Rabies
B. Jason Theiling, MD FACEP
2/3/2015
Objectives of this Module:
1) Understand the relevant history elements that should be extracted from a patient with potential rabies exposure
2) Describe the treatment considerations between a known exposure, a suspected exposure and a presumptive exposure.
3) Understand the basics of medication administration and for both rabies IG and rabies vaccine
4) Understand the regulatory guidelines regarding treatment and animal quarantine
Patient History:
A 19 year old man with no significant history presents with complaints of a bat being found in his apartment this morning when he woke up. Otherwise feels well. No specific complaints
What additional history is important to consider?
· Any sings of symptoms of trauma (bite)
· Other immunizations
· Any wounds or bite marks
· Others that were in the residence as well that could be exposed
PMH:
1. ADHD- States it is mild and really only needs to use Adderall when studying or taking tests
FMH: Non-contributory
Social Hx: Drinks ETOH, “socially” though notes 6-8 beers 3-4 times a week. Denies drug use. Smoke cigarettes, “only when I’m drinking”
Medications
1. Adderall- as noted
Interim History:
Pt notes he was sleeping with his window open because his AC in the apartment is broken and the property manager has not fixed it yet. Window is on second floor, no fire escape or access from below
Woke this AM and noticed a bat was flying around, seemingly stuck in the corner of the room unable to get back out of the window
Pt notes he used his tennis racquet to swat the bat out of the room. Denies direct contact with the animal.
Here for concern of contracting Ebola from the animal.
Do people contract Ebola from Bats?
No, that’s silly. Reassure the patient that, especially that he has never traveled outside of the US, that he has no contact with a person known to have Ebola , that he has no flu like symptoms and that he is afebrile, that he does not have Ebola.
What disease process that is potentially more deadly than Ebola should we consider?
Rabies. In fact, according to the CDC Once clinical signs of rabies appear, the disease is nearly always fatal.
What are the symptoms of rabies infection?
Generally , initial symptoms are non-specific and are flu like in nature with weakness, headaches, fatigue and myalgias which may last for days.
As the disease progresses, the person may experience delirium, abnormal behavior, hallucinations, and insomnia.
T: 36.8 RR: 18 HR: 85 BP: 125/74
Gen: Well developed, well nourished young aged man, no acute distress, Awake alert and oriented X3
Head: Atraumatic, normocephalic, careful inspection of the head reveals no bites or wounds
Eyes: Pupils reactive bilaterally, spontaneous eye opening, EOMI, non-icteric
Mouth: MM are moist with no posterior pharyngeal swelling or asymmetry
Neck: Symmetric with no lymphadenopathy of the lymph notes of the head and neck, no stridor over the trachea, again careful inspection of the neck shows no bites or wounds
Lungs: Clear bilaterally, no wheeze rhonchi or rales
Heart : Rate is normal, regular, no murmurs, rubs or gallops
Abd: soft, non-tender
Ext: No edema, 2+ pulses, no swelling
Neuro: 5/5 strength of the upper ext flexion and ext at the shoulder, elbows and wrists with 5/5 grip bilaterally. The lower ext also show 5/5 strength with fleion and extension of the hips, knees, and ankes. Finger to nose is intact, heel to shin is in tact. Babinski is down going bilaterally. Reflexes are normal in upper and lower ext. Rhomberg is normal. Gait is steady with tandem walk in tact.
What are the initial treatment considerations for evaluation of a patient presenting with concern for rabies exposure.
As animals serve as the principal vectors for rabies in the US and the transmission of the virus occurs through the saliva in the bite. As such, the initial consideration in evaluation should be focused on the site of the bite, if known. Often, concern for rabies occurs following being bitten by domesticated animals, like dogs. These bites can cause significant local traumatic damage and will need to be evaluated and managed independently.
What makes this case different?
The concern here is that the patient was bitten by a bat (or at least exposed to a bat). The teeth of bats are very small and often bites are not felt and rarely detectable. The likelihood such a bite causing significant traumatic damage is very unlikely.
What animals are commonly considered vectors for rabies in the US?
Per the CDC, any mammal can get rabies. The most common wild reservoirs of rabies are raccoons, skunks, bats, foxes, and coyotes. Domestic mammals can also get rabies. Cats, cattle, and dogs are the most frequently reported rabid domestic animals in the United States.
What additional information/history should be collected?
1) Describe what the animal was doing prior to getting. (rabid animals often times act erratically and will be unusually aggressive)
a. Was the animal acting strangely?
b. Was it provoked prior to biting?
c. Was the animal growling or hissing inappropriately?
d. Was it foaming at the mouth? (this is very unlikely in general almost never reported, but expected to be asked by most patients)
2) Do you know the animal, is it yours or does it belong to someone you know?
3) Do you know if the animal has all its shots?
4) Is the animal able to be easily located
5) Does the animal have a history of attacking or biting
What are the protocols regarding evaluating animals following an animal bite.
Again CDC guidelines:
“A healthy domestic dog, cat, or ferret that bites a person should be confined and observed for 10 days. Any illness in the animal during the confinement period or before release should be evaluated by a veterinarian and reported immediately to the local public health department.
If signs suggestive of rabies develop, postexposure prophylaxis should be initiated. The animal should be euthanized and its head removed and shipped, under refrigeration, for examination by a qualified laboratory.
If the biting animal is stray or unwanted, it should either be confined and observed for 10 days or be euthanized immediately and submitted for rabies examination.”
These measures should be initialed through animal control.
How is this case different?
Rarely are bats able to be obtained for observation or euthanasia.(Nor should this be attempted) As such exposure to a bat should be considered exposure to a rabies + animal and post exposure prophylaxis initiated.
What post-exposure prophylaxis should be initiated?
For people who have never been vaccinated against rabies previously, postexposure anti-rabies vaccination should always include administration of both passive antibody and vaccine.
People who have been previously vaccinated or are receiving preexposure vaccination for rabies should receive only vaccine.
How and where should the vaccine and antibody be administered?
Often times people are bit on the hand, usually the dominate hand, either because they are trying to pet the animal or defend themselves from the animal at the time they are bitten. These wounds are difficult to infiltrate with the entire volume of Immune Globulin. As such attempt should be made by the provided to place as much at the wound site as possible with the remaining amount going in the large muscular group just proximal to the wound.
What are the locations of the IM injections.
What is the schedule for Rabies Vaccines?
HRIG and the initial vaccine should be given on day 0 (day of the initial medial encounter)
Vaccine only should be given on days 3, 7, and 14
Additional vaccines can be given in the deltoid opposite the site of initial bite.
Vaccine and HRIG illustrations follow: