Actinomycosis

Four cases of primary endobronchial actinomycosis associated with an inhaled foreign body are described. In the light of these cases and those previously reported in the literature, we describe the main features of this uncommon association. All patients were > 55 years old, were predominantly men, and were usually in a debilitated state. In > 50% of cases, the clinical presentation was suggestive of lung cancer. Thoracic CT rarely revealed a foreign body, but the granulomatous reaction of the bronchial wall was sometimes suggestive of bronchial thickening. Sulfur granules identified on bronchial biopsies were highly suggestive of actinomycosis in most cases, but microbiological culture findings were usually negative. Antibiotics generally ensure good recovery. Extraction of the foreign body was delayed after antibiotic therapy in one half of cases, suggesting the need for endoscopic follow-up in bronchial actinomycosis.

Key words: actinomycosis; bronchus; endoscopy; foreign body; thoracic CT

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Actinomycosis is a chronic suppurative infection due to a group of anaerobic or microaerophilic bacteria belonging to the resident flora of the oropharynx and GI tract. Actinomyces israelii is the main representative pathogen in human infection, although most cases of actinomycosis are thought to be polymicrobial.

Twenty percent of cases of actinomycosis are located in the thorax. (1) Primary endobronchial actinomycosis is rare and very uncommon in association with foreign body aspiration. (2) In this context, bronchial infection is thought to result from direct aspiration of an Actinomyces-contaminated foreign body.

We report four cases of endobronchial actinomycosis associated with bronchial foreign body. In the light of these cases and those previously reported in the literature, we describe the diagnostic, pathologic, bacteriological and therapeutic features of this association, which must be considered more systematically.

CASE REPORTS

Between January 1996 to September 1999, four cases of endobronchial actinomycosis associated with foreign body were observed at Reims University Hospital. Clinical data, diagnostic procedures, and treatments are summarized in Table 1.

These four patients were men between the ages of 56 and 79 years (mean age, 70 years) with a history of smoking (19 to 33 pack-years). Each patient presented in a debilitated state: metastatic cervical node (patient 1), noninsulin-dependent diabetes mellitus (patient 2), previous lung cancer treated by upper and middle lobectomy 1 year previously (patient 3), and alcoholism (patient 4).

Presenting symptoms were left chest pain with fever related to pleural effusion (patient 2) and persistent purulent bronchitis (patients 3 and 4). One patient (patient 1) had no respiratory symptoms. None of the patients reported any history of choking. Laboratory data revealed a raised leukocyte count (11.9 x [10.sup.6]/L) in one case (patient 2) and inflammatory signs in two cases (patient 2 and patient 4). The pleural effusion in patient 2 was a cloudy exudate containing 1,500 leukocytes per microliter with a predominance of polymorphonuclear leukocytes.

Chest radiography revealed a tooth in the right hilar region in one patient (patient 1) [Fig 1]. Related images, such as a left pleural effusion associated with lower lobe consolidation or an alveolar opacity in the right lower lobe, were the main presenting signs in two patients (patient 2 and patient 4) and were confirmed by CT. Chest radiographic findings were normal in the last patient (patient 3). Thoracic CT showed calcified material corresponding to a tooth in the bronchus intermedius in one case (patient 1). No foreign bodies were observed in the other cases, but an obstructive high-density mass was seen in the lumen of the left lower lobe (Fig 2) or right main bronchus (patient 2 and patient 4). In patient 3, with normal chest radiographic finding, CT showed segmental thickening of the right bronchus.

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Fiberoptic bronchoscopy revealed a mass suggestive of a tumor obstructing 40 to 60% of bronchial lumen in two cases (patient 1 and patient 2), but the foreign bodies (a tooth and a chicken bone) were not identified at the initial examination. They were only visualized after 3 to 4 months of antibiotic therapy, and were removed by cryotherapy in one case and biopsy forceps in the other case. In the two remaining cases (patient 3 and patient 4), the bronchial mucosa was inflamed and necrotic. The foreign body was identified and immediately removed (grape seeds and a bean). In all cases, bronchial biopsies revealed a granulomatous inflammatory reaction in the mucosa. Periodic acid-Schiff-positive filaments consistent with actinomycosis infection were identified on bronchial biopsies in two cases, and sulfur granules were detected in one case. In the last patient, periodic acid-Schiff-positive filaments were identified only on cytologic examination of paraffin-embedded respiratory tract secretions.

