Rabies

 

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Definition/Description [1]

Rabies is derived from the Latin word meaning rage or fury because animals with this disease are often agitated or excited and attack anything in their way.  It is also know as hydrophobia, which means fear of water, because one of the symptoms is an inability to swallow water.  Humans and most warm-blooded animals can get this disease.  Rabies is an infectious, zoonotic disease that destroys brain cells and can lead to death if left untreated before symptoms appear.  It is caused by a virus that lives in the saliva of a host or carrier and can be transmitted by being bitten by the carrier or if the infected saliva enters an open wound or mucous membranes.  Rabies has been reported as being transmitted to people after breathing in air from caves that contained millions of bats and through organ transplants from an infected person.  The most common sources of infections for humans are from wild animals and dogs.

Prevalence [2] [3]

It is estimated that every ten minutes a person dies from being infected by rabies and 10 to 12 million people are immunized with rabies postexposure prophylaxis (RPEP) every year.  Rabies can be found in almost all countries around the world, but Asia and Africa are the most common places in which people die from rabies, usually as a result of a rabid dog bite.  It is estimated that 40,000-70,000 humans die each year as a result of the rabies virus and it is suspected that thousands more deaths go unreported.

Characteristics/Clinical Presentation

The clinical presentation of this disease greatly depends on whether the patient is an animal or a human.  If dealing with an animal with rabies it is best to stay away because the animal will likely attack.  They can be very aggressive even if it has been known to be a very good natured pet.  Once the virus has begun to show symptoms in an animal, it is too late for any kind of intervention.  The best thing to do is to stay far away and notify the proper authorities to have the animal humanely euthanized.  

Two forms of rabies exist; furious and paralytic.  Furious rabies is the most common with symptoms consisting of hydrophobia, hyperactivity, pharyngeal spasms leading to paralysis, coma and death.  Paralytic rabies is less common and presents as paralysis leading to death.  There are five stages of the disease.  Stage one is the incubation phase which can range from 10 days to 2 years.  Stage two is the prodrome stage in which flu-like symptoms may be present and occurs 2-10 days after exposure and can last up to 2 weeks.  Stage three is known as the acute neurological symptom stage where more CNS involvement is noted with symptoms such as diplopia, dysarthria, nystagmus, mild to moderate paralysis, confusion, anxiety, paranoia, insomnia, hallucinations or delerium.  Excessive saliva, difficulty swallowing and fear of water and other liquids can also present in this stage of the disease.  Stage four is coma and stage five is death.[4][5][6]

Associated Co-morbidities

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Medications

Diagnostic Tests/Lab Tests/Lab Values [6]

The most useful test is the reverse transcription polymerase chain reaction test (RT-PCR).  The CDC requires that a suspected person have their saliva, serum, and cerebrospinal fluid checked as well as a neck biopsy.  This information should be sent to the CDC after the health department has been contacted.  The gold standard test for rabies is viral testing of the brain tissue of the deceased individual.

Etiology/Causes [1]

Rabies is a zoonotic disease and is caused by a virus that can live in the saliva of most mammals.  The most common cause of transmission to another mammal is by way of a bite from the infected one.  It can also be transmitted through the mucous membranes by way of airborne particles.  Both humans and animals can be infected by this disease which will lead to death if not properly treated before symptoms begin to show.  Once the symptoms begin to present themselves, the prognosis is very poor.  Once the virus enters the body, it travels along the nerves to the CNS producing inflammation.  Symptoms usually develop in about ten days but can take seven months or longer after exposure.  The disease can progress very rapidly and only lasts two to twelve days before death occurs.

Systemic Involvement [2]

Rabies causes inflammation of the CNS once it enters the body and can quickly lead to death if not aggressively treated.  Pain, burning or numbness at the site of infection can be among the first symptoms to present.  Complaints of headache and sleeplessness are also reported.  Muscle spasms in the throat can make it difficult to swallow especially at the sight of water for some infected individuals which is known as hydrophobia.  In later stages of the inflammation, unconsciousness, respiratory and cardiovascular failure can occur and lead to death.

