Pediatric Annals

Special Issue Article 

Back to the Basics: Community-Acquired Pneumonia in Children

Kathleen Boyd, MD


Community-acquired pneumonia (CAP) is a common childhood infection and often a reason for inpatient admission, especially when a child is hypoxic or in respiratory distress. Despite advances in technology and diagnostics, it remains difficult to accurately differentiate bacterial CAP from a viral process. Most of the laboratory tests routinely done in inpatient medicine, such as complete blood counts and acute phase reactants, do little to differentiate a viral pneumonia from a bacterial pneumonia. Clinicians must rely heavily on the clinical presentation and decide whether to treat empirically with antibiotics. Guidelines published by the Infectious Disease Society of America in 2011 have helped clinicians standardize the diagnosis and treatment of CAP. The guidelines recommend relatively narrow-spectrum antibiotics, such as ampicillin or penicillin, as empiric coverage for the fully immunized child older than age 3 months who requires hospitalization for CAP. [Pediatr Ann. 2017;46(7):e257–e261.]


Community-acquired pneumonia (CAP) is a common childhood infection and often a reason for inpatient admission, especially when a child is hypoxic or in respiratory distress. Despite advances in technology and diagnostics, it remains difficult to accurately differentiate bacterial CAP from a viral process. Most of the laboratory tests routinely done in inpatient medicine, such as complete blood counts and acute phase reactants, do little to differentiate a viral pneumonia from a bacterial pneumonia. Clinicians must rely heavily on the clinical presentation and decide whether to treat empirically with antibiotics. Guidelines published by the Infectious Disease Society of America in 2011 have helped clinicians standardize the diagnosis and treatment of CAP. The guidelines recommend relatively narrow-spectrum antibiotics, such as ampicillin or penicillin, as empiric coverage for the fully immunized child older than age 3 months who requires hospitalization for CAP. [Pediatr Ann. 2017;46(7):e257–e261.]

Community-acquired pneumonia (CAP) is one of the most common childhood infections worldwide and continues to be a common reason for inpatient admission.1 With more than 150,000 children requiring hospitalization for pneumonia each year, CAP remains both prevalent and costly.2 Due to relatively newer vaccines (Hib and pneumococcal), accessible antibiotics, and advances in diagnostics and monitoring, the once significant mortality rates associated with CAP have decreased in the industrialized world and mortality is now seen primarily in those children with severe, underlying chronic disease.3,4 However, diagnosis and treatment of pneumonia can still be less than straightforward even in otherwise healthy children.5 This article reviews the diagnosis, testing, and treatment of CAP as described in recently published evidence-based guidelines.


Both the British Thoracic Society6 and the Infectious Diseases Society of America (IDSA)7 have published evidence-based guidelines in the past 6 years regarding the diagnosis and treatment of CAP in children. Both sets of guidelines emphasize that the diagnosis of CAP should be based primarily on clinical criteria. Unfortunately, accurately diagnosing pneumonia in children, particularly whether it is of viral or bacterial etiology, remains challenging, especially because there exists no clear-cut method short of lung biopsy or bronchoalveolar lavage to secure an accurate diagnosis.1,6,7 In adults, gram stain and culture of sputum is widely used to identify the bacteria responsible for pneumonia, but most young children cannot provide adequate sputum samples.1 Additionally, almost 30% of pediatric CAP cases are mixed infections due to viruses and Streptococcus pneumoniae or atypical bacteria and pneumococci.4 Although S. pneumoniae remains the most common bacterial pathogen responsible for CAP, we have seen a markedly reduced incidence in pneumococcal pneumonia in the past decade due to pneumococcal vaccines.3,8

Presenting Signs and Symptoms

Pneumonia is defined as a lower respiratory tract infection associated with respiratory symptoms and fever as well as parenchymal involvement noted by either examination or infiltrate on chest X-ray.5 Although cases of pneumonia occur throughout the calendar year, there is an increased incidence in the fall and winter likely due to an increase in predisposing viral infections.6 Fever and cough are the hallmark of pneumonia in children of all ages. Tachypnea, nasal flaring, and hypoxia may precede the cough (Table 1). The World Health Organization recommends using retractions and tachypnea to diagnose pneumonia in children younger than age 5 years.9 After age 5 years, tachypnea becomes a less specific and sensitive indicator of pneumonia.1,5

Tachypnea in Children

Table 1:

