Rosen & Barkin's 5-Minute Emergency Medicine Consult (642 page)

• Presence of an infection with an associated systemic inflammatory response
  
• The systemic inflammatory response syndrome (SIRS) is composed of 4 criteria:
  
  • Temperature >38°C or <36°C
    
  • Heart rate >90 bpm
    
  • Respiratory rate >20/min or PaCO
    ₂
    <32 mm Hg
    
  • WBC >12,000/mm
    ³
    , <4,000/mm
    ³
    , or >10% band forms
    
• Sepsis = infection with ≥2 SIRS criteria:
  
  • Release of chemical messengers by the inflammatory response
    
  • Macrocirculatory failure through decreased cardiac output or decreased perfusion pressure
    
  • Microcirculatory failure through impaired vascular autoregulatory mechanisms and functional shunting of oxygen
    
  • Cytopathic hypoxia and mitochondrial dysfunction
    
• Hemodynamic changes result from the inflammatory response:
  
  • Elevated cardiac output in response to vasodilatation
    
  • Later myocardial depression:
    
• Multiple organ dysfunction syndrome (MODS):
  
  • Adult respiratory distress syndrome (ARDS)
    
  • Acute tubular necrosis and kidney failure
    
  • Hepatic injury and failure
    
  • Disseminated intravascular coagulation
    
• Sepsis should be viewed as a continuum of severity from a proinflammatory response to organ dysfunction and tissue hypoperfusion:
  
  • Severe sepsis: Sepsis with at least 1 of the following organ dysfunctions:
    
    • Acidosis
      
    • Renal dysfunction
      
    • Acute change in mental status
      
    • Pulmonary dysfunction
      
    • Hypotension
      
    • Thrombocytopenia or coagulopathy
      
    • Liver dysfunction
      
  • Septic shock: Sepsis-induced hypotension despite fluid resuscitation:
    
    • Systolic BP <90 mm Hg or reduction of >40 mm Hg from baseline
      
• Sepsis is the 10th leading cause of death in US:
  
  • In-hospital mortality for septic shock is ∼30%
    

• Gram-negative bacteria most common:
  
  • Escherichia coli
    
  • Pseudomonas aeruginosa
    
  • Rickettsiae
    
  • Legionella
    spp.
    
• Gram-positive bacteria:
  
  • Enterococcus
    spp.
    
  • Staphylococcus aureus
    
  • Streptococcus pneumoniae
    
• Fungi (
  Candida
  species)
  
• Viruses
  

• Children with a minor infection may have many of the findings of SIRS.
  
• Major causes of pediatric bacterial sepsis:
  
  • Neisseria meningitidis
    
  • Streptococcal pneumonia
    
  • Haemophilus influenzae
    

DIAGNOSIS

• Question for signs of infection and a systemic inflammatory response:
  
  • Fever
    
  • Dyspnea
    
  • Altered mental status:
    
    • Change in mental status
      
    • Confusion
      
    • Delirium
      
  • Nausea and vomiting
    
• Look for a source of the infection:
  
  • Cough, shortness of breath
    
  • Abdominal pain
    
  • Diarrhea
    
  • Dysuria/frequency
    
• Past history should highlight risk factors and immunosuppressive states:
  
  • Underlying terminal illness
    
  • Recent chemotherapy
    
  • Malignancy
    
  • History of a splenectomy
    
  • HIV
    
  • Diabetes
    
  • Nursing home resident
    

• An elevated respiratory rate is an early warning sign of sepsis and occurs without underlying pulmonary pathology or acidosis.
  
• BP is often normal early in sepsis.
  
• Hypotension when septic shock occurs
  
• Extremities are often warmed and flushed despite hypotension.
  
• Look for a source of the infection:
  
  • Abdominal exam
    
  • Rectal exam to assess for an abscess
    
  • Chest exam for signs of pneumonia
    
  • Any rash is important:
    
    • Localized erythema with lymphangitis (streptococcal or staphylococcal cellulitis)
      
    • Rash involving palms of hands and soles of feet (rickettsial infection)
      
    • Petechiae scattered on the torso and extremities (meningococcemia)
      
    • Ecthyma gangrenosum (pseudomonas septicemia)
      
    • Round, indurated, painless lesion with surrounding erythema and central necrotic black eschar
      
  • Decubitus ulcers
    
  • Indwelling catheter:
    
• CNS infections:
  
  • Coma
    
  • Neck stiffness (meningitis)
    

• Serum lactate should be done early in the course to assess severity and need for goal-directed therapy
  
• Blood cultures prior to antibiotics:
  
  • Broad spectrum of lab tests and imaging studies to locate the source of the infection and assess for MOF.
    
  • Placement of a central line with an ScvO
    ₂
    catheter may be used to adjust therapy.
    

