Although overall rates of bacterial pneumonia have been declining in children, the incidence of complications such as parapneumonic effusions and empyema has increased. In the USA, pneumonia in children occurs at an estimated rate of 30–40 per 100,000. Parapneumonic effusions (PPE) can complicate pediatric pneumonia in 28–53% of patients. Similarly, in patients between 2 to 4 years of age, empyema rates nearly tripled from 3.7/100,000 to 10.3/100,000 during the last years. While empyema in children is less serious compared to adults where mortality can approach 20%, it still poses a considerable burden on hospitals and families.
One of the most frequent complications following parapneumonic effusions in children is pleural empyema (please see the thoracoscopy view of pleural empyema in a child, the asterisk is the lung, on the right is the removed fibrin tissue).
The Diagnosis
The diagnosis is usually a progressive clinical picture beginning with pneumonia. Patients with empyema almost always demonstrate some degree of respiratory distress, malaise, persistent fever, or pleuritic chest pain. Diminished breath sounds with dullness to percussion on the affected side are found on examination. An ileus is common as is a lack of appetite.
Initial imaging is a chest radiograph (CXR) which shows poor penetration on the affected side. However, it is often difficult to distinguish between parenchymal consolidation and pleural fluid on a plain film. Decubitus films may help distinguish between non-lobulated and lobulated effusions. Ultrasonography (US) is portable, relatively inexpensive, and does not involve radiation. It is very sensitive in diagnosing lobulated fluid and can be used to guide percutaneous drainage and catheter placement. Some authors suggest that ultrasound is superior to CT in the identification of pleural debris or loculations. Ultrasound can reliably differentiate between parenchymal and pleural-based processes.
Currently, chest CT scans can be performed effectively with the use of automatic dose modulation software that limits the radiation dose. Despite this ability to limit radiation exposure with CT scans, consensus statements are clear in their recommendations for performing CT only when needed, such as preoperative planning in some cases.
Management of Parapneumonic Effusion
After the diagnosis of PPE is made, the first branch in the management algorithm depends on the nature of the fluid. With a free-flowing effusion and no solid components or signs of frank pus, the nature of the intervention will depend on the size of the effusion and the symptoms. Classifying the size is difficult to define precisely. However, in general, small effusions are defined as having ≦1 cm rim of fluid, moderate effusions have a 1-2 cm rim, and large effusions have ≧ 2 cm rim on decubitus films. The size of the effusion is not the only predictor of the intervention needed. Some authors advocate the need for intervention based on symptoms like feeding intolerance, tachypnea, and an increased oxygen requirement. After deciding to drain the effusion, options include single or multiple thoracenteses versus tube thoracostomy or catheter drainage. The British Thoracic Society guidelines recommend a chest tube for cases in which the first thoracentesis fails to adequately drain the effusion in order to avoid multiple thoracentesis attempts.
Empyema
Empyema is diagnosed by identifying solid components in the pleural fluid on imaging studies or pus during thoracentesis or tube catheter placement. The definitive management for empyema has traditionally been operative debridement, which is currently performed via video-assisted thoracoscopy surgery (VATS). VATS has resulted in earlier and more complete resolution of empyema than chest tube drainage alone in both retrospective and prospective studies, translating into shorter hospitalization with VATS as the initial therapy However, the superiority of operative mechanical debridement as a definitive management strategy has been increasingly challenged by chemical debridement with fibrinolysis. Examples of fibrinolytic include urokinase, streptokinase, and tissue plasminogen activator (tPA). When comparing fibrinolysis to VATS, the burden to the patient should be considered as one therapy is a nonoperative intervention requiring single sedation, and the other is an operation under general anesthesia. Available evidence suggests that thoracoscopy debridement is neither superior nor inferior to fibrinolytic therapy as a primary treatment modality. Therefore, if performed at the time of diagnosis, VATS remains an equivalent option to facilitate early recovery when fibrinolysis is not feasible, given individual hospital and physician resources.
LUNG ABSCESS
The pulmonary abscess is often assumed to develop as a primary process in a previously normal lung, usually as a result of necrotizing pneumonia. However, a pulmonary abscess in a child without an antecedent history ought to be considered a secondary abscess that arises in an infected pulmonary anomaly such as a cystic pulmonary adenomatoid malformation, bronchogenic cyst, or foreign body. Most primary lung abscesses are located in the posterior segment of the right upper lobe and the superior segments of the right and left lower lobes.
In the patient with known pneumonia, the nonresponding patient who develops a suspicious lesion on the chest film should undergo CT to evaluate for an abscess. In general, an operation should be avoided as abscesses can usually be successfully treated with antibiotics alone. CT-guided drainage or catheter placement is usually needed if the lesion is peripheral and not connected to the airway. Retrospective data suggest that drainage shortens hospitalization and facilitates earlier recovery Alternatively, pulmonary resection may be required for abscesses that are more centrally located and resistant to medical management.
Patients with fungal isolates and immunocompromised patients generally require early and aggressive pulmonary resection. However, as a general statement, patience should be employed in managing pulmonary abscesses.
PNEUMATOCELE
Pneumatoceles are thin-walled, air-filled, intraparenchymal pulmonary cysts. They typically occur secondary to underlying bacterial pneumonia, a treated abscess, or as a result of trauma. Although pneumatoceles have been associated with a variety of underlying bacterial organisms, the majority appear to be the result of staphylococcal pneumonia. In addition, pneumatoceles have been found in cases of pulmonary tuberculosis and measles. Additional complications associated with pneumatoceles include the development of secondary infections, empyema, and bronchopleural fistulas.
Management
Most pneumatoceles will involute over time and do not require any specific therapy other than supportive care and appropriate antibiotic coverage. In the case of a rapidly enlarging and/or tension pneumatocele resulting in respiratory compromise, urgent decompression may be needed. In addition to closed-tube thoracostomy or cystostomy, percutaneous catheter drainage using fluoroscopy and ultrasound has been reported to be an effective means of decompression. Open drainage with decortication and overseeing of the cyst wall is rarely necessary. The majority of pneumatoceles decrease in size and resolve over a period of several weeks to months, assuming that the underlying infectious cause is adequately treated. In uncomplicated cases, no residual pulmonary compromise or radiologic sequelae are likely.
BRONCHIECTASIS
Bronchiectasis is defined as a permanent dilatation of segmental airways, rarely happens in children, and may be a transitory disease in patients with complicated pneumonia. As might be expected, congenital abnormalities are more likely to result in diffuse distribution with bilateral disease, whereas acquired bronchiectasis is more likely to be focal. The focal disease is more common in the left lower lobe, lingual, or right middle lobe. Many cases remain idiopathic without an explanation for the source of the parenchymal or airway damage. The treatment of bronchiectasis is mostly conservative until the disease is considered irreversible.
Hope this helps!
Davit Dallakyan MD, PhD, eMBA
Head of the Pediatric Thoracic Surgery Department
“Sourb Astvatsamayr” Medical Center