Tachypnea in Children

Overall, most clinical signs have poor sensitivity and specificity in helping to identify CAP. At times, clinicians can also be fooled. Right lower lobe pneumonia can present with abdominal pain mimicking appendicitis, and upper lobe pneumonia can present with radiating neck pain and stiff neck, mimicking meningitis.5,6 Typically, pneumococcal pneumonia presents acutely with fever, tachypnea, nonproductive cough, and decreased breath sounds or crackles over the affected lobe.5 Atypical pneumonia, due to Mycoplasma pneumoniae or Chlamydia pneumoniae, often has a more nonspecific presentation with fever, myalgia, malaise, sore throat, headache, photophobia, and gradually worsening cough. Pneumonia caused by Mycoplasma may also have extrapulmonary symptoms such as myocarditis, arthritis, or meningoencephalitis.5 Viral pneumonia, often caused by respiratory syncytial virus (RSV), has a more gradual onset, typically occurring after an upper respiratory infection that progresses into lower tract symptoms including wheezing and retractions. The respiratory examination is more diffuse or multilobar in a viral process.


In addition to presenting signs and symptoms, a patient's history is important to keep in mind when considering a diagnosis of pneumonia, specifically their travel history or history of being immunocompromised. Notable travel or birth history outside of the United States, at-risk living arrangements, known sick contacts, or exposure to persons with chronic cough should raise the clinical suspicion for tuberculosis (TB). Although the incidence of TB in the US has greatly declined in the past few decades, Mycobacterium tuberculosis remains an important pathogen given the ever-increasing mobility and diversity of our population.5,10 History of exposure to rivers, lakes, water distribution centers, or air-conditioning towers should heighten suspicion for Legionella pneumophilia as a possible etiology of pneumonia, especially in an immunocompromised patient.5 Organisms such as Pseudomonas aeruginosa, Pneumocystis jirovecii (formerly known as Pneumocystis carinii), Aspergillus, and Candida should also be considered in the differential diagnosis when a patient is immunocompromised.

Chest Radiography

Although sometimes necessary to aid in decision-making in an uncertain clinical scenario, routine chest X-rays are not necessary for the diagnosis of CAP in the outpatient setting.7 If a child has a fever, cough, and a focal examination consistent with a “classic” bacterial pneumonia but is otherwise safe to be treated as an outpatient, a chest X-ray will likely not change management and will only expose the child to unnecessary radiation. If the child does not respond as anticipated in the standard 48 to 72 hours after beginning treatment, it is then useful to perform a chest X-ray to evaluate for complicated CAP. In hospitalized patients, chest X-rays are recommended by the IDSA guidelines to document the presence of parenchymal infiltrates and document any evidence of pleural effusion.7 It is not necessary to perform serial radiographs in hospitalized patients. Repeat chest X-rays are only helpful in patients who fail to respond to therapy or fail to demonstrate clinical improvement within 48 to 72 hours of beginning a course of antibiotics. Even in patients with complicated pneumonia, repeat chest X-rays are only useful in patients with worsening distress or clinical instability and are not necessary in patients who remain clinically stable, even after chest tube placement or video-assisted thorascopic surgery (VATS). Follow-up X-rays 4 to 6 weeks after completing treatment should only be obtained in patients with recurrent pneumonia involving the same lobe or in those patients with lobar collapse at initial X-ray, so the physician can look for possible anatomic abnormalities.7

Diagnostic Testing

According to the recent IDSA guidelines,7 a complete blood count is not a necessity in children with mild CAP but may be somewhat helpful in the hospital setting in children with more severe disease. In general, reliance on the white cell count to help manage CAP should be discouraged, as white cell counts can be elevated or depressed in both viral and bacterial infections. In contrast, anemia and thrombocytopenia may predict a more complicated course of illness and indicate more severe disease.7,11

Acute phase reactants, such as C-reactive protein (CRP), erythrocyte sedimentation rate, and procalcitonin, although often examined, are not helpful as determinants to distinguish between viral and bacterial causes of CAP; however, they can be used in the inpatient setting at times to monitor response to therapy.7 CRP, when evaluated early, can be helpful in indicating more severe disease.11 There is increasing literature to support that elevated procalcitonin suggests a bacterial etiology of CAP, but there exists no precise cut-off to separate a viral from a bacterial process or even mild from severe disease.12 It is important to note also that these tests do not take the place of clinical assessment and often do not contribute to the overall management of CAP.

