BITES, STINGS Flashcards
High Risk Wounds
- Hand or foot bites
- Extremity bite with underlying venous/lymphatic compromise
- Puncture or crush injury
- Cat bite (due to deep puncture)
- Immunosuppression
- Wounds w/delayed presentation ≥12 hrs old on extremity, ≥24 hrs on face
- Bite near vascular graft or prosthetic joint`
Time from bite to signs/symptoms of infection
24 hrs for dogs/12 hrs for cats
Dog & Cat Bites - Management
• Do NOT close a puncture wound
• Do NOT close any high-risk wounds
Antibiotic Prophylaxis (3-5 days) & Empiric Treatment (5-14 days)
• Mupirocin ointment TID for minor wounds
• Amoxicillin-clavulanate (Augmentin)
• Adults - 875/125mg BID
• Peds - 7:1 formulation: 22.5mg/kg BID
Human Bites
≈ 25% become infected
• 2-24 hrs for infection onset
• Likelihood of infection: location, depth, host factors
• Relevant pathogens:
• Oral flora - group A Strep, Fusobacterium, Peptostreptococcus,
• Skin flora – staphylococci and streptococci
Human Bite mgmt - uninfected v infected
Uninfected – wound care, abx prophylaxis, tetanus, Hep B/C, HIV…. if infected, add imaging and a surgical consult
Human bite abx mgmt
Antibiotic Prophylaxis (3-5 days) & Empiric Treatment (5-14 days)
• Mupirocin ointment TID for minor wounds
• Amoxicillin-clavulanate (Augmentin)
• Adults - 875/125mg BID
• Peds - 7:1 formulation: 22.5mg/kg BID
Fleas
- Wingless, 1-8mm, dark brown insect capable of jumping 2 feet
- Live on livestock, pets & humans
- Cat flea most likely to bite humans
Flea clinical presentation
- Clusters of red papules
- Legs, ankles, axillae, skin folds
- Children more sensitive – papular urticaria
Flea clinical mgmt
Management • Home extermination, treat pets • Pruritus relief is primary goal • Topical corticosteroids • Burow’s solution or calamine lotion • Treat for secondary infection
Black Widow
- Western 1⁄2 of US & Southeast (Maryland, Southern Ohio, and lower states)
- Rarely indoors
- Clutter around homes (sheds, garages, etc.)
Brown Recluse
- Midwest & Southern extending Westward
- Rarely outdoors, inside homes (basements, cupboards, attics) • If outdoors – cool, dark places other than live vegetation
Black Widow Bite
- Asymptomatic to sharp sting
- Systemic reaction (20 min – 2 hours after bite)
- Spreading severe pain & localized diaphoresis at site of bite
- Abdominal rigidity, muscle spasms, headache, nausea, vomiting • Infants & preschool children – seizures and tetany
Brown Recluse Bite
Typically painless bite
• Red papules or plaque with central pallor
Systemic reaction (1-2 days/rare)
• Expanding necrotic ulcer at site of bite
• Malaise, nausea, vomiting, fever, myalgia
• Rarely – acute hemolytic anemia, DIC, thrombocytopenia
Cutaneous Larva Migrans
• Infection with cat or dog hookworm larvae
• Parasitic infestation of epidermis
• Eggs passed through stool into sand
or soil, grow into larvae
• Larvae penetrate epidermis →
migration for weeks → trail of inflammation → spontaneous resolution
Cutaneous Larva Migrans
Clinical Presentation
• Begin with pruritic papules
• Within a few days; intensely pruritic serpiginous tracts • Larvae migrate from 2mm up to 2cm/day
• Can occur days to weeks after exposure
-Dermoscopy – brown, translucent, structureless areas (larva bodies) & dotted red vessels (burrow)
Cutaneous Larva Migrans mgmt
stromectal, topical steroids, antihistmaines, spontaneous resolution in 4-6 weeks
Pediculosis
Transmission through direct contact with infested persons or fomites Feed on human blood, can live up to 10 days without feeding
Pediculosis Capitis
- School age children, girls > boys, whites > blacks
- Occipital scalp, neck and postauricular skin most affected
- Allergic reaction to lice saliva causes pruritus
- Medication resistant
- Eyelashes may be involved
Pediculosis Corporis
- Pruritus is chief complaint
- Linear excoriations on neck, trunk, axillary folds, and waist
- Louse is visible with naked eye (2-4mm)
- Lay eggs along clothing seams, feeds, then returns to clothing
Pediculosis Pubis
STD, P. pubis is translucent, 1mm length, 4 of 6 legs are crab-like claws • Found at base of hair shaft
Pediculosis - Diagnosis
- Pruritus of any hair-baring area without evidence of other causes
* Excoriations - Corporis - Linear on trunk, neck, waist, axilla • Capitis – postauricular & occipital scalp
- Wet combing for live lice
- Dermoscopy – lice and nits on body & clothing
- Nits cemented securely to hair shaft
- Wood’s lamp – nits fluoresce pale blue, can be gray or white
Pediculosis Capitis- Management
OTC pediculicides – highly resistant, retreat in 8-10 days
• Pyrethrins w/piperonyl butoxide (RID, Pronto) - ≥ 2 years or older • Permethrin 1% (Nix) - ≥ 2 months or older
