Streptococcus pyogenes-Induced Necrotizing Pneumonia With Pleural Effusion in a Child: Role of Medical Thoracoscopy

Introduction

Necrotizing pneumonia is a severe and potentially fatal respiratory condition in children, characterized by the destruction of lung tissue, formation of necrotic cavities, and frequent involvement of the pleura, primarily affecting preschool and school-aged children [1]. Although various pathogens can cause necrotizing pneumonia, Streptococcus pyogenes is an uncommon but particularly aggressive culprit due to its unique virulence factors that trigger intense inflammatory reactions and rapid tissue death [2,3]. Children with S. pyogenes-induced necrotizing pneumonia often exhibit persistent high fever, a stubborn cough that doesn’t respond to typical treatments, and signs of widespread bodily toxicity. Without immediate medical attention, the condition can quickly worsen, leading to complications like empyema and pneumothorax [4]. Diagnosis relies heavily on chest computed tomography (CT) scans, which reveal telltale signs such as lung cavities and localized fluid collections. Early detection and treatment are crucial to prevent lasting damage to a child’s respiratory system and ensure the best possible recovery.

Respiratory viral infections exhibit high incidence rates in children and significantly increase susceptibility to secondary bacterial infections. Common pathogens, including respiratory syncytial virus, influenza virus, adenovirus, and human metapneumovirus, can substantially compromise the innate protective mechanisms of the respiratory system [5]. These viruses impair mucociliary clearance, disrupt mucosal barrier integrity, and modify the inflammatory response, thereby creating favorable conditions for bacterial adherence and proliferation [6]. The synergistic interaction between viral and bacterial pathogens represents a well-established phenomenon in pediatric pulmonology. The progression from viral upper respiratory infections to bacterial lower respiratory tract involvement constitutes a critical clinical transition requiring heightened vigilance.

Medical thoracoscopy, a pediatric-adapted minimally invasive technique, provides several advantages over percutaneous drainage, such as direct visualization of the pleural space, targeted removal of purulent material, breaking down adhesions, and obtaining samples for pathogen identification [7,8]. However, whether medical thoracoscopy is superior to percutaneous treatments for managing complications of necrotizing pneumonia remains debated. Three randomized controlled trials have shown no significant difference in outcomes between thoracoscopic treatment and chest tube drainage with fibrinolytics for pediatric empyema [9–11].

We present a 7-year-old girl with S. pyogenes-associated necrotizing pneumonia who developed azithromycin-refractory disease initially and was successfully managed via medical thoracoscopy. This case highlights 2 important clinical observations. First, it demonstrates how human metapneumovirus infection can serve as a predisposing factor for subsequent bacterial pneumonia in children. Second, it illustrates the development of opportunistic necrotizing pneumonia caused by S. pyogenes after viral infection. These observations provide valuable insights into the diagnosis, timely intervention, and optimal management of this serious pediatric condition.

This case report was prepared in accordance with the CARE (Case Report) guidelines to ensure completeness and transparency. This study follows the CARE guidelines reporting standards.

Case Report

INITIAL SYMPTOMS AND LOCAL HOSPITAL TREATMENT:

Prior to her presentation at our institution, the patient had sought medical attention at a local hospital due to progressive respiratory symptoms. Initial diagnostic evaluations there included a respiratory pathogen panel, which yielded negative results, and routine complete blood count, which showed no significant abnormalities. Chest CT imaging performed at that facility revealed bilateral lower lobe opacities consistent with a clinical diagnosis of bronchitis. The patient received empirical treatment consisting of intravenous azithromycin administered for 3 consecutive days, a single dose of dexamethasone and 2 doses of methylprednisolone. Despite this therapeutic regimen, her clinical condition failed to improve. Specifically, she continued to present with persistent fever and recurrent episodes of blood-tinged sputum, which prompted her referral to our tertiary care center for further evaluation and management.

FIRST ADMISSION TO OUR HOSPITAL:

On March 15, 2025, a 7-year-old girl was admitted to the Department of Gastroenterology due to a series of concerning symptoms that had developed over the preceding week. Her illness began with a fever that had lasted for 7 days, reaching a peak temperature of 39.8°C. Six days before admission, she developed a worsening cough with white sputum occasionally containing blood. In the 2 days preceding admission, the cough had intensified, producing blood-tinged sputum. In the 24 hours leading to her admission, she also developed abdominal pain, diarrhea, and vomiting.

The patient’s vital signs were stable, showing a slightly elevated temperature of 37.5°C, a heart rate of 108 beats per minute, and a respiratory rate of 22 breaths per minute. Blood pressure was measured at 90/37 mmHg with oxygen saturation at 98% on room air. Upon physical examination, the child appeared alert but displayed mild lethargy. The pharynx was erythematous with Grade I tonsillar enlargement, and coarse lung sounds were noted bilaterally. Right upper quadrant tenderness was present without rebound tenderness, while the rest of the systemic examination revealed no significant abnormalities.