Blood cultures are not routinely necessary in the relatively well-appearing, fully vaccinated child with uncomplicated CAP.7 The overall rate of bacteremia in hospitalized children with uncomplicated CAP is low (in the range of 1%–3%), with risk of a false-positive result being nearly the same.13 The IDSA guidelines state that cultures should be drawn in children admitted for moderate to severe CAP if it presumed to be of bacterial origin,7 although the evidence is weak. Several studies adhering to the IDSA guidelines have supported higher rates of bacteremia associated with complicated CAP, patients with radiographic evidence of pleural effusion, or empyema.13 Therefore, as the guidelines recommend, it is reasonable and recommended to obtain a blood culture in children suspected of having moderate to severe disease on admission or in children who fail to show improvement after 48 to 72 hours of treatment with antibiotics, as those signs and symptoms often suggest a more complicated process.7,13

Testing for Viral Pathogens

Nasopharyngeal swabs for rapid polymerase chain reaction testing or immunofluorescence may be helpful particularly if test results can be back in less than 24 hours.14 When reliable and rapid testing for a viral pathogen or atypical bacteria is available, it should be used in the evaluation of the child with CAP if it will change clinical management. A positive test may result in decreased antibiotic use if the clinical history is consistent with a viral cause and the patient is clinically stable enough to allow for watchful waiting.7 Antibiotics are not necessary in a patient who tests positive for a virus as long as the clinical, laboratory, or radiographic findings do not suggest a bacterial super-infection. Currently, rapid tests exist for RSV, influenza, parainfluenza, adenovirus, coronavirus, picornavirus, and human metapneumovirus, as well as for Mycoplasma pneumonia, Chlamydia pneumonia, and Bordetella pertussis, although the majority of these tests remain very expensive.5

Which Patients Require Hospitalization?

CAP is often an outpatient diagnosis, and the majority of children can be managed on an outpatient basis. Many studies have shown that oral antibiotics in an otherwise stable child who can tolerate enteral medication are equivalent to parenteral antibiotics.15 Unfortunately, not all cases of CAP can be treated on an outpatient basis. Most of the time, the burden of pneumonia-related hospitalization is highest in children younger than age 5 years, and studies have shown decreasing rates of pneumonia admissions with increasing age.4 It's important to keep in mind that some of the most severe infections are virally mediated, with RSV being the most common etiology of pneumonia in children younger than age 2 years.3

Although most patients can be monitored and treated on an outpatient basis, there are some children who require additional monitoring and support. Strong evidence exists to support inpatient admission for infants and children with moderate to severe CAP, particularly those children who show signs of respiratory distress (tachypnea, grunting, flaring, retractions) and hypoxemia (oxygen saturations <90%–93%).7 Patients who are persistently vomiting and unable to tolerate oral medication or are at risk for dehydration should also be considered for admission. Infants younger than age 3 to 6 months with CAP may benefit from admission because these patients have poor physiologic reserves and the highest likelihood of worsening quickly, although this is not a hard and fast rule. It is always an acceptable option to admit patients for whom there is concern that adequate follow-up or outpatient observation cannot be guaranteed.


In most cases of CAP, the chances of determining a specific etiology are low, leading practitioners to treat empirically or carefully observe if a virus is suspected.5 The 2011 IDSA guidelines state that fully immunized infants (having received all scheduled 2-, 4-, and 6-month vaccines) and young to school-aged children admitted for CAP should be started on ampicillin or penicillin G for CAP on the presumption that S. pneumoniae is the most likely bacterial etiology.7 This must also take into consideration local antibiotic-resistance patterns and presumes no significant local resistance based on hospital antibiograms. The antibiotic coverage should be broadened to include a third-generation cephalosporin (ceftriaxone or cefotaxime) in infants or children who are not fully immunized or in places where there are known invasive pneumococcal strains with high levels of penicillin resistance. Addition of a macrolide is recommended when M. pneumoniae or C. pneumoniae is suspected.7 Vancomycin or clindamycin should be added when methicillin-resistant Staphylococcus aureus is of concern.

