Bites, Sitngs And Infestations Flashcards
Approach to general bites and infectious wounds
1) ensure neuro vasculature status
- **make sure to look for bone and joint involvement
2) ensure tetanus vaccination status is up to date
- give toxoid = patient last vaccine was 10 yrs for clean wound; 5 yrs for dirty wound
- ***give immunoglobulin if patient has never had 3 full doses of the tetanus vaccine
3) treat prevent infection
- rabies = vaccine and immunoglobulin if no vaccine history; vaccine only if prior whole series vaccine was given.
- antibiotic most prescribed = clavulonic acid orally
- if bonejoint involvement = IV antibiotics always
4) wound care with irrigation with tap water or sterile water
5) closure or no closure
- **usually wound is left OPEN to heal by secondary intent
- **Absolute exception = facial wounds that would cause deformities (ALWAYS CLOSE)
- ** NEVER close wounds of hands and feet
- dont close cat or human bites usually
**closure criteria = uninflected, <24 hrs old and not on hand/foot and not immunocompromised
Human bites
10-34 yr group is most common
- breast = assume sexual assault
- arm bites > 2.5cm diameter = assume child abuse via an adult
2 broad categories
1) Clenched fist injuries (CFI)
- occurs in fights and mostly at MCP joints of 3rd/4th fingers
2) occlusive bites (more common)
- caused by children usually
Common bacteria in human bites
Staph/strep are most common
Also
- bactericides
- corynebacterium
- *only seen in human bites = elkinella corrodens**
- causes blood culture (-) endocarditis
- MUST treat this with amoxicillin-clavulonic acid
Cat bites
More likely in women and typically in upper extremity and hands/fingers
- 80% own the pet
- *most common deep infection bite (80%)**
- cellulitis, tenosynovits (requires surgery) osteomyelitis and joint injuries with abscesses (requires drainage)
- *Unique Bacteria = pasteurella multocida and bartonella henselae**
- 31% mortality due to sepsis
- tender lymphadenopathy
- headache, malaise and fever
always get x-rays to determine deep tissue involvement
Cat scratch fever
Caused by bartonella henselae
- bacteria found under cat nails and fences
Symptoms
- regional lymphadenopathy and fever and systemic symptoms
Treatment
- antibiotics
- DONT incision and drainage to lymph nodes
(Causes fistulous tracks that dont heal ever)
Dog bites
4.5 million dog bites per year, way more common in younger males
Adults = arm/hand Children = face and head and neck
Dog bites are more likely to kill due to injury and trauma damage
Infection rate = 30%
- is always polymicrobial (pasturella, staph,strep, neisseria, moraxella, bactericides, fusobacterium)
- Unique dog pathogen = capnocytophaga canimorsus*
- high risk for gangrene and sepsis
- usually only seen in cultures with immunocompromised people
- mortality = 30% (endocarditis, meningitis and sepsis)
always get xrays
What labs to check for infection.?
CBC, ESR, CRP
What is the #1 cause of surgery in human fight bites?
Tenosynovits
- shows necrosis and inflammation with extreme pain at tendons
Snakebites
Pretty rare with 45000 a year in US
- 97% = lower extremities
Most common venomous snake in US = pit viper
No data for morbidity but usually only kills in very young and elderly patients
- worst states = NC/AR/TX/GA
Most toxic snakes
- vipers (rattlers and copperheads, moccasin, pit viper)
- elapids (coral snakes, cobras and black mambas)
- red on black = venom lack!
- red on yellow = kills a fellow! (Venomous)
Effects of viper poison
Cell injuries, rhabdomyolysis, tender lymphadenopathy, sepsis, hemorrhagic bullae and compartment syndrome are common
Toxin does direct cellular injury
Systemic symptoms are prominent
- can also develop IgE mediated anaphylaxis
- also high risk of superinfection with gram (-) organisms
** if vipers gave venom in their bite, the site of the bite will be oozing. If not = may have been a “dry bite”
Treatment of venomous snake bites
Give Antivenin ASAP!