All patients were treated with antibiotics for 3 to 6 months: amoxicillin, 3 g/d, in three cases, and erythromycin in one case because of documented allergy to [beta]-lactam antibiotics. A favorable course was observed after prolonged antibiotic therapy and foreign body extraction in three cases, but the remaining patient died 3 months later from Pseudomonas aeruginosa pneumonia associated with chemotherapy-induced neutropenia.

DISCUSSION

Bronchial involvement is a rare form of thoracic actinomycosis (3) that has sometimes been reported to be associated with foreign bodies. The four cases presented here and the seven cases previously reported (3,5-9) illustrate the main clinical features of this association (Table 1).

All patients were > 55 years old and presented a male predominance (nine men and two women). This sex ratio has also been reported for thoracic actinomycosis. (1) Two types of situations predisposing to actinomycosis are reported: debilitated state, such as noninsulin-dependent diabetes mellitus (27%); neoplasm (18%), or poor dental hygiene (36%); and conditions that facilitate foreign body aspiration, such as mental retardation (9%). The main symptoms are cough (63%), recurrent pneumonia (27%), and hemoptysis (36%). A history of choking was never reported in any case of foreign body aspiration associated with actinomycosis, but a large series of bronchial foreign body aspiration in adults reports choking in only 50% cases. (10)

Thoracic CT showed a radiopaque foreign body in two of our cases and in one previously reported case (two chicken bones and one tooth, respectively), using endoluminal three-dimensional reconstruction in one case. (9) Bronchial involvement consisting of a thickened bronchial wall was identified in three of our cases, and has been previously reported in two cases in the literature. (4,9) Other indirect signs are seen on CT scan: dense pulmonary alveolar opacity (45%), atelectasis (36%), pleural effusion (18%), or bronchiectasis (9%). Endoscopically, an obstructive endoluminal mass was found in all cases, and the foreign body was detected immediately in only 45% of cases. This type of presentation, suggestive of lung cancer, is frequently reported in endobronchial actinomycosis not associated with foreign body. (11) It therefore seems important to perform follow-up bronchoscopy after antibiotic therapy to exclude the presence of a foreign body.

Actinomycosis infection was diagnosed on bronchial biopsies in all cases. The presence of sulfur granules in biopsy samples is highly suggestive of actinomycosis. (12) In contrast, culture findings are usually negative, as A israelii is a strict anaerobe and is frequently associated with nonanaerobic contaminants. Bronchial aspiration samples may also be contaminated by oral flora.

A israelii is usually sensitive to penicillins. Other effective antibiotic families are tetracyclines, lincosamides, and trimethoprim-sulfamethoxazole. (12) The optimal duration of treatment has not been clearly established, but treatment for at least 45 days seems to be necessary in the case of thoracic actinomycosis. (1) Our patients were treated with penicillin G or ampicillin, but one patient allergic to [beta]-lactam antibiotics was treated with a macrolide. Clindamycin can be an alternative therapy in these situations.

Bronchoscopic removal of the foreign body was effective in all cases. However, in 45% of cases, the foreign body was only detected some time after starting antibiotics. Extraction procedures required bronchial aspiration (3 of 11 cases), biopsy forceps (6 of 11 cases), YAG laser (1 of 11 cases) or cryotherapy (1 of 11 cases).

This review of the literature concerning endobronchial actinomycosis associated with foreign body aspiration confirms the development of this infection in debilitated patients with poor oral hygiene, frequently mimicking lung cancer. Endobronchial actinomycosis is usually diagnosed on histologic examination of bronchial biopsies and requires investigation of an associated bronchial foreign body, which may be missed on the initial assessment.

REFERENCES

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(8) Dicpinigaitis PV, Bleiweiss IJ, Krellenstein DJ, et al. Primary endobronchial actinomycosis in association with foreign body aspiration. Chest 1992; 101:283-285

(9) Mignon F, Mesurolle B, Chambellan A, et al. Granulomatous reaction to a foreign body mimicking bronchogenic tumor: CT findings with virtual endoscopy. J Radiol 1997; 78:1181-1184

(10) Lan RS. Non-asphyxiating tracheobronchial foreign bodies in adults. Eur Respir J 1994; 7:510-514

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* From the Department of Respiratory and Allergic Diseases, Hopital de la Maison Blanche, 51092 Reims, France. Manuscript received January 11, 2001; revision accepted January 22, 2002.

Correspondence to: Francois Lebargy, MD, PhD, Service de Pneumologie, CHU de la Maison Blanche, 45 rue Cognacq Jay, 51092 Reims, France; e-mail: flebargy@chu-reims.fr

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