This recommendation for initiation of relatively narrow-spectrum antibiotics in fully immunized children is a significant departure from previous practice. A large, retrospective, multicenter study of children's hospitals looked at data from 2005 to 2010 and demonstrated that fewer than 10% of children with CAP at that time were started on an aminopenicillin as empiric therapy.16 It was much more common to start all patients admitted for CAP on a broad-spectrum, third-generation cephalosporin.16 Outcomes studies since the implementation of the IDSA guidelines have shown no increase in unintended negative consequences, and no changes in cost, length of stay, or adverse outcomes.2,17 Typically, children on appropriate therapy should begin to show clinical improvement within 48 to 72 hours.


Complications, most commonly parapneumonic effusions, have been increasing in the US and Europe, especially with bacterial pneumonias. The rate of complications with pneumococcal pneumonia in hospitalized patients is quoted as 40% to 50%.3 Children with comorbidities such as asthma or chronic illness are more likely to suffer from complications. Prolonged fever or worsening respiratory symptoms despite adequate antibiotics are reasons to suspect a complication such as a parapneumonic effusion/empyema, or less commonly necrotizing pneumonia or a lung abscess.5–7 Chest radiography should be used to confirm the presence of complicating pleural fluid, but if inconclusive then further imaging with either a chest computed tomography or ultrasound is recommended.7

The size of the pleural fluid is an important factor in determining management. Small parapneumonic effusions (defined as <10 mm on lateral radiograph or opacification less than one-fourth of the hemithorax) can typically be managed with antibiotics alone and do not require needle thoracentesis or chest tube drainage.5 In most instances, these children would start therapy on intravenous (IV) antibiotics and then transition to 2 to 4 weeks of oral therapy after their clinical status has stabilized.7,18 Moderate-sized effusions (defined as a >10-mm rim of fluid with less than one-half of the hemithorax opacified) will typically respond best to chest tube drainage with VATS or fibrinolytics, particularly if the patient exhibits any respiratory distress. A large effusion that opacifies more than 50% of the hemithorax requires chest tube drainage with VATS or fibrinolytics.5

A pulmonary abscess or necrotizing pneumonia can initially be treated with IV antibiotics. Well-defined peripheral abscesses that are not connected to the bronchial tree may be drained by image-guided aspiration or via drainage catheter, but most abscesses will drain through the bronchial tree and heal without invasive intervention.7

Discharge Criteria and Follow-Up

Most children are ready for discharge when they are clinically improved, showing no signs of respiratory distress and maintaining good oxygenation on room air (Table 2). Typically, discharge readiness also means significantly improved fever for at least 12 to 24 hours and the ability to stay hydrated without supplemental nasogastric or IV fluids.5,7

Discharge Criteria for CAP

Table 2:

Discharge Criteria for CAP

A follow-up visit with a primary care provider is appropriate soon after hospital discharge to ensure continued improvement, the ability to tolerate any outpatient medication prescribed, and adherence to the treatment regimen.5 Repeat chest radiographs are not indicated in CAP unless the child clinically worsens or has a history of recurrent pneumonias in the same lobe.7 It is important to tell the parents that their child's cough may linger for 2 to 4 weeks after pneumonia and that persistent cough does not indicate treatment failure. However, contingency planning is essential, and if the patient's cough worsens or fever or respiratory distress develops, that would be reason for reevaluation.


CAP is a disease that affects many children and one that can be challenging for even the most astute clinician to diagnose. In times of diagnostic uncertainty, evidence-based guidelines can provide a roadmap for appropriate evaluation and treatment. The guidelines discussed in this article can help steer evaluation and treatment for children with CAP from the pediatrician's office, to the inpatient unit, and home again.


