POTD: Dogmentin or Don't

Hi Everyone,

I hope you had a wonderful holiday with loved ones! Today's POTD addresses a subject matter that I hope everyone avoided while at home with family fighting over food and attention: dog bites. Fur babies are well known to the streets of NYC, and sometimes their bite marks can find their way into our ED. How do we manage these bites? And what does the evidence say we should be doing? 

The Current Dogma of Antibiotics

The classical practice we learn in EM training is to give antibiotics for any dog bite given the copious amounts of bacteria swirling around in a dog's mouth. The easy memory trick is to give Augmentin aka Dogmentin for any dog bite wound. But is this really helping prevent infection? See the studies below for evidence

• Coyle, C., Shi, J., & Leonard, JC. (2024). Antibiotic prophylaxis in pediatric dog bite injuries: Infection rates and prescribing practices. Journal of the ACEP Open: Antibiotics did not change the rate of infection in pediatric dog bite injuries, with overall infection rate of about 5.2%. TLDR of the paper: a 2024 retrospective study demonstrated prophylactic antibiotics did not affect the infection risk for dog bites.

• Quinn, JV., McDermott, D., Rossi, J., Stein, J., & Kramer, N. (2010). Randomized control trial of prophylactic antibiotics for dog bites with refined cost model. Western Journal of Emergency Medicine: Antibiotics did not reduce the rate of infection from dog bites. There is separate analysis of the paper that states giving antibiotics is cost effective if the infection rate is greater than 5%, but that's not the primary focus for us. TLDR of the paper: a 2010 RCT demonstrated prophylactic antibiotics did not affect the infection risk for dog bites.

• Saconato, H., & Medeiros, I. (2001). Antibiotic prophylaxis for mammalian bites. Cochrane Database Systematic Review: Antibiotics did not reduce the rate of infection from dog or cat bites. However, antibiotics for hand wounds specifically, which have higher infection rates at baseline, did appear to decrease the infection rate, with a number needed to treat of 4. TLDR of the paper: a 2001 systematic review demonstrated prophylactic antibiotics did not affect the infection risk for dog bites, with the exception of bites on the hand.

• Cummings, P. (1994). Antibiotics to prevent infection in patients with dog bite wounds: a meta-analysis of randomized trials. Annals of Emergency Medicine: Antibiotics did reduce the rate of infection from dog bites. Relative risk of infection with antibiotics was 0.56. TLDR of the paper: a 1994 meta-analysis demonstrated prophylactic antibiotics did decrease the infection risk for dog bites.

So a 1994 meta-analysis, which seemingly included similar studies to a 2001 systematic review, came to the opposite conclusion... how? There appears to be one study that is the major difference between the two reviews, which is below.

• Brakenbury, PH., Muwanga, C. (1989). A comparative double blind study of amoxicillin/clavulanate vs placebo in the prevention of infection after animal bites. Archives of Emergency Medicine: Infection occurred in 33% of patients given augmentin vs. 60% of patients given placebo, a staggering and statistically significant result that suggests antibiotics did reduce the rate of infection. However, the paper includes a loose definition of what was classified as infection, stating "infection was defined as the presence of erythema and tenderness beyond that expected 24 hours after the injury with or without purulent discharge, cellulitis or lymphangitis." TLDR of the paper: a 1989 RCT demonstrated that augmentin did decrease the infection risk in dog bites, but with a lenient definition of infection.

This paper alone is what drove the statistical significance of the 1994 meta-analysis. So, to put it plainly, if you believe in the definition of infection stated by this 1989 paper and the significance of this single RCT, give antibiotics! If you don't, the evidence would support your decision to hold off on prophylactic antibiotics. When considering antibiotics, also think about side effects, allergies, resistance, and shared-decision making.

Getting Closure on Closure

So we have figured out our antibiotics, but what about suturing the wound? The thought is that suturing close these bacteria-prone wounds makes it a nidus for abscess formation. Does that play out in the literature? There are a few studies that address this.

• Paschos, NK., Makris, EA., Gantsos, A., & Georgoulis, AD. (2014). Primary closure versus non-closure of dog bite wounds. A randomised controlled trial. Injury: There was no difference in infection rate between primary closure vs. non-closure. Whether or not the patient presented before or after 8 hours did affect infection risk, but closure played no role. Cosmetic outcome, however, was better in primary closure group. Important groups that were excluded from the study were immunocompromised patients and complex wounds. TLDR of the paper: a 2014 RCT demonstrated that closing dog bite wounds did not change infection outcomes, but it did improve cosmetic outcomes.

