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 Table of Contents  
RADIOLOGY ROUNDS
Year : 2021  |  Volume : 1  |  Issue : 1  |  Page : 85-88

Opaque hemithorax in a child: The eyes see what the mind suspects


1 Department of Pediatrcs, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Pediatric Pulmonology Unit, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
3 Pediatric Emergency and Intensive Care Unit, PGIMER, Chandigarh, India
4 Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Date of Submission14-Oct-2020
Date of Decision23-Oct-2020
Date of Acceptance29-Oct-2020
Date of Web Publication27-Feb-2021

Correspondence Address:
Dr. Joseph L Mathew
Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ipcares.ipcares_29_21

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  Abstract 

Background: Children with acute febrile respiratory illnesses are commonly seen in the emergency department. Apart from the initial stabilization, they need to be assessed for the underlying cause, and clinicians should formulate differential diagnoses to start treatment. Radiological investigations including x-ray and ultrasonography are often used to narrow down the initial possibilities based on history and examination. A child presenting with an opaque hemithorax is one such scenario. Clinical Description: A 3-year-old boy presented with a short duration of fever, cough and respiratory distress. Examination showed rightward mediastinal shift with dull percussion note and reduced breath sounds over the left hemithorax, along with congested neck veins, stridor and left sided wheeze. Chest x-ray showed an opacified left hemithorax and ultrasonography suggested moderate pleural effusion. Management: Complicated pneumonia with parapneumonic effusion (or empyema) was considered, but a diagnostic pleural tap was dry. The possibilities were revised to include cystic space occupying lesions with mediastinal compression. Computed tomography of the chest confirmed a mass lesion with predominantly cystic components. The patient underwent surgical excision, and histopathology showed pleuropulmonary blastoma. Conclusion: Although respiratory infections are common in childhood, clinical evaluation and judicious use of imaging modalities can uncover less common conditions. Although bedside ultrasonography is a handy tool in the emergency department, it is not infallible.

Keywords: Chest ultrasonography, opaque hemithorax, whiteout lung, pleuropulmonary blastoma


How to cite this article:
Kumar K, Mathew JL, Muralidharan J, Singhal KK, Sodhi KS, Vaidya PC, Singh M. Opaque hemithorax in a child: The eyes see what the mind suspects. Indian Pediatr Case Rep 2021;1:85-8

How to cite this URL:
Kumar K, Mathew JL, Muralidharan J, Singhal KK, Sodhi KS, Vaidya PC, Singh M. Opaque hemithorax in a child: The eyes see what the mind suspects. Indian Pediatr Case Rep [serial online] 2021 [cited 2023 Feb 3];1:85-8. Available from: http://www.ipcares.org/text.asp?2021/1/1/85/310227



Acute respiratory illness is the most common reason for children presenting to the emergency department (ED). In a prospective study of children requiring hospitalization for acute febrile illnesses, at a tertiary care center in North India, 28.5% had respiratory diseases.[1] After stabilization of the airway, breathing, and circulation, such children require a thorough review of the history and physical examination, followed by rational investigations, including radiological imaging. An adequately exposed, well-centered, nonrotated chest X-ray provides invaluable information whether the disease is unilateral or bilateral, diffuse or localized, and if the pleura, major airways, mediastinum, heart, and/or bony cage are involved. This helps in narrowing down the clinical differential diagnoses. Chest ultrasonography (USG) is now becoming popular for bedside evaluation, as it is readily available, avoids radiation exposure, and is less expensive than computed tomographic (CT) scanning. Although the accuracy of USG for parenchymal lesions (compared to X-ray) is debatable, it is highly sensitive for pleural lesions, especially pneumonias complicated by pneumothorax, pleural effusion, or empyema.[2] However, the interpretation of imaging findings may be associated with observer variation.

The importance of rational clinical judgment in making a bedside diagnosis cannot be overemphasized. We describe a young boy with an apparently common, acute febrile respiratory illness, slightly atypical examination findings, and a specific radiological phenotype. The objective of presenting this case is to highlight the clinical reasoning that was applied while synthesizing clinical and radiological findings and the importance of considering uncommon, noninfective etiologies once preliminary investigations exclude common ones.


  Clinical Description Top


A 3-year-old boy presented to the ED with fever, cough, and difficulty in breathing for 15 days. The illness had started with fever, which was high grade, intermittent but responded to oral antipyretics. After 3 days, the child developed a dry cough, which was nonparoxysmal, had no particular diurnal pattern, no specific exacerbating or relieving factors but progressively increased in severity. It was associated increased respiratory rate and effort of breathing and chest indrawing. The fever lasted for 5 days; however, respiratory symptoms progressively worsened. There was no history of preceding viral prodrome, skin lesions, chest discomfort, wheezing or stridor, hemoptysis, witnessed foreign-body aspiration, sudden bout of cough or choking, weight loss, or contact with tuberculosis. Past history, birth details, neurodevelopment, and family history were noncontributory. The child had been completely vaccinated for age.

