Rosen & Barkin's 5-Minute Emergency Medicine Consult (391 page)

Sepsis

CODES

• 279.2 Combined immunity deficiency
  
• 279.3 Unspecified immunity deficiency
  
• 279.8 Other specified disorders involving the immune mechanism
  

BASICS

• Impetigo is a common infection of the skin
  
• Primary infection:
  
  • Infection of minor breaks in the skin
    
• Secondary infection:
  
  • Infection of previously existing skin lesions, known as “impetiginization”
    
• Most prevalent in children aged 2–5 yr
  
• More common in summer months and warm and humid climates
  
• Predisposing factors:
  
  • Minor trauma, esp. around nose area
    
  • Burns
    
  • Insect bites
    
  • HIV infection
    
  • Diabetes mellitus
    
  • Existing skin disease
    
  • Varicella infection
    
• Complications:
  
  • Acute poststreptococcal glomerulonephritis
    
    • 1–5% in patients with nonbullous impetigo
      
  • Sepsis
    
  • Cellulitis
    
  • Endocarditis
    
  • Toxic shock syndrome
    
  • Staphylococcal scalded skin syndrome (SSSS)
    

• Classic impetigo:
  
  • The result of bacteria entering through traumatic skin portal from scratch, abrasion, or insect bite
    
  • Caused by
    Staphylococcus aureus,
    group A β-hemolytic streptococci, or both
    
  • Often associated with poor hygiene
    
  • Treatment of both streptococci and
    S. aureus
    
• Bullous impetigo:
  
  • Caused by
    S. aureus
    , phage group II
    
  • Epidermal cleavage is caused by staphylococcal exfoliative toxins A, B, and D, which are serine proteases that bind and cleave desmoglein 1, an intercellular adhesion molecule in desmosomes
    

Zinc supplementation to mother during pregnancy may lead to decreased incidence in infants

DIAGNOSIS

• Classic (nonbullous) impetigo:
  
  • Begins as a single 2–4 mm erythematous macule or papule that may evolve into a vesicle or pustule, on a red base
    
  • Rupture of the vesicle, usually within 24 hr, leaves a honey-colored, dark brown, or reddish-black exudative crust
    
  • Highly contagious
    
  • Often pruritic, may be spread from the original site of infection by scratching
    
  • Mild lymphadenopathy may be seen, usually not lymphadenitis
    
  • Systemic manifestations are rare
    
  • Rheumatic fever does not occur following streptococcal skin infection
    
  • Skin infections with nephritogenic strains of group A streptococci are major antecedents of poststreptococcal glomerulonephritis
    
• Bullous impetigo:
  
  • Occurs most commonly in the neonate, but can occur at any age
    
  • Lesions begin as vesicles that turn into flaccid bullae with clear yellow fluid
    
  • Nikolsky sign is absent
    
  • Large, fragile bullae rupture quickly, leaving only a shiny, erythematous base with peeling edges
    

Fever and constitutional symptoms are uncommon

• Common sites of infection:
  
  • Face
    
  • Extremities
    
  • Scalp
    
• The diagnosis is made based on observation of the classic exam findings, especially appearance, and distribution
  

Cultures of fluid from bullae or pustules may be considered in those cases refractory to traditional therapy or if methicillin-resistant
S. aureus
(MRSA) is of particular concern during an outbreak

• Antistreptolysin O titer after streptococcal impetigo is scant
  
• AntiDNase B response readily occurs; 90% of patients with nephritis complicating streptococcal skin infections have elevated titers
  
• Urinalysis to evaluate for hematuria or proteinuria which might suggest onset of poststreptococcal glomerulonephritis
  

Not usually indicated

• Biopsy is generally not needed for diagnosis
  
• If biopsy is performed:
  
  • Subcorneal epidermal cleavage plane
    
  • Inflammatory infiltrate of neutrophils and lymphocytes in the upper dermis
    
  • Subcorneal blisters with occasional acantholytic cells
    
• Gram stain of blister fluid may show PMNs and gram-positive cocci in chains or clusters
  

• Herpes simplex
  
• Varicella zoster (shingles)
  