• Wu, PS., Beres, A., Tashjian, DB., & Moriarty, KP. (2011). Primary repair of facial dog bite injuries in children. Pediatric Emergency Care: There were no infections in a group of pediatric patients with dog bite wounds to the face who had their laceration repaired either in the ED or the OR. TLDR of the paper: a 2011 retrospective study demonstrated that closing dog bite wounds did not change infection outcomes, either in the ED or the OR.

• Chen, E., Hornig, S., Shepherd, SM., & Hollander, JE. (2000). Primary closure of mammalian bites. Academic Emergency Medicine: There was a 5.5% change of developing infection in a group of patients who had primary closure of their dog bite wound and received prophylactic antibiotics. TLDR of the paper: a 2000 observational study demonstrated that closing dog bite wounds was associated with a similar baseline infection risk to that seen in other studies.

• Maimaris, C. & Quinton, DN. (1988). Dog-bite lacerations: a controlled trial of primary wound closure. Archives of Emergency Medicine: Suturing dog bite wounds neither increased infection rate nor improved cosmetic outcomes, and no prophylactic antibiotics were given. TLDR of the paper: a 1988 RCT demonstrated that closing dog bite wounds did not change infection outcomes.

It looks like the current evidence is suggesting that primary closure is safe when it comes to infection risk in dog bites, but to take into account the clinical characteristics of your patients (i.e. immunocompetence), characteristics of the wound (i.e. complexity and depth), and cosmetic preferences.

Keeping UpToDate With The Dog Bites

This really goes against how most of us have been practicing: antibiotics and leave open. When it comes down to it, the evidence really does point one way: no antibiotics and close. That seems radical to me. And that's what UpToDate seems to agree with at the moment; the algorithm does in fact give the option of antibiotics or no antibiotics (in very particular cases) and closing or not closing (in other very particular cases), but there's currently no pathway that is suggesting no antibiotics and closing. 

TLDR of all the TLDRs

• Most of the evidence suggests you don't need to give antibiotics for every dog bite to prevent infection

• All of the evidence suggests you don't need to leave open every dog bite wound to prevent infection

• Patient characteristics, laceration characteristics, and cosmetic preferences are important

• Just follow the UpToDate algorithm honestly

Cheers,

Kelsey

Resources:

1) https://first10em.com/dog-bite/

2) Brakenbury PH, Muwanga C. A comparative double blind study of amoxycillin/clavulanate vs placebo in the prevention of infection after animal bites. Archives of emergency medicine. 6(4):251-6. 1989. PMID: 2692580 

3) Chen E, Hornig S, Shepherd SM, Hollander JE. Primary closure of mammalian bites. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 7(2):157-61. 2000. PMID: 10691074

4) Cummings P. Antibiotics to prevent infection in patients with dog bite wounds: a meta-analysis of randomized trials. Annals of emergency medicine. 23(3):535-40. 1994. PMID: 8135429

5) Maimaris C, Quinton DN. Dog-bite lacerations: a controlled trial of primary wound closure. Archives of emergency medicine. 5(3):156-61. 1988. PMID: 3178974 

6) Medeiros I, Saconato H. Antibiotic prophylaxis for mammalian bites. The Cochrane database of systematic reviews. 2001. PMID: 11406003

7) Wu PS, Beres A, Tashjian DB, Moriarty KP. Primary repair of facial dog bite injuries in children. Pediatric emergency care. 27(9):801-3. 2011. PMID: 21878832

8) Coyle C, Shi J, & Leonard JC. Antibiotic prophylaxis in pediatric dog bite injuries: Infection rates and prescribing practices. Journal of the American College of Emergency Physicians Open, 5(3), e13210. 2024.

POTD: Fishhook Injury

Hi everyone,

Caroline and I have the great privilege of serving as your admin residents for this upcoming block. Throughout the next four weeks, if there are any topics floating in your head that you would like us to dive further into, send it our way!

For today's POTD, I wanted to explore the unfortunate case of a fishhook injury, with a particular focus on fishhook removal techniques if it ever maneuvers its way into your ED. Over the weekend, the south side team successfully removed a fishhook lodged in a patient's pinky finger, and, by the leadership of Dr. Sanjeevan and the grip strength of Dr. Weber, the patient was able to ambulate out of the ED with all digits intact and ready for another day of fishing in Red Hook.