Pediculosis Corporis- Management
Bathe thoroughly, heat wash/dry infested linen and clothing, • Permethrin 5% cream to entire body for 8-10 hrs – single application
• Low- to medium-potency topical corticosteroid for symptom relief
Pediculosis Pubis - Management
Pyrethrins w/piperonyl butoxide (RID, Pronto): ≥ 2 years or older
Permethrin 1% (Nix): ≥ 2 months or older • Ensure skin is cool/dry
• Apply to all suspect areas
• Wash after 10 minutes
• Remove nits with nit comb, tweezers, or fingernails • Retreat in 10 days
Scabies Presentation
- Pruritus – severe, worse at night
- Small erythematous papules with excoriation
- Burrows – thin serpiginous lines, can be red, gray or brown
- Distribution, rarely localized
- Web spaces, wrists, axillary folds, waist, buttocks, male genitalia, periareolar skin, extensors
Scabies – Management
Permethrin 5% cream, ≥ 2months and older
• Apply neck down, wash after 8-14 hrs, repeat in 1 week
Ivermectin 200 mcg/kg PO single dose, repeat 1-2 weeks
clothing, linen, furniture
Treat all household members
Advise patients itching may persist several weeks after treatment
Crusted (Norwegian) Scabies mgmt
• Permethrin 5% cream – full body application, wash after 8-14 hrs • Repeat daily for 7 days, then 2X/week until symptom resolution
AND
• Oral ivermectin 200 mcg/kg/dose on days 1, 2, 8, 9, and 15
Lyme Disease
Borrelia burgdorferi, New England states, west coast, and upper Midwest, Transmission takes 24-48 hrs once tick attaches and feeds
Early Localized Lyme
Days to Weeks • Erythema migrans (EM)
• Nonpainful, expanding erythema w/central clearing (≈ 80% of patients) & flu-like symptoms with no cough
Early Disseminated Lyme
Weeks to Months
• Mult EM lesions and/or neuro/cardiac findings • ≈ 10% develop neuro symptoms
• motor/sensory radiculoneuropathy
Late Disease lyme
Months to Years
• Arthritis one or few large joints, knee common
• Neuropathies, mild encephalopathy, acrodermatitis chronica atrophicans
Lyme Disease – Serologic Testing
early - nothing, false negatives. weeks-mo: Detectable IgM & IgG antibodies to B. burgdorferi, late: IgG Western blot should be positive
IgM antibodies take 1-2 wks, IgG take 2-6 wks following onset of EM
Lyme 2 tiered testing
ELISA, if + then western blot – Detects IgM & IgG antibodies to multiple components of the spirochete
Considerations in early lyme testing
IgM antibodies take 1-2 wks, IgG take 2-6 wks following initial EM
• In early EM, seronegative (treatment initiated based on clinical findings)
• Early treatment with antibiotics may prevent seroconversion
Considerations (later disease lyme)
Seropositive titers persist for years, despite resolution with treatment
• Retesting not useful, interpret future positive test carefully
Lyme Disease – Management
Prophylaxis – within 72 hrs of bite
Doxycycline 200mg PO, single dose
early lyme tx
Early Disease – treat for 2-3 wks (Adults), 2 wks (Peds)
• Doxycycline – 100mg BID adults, 2.2 mg/kg BID children
• Amoxicillin – 500mg TID adults, 50mg/kg/day in 3 divided doses
• Preferred for pregnancy
Suspect Lyme if patient presents with
flu-like symptoms and no
cough during summer months
Primary EM lesions are
> 5cm & slowly expanding
• Rarely pruritic or burning, lack scaly, typically asymptomatic
Rocky Mountain Spotted Fever
• Gram-negative bacterium Rickettsia rickettsii
• Transmitted via Brown dog tick, Rocky Mountain
wood tick, American dog tick
• High fatality if not treated (20%-30%)
• > 90% of cases occur April – Sept
• Southeast and Central states of US
Clinical Presentation RMSF
- 3-12 days after infection
- Fever, headache, and myalgia (almost always present) • Abdominal pain (esp. in children), nausea, and vomiting
- 3-5 days after onset of fever, rash appears
RMSF Rash
Papular rash starts on wrists, forearms, ankles & spreads to trunk • Papules progress to petechiae in 5-6 days
• Palms/soles affected later in disease
• Hand/pedal (especially children) and periorbital edema
Clinical Presentation & Diagnosis RMSF
- Headache, fever, myalgia w/wo petechial eruption on palms/soles
- Labs – norm WBC at presentation, then thrombocytopenia
RMSF Dx
- Indirect immunofluorescence (IIF) for IgM & IgG antibodies
- Antibodies appear 7-10 days after onset of symptoms
- IgG antibodies titers persist for years
- Do not use IgM alone to make dx of acute RMSF (false positives)
- Direct immunofluorescence (DIF) for R. rickettsii
- Before or within 12 hrs of antibiotics
RMSF - Management
Doxycycline – treat at lest 3 days after fever resolves (1-2 weeks)
• Adults & children > 45kg: Doxycycline 100mg BID
• Children < 45kg: Doxycycline 2.2mg/kg/dose BID (daily max 200mg )
• Pregnant women: Doxycycline at adult dose
