What additional investigations are indicated in an unvaccinated child with cough and normal exam, vitals, and chest X-ray (CXR)?

From the Guidelines

In an unvaccinated child with cough and normal exam, vitals, and chest X-ray (CXR), further investigations are not immediately indicated unless the cough persists after 4 weeks of appropriate antibiotics or if specific cough pointers are present.

Initial Approach

• The child should be assessed for the effect of cough on the child and the family as part of the clinical consultation 1.
• A systematic approach, such as using a validated guideline, should be taken to determine the cause of the cough, based on cough characteristics and associated clinical history 1.
• If the child has a chronic wet or productive cough unrelated to an underlying disease and without specific cough pointers, antibiotics targeted to common respiratory bacteria should be prescribed for 2 weeks 1.

Further Investigations

• If the wet cough persists after 4 weeks of appropriate antibiotics, further investigations such as flexible bronchoscopy with quantitative cultures and sensitivities, with or without chest computed tomography, should be undertaken 1.
• If specific cough pointers are present (e.g., coughing with feeding, digital clubbing), further investigations to assess for an underlying disease should be undertaken, including flexible bronchoscopy and/or chest computed tomography, assessment for aspiration, and/or evaluation of immunologic competency 1.
• Tests evaluating recent Bordetella pertussis infection should be undertaken if pertussis is clinically suspected 1.

Additional Considerations

• A chest radiograph and, when appropriate, spirometry (pre- and post-β2 agonist) should be undertaken as part of the initial assessment 1.
• Additional tests, such as skin prick test, Mantoux, bronchoscopy, or chest CT, should not be routinely performed and should be individualized based on the clinical setting and the child’s clinical symptoms and signs 1.

From the Research

Additional Investigations for Unvaccinated Child with Cough

In an unvaccinated child presenting with cough and normal exam, vitals, and chest X-ray (CXR), several additional investigations may be indicated to rule out underlying conditions.

• Pertussis testing: Given the child's unvaccinated status, pertussis (whooping cough) should be considered, especially if the cough is paroxysmal or accompanied by whooping or posttussive vomiting 2.
• Complete Blood Count (CBC): Leukocytosis and lymphocytosis are common in pertussis, so a CBC may be helpful in supporting the diagnosis 2.
• Nasopharyngeal swab: A nasopharyngeal swab can be used to isolate Bordetella pertussis, the causative agent of pertussis 2.
• Further imaging: Although the CXR is normal, other imaging modalities like chest computed tomography (CT) scan may be necessary to exclude pulmonary abnormalities potentially associated with chronic cough, as a normal CXR has a relatively low negative predictive value (NPV) in this context 3.
• Bronchoalveolar lavage (BAL): In some cases, BAL may be considered to identify lung infection and airway inflammation, especially if other tests are inconclusive 4.

Considerations

It is essential to note that the presence of fever, duration of cough, and other clinical characteristics can influence the decision to perform additional investigations. For example, a child with fever for 1 day or longer or with worsening cough may be at greater risk for occult pneumonia, which may not be apparent on a normal CXR 5.

Diagnostic Approach

The diagnostic approach should be guided by the child's clinical presentation, vaccination status, and the results of initial investigations. A thorough evaluation, including a detailed history and physical examination, is crucial in determining the need for additional tests. 6, 2, 5, 4, 3