The patient presented with significantly elevated inflammatory markers, including white blood cell count, C-reactive protein, erythrocyte sedimentation rate, and procalcitonin, along with a positive human metapneumovirus nucleic acid test (Table 1). Other laboratory tests, such as biochemical, coagulation, fecal, and urine analyses, showed no notable abnormalities. Chest CT imaging revealed bilateral lower lobe patchy opacities (Figure 1A, 1B). Oxygen support was administered via nasal cannula from March 15–16 and 18–19, and via face mask from March 16–18. Treatment included intravenous linezolid (March 16–24), ceftriaxone (March 15–24), and methylprednisolone (March 16–20). Flexible bronchoscopy (FB) on March 19 identified abundant bronchial secretions, and bronchoalveolar lavage (BAL) was performed (Figure 2A–2F). BAL fluid analysis detected S. pyogenes (2434 sequences, 3.73% relative abundance). The patient’s fever resolved by March 17, and after achieving clinical stability, she was discharged on March 24.

SYMPTOM RECURRENCE AND READMISSION:

On March 25, the patient was readmitted to the Department of Respiratory Medicine due to a 12-hour episode of abdominal pain accompanied by mild cough and yellow purulent sputum. Repeat laboratory tests indicated elevated levels of white blood cells and C-reactive protein, along with persistently high procalcitonin (Table 1). An abdominal ultrasound showed no abnormalities, while pleural ultrasound revealed a right-sided septated effusion measuring 1.9 cm in thickness. High-throughput sequencing of the pleural fluid did not detect any pathogenic organisms. A chest enhanced CT scan performed on March 26 confirmed the presence of bilateral lower lobe necrotizing pneumonia with cavitation (Figure 1C, 1D). The patient’s final diagnosis indicates a primary viral lower respiratory infection caused by human metapneumovirus, which was further complicated by a secondary infection of necrotizing pneumonia due to S. pyogenes, also involving the pleural space. It is believed that the initial human metapneumovirus infection acted as a predisposing factor, creating favorable conditions that led to the subsequent S. pyogenes infection.

DEFINITIVE TREATMENT AND RECOVERY:

On March 28, under general anesthesia, the patient underwent medical thoracoscopy, pleural biopsy, thoracic irrigation, closed chest drainage, and FB-guided BAL. During the procedure, FB showed minimal tracheobronchial secretions, and BAL of the right lower lobe yielded purulent fluid. Medical thoracoscopy identified approximately 100 mL of reddish purulent fluid, which was completely aspirated, mild pleural adhesions were bluntly lysed, and purulent exudate was sampled via biopsy. The reddish purulent effusion was sent for microbiological culture and analysis. Culture results confirmed the presence of S. pyogenes, and biochemical analysis showed elevated lactate dehydrogenase levels (1200 U/L) and low glucose levels (2.1 mmol/L), consistent with empyema. The thoracic cavity was irrigated with normal saline, and a chest drainage tube was placed (Figure 3A–3D). The procedure was completed without complications. FB-guided biopsy of the right lower lobe revealed inflammatory fibrinoid necrotic tissue (Figure 4).

After surgery, the patient was treated with intravenous ceftriaxone from March 25 to April 7, along with intravenous linezolid from March 26 to April 9, followed by oral step-down therapy until April 11. Intravenous methylprednisolone was administered from March 30 to April 4, alongside supportive care including intravenous ambroxol to aid expectoration, nebulization therapy, and fluid replacement. Her fever subsided by March 30, and her chest pain showed significant improvement by April 3, leading to her discharge. Follow-up chest CT scans confirmed the resolution of necrotizing pneumonia (Figure 1E, 1F). Telephone follow-ups at 1-, 3- and 6-months post-procedure revealed no significant adverse effects, and the child fully resumed normal daily activities. The treatment timeline of the patient is shown in Table 2.

Discussion

LIMITATIONS:

This study has several limitations that warrant consideration. As a single-patient case report, our findings cannot be generalized to the broader population of pediatric patients with S. pyogenes necrotizing pneumonia, and larger studies are needed to confirm the effectiveness of medical thoracoscopy in this specific patient group. The utility of medical thoracoscopy in pediatric necrotizing pneumonia remains debated, as existing comparative studies have shown comparable outcomes between fibrinolytic therapy and thoracoscopic treatment for childhood empyema [10,11]. In this case, medical thoracoscopy offered minimal additional diagnostic benefit since the infection was already identified through bronchoscopy and the extent of pleural/lung involvement was clearly visible on chest CT scans. Additionally, we cannot definitively assess how much the concurrent human metapneumovirus infection contributed to the disease severity due to the absence of serological testing. Finally, because the patient received a full 14-day course of intravenous antibiotics, it is difficult to isolate and evaluate the specific impact of the thoracoscopic procedure on the patient’s clinical recovery.

Conclusions