, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

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

Managing Editor

Eric L Weiss, MD, DTM&H, Director of Stanford Travel Medicine, Medical Director of Stanford Lifeflight, Assistant Professor, Departments of Emergency Medicine and Infectious Diseases, Stanford University School of Medicine
Eric L Weiss, MD, DTM&H is a member of the following medical societies: American College of Emergency Physicians, American College of Occupational and Environmental Medicine, American Medical Association, American Society of Tropical Medicine and Hygiene, Physicians for Social Responsibility, Southeastern Surgical Congress, Southern Association for Oncology, Southern Clinical Neurological Society, and Wilderness Medical Society
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

Robert E O'Connor, MD, MPH, Professor and Chair, Department of Emergency Medicine, University of Virginia Health System
Robert E O'Connor, MD, MPH is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Physician Executives, American Heart Association, American Medical Association, Medical Society of Delaware, National Association of EMS Physicians, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

 
 
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