pneumonia%20-%20community-acquired%20(pediatric)
PNEUMONIA - COMMUNITY-ACQUIRED (PEDIATRIC)
Community-acquired pneumonia is the presence of signs and symptoms of lower respiratory tract infection acquired outside of the hospital.
The most common bacterial cause of childhood pneumonia is Streptococcus pneumoniae. It usually causes about 1/3 of radiographically-confirmed pneumonia in children <2 years of age.
Viruses commonly affect children <1 year of age than those aged >2 years, respiratory syncytial viruses (RSV) being the most frequently detected virus.
Mixed infection may occur in 8-40% of community-acquired pneumonia cases.

Diagnosis

  • Diagnosis of community-acquired pneumonia (CAP) is primarily based on history and physical findings (eg signs and symptoms of respiratory distress, fever)
    • Laboratory and radiographic exams may aid in the diagnosis of severe cases or in patients who failed to show clinical improvement after initiation of antibiotic therapy

Assessment

  • Necessary to identify patients who may be effectively treated as outpatient and who may need hospitalization
  • Patient’s history, presentation and physical examination are the major determinants of the severity of illness and appropriate site of care
  • Severity should be based on patient’s overall clinical appearance and behavior (eg degree of alertness and eagerness to feed)

    Infants

    Older Children

    Mild to Moderate CAP

    Severe CAP

    Mild to Moderate CAP

    Severe CAP

    Temperature

    <38.5°C

    ≥38.5°C

    <38.5°C

    ≥38.5°C

    Respiratory rate

    <50 breaths/minute

    >70 breaths/minute

    <50 breaths/minute

    >50 breaths/minute

    Breathing effort

    • Mild chest recession
    • Moderate-severe chest recession
    • Nasal flaring
    • Cyanosis
    • Intermittent apnea
    • Grunting
    • Mild breathlessness
    • Severe difficulty in breathing
    • Nasal flaring
    • Cyanosis
    • Grunting

    Other features

    • Taking full feeds
    • Not feeding
    • Increased heart rate
    • Capillary refill time ≥2 seconds
    • No vomiting
    • With signs of dehydration
    • Increased heart rate
    • Capillary refill time ≥2 seconds
    Modified from: Harris M, Clark J, Coote N, et al, on behalf of the British Thoracic Society Standards of Care Committee. British Thoracic Society guidelines for the management of community acquired pneumonia in children: update 2011. Thorax. 2011;66(2):ii16.

History

  • Patient’s age, immunization status
    • Age is a good predictor of the causative agent
      • Viruses are often linked in up to 50% of pneumonia in young children
      • S pneumoniae followed by atypical pneumonia (eg Mycoplasma and Chlamydia) is the most likely pathogen in older children with pneumonia of bacterial origin
    • Immunization status is important because children fully immunized against Haemophilus influenza type B and S pneumoniae are less likely to be infected with these pathogens
  • Symptoms may include fever, difficulty in breathing, cough, chest or abdominal pain with or without vomiting, headache
    • Patients with cough or difficulty of breathing with either lower chest indrawing, nasal flaring, or grunting are considered to have severe pneumonia
    • Patients with cough or difficulty of breathing with either cyanosis, severe respiratory distress, inability to drink or vomits everything, or lethargy, unconsciousness, convulsions have very severe pneumonia
  • Should also take note of the season of the year, daycare attendance, exposure to tobacco smoke or infectious diseases (eg tuberculosis), history of travel, or coexisting illnesses [ie cardiac or pulmonary disorders (eg history of severe or recurrent pneumonia, bronchopulmonary dysplasia, cystic fibrosis, congenital heart disease), immunodeficiencies, neuromuscular diseases (eg severe cerebral palsy)]  

Physical Examination

  • Combination of clinical findings are more predictive in diagnosing community-acquired pneumonia (CAP)
  • Check for temperature
    • Fever in viral pneumonia is generally lower than in bacterial pneumonia; bacterial pneumonia presents with persistent or recurrent temperatures of ≥38.5°C over the prior 24-48 hours
  • Respiratory rate (RR)
    • Study shows significant correlation between RR and oxygen saturation
    • Less sensitive and specific in the first 3 days of illness
    • Criteria for tachypnea based on age as defined by World Health Organization (WHO):
      • ≥60 breaths/minute in <2 months old
      • ≥50 breaths/minute in 2-11 months old
      • ≥40 breaths/minute in 1-5 years old
      • >20 breaths/minute in ≥5 years old
    • Tachypnea may be a marker for respiratory distress and/or hypoxemia but may also be secondary to fever, dehydration or concurrent metabolic acidosis
    • Increased work of breathing is associated with changes radiologically
  • Respiratory signs may include intercostal, subcostal, or suprasternal retractions, nasal flaring, crackles or wheezing on auscultation
    • Decreased breath sounds, scattered crackles, or rhonchi are usually heard over the affected lung field in the early course of illness
    • Dullness on percussion and decreased breath sounds are usually appreciated when increased consolidation and complication develops

