589917
research-article2015
CPJXXX10.1177/0009922815589917Clinical PediatricsHendaus and Janahi
Commentary
Parapneumonic Effusion in Children: An Up-to-Date Review
Clinical Pediatrics 2016, Vol. 55(1) 10–18 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0009922815589917 cpj.sagepub.com
Mohamed A. Hendaus, MD, FAAP1,2 and Ibrahim A. Janahi, MD, FCCP, FRCPCH1,2
Introduction
Microbiology
Respiratory diseases are a very common source of morbidity and mortality among children.1 In the United States, the rate of pneumonia in children is 20 to 40 cases per 100 000 and pneumococcal pneumonia comprises 20% to 60% of community-acquired cases.2,3 Pleural effusions develop in approximately 40% of children hospitalized with bacterial pneumonia.4 There has been a decrease in the incidence of bacterial pneumonia.5 part of it attributed to the debut of the conjugate pneumococcal vaccine.6 However, rates of parapneumonic effusion (PPE) were noticed to increase5,7-9 In children younger than 2 years, the PPE rate significantly raised in North America from 3.5 cases per 100 000 children in 1996-1998 to 7.0 cases per 100 000 children in 2005-2007.8 During the same periods, the PPE rate increased from 3.7 to 10.3 cases per 100 000 children between the age 2 and 4 years.10 In Europe, there was a substantial increase in the incidence of PPE from 1.25 cases per 100 000 persons to 13.65 cases per 100 000 from the period from 2000 to 2012.11 The overall mean age of children with PPE in developed countries and Southeast Asia is 3 to 6 years.12 The steps that lead to the development of PPE and empyema are the following: stage 1, also described as the early exudative phase, constitutes the collection of thin reactive fluid and few cells in the pleural space; stage 2, described as the fibropurulent phase, involves the formation of loculations; and stage 3 is the organizing phase and it involves the creation of a thick layer of fibrin that encloses the lung.13 The management of pleural effusion in children has been a topic of dispute between physicians and surgeons. Many treatment modalities have been suggested and applied, including intravenous antibiotics with or without thoracocentesis, chest drain insertion, intrapleural fibrinolytics, and video-assisted thoracoscopic surgery (VATS). In this review, we detail up-to-date review of pleural effusion in children, including medical and surgical modalities.
The probability to identify an organism in the pleural fluid specimens is low.4,14-20 The British Thoracic Society (BTS) recommends that Gram stain, acid fast bacilli stain, and microbiologic culture be obtained on all pleural fluid samples.21 In addition, nucleic acid amplification through polymerase chain reaction (PCR) and antigen testing are indispensable tools in the detection of microorganisms in cases with PPE.17,22 In a study conducted in Spain, pneumococci were detected in 79% of culture-positive and 84% of culture-negative samples using real-time PCR; almost 50% were serotype 1.4 Le Monnier et al17 found that the sensitivity and specificity of the latex antigen detection in PPE were 90% and 95%, respectively. It is also recommended to obtain a pleural fluid white blood cell (WBC) count, with cell differential analysis to differentiate between bacterial, mycobacterial and malignancy etiologies.22 Although different organisms can cause PPE and empyema, Streptococcus pneumoniae is considered to be the most common cause.12,23-29 The effect of age on PPE was not consistent reliable among studies; for instance Ampofo et al found that children affected with complicated pneumococcal pneumonia were older than those with other forms of invasive pneumococcal disease (37 vs 25 months; P < 0.001).30 In addition, the percentage of complicated pneumococcal pneumonia increased from 26.4% in infants to 53% in children older than 61 months.31 However, a study conducted in Southeast Asia showed that the highest percentage of PPE among children were in those younger than 4 years.12 In terms of pneumococcal serotypes, type 1 and 19A displayed strong associations with pneumococcal PPE and empyema worldwide.16,26 In the United States, serotype 3 1
Hamad Medical Corporation, Doha, Qatar Weill-Cornell Medical College, Ar-Rayyan, Qatar
2
Corresponding Author: Mohamed A. Hendaus, Department of Pediatrics, Academic General Pediatrics Division, Hamad Medical Corporation, Doha 3050, Qatar. Email:
[email protected]
