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Approach to the Critical Patient
Immediate priorities
Stabilization and escalation
Airway compromise
If stridor or inability to protect airway, airway team activation
If facial bite with expanding hematoma, early airway planning
Breathing compromise
If hypoxemia or respiratory distress, resuscitation bay
If aspiration risk from intoxication, continuous monitoring
Circulation compromise
If hypotension or septic shock physiology, sepsis pathway
If uncontrolled hemorrhage, hemostasis and urgent surgical consultation
Sepsis trigger set
Fever or hypothermia
Tachycardia
Hypotension
Altered mental status
Analgesia plan
Local anesthesia option
Regional block option for hand injuries
Non-opioid first line when feasible
High-risk injury patterns
Clenched fist injury over MCP
Dorsal MCP laceration after punching teeth
High risk extensor tendon and joint capsule violation
Rapid progression to septic arthritis and tenosynovitis
Hand bites
High infection risk
Deep space involvement risk
Function-threatening complications
Face bites
Cosmetic and functional structure involvement
Consider early specialty consultation
Genital bites
High contamination risk
Urology or gynecology consultation threshold low
Key decision points
Wound risk stratification
Time from injury
More than 12 hours since injury
More than 24 hours since injury
Depth and structure involvement
Tendon sheath concern
Joint involvement concern
Bone exposure concern
Contamination and devitalized tissue
Crush component
Necrotic edges
Host risk
Diabetes
Immunosuppression
Asplenia
Peripheral vascular disease
Consultation triggers
Hand surgery or plastics
Clenched fist injury pattern
Any tendon dysfunction
Any joint penetration concern
Deep space infection concern
Neurovascular compromise
Infectious diseases
Concern for HIV nPEP indication
Hepatitis B prophylaxis decision support
Severe infection with resistant pathogen risk
Social work and safeguarding
Assault and safety concerns
Intimate partner violence concern
Child protection involvement concern
Wound care essentials
Bedside wound management bundle
Copious irrigation
High volume saline irrigation
Avoid high-pressure injection into closed spaces
Exploration
Full depth visualization when feasible
Tendon and joint capsule evaluation for hand injuries
Debridement
Devitalized tissue removal
Foreign material removal
Hemostasis and dressing
Non-adherent dressing
Bulky dressing for hand
Splinting for hand bites
Position of function
Elevation plan
History
Exposure and mechanism
Bite event details
Occlusive bite
Direct tooth compression
Location and number of bites
Clenched fist mechanism
Punch to mouth
Dorsal MCP injury onset
Time from injury
Minutes to hours
More than 12 hours
More than 24 hours
Wound care before arrival
Irrigation performed
Topicals applied
Closure attempts
Source person considerations
Known or unknown source
Identifiable source available for testing
Unknown source
Blood exposure description
Blood in biter mouth
Victim bleeding at time of bite
Infectious risk history if available
HIV status known
Hepatitis B status known
Hepatitis C status known
Symptoms and progression
Local symptoms
Pain severity and trend
Increasing pain over hours
Pain out of proportion
Swelling progression
Rapid swelling
Spreading edema
Redness and warmth
Expanding erythema
Lymphangitic streaking
Drainage
Purulence
Serosanguinous drainage
Functional symptoms
Hand function
Finger extension limitation
Finger flexion limitation
Grip weakness
Joint symptoms
Pain with range of motion
Joint stiffness
Neurovascular symptoms
Numbness
Tingling
Coldness or color change
Systemic symptoms
Fever
Chills
Malaise
Nausea or vomiting
Patient risk factors
Comorbidities
Diabetes
Chronic kidney disease
Chronic liver disease
Peripheral vascular disease
Immunocompromise
Steroids
Chemotherapy
Transplant
Advanced HIV
Medication and allergy history
Beta-lactam allergy details
Previous MRSA colonization or infection
Anticoagulant use
Immunization status
Tetanus vaccine timing
Hepatitis B vaccination series status
Physical Exam
Vitals and general
Physiologic status
Temperature
Fever
Hypothermia
Heart rate
Tachycardia
Relative bradycardia
Blood pressure
Hypotension
Hypertension with pain
Respiratory status
Tachypnea
Hypoxemia
Mental status
Confusion
Lethargy
Wound and soft tissue exam
Local wound assessment
Location and size
Face
Hand
Genital
Depth indicators
Visible tendon
Visible fat
Visible bone
Infection signs
Erythema border
Warmth
Induration
Fluctuance
Purulence
Necrosis indicators
Dusky tissue
Bullae
Crepitus
Foreign body indicators
Tooth fragment concern
Embedded debris concern
Hand focused exam