• Serum lactate:
  
  • >4 mmol/L defines severe sepsis
    
  • Normal lactate does not rule out septic shock
    
• CBC with differential:
  
  • Leukocytosis is insensitive and nonspecific
    
  • Neutrophil count <500 cells/mm
    ³
    should prompt isolation and empiric IV antibiotics in chemotherapy patients.
    
  • >5% bands on a peripheral smear is an imperfect indicator of infection.
    
  • Hematocrit:
    
    • Patients should be maintained with a hematocrit >30% and hemoglobin >10 g/dL.
      
  • Platelets:
    
    • May be elevated in the presence of infection or sepsis-induced volume depletion
      
    • Low platelet count is a significant predictor of bacteremia and death.
      
• Electrolytes, BUN, creatinine, glucose:
  
• Ca, Mg, pH
  
• C-reactive protein
  
• Cortisol level
  
• INR/prothrombin time/partial thromboplastin time
  
• Liver function tests
  
• ABG or VBG:
  
  • Mixed acid–base abnormalities: Respiratory alkalosis with metabolic acidosis
    
  • VBG correlates very closely with ABG, except for SaO
    ₂
    
• Blood cultures:
  
  • From 2 different sites
    
  • 1 may be drawn through an indwelling central line (i.e., Broviac).
    
• Urine analysis and culture
  

• CXR:
  
  • Determine whether pneumonia is the infectious source.
    
  • Fluffy, bilateral infiltrates may indicate that ARDS is already present.
    
  • Free air under the diaphragm indicates the source of the infection in intraperitoneal and a surgical intervention is mandatory.
    
• Soft tissue plain films:
  
  • Indicated if extremity erythema or severe pain
    
  • Air in the soft tissues associated with necrotizing or gas-forming infection
    
• Imaging studies to locate the source of the infection based on the presentation:
  
  • CT scan of the abdomen and pelvis
    
  • Abdominal US for gallbladder disease
    
  • Transthoracic or transesophageal echocardiogram
    

• Lumbar puncture:
  
  • For meningeal signs or altered mental status
    
• Central venous access:
  
  • Central venous pressure (CVP) and ongoing measurement of central venous oximetry.
    

• Pancreatitis
  
• Trauma
  
• Hemorrhage
  
• Cardiogenic shock
  
• Toxic shock syndrome
  
• Anaphylaxis
  
• Adrenal insufficiency
  
• Drug or toxin reactions
  
• Heavy metal poisoning
  
• Hepatic insufficiency
  
• Neurogenic shock
  

TREATMENT

Aggressive fluid resuscitation for hypotension

• ABCs
  
• Supplemental oxygen to maintain PaO
  ₂
  >60 mm Hg
  
• Intubation and mechanical ventilation if shock or hypoxia are present
  
• Administer 0.9% NS IV.
  

• Early goal-directed therapy:
  
  • 500 cc boluses of 0.9% saline up to 1–2 L empirically
    
  • Place central line.
    
  • Continue 500 cc saline boluses until CVP >8 cm H
    ₂
    O.
    
  • If the mean arterial pressure <65 mm Hg and CVP >8, then initiate pressors:
    
    • Norepinephrine or dopamine to raise BP
      
    • Norepinephrine is preferred if tachycardia or dysrhythmias are present.
      
    • Epinephrine for cases where shock is refractory to other pressors
      
    • If the ScvO
      ₂
      <70 and HCT <30, transfuse 2 U PRBCs.
      
    • If ScvO
      ₂
      >70 and HCT >30 and MAP >60, then add dobutamine.
      
• Administer antibiotics early, based on the most likely organisms or site of infection.
  
• If source identified, or highly suspected, treat the most likely organisms:
  
  • Cover for MRSA, VRE, and
    Pseudomonas
    if there are risk factors
    
  • Pulmonary source:
    
    • 2nd- or 3rd-generation cephalosporin and gentamicin
      
  • Intra-abdominal source:
    
    • Ampicillin and metronidazole and gentamicin
      
    • Cefoxitin and gentamicin
      
  • Urinary tract source:
    
    • Ampicillin or piperacillin and gentamicin or levofloxacin
      
• Consider stress-dose hydrocortisone if recent steroid use or possible adrenal insufficiency
  

• Antibiotic therapy based on age:
  
  • <3 mo (2 drugs): Ampicillin and gentamicin or cefotaxime (50–180 mg/kg/d div. q4–6h)
    
  • ≥3 mo: Cefotaxime or ceftriaxone (50–100 mg/kg/d div. q12–24 h)
    
• Initiate vasopressors after no response to 60 mL/kg IV fluid.
  
• Avoid hyponatremia and hypoglycemia.
  
• Dexamethasone for children with bacterial meningitis:
  
  • 0.15 mg/kg q6h for 4 days