• Atopic dermatitis
  
• Contact dermatitis
  
• Dermatophytosis
  
• Erysipelas
  
• Candidiasis
  
• Scabies
  
• Folliculitis
  
• Pediculosis
  
• Pemphigus vulgaris
  
• Bullous pemphigoid
  
• Seborrheic dermatitis
  
• Thermal burns
  
• Stevens–Johnson syndrome
  
• Bullous erythema multiforme
  
• SSSS, caused by systemic spread of exfoliatin in susceptible individuals
  
• Pemphigus neonatorum (Ritter disease), or SSSS in the newborn
  
• Toxic epidermal necrolysis
  
• Cutaneous anthrax
  

TREATMENT

• Apply dressings to cover for transport
  
• Gloves must be worn, as agents can be transmitted person to person
  
• Cautions:
  
  • Maintain universal precautions
    
  • Siblings of affected children in same household should be checked for lesions
    

In healthy children or adults, classic or bullous impetigo is not a life-threatening condition and does not require resuscitative measures

• Small nonbullous lesions may be treated with topical therapy alone
  
• Larger, widespread lesions, or presence of bullous impetigo, or presence of lymphadenopathy should be treated with systemic therapy
  
• Systemic treatment should include a β-lactamase–resistant penicillin, cephalosporin, or macrolide antimicrobial for 10 days:
  
  • If no response, check for MRSA and switch antibiotic to cover for MRSA
    
• Systemic antibiotic advisable during epidemics of acute poststreptococcal glomerulonephritis or in communities with widespread MRSA
  
• Local care should include cleansing, removal of crusts, and application of wet dressings to the affected areas
  

• All treatment regimens are 10 days, except for topical retapamulin, which is used for 5 days and may enhance compliance, and oral azithromycin, which lasts 9 days when taken for 5 days
  
• Avoid use of erythromycin if high incidence of erythromycin resistance of streptococci or staphylococci in the community
  
• Oral:
  
  • Amoxicillin/clavulanic acid: 250 mg PO q8h (peds: 30 mg/kg/d PO in div. doses q8h)
    
  • Azithromycin: 500 mg PO on day 1; 250 mg PO days 2–5 (peds: 10 mg/kg PO on day 1; 5 mg/kg PO days 2–5)
    
  • Cephalexin: 500 mg PO QID (peds: 25–50 mg/kg/d PO in div. doses q8–12h)
    
  • Clarithromycin: 250 mg PO q12h (peds: 15 mg/kg in div. doses q12h)
    
  • Clindamycin: 150 mg PO TID (peds: 5 mg/kg TID)
    
  • Dicloxacillin: 250 mg PO q6h (peds: 25–50 mg/kg/d PO in div. doses q6h)
    
  • Doxycycline: 100 mg PO q12h when MRSA suspected: (Peds over 8 yr and under 45 kg, give 4.5 mg/kg/d in div. doses q12h). Not recommended for children under 8 yr
    
  • Erythromycin ethylsuccinate: 250 mg PO q6h (peds: 40 mg/kg/d PO in div. doses q6h)
    
  • Trimethoprim–sulfamethoxazole DS: 1 tab PO BID for 10 days (peds: >2 mo; 4 mg/kg of trimethoprim component PO q12h for 10 days); Useful when MRSA suspected
    
  • Linezolid: 600 mg PO BID—expensive, used only for multiallergic patients or MRSA (peds: Not approved for children)
    
• Topical:
  
  • Mupirocin (2% ointment [Bactroban]): Adult and peds: Apply topically to affected area TID (nonbullous impetigo only) for 10 days.
    
  • Retapamulin (1% ointment) (Altabax): Adult and peds >9 mo: Apply topically to affected areas BID for 5 days.
    

Topical:

• Mupirocin: (up to 46% of US 300 strain of Community-acquired MRSA carry gene encoding for resistance to mupirocin)
  

• Topical:
  
  • Retapamulin (package insert says not for MRSA due to not enough cases studied, but has shown effect on mupirocin-resistant MRSA)
    
• Oral antibiotics:
  
  • Amoxicillin/clavulanic acid
    
  • Cephalosporins
    
  • Dicloxacillin
    
  • Erythromycin
    
  • Doxycycline