- indications = progression of local injury, coagulopathy, systemic effects
- side effects = anaphylactic reactions and serum sickness as well as pyretic effects
- *NEVER use tourniquets As well as incisions and suction of the bite
- increases neuro vascular injuries and contamination with oral flora for superinfection
Effects of elapid poisoning
Neurotoxic and irreversibly binds to ACh receptors
- casues ptosis, double vision, dysphagia, aphasia, descending paralysis and muscle weakness
- ultimately = respiratory failure And death
Treatment = antivenin
Gilamonsters
No deaths ever recorded
Grinds venom into the tissues and causes
- local pain, swelling and weakness
- hypotension and MIs are possible
Brown recluse bites
live in woodpiles and cellars. Are quartersized and brown
Are initially painless
- then erupt not a “volcano” lesion and leads to ischemic necrosis. Also hemolysis thrombocytopenia and renal failure within days if left untreated
- **kills even fast in children and elderly
Treatment
- hyperbaric oxygen chamber and surgical debridement
- acetaminophen/NSAIDs and opiods
- NEVER use ice! (Increases ischemia)
- can use dapsone unless G6PD patient (will cause hemolysis)
Black window bites
Red hourglass shaped and found in woodpiles and homes
Toxin = a-latrotoxin
- disables neuronal membranes by perimently opening ion channels and depletes ACh
Symptoms:
- immediate pain
- “target lesion”
- nausea/vomiting
- abdominal cramps that mimics appendicitis/peritonitis**
- cardiac arrhythmias (kills)
Treatment
- CAN use pain meds and ice
- can also give benzos and antivenin as well
- calcium gluconate is helpful also
Scorpions
Only dangerous one is bark scorpion
- nocturnal and live under rocks/logs and floor crevices
Venom = C. Sculpturatus
- casues repetitive firing of axons by sodium channels activation
Symptoms:
- immediate pain at site with local edema, erythema, and numbness/weakness at site
- systemic = anxiety, restlessness, spasms, N/V, hyperthermia, etc.
- **roving eye movements and nystagmus
- syncope and cardiac arrthymias and respiratory arrest (kills)
Treatment: supportive care
- ice and pain medications
- opiate pain medications
- benzos IV
- nitroprusside (only in extreme hypertension)
Bees/wasps/fire ants
Venom is not bad, but if allergic is deadly (1st sting = Okay; 2nd sting = bad anaphylaxis)
Allergic reaction via anaphylaxis
- IgE mediated within 30 minutes of sting
- casues CV collapse if not treated
Delayed reaction allergic reaction
- serum sickness-like symptoms (fever, joint pain, malaise)
- type 3 hypersensitivity
Treatment:
- anaphylaxis = epinephrine
- ice pain meds
- IV antihistamines and corticosteroids = severe only
Jellyfish and stingrays
All possess venom
- causes local skin reactions and intense pain
- ***box jellyfish = respiratory arrest ONLY
Treatment = remove stinger by picking, DONT SCRUB.
- immerse in hot water and topical lidocaine
- lacerations = repair and antibiotics prophylactically (cover vibrio and gram (-) species)
- usually ciprofloxacin and tetracycline
- severe only = intubation and respirator
Scabies
Caused by sarcoptes scabie
Burrow under skin and deposit eggs
Leaves pustules and can be confused with impetigo and atopic dermiattis
Treatment = permethrin cream
- NEVER give lindane in children = neuotoxin
Bed bugs
Feed off blood and cause red itchy papules
- confused with hives and eczema
- looks like mosquito bites
Treatment = fumigation of house and toss bedding and clothes
Mites
Transmitted by ticks
Causes rickettsial pox
- vesicular rash what then turns into black eschar lesions
- mild systemic symptoms (fever, chills, swollen nodes, myalgias)
Fleas
Symptoms are most common in people that are sensitized to them
- the bites themselves dont do anything
***Complications = secondary infection due to scratching the rash
Treatment
- fumigate and wash well
Lice
Most common infestation in US
- typical in young children
Symptoms:
- intense pruritus and red macules (mimics dandruff or tinea)
Treatment
- iD lice on hair shafts
- permethrin 1% topical = #1
- also clean all hair products and may have to shave head
- DONT fumigate and DONT miss school
Antivenin information
Pregnancy is NOT contraindication
Indicated in any patient with moderate-severe envenomation from snakes and reptiles
Antivenin often can reverse all signs and symptoms if administered before neurologic changes
Always administer IV
What populations should be admitted for observation for venous stings/bites?
Pregnancy
Children
Very elderly
need to play it safe with these populations
4 criteria for closing a mammal bite wound
Uninflected
Less than 24 hrs old
Not located on hand or foot
Healthy immune system
Tetanus prophylaxis criteria
1) less than 3 doses or unknown tetanus doses but is uninflected
- clean the wound and give tetanus vaccine
2) Same as #1, but more severe/contaminated
- clean wound and give BOTH vaccine and Immunoglobulin
3) more than 3 doses of tetanus vaccine has been given to the patient in history and the wound is uninflected
- clean wound and give vaccine only if last vaccine is 10+ years ago
4) same as #3 but more severe/contaminated
- clean wound and give vaccine only if last vaccine is 5+ years ago
Rabies prophylaxis
If animal is positive or unknown
- person was not vaccinated = rabies vaccine and IVIG
- person has been vaccinated = only rabies vaccine
If animal is known to be negative
- NO rabies vaccine or IVIG
