​Kembara Xtra - Medicine - Human and Animal Bite

​Kembara Xtra - Medicine - Human and Animal Bite 

Animal bite rates differ depending on the species: dogs (60–90%), cats (5–20%), rats (2–3%), people (2–3%), and (rarely) other creatures like snakes.
Systems possibly impacted: any possible pediatric considerations
Children under the age of five are more likely to be bitten on the face, upper extremities, or trunk.

All ages, however children > adults in terms of prevalence and incidence of epidemiology (dog bites: male > female patients; cat bites: female > male patients).
3 to 6 million animal bites occur annually in the US, accounting for 1% of all injury-related ED visits. Of these, 1-2% require hospitalization, and 20 to 35 victims pass away as a result of dog bite complications each year.


Pathophysiology 
Dog bites are much more frequent than cat bites, and the majority of dog bites come from household pets the victim is familiar with.
The majority of cat bites (90%) are prompted.
Human bites can also happen accidentally (for example, paronychia from nail biting, thumb sucking, or non-malicious bites to the face, breasts, or genital areas), though this is less common. Human bite wounds are often caused by striking another person in the mouth with a closed fist.
Animal bites can result in crush injuries as well as tearing, punctures, scrapes, and avulsions.

Infection results from oral flora contamination.
Cat bites frequently result in puncture-style wounds.


Risk Elements 
Dogs that are older or male are more inclined to bite.
Human bites with clenched fists are usually linked to drug or alcohol usage.
Patients who present more than 8 hours after the bite are more likely to become infected.

Prevention
Animal risks education for kids and adults, enforcement of animal control regulations, and information for pet owners are all important.


Providing History A thorough account of the incident, including whether it was provoked or not, the type and breed of the animal, its vaccination status, and its whereabouts The site of the bite The geographical setting The underlying medical history, in particular comorbid illnesses and immunocompromise

 Confirm vaccination history, especially for rabies and tetanus.

clinical assessment
Dog bites: The most frequent sites of injury in adults and children, respectively, are the hands and the face. The related crush injury is more likely.
Cat bites primarily affect the hands, with the lower extremities, face, and trunk following.
Human bites that were done on purpose result in an oval or semicircular region of erythema and bruising, with or without a break in the skin.
- Clenched-fist wounds, which occur when one strikes the other's teeth with the fist while holding it clenched - Document neurovascular status. Tenosynovitis (hand/finger bites) signs include finger held in flexion, fusiform swelling, pain along tendon sheath, and pain with active/passive extension of the affected digit. Signs of wound infection include fever, erythema, swelling, tenderness, purulent drainage, and lymphangitis.

Alert
Cat bites have increased risks of osteomyelitis, tenosynovitis, and septic arthritis and are twice as likely to get infected than dog bites.
Child Safety Considerations
Human bite marks on a child that have an intercanine distance of >3 cm were probably made by an adult, which is cause for alarm for possible child abuse.

Multiple Diagnoses 

Examine other potential trauma factors.


Examinations and diagnostic procedures
Initial examinations (lab, imaging)
Gram stain and culture wound drainage: If the site is not healing, culture for unusual infections (fungi, Nocardia, and mycobacteria); hold bacterial cultures for 7–10 days (some pathogens are slow-growing).
A positive culture will come back from 85% of bite wounds; the majority are polymicrobial.
If bacteremia is suspected, get aerobic and anaerobic blood cultures before beginning antibiotic treatment.
Recent antibiotic treatment might have affected culture outcomes.
To assess for fractures in clenched-fist injuries, get a radiograph.

Alert

Get a plain radiograph if the bite site is close to a bone or joint to check for bone damage (baseline imaging is also useful for subsequent comparison if osteomyelitis is suspected).

Tests in the Future & Special Considerations

• CT scan for severe skull bites; plain radiograph and/or MRI for probable osteomyelitis. Abscess formation can be discovered using ultrasound.
Other/Diagnostic Procedures
Particularly in severe hand wounds, surgical investigation may be required to ascertain the extent of damage or to drain deep infections (such as tendon sheath).

Interpretation of Tests
The most prevalent microbes are:
Streptococci spp., Staphylococcus aureus, Staphylococcus intermedius, Neisseria spp., Capnocytophaga canimorsus, Bacteroides spp., Fusobacterium spp. are all present in 50% of dog bites in addition to Pasteurella spp.
Cat bites: Pasteurella species found in 75% of bites; Streptococcus species (including Streptococcus pyogenes); Staphylococcus species (including methicillin-resistant S. aureus [MRSA]); Neisseria species; Moraxella species; Porphyromonas species; Fusobacterium species; Bacteroides species.
Human bites can harbor a variety of anaerobic bacteria, such as Fusobacterium, Peptostreptococcus, Prevotella, and Porphyromonas spp., as well as the bacterium Eikenella corrodens (15–29%), Streptococcus spp., S. aureus (including MRSA), and others.
– Case studies indicate the transfer of viruses, including HIV, herpes simplex, and hepatitis B/C, notwithstanding their rarity.
S. aureus, Streptococcus spp., Vibrio spp. (saltwater, brackish water), Aeromonas spp. (freshwater), Mycobacterium spp., and Pseudomonas spp. are among the bacteria that can cause aquatic bites.
Pseudomonas aeruginosa, Proteus spp., Salmonella, Bacteroides fragilis, and Clostridium spp. were found in reptile bites.
Rat-bite fever is brought on by rodent bites and the bacteria Streptobacillus moniliformis or Spirillum minus.
Monkey bites - All monkey bites can spread rabies, while macaque monkey bites can spread the potentially lethal herpes B virus.
Pigs are the most probable ungulate (hooved mammal) to bite; polymicrobial infections (Staphylococcus and Streptococcus spp., Haemophilus influenzae, Pasteurella, Actinobacillus, and Flavobacterium spp.) are common in these cases.
ALERT
After receiving a dog bite infected with C. canimorsus, asplenic patients and those with underlying hepatic illness are at risk for bacteremia and deadly sepsis.