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Hendaus and Janahi was the most frequent cause of pneumococcal necrotizing pneumonia and serotype 1 was the most prevalent in uncomplicated pneumococcal pneumonia.32 In Taiwan, serotypes 14 and 3 were the most common serotypes causing complicated pneumococcal pneumonia.33 Furthermore, in England, serotypes 1 and 3 were the common serotypes found in children with PPE.34 Other organisms that cause PPE are methicillin-sensitive Staphylococcus aureus (MSSA),35,36 methicillinresistant S aureus (MRSA),29,37-39 S pyogenic,19,29,38 Haemophilus influenzae type b,21,40 Mycoplasma pneumoniae, viridians streptococci, and streptococci of Lancefield group F39,21 Enterobacteriaceae, Klebsiella spp and Pseudomonas aeruginosa, and Yersinia,21,36 Bacteroides species, Peptostreptococcus,41 Streptococcus milleri,38,41 Fusobacterium necrophorum infection (Lemierre syndrome) in older children,38,43 and Mycobacterium tuberculosis.21 PPE can be also due to fungal species such as C albicans, C tropicalis, C krusei, C glabrata,44,45 which can sometimes lead to gastrointestinal perforation.46
Imaging Chest Radiograph Chest radiography is usually the first imaging modality in the work up of PPE, but it cannot confirm the diagnosis. Chest radiograph might show early signs of PPE such as obliteration of the costophrenic angle and a meniscus shape area up the lateral chest wall.47
Ultrasonography Ultrasonography (U/S) is a safe and inexpensive mode of imaging and can be used to confirm the presence of pleural effusion.48 In addition, it can be used to guide catheter insertion and percutaneous drainage.49 Furthermore, U/S can differentiate between pleural and parenchymal involvement,21 and many clinicians prefer this mode of imaging over computed tomography (CT) for diagnosis.48,50 A lenticular shape might imply the presence of a loculation when using this mode of imaging.47 The efficacy and safety of the U/S were reported in 2 large studies indicating that PPE can be managed properly without the use of chest CT.51,52 However, U/S is inferior to CT of chest in detecting loculated effusions in the mediastinal area and in the fissures.53
Computed Tomography A CT scan is not indicated for the initial diagnosis and management of uncomplicated PPE.48,50 A CT scan of the chest is warranted in complicated cases of PPE
because it can detect lung pathology and pulmonary abscess54 and it is also recommended in preoperative cases of PPE.21,22 However, the disadvantages of chest CT are the exposure of a patient to relatively high radiation,53 the inability to visualize thin pleural septations or fibrin,55 and the possibility of the need for sedation.53
Diagnostic Tap If the health care provider suspects that the effusion is not of infectious etiology, then it will be recommended to perform a diagnostic tap for cytological analysis before chest drain insertion to avoid complications associated with anaesthesia, surgery or sedation.21
Biochemistry/Microscopy Fluid from bacterial infections, and sometimes tuberculosis, are predominantly neutrophils while lymphocytosis is detected in autoimmune diseases, tuberculosis, chylothorax, and malignancy; moreover, turbid indicates high cell count or high lipid content.53 Serous fluids are categorized into transudates and exudates. Transudative effusion usually refers to a noninflammatory process (alteration of hydrostatic or colloid osmotic pressure), where it infers from ultrafiltration process across a membrane and it is usually low in protein. On the other hand, exudates refer to an inflammation or inflammatory process, where it infers capillary permeability.21 A pleural fluid:serum protein ratio greater than 0.5, a pleural fluid lactate dehydrogenase activity greater than 200 U/L, or a pleural fuid:serum lactate dehydrogenase ratio greater than 0.6 is usually diagnostic of exudative effusion.56 However, the BTS states that pleural fluid parameters, such as glucose, protein, lactate dehydrogenase levels, and pH are not recommended since they do not change the management of PPE.21
Management Prevention The preferred treatment of PPE is prevention via up-to-date immunization.53
Antibiotics Use Many practitioners opt for antibiotics alone when managing a small PPE in patients with no respiratory distress; although it is an acceptable option, further intervention must be followed if the effusion is enlarging or patient is deteriorating.5,21
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Clinical Pediatrics 55(1)
The initial treatment of all pleural effusion should be the use of antibiotics. For children with small effusions (