Medical Management (current best evidence) [4] [5] [6]

Medical management includes taking a good history of the incident paying particular attention to possible rabies exposure and assessing the risk.  Lab testing and differential diagnosis may be performed to rule out other possible causes of concern.  If an animal is suspected to have rabies, it should be quarantined for 10 days and observed for signs of illness.  If the animal is not available or able to be obtained and the bite was unprovoked, it should be considered a high risk for rabies and appropriate action should be taken.  Once rabies is suspected, three step should be taken in the treatment process.  The first step is wound care to avoid infection.  The wound should be cleaned immediately with soap and water for five minutes and irrigated with a virucidal agent.  Wound closure should be avoided and the wound should be closely monitored.  the next step is to administer five doses of the postexposure vaccination or rabies postexposure prophylaxis (RPEP) as soon as possible on a rotation of day 0 (earliest day possible), 3, 7, 14, and 28.  The infected person should also receive the human rabies immunoglobulin (HRIG) to boost antibodies until the body can produce its own. The third step is to monitor closely.  Only one person has been reported to have ever survived rabies after the onset of symptoms without receiving the rabies vaccine and only eight total cases of survival of have been reported after the onset of symptoms.  All cases were left with varying degrees of brain damage.

Key point:

  • Prevention- have pets vaccinated and look into pre-exposure prophylaxis treatments if traveling abroad where rabies is more prevelent
  • Best to receive post exposure prophylaxis if rabies is remotely suspected before symptoms begin.  Prognosis is very grim after onset of symptoms.  No treatments proven to halt progression of disease after symptoms begin.

Physical Therapy Management (current best evidence)

  • Wound Care Management of the bitten area.
  • Maintain ROM to prevent contractures of the patient if in a paralytic or comatosed state.

Differential Diagnosis[7] [6]

Case Reports/ Case Studies

(case studies should be added on new pages using the case study template)

1. Wertheim HF, Nguyen TQ, Nguyen KA, de Jong MD, Taylor WR, Le TV, Nguyen HH, Nguyen HT, Farrar J, Horby P, and Nguyen HD. Furious Rabies after an Atypical Exposure. March 2009. Available online at: 
www.ncbi.nlm.nih.gov/pmc/articles/PMC2656546/

2. Kietdumrongwong P, Hemachudha T. Pneumomediastinum as initial presentation of paralytic rabies: A
case report. October 2005. Available online at:
www.ncbi.nlm.nih.gov/pmc/articles/PMC1282576/pdf/1471-2334-5-92.pdf

3. Human rabies -- Virginia, 2009. MMWR: Morbidity & Mortality Weekly Report [serial on the Internet]. (2010, Oct), [cited April 6, 2011]; 59(38): 1236-1238. Available from: CINAHL with Full Text. Available online at: http://www.cdc.gov/mmwr/pdf/wk/mm5938.pdf

4. Human rabies -- Kentucky/Indiana, 2009. MMWR: Morbidity & Mortality Weekly Report [serial on the Internet]. (2010, Apr 9), [cited April 6, 2011]; 59(13): 393-396. Available from: CINAHL with Full Text. Available online at: http://www.rabiescontrol.net/assets/files/Scientific%20Literature%20pdfs/MMWRPostmortem.pdf

Resources

Centers for Disease Control. Available online at:  http://www.cdc.gov/rabies/

Mayo Clinic. Available online at:  http://www.mayoclinic.com/health/rabies/DS00484 

World Health Organization. Available online at:  http://www.who.int/rabies/en/ 

National Center for Biotechnology Information. Available online at:  http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002310/

Recent Related Research (from Pubmed)

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References

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  1. 1.0 1.1 RABIES. (n.d.), [cited March 17, 2011]; Available from: Funk & Wagnalls New World Encyclopedia.
  2. 2.0 2.1 Powell J. Evaluating risk: rabies exposure and occupational implications. AAOHN Journal [serial on the Internet]. (2009, Nov), [cited March 17, 2011]; 57(11): 465-471. Available from: CINAHL with Full Text.
  3. Collins V. The deadly risk of rabies. Practice Nurse [serial on the Internet]. (2008, June 20), [cited April 7, 2011]; 35(12): 14-16. Available from: CINAHL with Full Text.
  4. 4.0 4.1 Ainsworth S. Understanding the risk of rabies. Practice Nurse [serial on the Internet]. (2009, 2009 Jan 16 16), [cited March 17, 2011]; 37(1): 10. Available from: CINAHL with Full Text.
  5. 5.0 5.1 Driver C. Clarification on rabies... 16 January... (Understanding the risk of rabies, pages 10-12). Practice Nurse [serial on the Internet]. (2009, Feb 13), [cited March 17, 2011]; 37(3): 40. Available from: CINAHL with Full Text.
  6. 6.0 6.1 6.2 6.3 Powell J. Evaluating risk: rabies exposure and occupational implications. AAOHN Journal: Official Journal Of The American Association Of Occupational Health Nurses [serial on the Internet]. (2009, Nov), [cited April 5, 2011]; 57(11): 465-471. Available from: MEDLINE.
  7. Reed Group, Medical Disability Advisor, MDGuidelines. Accessed April 1, 2011. Available online: http://www.mdguidelines.com/rabies/differential-diagnosis