Pneumonia in healthy Canadian children and youth: Practice points for management

N Le Saux, JL Robinson; Canadian Paediatric Society, Infectious Diseases and Immunization Committee

Paediatr Child Health 2011;16(7):417-20

Index of position statements from the Infectious Diseases and Immunization Committee

ABSTRACT

Although immunization has decreased the incidence of bacterial pneumonia in vaccinated children, pneumonia remains common in healthy children. Unless it is totally impractical, a chest radiograph should be performed to confirm the diagnosis of pneumonia. Factors such as age, vital signs and other measures of illness severity are critical in the decision regarding whether to admit a patient to hospital. Because Streptococcus pneumoniae continues to be the most common cause of bacterial pneumonia in children, prescribing amoxicillin or ampicillin for seven to 10 days remains the mainstay of empirical therapy for nonsevere pneumonia. If improvement does not occur, consideration should be given to searching for complications (empyema or lung abscess). Routine chest radiographs at the end of therapy are not recommended unless clinically indicated.

Key Words: Antimicrobial therapy; Bacterial pneumonia; Viral pneumonia

• Introduction
• Definition
• Etiology
• Symptoms and signs of acute pneumonia
  • Table 1
• Investigations
  • Imaging
  • Detection of the pathogen
  • Bloodwork
• Guidelines for referral to hospital or hospital admission
• Management
  • Table 2
  • Table 3
• Penicillin allergy
• Expected clinical course and follow-up for uncomplicated pneumonia
• Acknowledgements
• References

Most physicians who care for children and youth have had experience in managing acute pneumonia. The WHO has estimated that in developed countries, one in 20 children younger than five years of age will contract pneumonia each year (1,2). Pneumococcal conjugate vaccines have been shown to decrease radiologically proven pneumonia admission rates by an average of 27% (3-6).

The present practice point focuses on the current diagnosis and management of uncomplicated acute community-acquired pneumonia in healthy immunized children with no underlying pulmonary pathology aside from mild reactive airways disease. The practice point does not apply to persistent (chronic) pneumonia syndromes (with symptoms for more than two weeks), aspiration pneumonia or recurrent pneumonias, or those associated with chronic medical problems such as immunodeficiency, because these pneumonias may be caused by different pathogens or require more extensive investigation.

DEFINITION AND HOST RISK FACTORS
Pneumonia is an acute inflammation of the parenchyma of the lower respiratory tract caused by a microbial pathogen. Bacterial infections are usually primary but, occasionally, viral respiratory tract infections such as influenza can increase the subsequent risk of bacterial pneumonias (7). In uncomplicated pneumonia, there is no evidence of empyema (pus in the pleural space), a lung abscess or a necrotic lung.

ETIOLOGY
The most common causes of pneumonia in infants and preschool children are viruses that usually, but not exclusively, circulate in winter (eg, respiratory syncytial virus, influenza, parainfluenza virus and human metapneumovirus). Viruses as a sole cause of pneumonia are less common in older children with the exception of influenza (8).

Among bacteria, Streptococcus pneumoniae continues to be the most significant pathogen in children of all ages (9). Group A streptococcal pneumonia is much less common. Although Staphylococcus aureus is not a common cause of paediatric pneumonia, it has been increasingly encountered in communities where methicillin-­resistant Staphylococcus aureus is prevalent. Haemophilus influenzae type b has almost disappeared because of vaccination. Mycoplasma pneumoniae and Chlamydophila pneumoniae are more common causes of pneumonia among school-­age children, but they occasionally cause pneumonia in younger children (10,11).

SYMPTOMS AND SIGNS OF ACUTE PNEUMONIA
The symptoms of pneumonia may be nonspecific, especially in infants and younger children. Acute onset of fever, cough, difficulty breathing, poor feeding or vomiting, and lack of interest in normal activities are common. Chest or abdominal pain may be a prominent feature. Abrupt onset of rigors favours a bacterial cause. A significant, persistent cough may predominate in pneumonia caused by M pneumoniae. During influenza season, consider influenza, with or without a secondary bacterial component, as a cause of pneumonia.

Children typically experience fever and tachypnea (determined by counting the respiratory rate for 60 s in a calm state; see Table 1). Indrawing, retractions and/or a tracheal tug will indicate respiratory distress (dyspnea) (12). Decreased oxygen saturation indicates hypoxemia and should be measured in all hospital settings. Cyanosis will only be evident with very severe hypoxemia. Normal oxygen saturation does not exclude pneumonia, especially early in the course of the illness.

Physical signs suggesting consolidation include dullness to percussion, increased tactile fremitus, reduced normal vesicular breath sounds and increased bronchial breath sounds – all of which can be difficult to detect in young children. The presence of wheezing should suggest the possibility that radiographic changes may be due to atelectasis and mucous plugging from asthma or bronchiolitis rather than pneumonia. Signs of an effusion are dullness to percussion, decreased tactile fremitus, and decreased or absent breath sounds. There may be associated signs of dehydration and/or sepsis (12).

INVESTIGATIONS

Imaging
Pneumonia is overdiagnosed in the absence of radiological confirmation. Radiological confirmation is encouraged whenever possible to support the clinical diagnosis and may be useful if the child subsequently deteriorates. Poorly defined nodules and patchy areas of opacity with variable hyperinflation and without effusion are more indicative of a viral etiology (13). Lobar or segmental consolidation with or without pleural effusions is suggestive of bacterial pneumonia due to S pneumoniae, group A streptococcus and, less commonly, S aureus. The atypical pathogens, M pneumoniae or C pneumoniae, classically produce focal infiltrates that appear to be more extensive than the clinical findings would suggest.

Detection of the pathogen
Determining the etiology of pneumonia is difficult in children because few children are bacteremic, and most cannot provide a sputum sample. If adequate sputum is available, it should be sent for Gram staining and subsequent culture (14). Culture of pleural fluid is suggested if it can be sampled. Additional invasive or molecular testing should be pursued if the child fails to improve or worsens on therapy.

Routine viral testing of nasopharyngeal secretions is usually not indicated for outpatients with mild or moderate illness. Admitted children who have possible viral pneumonia should undergo viral testing of nasopharyngeal secretions because this will also assist in cohorting patients (15,16).

Bloodwork
Typical bacterial pneumonias usually show higher peripheral white blood cell counts than atypical bacterial or viral pneumonias. A complete blood count with differential testing and blood cultures are indicated for children who are hospitalized or worsening (9,17).

GUIDELINES FOR REFERRAL TO HOSPITAL OR HOSPITAL ADMISSION
Most children can be managed as outpatients. Specific criteria for admission are not available for children. Hospitalization is generally indicated if the child is unable to eat or drink, has an inability to comply with oral therapy, has a concerning social situation, dehydration, hypotension, sepsis, oxygen saturations of lower than 92%, vomiting, tachypnea (Table 1), chest retractions, or any evidence of an empyema or lung abscess (14). There should be a low threshold for admitting children younger than six months of age because it can be difficult for caregivers to recognize deterioration.

MANAGEMENT
If the clinical picture and chest radiograph (CXR) are compatible with bacterial pneumonia, provide supportive care and choose empirical antimicrobials as shown in Table 2, following all steps in the algorithm. This algorithm places less emphasis on macrolides than previous recommendations did because there is increasing evidence that pneumonia due to M pneumoniae often resolves without therapy (18).

Suggested doses of antibiotics are listed in Table 3. In all situations, if a bacterium is detected in blood or pleural fluid, antimicrobial therapy should be modified to the narrowest spectrum agent based on susceptibility results.

In Canada, it is still standard to treat uncomplicated pneumonia for seven to 10 days (five days with azithromycin) (19). Pneumonia complicated by empyema or abscess formation requires a longer duration of therapy as determined by the clinical course. Oral step-down therapy is usually appropriate when patients are improved and afebrile.

If a virus is detected in a nasopharyngeal sample and/or CXR is most compatible with viral pneumonia, manage with supportive care (oxygen and rehydration if required) without antibiotics. Consider antivirals if influenza is suspected or proven, and the child has risk factors for severe disease (20) or requires admission, especially if symptoms have been present for less than 48 h.

PENICILLIN ALLERGY
If the previous suspected allergic reaction included an urticarial rash, hypotension or bronchospasm, the reaction may have been immunoglobulin E (IgE) mediated and all beta lactams should be avoided. For children with nonsevere pneumonia who are treated as outpatients, clarithromycin and azithromycin are reasonable choices, while keeping in mind that pneumococcal resistance to antimicrobials is increasingly common. For more severe pneumonias with suspected IgE-mediated penicillin allergy, options should be discussed with a paediatric infectious diseases physician. If the previous suspected allergic reaction did not appear to be IgE mediated, cephalosporins can be used. Cefuroxime axetil can be used in place of amoxicillin, while recognizing that pneumococcal coverage is inferior with these drugs.

EXPECTED CLINICAL COURSE AND FOLLOW-UP FOR UNCOMPLICATED PNEUMONIA
Clinical improvement (improved appetite, decreasing fever, resolution of tachypnea and decreasing oxygen requirements) should be evident within 48 h with bacterial pneumonia; however, improvement often takes longer with viral pneumonia. If the patient does not improve within the expected time frame, repeat the CXR to search for evidence of a complication (ie, empyema or abscess). Foreign body aspiration, reactive airways disease with atelectasis, congenital pulmonary anomaly, tuberculosis or unrecognized immunodeficiency with an opportunistic infection are also possible (Table 2).

Because radiographic resolution can take up to four to six weeks, repeat radiographs are not indicated for children with clinical improvement (21).

ACKNOWLEDGEMENTS: The authors acknowledge Dr Thomas Kovesi, Paediatric Respirologist, Children’s Hospital of Eastern Ontario (Ottawa, Ontario), for his thoughtful review of the physical examination portion of the document. This practice point was also reviewed by the Canadian Paediatric Society’s Community Paediatrics and Acute Care committees.

REFERENCES

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INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE
Members: Drs Robert Bortolussi, IWK Health Centre, Halifax, Nova Scotia (Chair); Jane Finlay, Richmond, British Columbia; Susanna Martin, Royal University Hospital, Saskatoon, Saskatchewan (Board Representative); Jane C McDonald, The Montreal Children’s Hospital, Montreal, Quebec; Heather Onyett, Queen’s University, Kingston, Ontario; Joan L Robinson, Edmonton, Alberta
Liaisons: Drs Upton D Allen, The Hospital for Sick Children, Toronto, Ontario (Canadian Pediatric AIDS Research Group); Janet Dollin, University of Ottawa, Ottawa, Ontario (College of Family Physicians of Canada); Charles PS Hui, Children’s Hospital of Eastern Ontario, Ottawa, Ontario (Health Canada, Committee to Advise on Tropical Medicine and Travel); Nicole Le Saux, Children’s Hospital of Eastern Ontario, Ottawa, Ontario (Canadian Immunization Monitoring Program, ACTive); Larry Pickering, Elk Grove, Illinois (American Academy of Pediatrics, Committee on Infectious Diseases); Marina I Salvadori, Children’s Hospital of Western Ontario, London, Ontario (Health Canada, National Advisory Committee on Immunization); John Spika, Ottawa, Ontario (Public Health Agency of Canada)
Consultants: Drs James D Kellner, Alberta Children’s Hospital, Calgary, Alberta; Noni E MacDonald, IWK Health Centre, Halifax, Nova Scotia; Dorothy L Moore, The Montreal Children’s Hospital, Montreal, Quebec
Principal authors: Drs Nicole Le Saux, Ottawa, Ontario; Joan L Robinson, Edmonton, Alberta

Posted: September 2011