Fishhook Anatomy

A fishhook is composed of the eyelet, shank, belly, barb, and tip. Most fishhooks are J hooks, with one shank and one barb, but occasionally you might see a treble hook, which is essentially multiple J hooks together all sharing a shank. The real troublemaker for fishhook injuries is the barb. Fear the barb. The sharp, reversed nature of the barb makes it so that a simple retrograde removal would be traumatic both to the surrounding tissue and the patient.

Preparation

1) Assess path of fishhook: Your removal technique will in part depend on the depth and location of the needle. Is the distal tip already near the surface? Is it going to hit any important structures on its way in or out? You may need further imaging to better clarify the track it took. If it involves the eye, consult ophtho. If it involves bone or tendon, consult ortho.

2) Local anesthetic/nerve block: Digital blocks work great for these when applicable.

3) Wound cleaning: Chlorhexidine or betadine like wild.

Techniques

1) Advance and Cut Technique: need hemostat, wire cutters/raptors, gauze, eye protection

a. Anesthetize.

b. Advance the fishhook further into the patient until the tip and the barb have both exited the skin.

c. Cut the barb off the fishhook with wire cutters or raptors. If using raptors, you can use the ring cutter function (shown below). Make sure you keep gauze over the barb and have eye protection on before you cut so as to avoid the cut barb from flying off and causing further injuries.

d. Reverse the hook back out of the skin.

2) String Technique: need string or strong suture, eye protection

a. Wrap a string or strong suture around the fishhook.

b. Push down on the shank to dislodge the barb as much as possible.

c. Pull on the string and jerk quickly. Watch out for the fishhook to come flying out of the skin.

3) Needle Technique: need 18 gauge needle

a. Anesthetize.

b. Advance an 18 gauge needle along the fishhook toward the tip and over the barb.

c. Reverse out both the needle and fishhook together as a unit.

4) Scalpel Technique: need scalpel, hemostat

a. Anesthetize.

b. Use #11 blade scalpel to cut down to the barb.

c. Grab barb with hemostat.

c. Pull entire fishhook up and out.

Post-Removal Care

1) Check for foreign bodies: Consider xray if any concern for retained objects.

2) Tetanus: Hit them with that tdap as indicated. 

3) Antibiotics: No trials have been done to study PO antibiotics after fishhook injury. You might consider adding on systemic antibiotics for immunocompromised folks, infection-prone areas, or contaminated hooks. At the very least, topical bacitracin and instructions on local wound care are always a good call.

Happy fishing,

Kelsey

Resources:

1) https://www.aliem.com/trick-fishhook-removal-techniques/

2) https://www.uptodate.com/contents/fish-hook-removal-techniques?search=fish%20hook%20removal&source=search_result&selectedTitle=1%7E1&usage_type=default&display_rank=1#H13

3) https://www.tampaemergencymedicine.org/blog/fish-hook-removal

4) https://www.emra.org/emresident/article/angling-for-success-techniques-for-fishhook-removal-in-the-ed

5) https://www.emrap.org/episode/ucprocedures/ucproceduresfishhookremoval

6) https://www.emrap.org/episode/fishhookremoval1/fishhookremoval1

7) https://www.emrap.org/episode/fishhookremoval/fishhookremoval

Snake Bites

Coral snake bites are relatively rare but potentially serious envenomations caused by the bites of venomous coral snakes, belonging to the Elapidae family. The most prevalent coral snake species in North America is the Eastern Coral Snake (Micrurus fulvius). They are the classic “red touch yellow, kill a fellow.” Here is a summary of key aspects related to coral snake bites:

Mechanism of Toxin: Coral snake venom primarily consists of neurotoxins that affect the nervous system. These neurotoxins which include micrurotoxin and micruroidin, target the neuromuscular junction at acetylcholine receptors, to which they inhibit. This can lead to respiratory depression.

Clinical Features of Coral Snake Bites:

1. Local Symptoms: Coral snake bites often do not cause significant local symptoms, such as pain or swelling, unlike many other venomous snake bites.

2. Neurological Symptoms: The primary clinical manifestation is neurotoxicity, characterized by weakness, difficulty swallowing, slurred speech, and respiratory failure. Patients can develop cranial nerve palsies.