General Management Measures 
As per local regulations, complete and submit the bite report.

 To reduce swelling, elevate the affected extremity.
To find out whether animals that bite frequently have rabies, get in touch with your local health authority.
Snake bite: If venomous, transport the patient for the necessary examination and antivenom; ensure that the patient is stable for transport; and check the patient's coagulation and renal condition.

Medication
Decide whether you need antirabies therapy, such as rabies immunoglobulin or the human diploid cell rabies vaccine, if you've been bitten by a wild animal (the main vectors in the US are bats and raccoons), if your pet has rabies, if it hasn't been vaccinated, or if the animal can't be quarantined for 10 days.
To identify the range of antibiotics appropriate for odd animals, consult the most prevalent microorganisms.

Tetanus, diphtheria, and pertussis (Tdap) formulation is typically preferred to Tetanus toxoid (Td) for previously immunized individuals with >10 years since their last dose.
Both hepatitis B immunoglobulin (HBIG) and the hepatitis B vaccine should be given to Anti-HBs negative patients who were bitten by HBsAg-positive people.
In general, HIV postexposure prophylaxis is not advised for human bites unless there has been a large amount of blood exposed to the broken skin.
Monkey bite: Get in touch with the CDC and think about taking a herpes B virus-fighting medication like valacyclovir.
Preemptive antibiotics are only advised for human bites and high-risk wounds (deep puncture, crush injury, venous or lymphatic compromise, hands or near joint, face or genitalia, immunocompromised hosts, requiring surgical repair, asplenic, advanced liver, edema). Preemptive antibiotic therapy lasts for 3 to 5 days; cellulitis/skin abscess treatment lasts for 5 to 10 days.

Alert
The pathogen MRSA, which can be acquired from pet colonies or human skin, should be taken into consideration. Doxycycline or TMP-SMX offer good coverage in cases of high suspicion.
Initial Line
Amoxicillin with clavulanate is the first-line antibiotic for preventative and curative care (2)[B].
Amoxicillin with clavulanate 875/125 mg PO BID for adults
Children should take amoxicillin and clavulanate at the following dosages: 3 months and 40 kg: 25 to 45 mg/kg/day q12h; 3 months and >40 kg: use adult dosage.
Immunocompromised patients, those with systemic infections requiring IV medication, and those with deep or severe wound infections:
- Adults: 3.0 g IV of piperacillin and tazobactam or 3.0 g IV of ampicillin and sulbactam every six hours (2)
- Children: IV administered in 4 split doses with a maximum of 3 g per dose, ampicillin and sulbactam 200 mg/kg/day (dosed on ampicillin component).

Next Line
Alternative oral regimens for adults include ciprofloxacin (500 to 750 mg PO BID) or trimethoprim-sulfamethoxazole (TMP-SMX; 1 DS tablet PO BID).
Children should take TMP-SMX (8 to 10 mg/kg/day of trimethoprim) PO in 2 separate doses with clindamycin 25 to 30 mg/kg/day PO in three divided doses, with a maximum of 400 mg TMP per treatment.
– Avoid using first-generation cephalosporins like cephalexin, penicillinase-resistant penicillins like dicloxacillin, macrolides like erythromycin, and clindamycin (when not combined with another medication) because they have no effect on Pasteurella multocida, which causes dog and cat bites, and Eikenella corrodens, which causes human bites.
Alternative intravenous regimens for adults include: levofloxacin 750 mg IV daily with metronidazole 500 mg IV every eight hours Pregnancy considerations
pregnant ladies with severe allergies who are unable to take penicillins or cephalosporin
Azithromycin – Pay great attention and take note of any possible elevated risk of treatment failure.


Motives for the Referral 

Deep facial and hand wounds should be reported to a plastic surgeon or hand surgeon.
An infectious disease specialist should be consulted regarding bites from primates or other odd species of animals.

Surgical Techniques

 Regular saline irrigation of the wound via a catheter tip to lower the risk of infection
Remove diseased tissue.
Débridement of piercing wounds is not recommended.
Think about main closure In bites to the face (cosmesis), if the wound is clean after irrigation, the bite is less than 12 hours old.
Wounds that are infected and those that provide a high risk of infection (cat bites, human bites, bites to the hand, crush injuries, and presentations that occur more than 12 hours after the event) ought not be left open.

For infected wounds, a delayed primary closure in 3 to 5 days is a possibility.
Splint the hurt hand.
Large, gaping wounds should be repaired using adhesive strips or widely spaced stitches.
Consider consulting a surgeon if the bite wound is deep, serious, or complex; bites to important structures should be handled as potential penetrating traumatic injuries.

Admission
Inpatient hospitalization is typically necessary for patients with deep or serious wound infections, systemic infections requiring IV therapy, and the immunocompromised.

Patient Follow-Up Monitoring
In 24 to 48 hours, recheck for infection.
Daily monitoring of infections to check for resolution; basing changes in antibiotic therapy on clinical response and culture results.

Patients should receive education on how to stay safe with animals and prevent being bitten.
Wounds should get better and close over the course of 7 to 10 days.

Complications include: Post-traumatic stress disorder (PTSD), death, septic arthritis, osteomyelitis, extensive soft tissue scarring, gas gangrene, hemorrhage, meningitis, endocarditis, and extensive soft tissue injuries.

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