Rosen & Barkin's 5-Minute Emergency Medicine Consult (140 page)

• Cannon ML, Antonio BL, McCloskey JJ, et al. Cavernous sinus thrombosis complicating sinusitis.
  Pediatr Crit Care Med
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• Carvalho KS, Garg BP. Cerebral venous thrombosis and venous malformations in children.
  Neurol Clin North Am
  . 2002;20:1061–1077.
  
• Laupland KB. Vascular and parameningeal infections of the head and neck.
  Infect Dis Clin North Am
  . 2007;21(2):577–590, viii.
  
• Misra UK, Kalita J, Bansal V. D-dimer is useful in the diagnosis of cortical venous sinus thrombosis.
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See Also (Topic, Algorithm, Electronic Media Element)

Headache

CODES

• 325 Phlebitis and thrombophlebitis of intracranial venous sinuses
  
• 437.6 Nonpyogenic thrombosis of intracranial venous sinus
  

BASICS

• Acute, spreading erythematous superficial infection of skin and SC tissues:
  
  • Variety of pathogens
    
  • Extension into deeper tissues can result in necrotizing soft tissue infection
    
• Progressive spread of erythema, warmth, pain, and tenderness
  
• Predisposing factors:
  
  • Lymphedema
    
  • Tinea pedis
    
  • Open wounds
    
  • Pre-existing skin lesion (furuncle)
    
  • Prior trauma or surgery
    
  • Retained foreign body
    
  • Vascular or immune compromise
    
  • Injection drug use
    

• Simple cellulitis:
  
  • Group A streptococci
    
  • Staphylococcus aureus
    —including resistant strains such as community-associated methicillin-resistant
    S. aureus
    (CA-MRSA; see below):
    
    • CA-MRSA risk factors include: Prior MRSA infection, household contact of CA-MRSA patient, daycare contact of MRSA patients, children, soldiers, incarcerated persons, athletes in contact sports, IV drug users, men who have sex with men
      
    • Different antibiotic susceptibility than nosocomial MRSA
      
    • CA-MRSA now sufficiently prevalent to warrant empiric treatment
      
    • Suspect CA-MRSA in unresponsive infections
      
• Nosocomial MRSA:
  
  • Risk factors: Recent hospital or long-term care admission, surgery, injection drug use, vascular catheter, dialysis, recent antibiotic use, unresponsive infection
    
  • Resistant to most antibiotics (see “Treatment”)
    
• Extremity cellulitis after lymphatic disruption:
  
  • Nongroup A β-hemolytic streptococci (groups C, B, G)
    
• Cellulitis in diabetics:
  
  • Can be polymicrobial with
    S. aureus
    , streptococci, gram-negative bacteria, and anaerobes, especially when associated with skin ulcers
    
• Periorbital cellulitis:
  
  • S. aureus
    
  • Streptococcal species
    
• Buccal cellulitis:
  
  • Haemophilus influenzae
    type B
    
  • Anaerobic oral flora, associated with intraoral laceration or dental abscess
    
• Less common causes:
  
  • Clostridia
    
  • Anthrax
    
  • Pasteurella multocida
    —common after cat and dog bites
    
  • Eikenella corrodens
    —human bites
    
  • Pseudomonas aeruginosa:
    
    • Hot-tub folliculitis—self-limited
      
    • Foot puncture wound
      
    • Ecthyma gangrenosum in neutropenic patients
      
  • Erysipelothrix species—raw fish, poultry, meat, or hide handlers
    
  • Aeromonas hydrophila
    —freshwater swimming
    
  • Vibrio species—seawater or raw seafood
    

• Facial cellulitis in children:
  
  • Streptococcus pneumoniae
    
  • H. influenzae
    type B, although incidence declining since introduction of HIB vaccine
    
• Perianal cellulitis:
  
  • Group A streptococci
    
  • Associated or antecedent pharyngitis or impetigo
    
• Neonates:
  
  • Group B streptococci
    

DIAGNOSIS

• Common to all syndromes:
  
  • Pain, tenderness, warmth
    
  • Erythema
    
  • Edema or induration
    
  • Fever/chills
    
  • Tender regional lymphadenopathy
    
  • Lymphangitis
    
  • Accompanying SC abscess possible
    
  • Suspect deep abscess especially if treatment failure on initial antibiotic
    
  • Superficial vesicles
    
• Buccal cellulitis:
  
  • Odontogenic cases more serious:
    
    • Toothache, sore throat, or facial swelling
      
    • Progressive extension into soft tissues of neck with fever, erythema, neck swelling, and dysphagia
      

• Facial cellulitis in children:
  
  • Erythema and swelling of the cheek and eyelid
    
  • Rapidly progressive
    
  • Usually unilateral
    
  • Upper respiratory tract symptoms
    
  • Risk for cavernous sinus thrombosis and permanent optic nerve injury
    
• Perianal cellulitis:
  
  • Erythema and pruritus extending from the anus several centimeters onto adjacent skin
    
  • Pain on defecation
    
  • Blood-streaked stools
    

Patients often incorrectly attribute CA-MRSA infection with spontaneous abscess to a spider bite

In simple cellulitis, physical findings can suggest the etiology and help narrow empiric antibiotic coverage:

• Staph etiology: Focal abscess or pustule with: Fluctuance, yellow or white center, central point or “head,” or draining pus, indolent progression
  
• Strep etiology: Sharply demarcated borders, lymphangitis, pre-existing lymphedema, concomitant nausea from toxin
  

• Cellulitis is a clinical diagnosis.
  
• Physical exam to reveal infection source
  

• WBC generally unnecessary
  
• Gram stain and culture to focus antimicrobial selection and reveal resistant pathogens (MRSA):
  
  • Aspirate point of maximal inflammation or punch biopsy if there is no wound to culture
    
  • Perform in treatment failures and consider in admitted patients
    
• Blood culture:
  
  • Usually negative in uncomplicated cellulitis
    
  • May identify organism in patients with:
    
    • Lymphedema
      
    • Buccal or periorbital cellulitis
      
    • Saltwater or freshwater source
      
    • Fever or chills
      

• Plain radiographs may reveal abscess formation, SC gas, or foreign bodies:
  
  • Extension to bone (osteomyelitis) not visualized early on plain radiographs
    
• Extremity vascular imaging (Doppler US) can help rule out deep venous thrombosis (DVT).
  
• US useful for diagnosing abscess if physical exam is equivocal or if there is a broad area of cellulitis
  
  • In cellulitis may see characteristic “cobblestone” appearance and thickening of SC layer, both due to edema
    
• CT or MRI can help rule out necrotizing fasciitis
  

• Necrotizing fasciitis
  
• Lymphangitis or lymphadenitis
  
• Thrombophlebitis or DVT:
  
  • Differentiation from cellulitis:
    
    • Absence of initial traumatic or infectious focus
      
    • No regional lymphadenopathy
      
    • Presence of risk factors for DVT
      
• Insect bite
  
• Allergic reaction
  
• Acute gout or pseudogout
  
• Ruptured Baker cyst
  
• Herpetic whitlow
  
• Neoplasm
  
• Phytophotodermatitis
  
• Erythema chronicum migrans lesion of Lyme disease
  
• Differential diagnosis of facial cellulitis:
  
  • Allergic angioedema
    
  • Conjunctivitis
    
  • Contusion
    

Differential diagnosis of perianal cellulitis:

• Candida intertrigo
  
• Psoriasis
  
• Pinworm infection
  
• Child abuse
  
• Behavioral problem
  
• Inflammatory bowel disease