POTD: Tick Bites

 Tick Removal – there are multiple tips and tricks to do this, but most sources suggest…

-       Using a pair of tweezers (or forceps) and attempting to grasp the tick as close to the skin surface as possible

-       Pull upwards with gentle, steady traction. Do not jerk or twist

-       Do NOT squeeze, crush, or puncture the body of the tick – this may expel infectious contents

-       After removing the tick, wash skin thoroughly with soap and water

What to do if mouth parts remain in the skin?

-       UpToDate says to leave it in and they’ll be expelled on their own

-       WikEM says to excise under local anesthesia… seems aggressive

Important Ticks for Identification – The CDC has a good guide. If you’re squeamish with bugs, you’ve been warned and please skip this part. There are 3 main types of ticks found in the US.

1)    Ixodes Scapularis or “deer ticks” = LYME DISEASE. Other ticks do not transmit Lyme disease

-       Brown, about the size of a poppy seed but can be larger when engorged

-       Primarily found in the North-East and Midwest, less commonly in the Western US

-       Most famously transmits Lyme Disease, also anaplasmosis, babesiosis

2)    Dermacentor species or “dog ticks”

-       Brown with a white collar, about the size of a pencil eraser 

-       Primarily found in the Rocky Mountain States (Colorado, Idaho, Montana, Nevada, Utah, Wyoming, etc.)

-       Most known for transmitting, you guessed it, Rocky Mountain Spotted Fever

3)    Amblyomma Americanum or “Lone Star Tick”

-       Brown or black with a white splotch

-       Primarily found in the South, but can also be found in the Eastern US

-       Most known for Southern Tick-associated rash illness (STARI) and ehrlichiosis

Who needs prophylaxis? IDSA recommends prophylaxis only if ALL OF THESE CRITERIA ARE MET. It should be specified that this is for prophylaxis against Lyme Disease only.

-       The tick is identified as a deer tick

-       Tick is estimated to have been attached >36 hours or engorged (it takes time for the bacteria to exit the gut of the tick and enter the bloodstream). Ticks found crawling on skin automatically do not count.

-       The antibiotic can be given within 72 hours of tick removal

-       The bite occurs in a geographic location that Lyme Disease is highly endemic (can be found on CDC website)

-       There is no contraindication to take doxycycline (primarily appears to be hypersensitive or children < 8). If there is a contraindication, no second-line antibiotic exists

The prophylaxis is a single dose of 200mg doxycycline, or 4mg/kg up to a max of 200mg for children.

Antibiotic treatment following a tick bite is not recommended as a means to prevent anaplasmosis, babesiosis, ehrlichiosis, Rocky Mountain spotted fever, or other rickettsial diseases. Rather, patients should be warned and be vigilant against symptoms such as fever, rash, or other symptoms concerning for these diseases.

https://www.cdc.gov/ticks/tickbornediseases/tickID.html

https://www.uptodate.com/contents/what-to-do-after-a-tick-bite-to-prevent-lyme-disease-beyond-the-basics

https://wikem.org/wiki/Tick_borne_illnesses

https://wikem.org/wiki/Tick_removal

POTD: Rabies Part 2 Rabies Vaccination

The much anticipated part 2 on rabies. 

Onto the actual important part of this POTD: Rabies post-exposure prophylaxis (PEP). Who gets it and how?

Who: UptoDate keeps recommending contacting local health officials for recommendations which, less face it, generally isn’t happening.

-       Anyone with a known or likely exposure to rabies defined as…

o   Bite or saliva-containing scratch from an animal with rabies

o   An open wound or mucus membrane exposure to saliva, CSF, or CNS tissue from an animal with rabies

-       Empirically to anyone with suspected exposure (pretty open-ended) 

-       Exposure of keratinized skin to saliva, blood, feces DOES NOT count as an exposure

For domesticated animals

-       High risk: undocumented vaccination status, aggressive behavior

-       If animal (dog, cat, ferret) able to be observed/quarantined for 10 days, can hold off PEP until end of 10-day period

o   Animals almost universally show signs within 10 days of rabies

For wild animals

-       High risk: bat, raccoon, skunk, fox

o   Start PEP, discontinue if animal able to be tested promptly and is negative

-       Low risk: squirrel, chipmunk, mouse/rat, rabbit/hare

o   Do not start PEP

How: There are 2 components, (1) the rabies vaccine and (2) rabies immune globulin (RIG)

1)    Rabies vaccine – administered 1mL IM specifically in the deltoid region (not gluteus muscle, risk of sciatic damage/lower response to vaccine). Has a very specific dosing schedule

a.     If patient has received pre-exposure prophylaxis: 2 doses, Day 0 and Day 3

b.     If patient unvaccinated: 4 doses, Days 0, 3, 7, and 14

                                               i.     If immunosuppressed, a 5th dose is given on Day 28

c.     Day 0 is first day that rabies vaccine is given

d.     It can be helpful to write the dosing schedule on the discharge papers for future providers (speaking from experience)

2)    RIG – only indicated if patient has not received pre-exposure prophylaxis

a.     20 U/kg – as much as possible infiltrated around the wound with the rest delivered IM in the opposite deltoid of the vaccine arm.

b.     If no obvious wound, place all IM

PEP should be given regardless of delay from time of exposure

Are there any adverse events with vaccination? Depends on the vaccine…

-       Usually local skin reactions (pain, redness, swelling, induration) with possible mild systemic symptoms (fever, headache, GI symptoms)

-       Hypersensitivity or anaphylaxis  can switch to a different vaccine formulation if possible

-       Counseling should be given on these symptoms to prevent patient non-compliance with future doses

FAQ

1)    What if they patient doesn’t closely follow the dosing schedule?