Neurovascular and function
Perfusion
Capillary refill
Distal pulses when applicable
Sensation
Median nerve distribution
Ulnar nerve distribution
Radial nerve distribution
Motor
Extensor tendon function
Flexor tendon function
Joint assessment
MCP tenderness
Pain with passive motion
Deep infection flags
Flexor tenosynovitis indicators
Fusiform digit swelling
Tenderness along flexor sheath
Pain with passive extension
Finger held in flexion
Septic arthritis indicators
Effusion
Severe pain with range of motion
Marked motion limitation
PITFALLS
Common misses
Dorsal MCP laceration treated as superficial
Joint penetration not recognized on initial exam
Primary closure of contaminated hand bite
Clindamycin monotherapy for human bite pathogens
Differential Diagnosis
Infectious and inflammatory
Soft tissue infection spectrum
Cellulitis
ICD-10 L03.1
Rapidly spreading erythema and warmth
Abscess
ICD-10 L02
Fluctuance or focal tenderness
Necrotizing soft tissue infection
ICD-10 M72.6
Pain out of proportion
Lymphangitis
ICD-10 I89.1
Proximal streaking
Deep structure infections
Septic arthritis
ICD-10 M00
Severe pain with motion
Osteomyelitis
ICD-10 M86
Persistent pain and systemic signs
Flexor tenosynovitis
ICD-10 M65.1
Kanavel sign cluster
Traumatic and structural
Trauma related
Tendon laceration
Extensor tendon injury
Flexor tendon injury
Fracture
Phalanx fracture
Metacarpal fracture
Retained foreign body
Tooth fragment retention
Debris retention
Exposure related
Bloodborne pathogen exposure
HIV exposure
Hepatitis B exposure
Hepatitis C exposure
Laboratory Tests
Infection and sepsis evaluation
Systemic infection labs
Complete blood count for systemic infection concern
Leukocytosis
Neutrophilia
C reactive protein for inflammatory burden
Rising trend support for deep infection
Normal value does not exclude early infection
Serum lactate for sepsis physiology
Elevated value supports hypoperfusion
Normal value does not exclude serious infection
Blood cultures for systemic toxicity
Fever
Hypotension
Metabolic and medication safety
Baseline chemistry
Electrolytes and kidney function for antibiotic dosing
Dose adjustment need
IV therapy planning
Glucose for diabetes screening and infection risk
Hyperglycemia worsens outcomes
Undiagnosed diabetes consideration
Microbiology and exposure baseline
Cultures and exposure testing
Wound culture only for established infection
Purulent drainage
Deep tissue specimen preferred if operative management
HIV baseline test when nPEP considered
Rapid HIV test or lab based antigen antibody
Baseline result before nPEP when feasible without delaying start
Hepatitis B baseline tests when prophylaxis considered
HBsAg if source testing available
Anti HBs if patient immunity uncertain
Hepatitis C baseline test for significant blood exposure
Anti HCV or HCV RNA based on local protocol
Pregnancy related
Pregnancy testing
Urine or serum pregnancy test when pregnancy possible
Antibiotic selection safety
HIV nPEP regimen safety
Diagnostic Tests
Scoring Systems
Systemic illness scoring
qSOFA for sepsis risk flag
Altered mentation
Respiratory rate 22 per minute or more
Systolic blood pressure 100 mmHg or less
SIRS screening for inflammatory response
Temperature abnormality
Heart rate 90 per minute or more
Respiratory rate 20 per minute or more
White blood cell count abnormality
Necrotizing infection support scores
LRINEC as adjunct only
Low sensitivity in early disease
Not a rule-out tool
MRI
Deep infection delineation
Osteomyelitis evaluation when plain films nondiagnostic
Persistent pain and swelling
Failure of therapy
Tenosynovitis and deep space infection evaluation
Equivocal exam
High-risk hand bite with severe pain
Contraindications and limitations
Delays in time-critical surgical infections
Implanted devices constraints
CT
Cross-sectional imaging indications
Facial bites with deep structure concern
Orbital involvement concern
Sinus involvement concern
Deep abscess evaluation when ultrasound limited
Gas concern
Complex anatomy
Foreign body detection adjunct
Radiolucent foreign body concern
Complex wound tract
Ultrasound (or US)
Point-of-care applications
Abscess versus cellulitis
Fluid collection identification
Guidance for drainage planning
Tendon integrity adjunct for superficial tendon concern
Dynamic evaluation support
Not a substitute for operative exploration when high suspicion
Doppler assessment adjunct
Perfusion concern in swollen digit
Reduced flow support for urgent consultation
Normal flow does not exclude compartment process
Plain radiography
X-ray indications
Hand bites and clenched fist injuries
Fracture detection
Tooth fragment detection
Any bite with foreign body concern
Radiopaque debris detection