Laboratory Tests

  • May not be necessary in uncomplicated pneumonia
Microbiology
  • Aids in determining the causative agent to provide a narrow-spectrum antimicrobial therapy that targets a specific bacteria or virus
  • Blood culture is not routinely done in a nontoxic, fully immunized children with community-acquired pneumonia (CAP)
    • Recommended in patients requiring hospitalization for presumed moderate to severe bacterial CAP, specifically those with complicated pneumonia
    • Should also be performed in outpatients who do not show clinical improvement and in those with progressive symptoms or clinical deterioration even after starting the antibiotic therapy
    • Follow-up blood culture is necessary to document resolution of bacteremia caused by S aureus, regardless of patient’s clinical status
  • Sputum Gram stain and culture is recommended in hospitalized older children and adolescents with more severe disease or in those in whom outpatient therapy has failed
Tests for Viral Pathogens
  • Tests that are specific and sensitive to rapidly identify influenza virus and other respiratory viruses should be done to evaluate children with CAP
    • Positive influenza test will guide appropriate antiviral agents to be used in both inpatient and outpatient settings, and may also decrease the need for additional diagnostic studies and antimicrobial use
Tests for Atypical Bacteria
  • School-aged children and adolescents presenting with signs and symptoms of possible M pneumoniae should be tested to identify the appropriate antibiotic to use
    • However, no single currently available test (eg culture, cold agglutinating antibodies, serology and molecular-based methods) offers the sensitivity and specificity desired in a clinically relevant time frame

Ancillary Diagnostic Tests

  • Complete blood count (CBC) provides evaluation of white blood cells and determines presence of anemia or thrombocytopenia which may guide antimicrobial intervention and identify presence of hemolytic-uremic syndrome, a rare complication of pneumococcal pneumonia
  • Acute-phase reactants [eg peripheral white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) concentration, procalcitonin concentration] should not be routinely done in fully immunized patients with CAP
    • May provide useful information in managing patients requiring hospitalization or those with complications
    • May be helpful in assessing patient’s response to therapy in conjunction with clinical findings
  • Pulse oximetry gives an estimate of arterial oxygenation in a non-invasive manner
    • More directly relevant in evaluating severity of disease in CAP
    • Should be done in all children with pneumonia and suspected hypoxemia
      • Presence of hypoxemia will determine the diagnostic tests needed and if hospitalization is warranted
      • Hypoxemia is a well established determinant for poor outcome in children and infants with systemic disease
    • Usually monitored continuously in a child with increased work of breathing or significant distress especially if the patient has a decreased level of activity or agitation

Imaging


Chest X-ray
  • Not necessary to confirm suspected community-acquired pneumonia (CAP) in outpatient setting since diagnosis of CAP is strongly suspected based on clinical findings
    • Cannot differentiate viral from bacterial CAP nor among different possible bacterial pathogens
  • Postero-anterior (PA) or lateral chest x-rays are indicated in patients with suspected or documented hypoxemia or significant respiratory distress, and in patients who did not respond to initial antibiotic therapy to confirm presence of possible complications (eg empyema, parapneumonic effusions, necrotizing pneumonia, pneumothorax)
    • Also recommended in hospitalized patients to determine the presence, size and character of parenchymal infiltrates, and to document possible complications
  • Daily chest x-ray is not required in stable patients with pneumonia complicated by parapneumonic effusion after chest tube placement or after video-assisted thoracoscopic surgery (VATS)
  • Follow-up chest X-ray should not be done routinely in patient who improved uneventfully from CAP but is recommended in patients who do not show clinical improvement and in those with progressive symptoms or clinical deterioration within 48-72 hours after starting the antibiotic therapy
    • Should also be obtained in patients with complicated pneumonia who has worsening respiratory distress or clinical instability or in those who are consistently febrile even after 48-72 hours of antibiotic use
    • Recommended after 4-6 weeks in patients with recurrent pneumonia in the same lobe and in patients with lobar collapse at first chest x-ray with suspicion of an anatomic anomaly, chest mass, or foreign body aspiration

Other Imaging Studies

  • Chest ultrasound is the imaging study of choice to assess pleural fluid loculations
    • Chest ultrasound has no ionizing radiation; hence, considered a safer imaging procedure than computed tomography (CT)
    • May be used as a guide in percutaneous needle aspiration for direct culture of infected lung tissue, chest tubing or thoracentesis
  • CT may also be used to confirm the presence of pleural fluid
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