On examination, the child was afebrile, hemodynamically stable but had tachycardia, tachypnea, mild suprasternal, intercostal, and subcostal chest retractions. Despite this, he was able to maintain normal oxygen saturation in room air. He was most comfortable sitting upright. An intermittent, faint stridor was audible. He had pallor and distended neck veins but no cyanosis, clubbing, edema, or significant lymphadenopathy. Weight and height were normal for age. There was a rightward shift of the trachea with reduced chest movements, decreased tactile fremitus, dull percussion note, and almost complete absence of breath sounds, anteriorly and posteriorly, on left. There was wheeze over the left interscapular area. Examination of other systems was normal, except for the cardiac impulse being palpable 2 cm medial to left midclavicular line.

What clinical differentials should be considered at first?

Before proceeding with any investigations, all possible causes of a acute febrile respiratory illness were thought of. The most common cause of such a presentation in India would be a complicated bacterial pneumonia. Since, isolated lung or lobar collapse would cause an ipsilateral mediastinal shift, and there was no hyperresonance to suggest a pneumothorax, a working diagnosis of pneumonia complicated by parapneumonic effusion or empyema was considered. The likely causative organism of community-acquired pneumonia in a fully immunized and presumably immunocompetent 3 year old would be Streptococcus pneumoniae or Staphylococcus aureus. The possibility of a left hemithoracic, predominantly cystic, space-occupying entity was considered next, as the tactile fremitus was reduced. This could be a hydatid cyst, a cystic congenital lung malformation, or a neoplastic lesion.

How would you plan preliminary management?

The child had been started on oxygen by nasal prongs and intravenous (IV) fluids on arrival. He was also started on broad-spectrum antibiotics (ceftriaxone and cloxacillin). Routine hematological and microbiological investigations were sent. A chest X-ray showed an almost completely opaque left hemithorax and confirmed contralateral mediastinal shift [Figure 1]. The heart size and contours could not be clearly identified. This was followed by a point of care USG, which revealed a moderate-sized left pleural effusion, with dense echoes and septations. A diagnostic needle thoracocentesis with a wide bore needle was attempted by a skilled clinician; however, no fluid could be aspirated. As it was unlikely that a pleural effusion large enough to cause severe respiratory distress would be dry on a properly performed aspiration, we decided to investigate for the other differentials that had been considered. By this point, some reports were available: hemoglobin was 9.5 g/dL, total leukocyte count was 12,560/mm3, there was no thrombocytopenia, and elevated C-reactive protein (24 mg/L).
Figure 1: Panel A: Chest X-ray just before surgery, showing opaque left hemithorax with contralateral mediastinal shift, with an endotracheal tube in situ. Panel B. Two sections of contrast enhanced computed tomography chest showing large mass with predominantly cystic components

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How would you revise the differential diagnoses?

Clinical features suggestive of mediastinal compression (intermittent stridor, congested neck veins, and left-sided wheeze) meant the possibility of a predominantly left-sided, intrathoracic mass that was encroaching upon the superior and middle mediastinum, with airway and vascular compression. Probable causes included a lung hydatid (now enlarging owing to bleeding or superinfection), a cystic congenital malformation (i.e., bronchogenic cyst) or a mediastinal tumor like a lymphoma or germ cell tumor. A primary lung neoplasm was considered unlikely on account of the young age and relatively short history.

A contrast-enhanced computed tomography scan of the chest was done, as it is one of the most sensitive investigations to localize a mediastinal lesion and delineate the tissue characteristics. This revealed a large mass (10.5 cm × 9.6 cm × 13.1 cm) occupying the left hemithorax, with predominantly cystic components and multiple enhancing septations [Figure 1]. There was a contralateral shift of the mediastinum and a small pleural effusion. There was no evidence of rib erosion, extrathoracic, or intraspinal extension. Factoring in the age of the patient, location of the lesion, and the presence of predominantly cystic components, a diagnosis of pleuropulmonary blastoma (PPB) was considered. Absence of cytopenia excluded bone marrow involvement. Biochemical markers (lactate dehydrogenase, beta-human chorionic gonadotropin, and alpha-fetoprotein) were noncontributory, thus excluding other childhood mediastinal tumors such as lymphoma, mediastinal germ cell, or yolk sac tumor.

