What imaging is recommended to evaluate a patient with complicated CAP?
-We strongly recommend based on low quality evidence consideration of further imaging including ultrasound (US) or chest computed tomography (CT) in a patient with a clinically significant effusion to evaluate size of effusion or development of empyema.
In a patient suspected of a pneumonia complication, we recommend consideration of history and physical exam findings to increase clinical suspicion. CXR findings of effusion or clinical suspicion should include a lateral decubitus view to confirm the presence of pleural fluid and attempt to estimate size. The PIDS/IDSA guideline defines significant effusion as a >10mm rim of fluid on a lateral decubitus film or greater than one-fourth of the hemithorax opacified on an upright chest radiograph (Bradley, Byington et al. 2011).
If further imaging is necessary, US or CT should be considered. The PIDS/IDSA guideline recommends chest US as first line imaging due to lack of radiation exposure compared to CT (Bradley, Byington et al. 2011). We recommend not delaying definitive diagnostic modality as early treatment of effusion/empyema is associated with decreased morbidity, hospital costs and length of stay(Bradley, Byington et al. 2011).
What empiric antibiotics are recommended for complicated CAP?
-We strongly recommend based on low quality evidence addition of antibiotic coverage for penicillin resistant Streptococcus pneumoniae and Staphylococcus aureus for patients with complicated pneumonia.
The diagnosis of complicated pneumonia, with an effusion or empyema identified on imaging, leads to additional concerns for S. aureus as the underlying bacterial etiology, in addition to the concern for resistant S. pneumoniae. While patients with viral pneumonia can have an associated effusion in up to 10% of patients (Bradley, Byington et al. 2011), we strongly recommend patients with empyema or effusions be treated as bacterial. Due to the concern with S. aureus, we strongly recommend additional coverage with clindamycin (40 mg/kg/day, IV) as well as coverage for resistant S. pneumonia with ceftriaxone (75-100mg/kg/day, IV)/cefotaxime (200 mg/kg/day, IV).
If the patient is considered severely ill with impending respiratory failure or sepsis, vancomycin (60mg/kg/day) is recommended in place of clindamycin to add coverage to clindamycin resistant S. aureus.
For a patient diagnosed and treated with complicated pneumonia, consultation with Infectious Diseases is recommended for assistance with transition to oral therapy as well as length of therapy.
Patients with a small effusion represent an interesting and potential difficult clinical challenge. The PIDS/IDSA guideline defines significant effusion as a >10mm rim of fluid on a lateral decubitus film or greater than one-fourth of the hemithorax opacified on an upright chest radiograph (Bradley, Byington et al. 2011). Treatment of patients with a significant effusion includes recommendations to expand coverage to include Staphylococcus aureus with clindamycin or possibly vancomycin and increase coverage for resistant S. pneumoniae from ampicillin to ceftriaxone. On review of the implementation of the CAP CPG, at CMH, 9-11% of patients were identified as having a small effusion on admission CXR. The clinical determination of whether these patients will develop a significant effusion as defined by PIDS/IDSA and require a drainage procedure is obviously unknown on presentation. The CMH PNA CPG evaluation did identify that the majority of patients with a small effusion that were treated with ampicillin alone did well, with none of the patients in the pre-CPG group meeting treatment failure criteria and three patients in the post-CPG group requiring broadening of antibiotic coverage for worsening clinical picture. With the concern for S. aureus in patients with effusion, we recommend following the recommendations for treatment of complicated pneumonia.