Suppurative mediastinal lymphadenitis caused by Actinomyces odontolyticus: Successfully diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration

JJ Wu¹, JL Wang¹, CF Tung², JS Tseng¹,  
¹ Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan
² Gastroenterology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan

Correspondence Address:
J S Tseng
Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung
Taiwan

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A 71-year-old man with a history of chronic hepatitis C and hepatocellular cell carcinoma presented to the emergency department of our hospital with acute onset of fever and chills since last 4 days. For the hepatocellular cell carcinoma, he had undergone radiofrequency ablation 1 year earlier and had clinically stabilized. The patient had been apparently fine until 2 months earlier, when he developed a nonproductive cough. On enquiry, he had no chest pain, shortness of breath, rashes, joint symptoms, gastrointestinal symptoms, dysuria, or weight loss.

On presentation to the hospital, the patient's body temperature was 38.9°C. His physical examination findings were unremarkable. Laboratory test results were notable for a white blood cell count of 13,380 per cubic millimeter (reference range: 4500 to 10,500), with neutrophils 79.9% and a high sensitivity C-reactive protein of 7.13 mg per deciliter (reference range: <0.3 mg per deciliter).

During hospitalization, the patient underwent empirical antibiotics treatment with intravenous cefazolin initially, which was then shifted to flomoxef sodium. However, the fever persisted. A computed tomography scan of abdomen showed stable disease of his hepatic tumor and there was no evidence of intraabdominal infection. The chest radiography suspected a protruding lesion over the right upper mediastinum [Figure 1]a and intensely increased gallium uptake of this area was observed in the gallium scan [Figure 2]a, which hinted the possibility of inflammation or tumor involvement. A computed tomography scan of chest detected a 3.5 cm mass in the right lower paratracheal space of the mediastinum with central necrosis and focal invasion into the pulmonary parenchyma [Figure 1]b and [Figure 1]c. He underwent bronchoscopy and endobronchial ultrasound (EBUS), which disclosed an irregular mass in the right lower paratracheal space with heterogeneous echogenicity [Figure 2]b. EBUS-guided transbronchial needle aspiration (TBNA) with 21-gauge aspiration needle was performed for tissue sampling [Figure 2]c. There were no definite malignant cells in the rapid on-site evaluation (ROSE) but abundant polymorphonuclear neutrophils were noted.{Figure 1}{Figure 2}

The pathology result turned out to be acute suppurative lymphadenitis, and the culture yielded Actinomyces odontolyticus. We adjusted the antibiotics to oral ampicillin/sulbactam (440/294 mg) twice daily. Fever subsided and his clinical symptom improved gradually. The patient underwent a detailed dental examination which ruled out any intra-oral focus of infection. Chest radiography performed after an 8-week course of antibiotics showed complete remission of the mediastinal lesion [Figure 1d-f].

Actinomycosis is a rare infectious disease caused by Actinomyces spp. Cervicofacial area, abdominopelvic cavity, and respiratory tract have been reported to be the most common locations being involved. Patients with poor oral hygiene, preexisting dental disease, diabetes, immunocompromised status, and alcoholism have a higher risk of developing actinomycosis.[1],[2] Primary lymph node infection by Actinomyces spp. is an even rarer condition.[3]

The clinical presentations of actinomycosis include local and constitutional symptoms, such as fever, weight loss, and night sweats. The image studies can mimic malignancy, tuberculosis, or fungal infection. Both the clinical and radiographic presentations are nonspecific; hence, the diagnosis is usually delayed.[1]

The presence of sulphur granules is usually highly suggestive of Actinomycosis. However, it is not 100% sensitive to this disease and it could be also observed in infectious diseases caused by other microorganisms.[1],[4] Identification of Actinomyces from aseptic specimens is another way to confirm the diagnosis.

Linear EBUS-guided TBNA has been used widely in the diagnosis of mediastinal lymph nodes, which is less invasive, has a high diagnostic yield, and can spare some patients from surgical biopsy.[5] ROSE is a useful tool in ensuring tissue adequacy and triage specimens for ancillary studies.[6] Routine microbiological studies of TBNA specimens should be considered when ROSE suggests an inflammatory disease or if ROSE assistance is unavailable.

The mainstay to treat actinomycosis is systemic antibiotics. Most Actinomyces spp. are susceptible to penicillin G or amoxicillin.[1],[3] Alternative treatment includes macrolides or clindamycin. A longer duration of antibiotics is usually required.

Actinomycosis is a rare disease, and primary lymph node infection, as in the present case, is an even rarer condition. In the case of mediastinal lymph node involvement, EBUS-TBNA could be a useful diagnostic tool.

Declaration of patient consent

The authors certify that appropriate patient consent was obtained.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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