Subcutaneous gas detection
Disposition
Level of care
Discharge criteria
Superficial wound without deep structure concern
No tendon dysfunction
No joint involvement concern
No systemic illness features
Afebrile
Hemodynamically stable
Reliable follow-up within 24 to 48 hours
Hand recheck arranged for hand bites
Wound care instructions understood
Admission criteria
Established infection requiring IV therapy
Rapidly progressive cellulitis
Significant edema or pain limiting function
Deep structure infection concern
Septic arthritis concern
Tenosynovitis concern
Osteomyelitis concern
High-risk host factors
Immunocompromised state
Poor outpatient reliability
Transfer criteria
Hand bites needing operative capability
Clenched fist injury with MCP involvement concern
Tendon laceration requiring repair
Face bites needing specialty repair
Vermillion border involvement
Eyelid or canal involvement
Follow-up timing
Reassessment planning
Hand bite recheck within 24 hours
Function reassessment
Infection progression check
Other bites recheck within 48 hours when prophylaxis given
Dressing change guidance
Antibiotic tolerance check
Treatment
Wound management
Local therapy
Irrigation and debridement strategy
High volume saline irrigation
Debridement of devitalized tissue
Closure strategy
Hand bites left open
Delayed primary closure consideration when clean and improving
Face bites primary closure consideration after irrigation and debridement
Immobilization and elevation
Splint for hand bites
Elevation above heart level
Antibiotics
Empiric coverage targets
Typical flora
Streptococcus species
Staphylococcus aureus
Eikenella corrodens
Oral anaerobes
Coverage cautions
Clindamycin monotherapy inadequate for Eikenella
First generation cephalosporins inadequate for Eikenella
Oral regimens
Amoxicillin clavulanate
Adult dose 875 mg 125 mg by mouth every 12 hours
Duration prophylaxis 3 to 5 days
Duration treatment 5 to 7 days
Penicillin allergy non-anaphylaxis
Cefuroxime by mouth
Add metronidazole by mouth for anaerobes
Avoid if immediate hypersensitivity history
Cefpodoxime by mouth
Add metronidazole by mouth for anaerobes
Avoid if immediate hypersensitivity history
Penicillin allergy immediate hypersensitivity
Doxycycline by mouth
Adult dose 100 mg every 12 hours
Add metronidazole 500 mg every 12 hours
Moxifloxacin by mouth
Adult dose 400 mg daily
Avoid in pregnancy
IV regimens
Ampicillin sulbactam
Adult dose 3 g IV every 6 hours
Transition to oral when improving
Total duration commonly 7 to 14 days for deep infection based on source control
Piperacillin tazobactam
Adult dose 4.5 g IV every 6 to 8 hours
Severe infection with polymicrobial risk
Penicillin allergy immediate hypersensitivity
Levofloxacin IV
Adult dose 750 mg daily
Add metronidazole 500 mg IV every 12 hours
Doxycycline IV
Adult dose 100 mg every 12 hours
Add metronidazole 500 mg IV every 12 hours
MRSA risk additions
MRSA risk features
Prior MRSA infection
Purulent infection
High local prevalence
Oral MRSA add-on options
Trimethoprim sulfamethoxazole
Add to regimen that covers Eikenella and anaerobes
Not adequate as monotherapy for human bite flora
Doxycycline
Add to regimen that covers anaerobes when needed
IV MRSA add-on options
Vancomycin IV per local dosing protocol
Add to beta-lactam bite coverage
Trough or AUC monitoring per protocol
Tetanus prophylaxis
Immunization and TIG decisions
Wound management principles
Wound cleaning and debridement
Antibiotics not used to prevent tetanus
Vaccine update thresholds
If incomplete primary series, tetanus vaccine indicated
If last tetanus vaccine more than 5 years for dirty wounds, booster indicated
TIG considerations
Unknown or incomplete immunization with dirty wound
Immunocompromised with uncertain immunity
Hepatitis B and HIV exposure management
Hepatitis B post-exposure approach
Patient immunity assessment
Completed hepatitis B vaccine series
Anti HBs known protective
Source status assessment
HBsAg positive
Unknown source
Prophylaxis options
Hepatitis B vaccine series initiation if non-immune
HBIG consideration per local protocol if high-risk source and non-immune
HIV nPEP considerations
Exposure features for consideration
Bite with blood exposure
Source known HIV positive with viremia risk
Significant tissue injury with blood present
Timing window
Most effective when started as soon as possible
Usual outer window 72 hours based on guideline frameworks
Baseline labs for nPEP
HIV test
Kidney function
Liver enzymes
Pregnancy test when applicable
Regimen selection
Local protocol first line regimen
Drug interaction and renal dosing check
Procedural and surgical management
Operative indications
Clenched fist injury with suspected joint penetration