  1. Esposito S, Principi N. Unsolved problems in the approach to pediatric community-acquired pneumonia. Curr Opin Infect Dis. 2012;25(3):286–291. doi: . doi:10.1097/QCO.0b013e328352b60c [CrossRef]
  2. Thomson J, Ambroggio L, Murtagh Kurowski E, et al. Hospital outcomes associated with guideline recommended antibiotic therapy for pediatric pneumonia. J Hosp Med. 2015;10(1):13–18. doi: . doi:10.1002/jhm.2265 [CrossRef]
  3. Principi N, Esposito S. Management of severe community-acquired pneumonia of children in developing and developed countries. Thorax. 2011;66:815–822. doi:. doi:10.1136/thx.2010.142604 [CrossRef]
  4. Jain S, Williams DJ, Arnold SR, et al. Community-acquired pneumonia requiring hospitalization among US children. N Engl J Med. 2015;372:835–845. doi: . doi:10.1056/NEJMoa1405870 [CrossRef]
  5. Gereige RS, Laufer PM. Pneumonia. Pediatr Rev. 2013;34(10):438–455. doi: . doi:10.1542/pir.34-10-438 [CrossRef]
  6. Harris M, Clark J, Coote N, et al. British Thoracic Society guidelines for the management of community acquired pneumonia in children: update 2011. Thorax. 2011;66(Suppl 2):ii1–23. doi: . doi:10.1136/thoraxjnl-2011-200598 [CrossRef]
  7. Bradley JS, Byington CL, Shah SS, et al. Pediatric Infectious Diseases Society and the Infectious Disease Society of America. Executive summary: the management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Disease Society of America. Clin Infect Dis. 2011;53(7):617–630. doi: . doi:10.1093/cid/cir625 [CrossRef]
  8. Griffin MR, Zhu Y, Moore MR, Whitney CG, Grijalva CG. US hospitalizations for pneumonia after a decade of pneumococcal vaccination. N Engl J Med. 2013;369(2):155–163. doi: . doi:10.1056/NEJMoa1209165 [CrossRef]
  9. World Health Organization. Pneumonia. Geneva, Switzerland: World Health Organization. 2016. Accessed June 16, 2017.
  10. Hodgson B, Kornfeld BD, Wild BM. When the great masquerader reveals itself-tuberculosis. Pediatr Ann. 2017;46(2):e51–55. doi: . doi:10.3928/19382359-20170120-01 [CrossRef]
  11. Williams DJ, Hall M, Auger KA, et al. Association of white blood cell count and C-reactive protein with outcomes in children hospitalized with community-acquired pneumonia. Pediatr Infect Dis J. 2015;34(7):792–793. doi: . doi:10.1097/INF.0000000000000724 [CrossRef]
  12. Principi N, Espisito S. Biomarkers in pediatric community acquired pneumonia. Int J Mol Sci. 2017;18(2):e447 doi: . doi:10.3390/ijms18020447 [CrossRef]
  13. Parikh K, Barber Davis A, Pavuluri P. Do we need this blood culture?Hosp Pediatr. 2014;4(2):78–84. doi: . doi:10.1542/hpeds.2013-0053 [CrossRef]
  14. Schulert GS, Hain PD, Williams SJ. Utilization of viral molecular diagnostics among children hospitalized with community acquired pneumonia. Hosp Pediatr. 2014;4(6):372–376. doi: . doi:10.1542/hpeds.2014-0018 [CrossRef]
  15. Korppi M. Diagnosis and treatment of community-acquired pneumonia in children. Acta Paediatr. 2012;101:702–704. doi: . doi:10.1111/j.1651-2227.2012.02648.x [CrossRef]
  16. Williams DJ, Hall M, Shah SS, et al. Narrow vs. broad-spectrum antimicrobial therapy for children hospitalized with pneumonia. Pediatrics. 2013;132(5):e1141–1148. doi: . doi:10.1542/peds.2013-1614 [CrossRef]
  17. Queen MA, Myers AL, Hall M, et al. Comparative effectiveness of empiric antibiotics for community-acquired pneumonia. Pediatrics. 2014;133(1):e23–29. doi: . doi:10.1542/peds.2013-1773 [CrossRef]
  18. Stockmann C, Ampofo K, Pavia AT, et al. Comparative effectiveness of oral versus outpatient parenteral antibiotic therapy for empyema. Hosp Pediatr. 2015;5(12):605–612. doi: . doi:10.1542/hpeds.2015-0100 [CrossRef]

Tachypnea in Children

Age Respiratory Rate (bpm)
Birth to 2 months >60
2–12 months >50
1–5 years >40
>5 years >20

Discharge Criteria for CAP


Afebrile for 12–24 hours


Oxygen saturations >90% for 12–24 hours


Normal vital signs and baseline mental status


Able to tolerate outpatient oral medications


Able to tolerate oral hydration


Near baseline activity level and appetite


Kathleen Boyd, MD, is a Clinical Instructor of Pediatrics, Stanford University School of Medicine.

Address correspondence to Kathleen Boyd, MD, 300 Pasteur Drive, Mail Code 5776, Stanford, CA 94305; email:

Disclosure: The author has no relevant financial relationships to disclose.


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