Specific management and outcome

The child was managed propped-up in the left lateral position, given IV hydrocortisone and started on invasive mechanical ventilation. A standard protocol for monitoring tumor lysis syndrome was followed. To relieve the mass effect and confirm the diagnosis, he underwent a left posterolateral thoracotomy with excision of the mass. Postoperative extubation was planned on day 3. The follow-up chest X-ray showed complete expansion of the left lung [Figure 2]. Histopathology confirmed the diagnosis of PPB type II. Metastases were excluded by positron-emission tomography CT. The patient received standard chemotherapy tumor recurrence and is currently doing well about a year after recovery.
Figure 2: Panel A. Chest X-ray immediately after the surgery showing the expanded left lung, small pneumothorax with a drainage tube in situ. Panel B. Chest X-ray 1 week after surgery, showing almost complete resolution

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  Discussion Top


In this case, the history, examination, and initial radiologic findings (chest X-ray and USG) were consistent with pneumonia complicated by pleural effusion or empyema. This is by far, the most common etiology for this type of presentation. However, there were some unusual features, notably neck vein congestion, intermittent stridor, and wheeze. Although these can also occur in empyema associated with pericardial effusion, once they are excluded a search for airway and vascular compression by a mass lesion should be initiated.

Clinicians evaluating children with complete or partially opaque hemithorax should consider differential diagnoses depending on the position of the mediastinum. An ipsilateral shift of mediastinal structures (trachea and heart) is seen with lung aplasia, agenesis or hypoplasia, or a collapsed lung which could be due to an obstructed main bronchus by an extrinsic (mediastinal mass, lymph node, etc.) or intrinsic lesion (foreign body, mucus plug, tumor, etc.). Contralateral shift should raise suspicion of a large pleural effusion, hemothorax or chylothorax, intrathoracic tumors, congenital diaphragmatic hernia (CDH), or other congenital thoracic malformations. In rare instances, the pathology could be in the heart or pericardium. The tracheal and cardiac position may remain unchanged in children with an opaque hemithorax if there is simultaneous presence of “volume-loss” and “volume-increase” such as in concomitant lung collapse and pleural effusion. Suspicion of congenital malformations such as CDH, lung hypoplasia, or sequestration is greater when the presentation is in the neonatal period or early infancy. On the other hand, in a toddler with witnessed or unwitnessed choking episode, exclusion of an aspirated foreign body takes precedence over other possibilities, warranting an urgent bronchoscopy.[3]

Chest USG is a helpful modality in children, although its limitations and dependence on operator expertise (for performance and interpretation) should be recognized. In the index case, the presence of cystic component within the mass, with associated septations, suggested a pleural empyema rather than mass lesion. In India, this relatively less expensive and less risky procedure is often ignored, with most clinicians preferring CT scans. CT and MRI scans undoubtedly provide greater clarity but at a high price, radiation (exceeding the ceiling if the child has already had numerous X-rays), risk of sedation, contrast reactions, and expense.

This patient had a PPB, the most common primary childhood lung malignancy. It is a rare tumor that accounts for around 0.5% of all malignant tumors in children. It belongs to a family of dysembryonic neoplasms such as retinoblastoma, hepatoblastoma, neuroblastoma, and Wilm's tumor. The tumor can arise from the lungs, pleura, or both and can be associated with pleural effusion and pneumothorax. It has three pathological types (I, II, and III) with progressively increasing solid and decreasing cystic components, and worsening prognosis. The presentation is usually before mid-childhood with acute respiratory distress or mimicking pneumonia. Type I is often misdiagnosed as a congenital pulmonary airway malformation because of a similar appearance on X-ray and CT.[4] Type II/III is managed by surgical resection and adjuvant chemotherapy or radiation. PPB may develop distant metastases.[5]

This case underlines the indispensability of following a step-wise deductive process to arrive at a diagnosis, comprising a detailed history, thorough physical examination, judicious use of investigations, and astute clinical reasoning.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Rauf A, Singhi S, Nallasamy K, et al. Non-respiratory and non-diarrheal causes of acute febrile illnesses in children requiring hospitalization in a tertiary care hospital in North India: A prospective study. Am J Trop Med Hyg 2018;99:783-8.  Back to cited text no. 1
    
2.
Stadler JA, Andronikou S, Zar HJ. Lung ultrasound for the diagnosis of community-acquired pneumonia in children. Pediatr Radiol 2017;47:1412-9.  Back to cited text no. 2
    
3.
Lucaya J, Garcés-Iñigo EF, García-Peña P, et al. White hemithorax in children. Pediatr Radiol 2011;41:916-24.  Back to cited text no. 3
    
4.
Lichtenberger JP 3rd, Biko DM, Carter BW, et al. Primary lung tumors in children: Radiologic-pathologic correlation from the radiologic pathology archives. Radiographics 2018;38:2151-72.  Back to cited text no. 4
    
5.
Messinger YH, Stewart DR, Priest JR, et al. Pleuropulmonary blastoma: A report on 350 central pathology-confirmed pleuropulmonary blastoma cases by the international pleuropulmonary blastoma registry. Cancer 2015;121:276-85.  Back to cited text no. 5
    


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