To summarize the clinical characteristics, imaging features, diagnosis, treatment and prognosis of pulmonary actinomycosis in children.

The clinical data of a child with pulmonary actinomycosis who was hospitalized in Children′s Hospital, Zhejiang University School of Medicine in December 2019 was retrospectively analyzed. The related literature published from January 1975 to January 2020 was retrieved from Wanfang, CNKI and PubMed databases with "pulmonary" or "thoracic" and "actinomycosis" and "pediatric" or "children" or "child" as the keywords. And the characteristics of pediatric pulmonary actinomycosis were summarized based on the literature review.

The patient was a boy aged 12 years and 6 months. He was admitted due to cough and chest pain for more than 20 days, with fever on the first three days. The chest CT scan in local hospital found inflammatory lesions in the right middle lobe, which was also suspected to be cavitation. The flexible bronchoscopy showed congestion and edema of bronchial mucosa in the right middle lobe, and bronchoalveolar lavage fluid smear was positive for acid-fast bacilli DNA, although both purfied protein derivatives tuberculin test and T-spot were negative. During the hospitalization, the child had persistent cough and chest pain, but no fever. Pathogen metagene sequencing of the bronchoalveolar lavage fluid detected Actinomyces (sequence number: 222) and Grevini Actinomycetes (sequence number: 185). The boy received intravenous cefoperazone sulbactam sodium for 2 weeks followed by oral amoxicillin clavulanate potassium for 6 weeks. Until April 2020, his clinical symptoms completely relieved, and the pulmonary lesions were significantly absorbed on the latest chest CT scan. Eight articles and 62 children with pulmonary actinomycosis were reported, but no related reports were retrieved from CNKI and Wanfang databases. The youngest case was 27 months old. The clinical presentations of this disease were nonspecific. The main symptoms included chest wall masses (8 cases), cough (23 cases), pain (chest, back, shoulders and armpits) (24 cases), fever (25 cases), weight loss (26 cases), etc.

The clinical manifestations and imaging features of pediatric pulmonary actinomycosis are nonspecific, therefore it could easily be misdiagnosed. For children with pneumonia of unknown etiology and failing to respond to routine antibiotics, the pathogen metagene sequencing of the bronchoalveolar lavage fluid will be helpful for diagnosis. With appropriate course of antibiotic treatment, the prognosis is good in most cases.

Actinomycosis; Child; Metagenome