3 | DISCUSSION
In this article, we describe an interesting case of pulmonary actinomycosis in a patient with a background of COPD, heavy smoking, and poor dental hygiene. The patient’s initial presentation with pleuritic chest pain, fever, productive cough, and dyspnea may give the impression of a clinical diagnosis of pneumonia. This makes pulmonary actinomycosis a very challenging condition to diagnose, and physicians need to maintain a high index of suspicion.
Actinomyces is a common commensal that forms part of the normal flora of the oral cavity. Pulmonary actinomycosis is caused by aspiration of the oropharyngeal secretions; this results in a direct invasion of the bronchopulmonary tree, putting the lower segments of the right lung at a higher risk [4]. Moreover, individuals with poor dental hygiene and alcoholism are more susceptible to develop pulmonary actinomycosis, which was the case in our patient. Other predisposing factors for pulmonary actinomycosis infection include underlying lung disorders such as chronic bronchitis, emphysema, and bronchiectasis [5], which was also noted in our case.
The radiological features of pulmonary actinomycosis aren’t specific; they may include consolidation, cavitation, abscess formation, draining sinuses, mass, and hilar or mediastinal lymph node enlargement. Pleural involvement may also result in pleural effusion, thickening, or empyema in about 15%–50% of cases [6]. These different findings make pulmonary actinomycosis difficult to spot early, leading to it being misdiagnosed as lung malignancy or pulmonary tuberculosis.
The diagnosis of pulmonary actinomycosis is challenging due to the difficulty of isolating the organism. Simple culture using a sputum sample, either expectorated or extracted using bronchoalveolar lavage (BAL), is inadequate for the diagnosis of pulmonary actinomycosis unless the patient presents with lung cavitation [2, 7]. The gold standard for diagnosis is the histopathological examination and bacterial culture in anaerobic conditions from a pleural biopsy sample, looking for gram-positive branching filamentous rods with yellow sulfur granules [1–3]. Although sulfur granules are considered to be a pathognomonic histological feature and quite suggestive of actinomyces, it is important to know that sulfur granules can also be found in nocardiosis, coccidioidomycosis, and aspergillosis [8]. Moreover, it is quite helpful to realize that a sample taken from the pleural effusion in patients with pulmonary actinomycosis is unlikely to grow or yield any bacterial growth [2].
The treatment regimen for pulmonary actinomycosis requires a prolonged course of high doses of beta-lactam antibiotics such as penicillin G, amoxicillin, or cephalosporin. The recommended treatment duration is 6–12 months with the administration of antibiotics intravenously over 2–6 weeks, followed by oral medications [3, 5]. In patients with penicillin allergies, the recommended options include clindamycin, doxycycline, and erythromycin, with the latter being a safe option for pregnant women [1–3]. Antibiotics are the cornerstone of actinomycosis treatment, and a good response is usually observed, as seen in our patient. Nevertheless, surgical management is indicated in patients who develop massive hemoptysis or a localized lung infection such as (empyema, or abscess), also in cases of sinus tracts or fistulas, and finally in those who don’t respond to medical treatment [9].
ACKNOWLEDGEMENT
Not applicable.
CONFLICTS OF INTEREST
All authors declare that there are no conflicts of interest.
CONSENT
Written consent for publication has been obtained from the patient and the authors.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.