Operative irrigation and debridement
Joint capsule exploration
Tendon injury
Repair planning
Early hand surgery involvement
Deep infection
Abscess drainage
Tenosynovitis washout
Bedside procedures
Incision and drainage for clear abscess
Ultrasound confirmation when uncertain
Culture from purulence when indicated
Special Populations
Pregnancy
Pregnancy considerations
Antibiotic selection
Amoxicillin clavulanate acceptable option in pregnancy when indicated
Avoid doxycycline
Fluoroquinolone use risk benefit discussion
HIV nPEP regimen selection
Pregnancy-safe regimen per local protocol
Obstetrics involvement for medication counseling
Imaging selection
Ultrasound preferred when adequate
X-ray when needed with shielding per local protocol
Geriatric
Older adult considerations
Higher risk of severe infection
Delayed presentation common
Blunted fever response
Medication safety
Renal dosing adjustments common
Higher adverse effect risk with fluoroquinolones
Disposition threshold lower
Admission consideration for hand bites with swelling or function change
Early follow-up reliability assessment
Pediatrics
Pediatric considerations
Weight-based antibiotics
Amoxicillin clavulanate
22.5 mg amoxicillin per kg per dose by mouth every 12 hours
Maximum 875 mg amoxicillin per dose
Ampicillin sulbactam
50 mg ampicillin per kg per dose IV every 6 hours
Maximum 2000 mg ampicillin per dose
Safeguarding
Bite from peer
Bite from caregiver or adult
Documentation of circumstance and safety plan
Follow-up planning
Next day hand recheck for hand bites
Low threshold for admission if unreliable follow-up
Background
Epidemiology
Human bite epidemiology
High infection risk compared with many other lacerations
Hand bites highest risk group
Clenched fist injuries high complication rate
Common contexts
Fights and assaults
Sports and playground injuries
Behavioral bites
Pathophysiology
Microbiology and injury mechanics
Polymicrobial inoculation
Aerobes and anaerobes mixed flora
Eikenella corrodens common organism
Hand anatomy vulnerability
Tendon sheath continuity supports spread
MCP joint capsule risk in clenched fist injuries
Delayed presentation worsens outcomes
Early signs may be subtle
Rapid progression to deep infection possible
Therapeutic Considerations
Treatment rationale
Early irrigation and debridement reduces bacterial load
Mechanical cleansing is key intervention
Source control prevents deep infection
Antibiotic strategy
Broad coverage for aerobes and anaerobes
Avoid agents with Eikenella gaps
Closure strategy rationale
Hand wounds often left open due to contamination
Face wounds may be closed selectively due to vascularity and cosmetic needs
Guideline alignment
IDSA support for amoxicillin clavulanate for bite wound infections
CDC wound management guidance for tetanus prevention
Patient Discharge Instructions
copy discharge instructions
Discharge instructions bundle
Wound care
Keep dressing clean and dry for 24 hours
Gentle wash with soap and water after 24 hours
Elevation as much as possible for the first 48 hours
Medications
Take antibiotics exactly as prescribed
Do not stop early even if feeling better
Pain control plan with dose limits
Activity
Avoid heavy use of affected hand
Keep splint on if provided
Follow-up
Recheck within 24 hours for any hand bite
Recheck within 48 hours for other bites when antibiotics prescribed
Return to emergency signs
Fever
Increasing redness or swelling
Red streaks up the arm or leg
Pus drainage
Worsening pain
New numbness or weakness
Trouble moving fingers or joint
Hand becoming pale, cold, or blue
Bloodborne exposure follow-up when applicable
Follow lab testing schedule provided
Start nPEP immediately if prescribed and do not miss doses
References
Guidelines and key sources
Evidence base
Infectious Diseases Society of America practice guideline for skin and soft tissue infections including bite wounds
Recommendation for agent active against aerobes and anaerobes such as amoxicillin clavulanate
Guidance framework for bite wound infection management
CDC clinical guidance for wound management to prevent tetanus
Wound cleaning and debridement
Antibiotics not recommended to prevent tetanus
CDC HIV post-exposure prophylaxis clinical guidance
Time-sensitive initiation framework
Baseline testing and follow-up structure
Practical antimicrobial references
Antimicrobial selection support
Reference tables for bite wound antibiotics
Outpatient oral regimen options
Inpatient IV regimen options
Eikenella susceptibility considerations
Resistance patterns relevant to clindamycin and first generation cephalosporins
Need for appropriate agent selection
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.