3. Respiratory Distress: Resulting from respiratory muscle paralysis. This is the primary concern after a coral snake bite.

Evaluation and Lab Abnormalities:

1. Clinical Assessment: Diagnosis is primarily clinical, based on the characteristic neurological symptoms and a history of coral snake bite.

2. Laboratory Tests: Laboratory abnormalities may include an elevated creatine kinase (CK) level due to muscle breakdown, reflecting the neurotoxic effects of the venom.

3. Coagulation Studies: Unlike some other venomous snake bites, coral snake envenomation usually does not cause coagulopathy. There are rare reported cases of DIC in coral snake bites, and given that patients may not remember the type of snake that bit them, it is not unreasonable to send DIC labs.

Medical Management:

1. Supportive Care: Normal wound care, clean the wound, update tetanus, watch for cellulitis. Do not attempt to “suck out” the venom. No indication for using a tourniquet. Extremities should be monitored for compartment syndrome.

2. Antivenom: The only specific treatment for coral snake envenomation is the administration of coral snake antivenom (Micrurus fulvius antivenom). However, this has been out of production and current stock is expected to end this year.

3. Ventilatory Support: Patients with respiratory failure may require mechanical ventilation until the effects of the venom wear off. This should be handled aggressively. If the patient shows any signs of respiratory failure, promptly intubate them.

It's important to note that coral snake bites are uncommon, and the severity of envenomation can vary. These patients often require admission for monitoring.

Crotaline bites, commonly referred to as snakebites from pit vipers such as rattlesnakes, copperheads, and cottonmouths, are the other clinically significant snakes in NA. Here's a summary covering the mechanism of toxin, clinical features, evaluation, and medical management:

Mechanism of Toxin: Crotaline venom primarily consists of enzymes and peptides that exert cytotoxic, hemotoxic, and proteolytic effects. Metalloproteinases and serine proteinases in the venom contribute to swelling and damage to capillaries. They also lead to coagulation abnormalities. 

Clinical Features of Crotaline Bites:

1.       Local Effects: Immediate pain, swelling, and ecchymosis at the bite site. Local tissue necrosis may occur, especially with rattlesnake bites.

2.       Systemic Effects: Hematologic abnormalities, such as thrombocytopenia and coagulopathy, due to venom-induced consumption coagulopathy. Systemic symptoms like nausea, vomiting, weakness, dizziness, and diaphoresis also occur. Severe envenomation can lead to shock, respiratory distress, and organ failure.

Evaluation, Including Lab Abnormalities:

1.       Clinical Assessment: Assess local and systemic signs of envenomation. Evaluate for signs of compartment syndrome in the affected limb. Patients can develop hypotension from significant third spacing.

2.       Laboratory Studies: Complete blood count (CBC) to assess for thrombocytopenia and coagulopathy. Coagulation studies, including prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen levels. Blood chemistry to assess organ function.

Medical Management:

1.       Supportive Care: Normal wound care, clean the wound, update tetanus, watch for cellulitis. Do not attempt to “suck out” the venom. No indication for using a tourniquet. Extremities should be monitored for compartment syndrome. Limbs should be measured. Patients should receive IVF and may need pressors.

2.       Respiratory support: Patients with bites to the head and neck are at risk for airway compromise due to edema. Early intubation should be considered in these patients.

 

3.       Antivenom Therapy: There are two antivenoms approved, Crofab and Anavip. Crofab is the original, Anavip was just approved in 2015.

1. Criteria for administration of Crofab or Anavip– significant progression of swelling, abnormal test results (plt less than 100k or fibrinogen less than 100), altered vital signs or altered mental status.

2. Crofab is given as 6 vials, usually diluted into 1 L of NS and run over an hour. Repeat doses (2 vials) may be given if symptoms persist at 6, 12, and 18 hours. Patients should be monitored for allergic reactions.

3. Anavip is a newer antivenom. It is given as 10 vials, repeated Q1H PRN for initial control of local signs of envenomation. 4 vials are given as maintenance for symptom recurrence.

Both antivenoms are quite expensive. Crofab is $3400 per vial and Anavip is $1200 a vial. Patients with systemic symptoms and receiving antivenom should go to the ICU.

Buchanan JT, Thurman J. Crotalidae Envenomation. [Updated 2022 Oct 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551615/

Hessel MM, McAninch SA. Coral Snake Toxicity. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519031/