Small deviations aren’t that important, and doses should be administered at the same intervals. For example, if day 7 dose is actually given on day 10, then the next dose should be scheduled on day 17 (or 7 days later), etc.

For more significant delays… consult ID? Seriously though, it likely involves antibody testing and titers, while attempting to follow the initial dosing patient was started on (maybe requires ID follow-up).

2)    What if patient received different formulations of rabies vaccine?

Just give them what you have and have them follow-up with their PCP or clinic for antibody titers. Theoretically the vaccines are interchangeable but not ideal.

3)    What if the patient is pregnant?

Not a contraindication, no evidence associated with fetal abnormalities or adverse pregnancy outcomes.

4)    If RIG was not initially administered? Like if a traveler returns from a foreign country and needs to have their scheduled doses at specifically YOUR emergency department

RIG can be administered on return if less than 7 days from initial vaccine administration. RIG should not be administered afterwards because it interferes with the normal immune response that the vaccine causes.

Last, but not least, general wound care like irrigation should always be performed along with tetanus. Antibiotics are a more nuanced discussion, and possibly a POTD for another day (although I lean towards providing a course for patients with animal bites in general).

TL; DR – and considerations for a busy, NY ED

-       If there was an exposure (actual bite, found in room with a bat) and patient is concerned – give PEP. No serious adverse events.

-       PEP = vaccines in a specific dosing regimen (0, 3, 7, 14, and maybe 28) and RIG (20U/kg) around the wound and the rest IM

-       Please write the dosing schedule with dates on the discharge papers. This makes this patient encounter incredibly easy for your fast track resident.

This is likely more than you ever wished to know about rabies. I learned a lot, like next time Mak needs the rabies vaccine I’ll make sure to give it in his arm instead of his butt.

https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-rabies?topicRef=16595&source=see_link

https://www.uptodate.com/contents/treatment-of-rabies?topicRef=8328&source=see_link

https://www.uptodate.com/contents/when-to-use-rabies-prophylaxis?sectionName=POST-EXPOSURE%20PROPHYLAXIS&topicRef=8303&anchor=H2&source=see_link#H2

https://www.uptodate.com/contents/rabies-immune-globulin-and-vaccine?topicRef=8328&source=see_link

POTD: Rabies Part 1

Rabies Vaccination

Hey all,

I’m mostly going to be doing POTD’s on topics I’ve accumulated throughout the year that I wanted to look into but never actually did. So, prepare for quite a few fast track complaints (unless I get a request for a topic – just e-mail/text me!).

Anyways, let’s talk about rabies. I’m sure everyone has heard or experienced a great rabies case in their career. No? That’s because since 1980 there has only been about 2-3 reported cases a year in the US, with ~30% of them related to US travelers returning abroad. It is an almost universally fatal disease if contracted but is also 100% preventable if an exposure is identified and given the proper prophylaxis.

So…briefly about rabies…

Epidemiology

-       Estimates 59,000 deaths worldwide, mostly due to inadequate control of rabies in domesticated animals

-       Transmission usually through exposure from saliva from an animal bite

o   No history of transmission from infected patients to healthcare personnel (though personally I look forward to the coming zombie apocalypse)

-       Normal reservoirs: ?dogs/cats to some extent, mostly bats, foxes, skunks, and raccoons

-       Incubation period: 1-3 months on average, though can occur several years later

Clinical Manifestations

-       Prodromal phase (~1 week): Non-specific low grade fever, chills, myalgias, malaise, fatigue, anorexia, sore throat, nausea, vomiting (COVID is that you?)

-       Clinical rabies: Encephalitic (80%) vs. Paralytic

o   Encephalitic = “classic” rabies

• Fever

•   Hydrophobia

•   Autonomic instability – hyperthermia, lacrimation, hypersalivation

•   Pharyngeal spasms and hyperactivity  stupor, coma, and death

• Agitation, aggression, combativeness

o   Paralytic = Less than 20%

•   Ascending paralysis not unlike Guillain-Barre Syndrome

•   As paralysis ascends, respiratory muscles lose tone and respiratory failure and death occurs

  After learning more about this, it’s possible some of us HAVE seen rabies and it’s never diagnosed…….. (I’ll definitely be putting it in my MDM from now on)

Diagnosis

-       As always, a good history and physical is paramount any of the above symptoms surrounding an animal bite is suggestive of rabies

-       Lab diagnosis – requires multiple samples from saliva, skin, serum, or CSF using multiple modalities (sensitivity of a single test not that high)  likely unimportant in the ED

-       Post-mortem – examining brainstem or other neural tissue directly

Differential – aka all of these are 1000% more likely than rabies

-       ANY OTHER CAUSE OF ENCEPHALITIS (West Nile, herpes, autoimmune, etc.)

-       Tetanus (another very common disease that we see frequently)

Treatment – almost universally ends in death. 29 well-documented cases of survival. Survival usually still causes severe neurological sequelae

-       The treatment is always proper prophylaxis

-       Palliation (not joking)

-       Supportive care/ICU level care and strategies = no good evidence/way above our level of care in the ED.

Hopefully you’ve learned a little more than you already did about rabies (although the key clinical symptom does appear to be hydrophobia). I, for one, will be splashing Mak with a little bit of water every day until he becomes agitated and then send him to the ED to be treated for rabies.