• Abstract:

Mediastinal actinomycosis in children is rare. A 11 year old Bahraini girl presented with fever, generalized weakness and body aches. A CT scan thorax confirmed the presence of a mass lesion in the mediastinum. The mass was surgically removed and the biopsy confirmed the diagnosis of actinomycosis.

• Introduction:

Actinomycosis is a chronic granulomatous suppurative disease characterized by peripheral spread with extension to contigous tissue in the formation of multiple draining sinus tract. These infection usually involve the cervico facial, thoracic, abdominal or pelvic region. Actinomycosis israeli is the predominant organism causing disease in human. Other implicated species in order of importance include: Arachriapropionica, A. Odontolyticus, A. meyeri, A. naeslundii, A. viscous and Bifido bacterium eriksonii^1,2. The three important sites of actinomycosis infection in order of frequency are cervicofacial, abdominal and thoracic. A British epidemiological surveys for the years 1971 and 1972 recorded 67 cases of actinomycosis, only six paediatric cases were described and none had intra thoracic involvement³. We report a child with a mediastinal actinomycosis, the clinical presentation and treatment.

• The Case:

A 11 year old Bahraini girl presented with fever, generalised weakness and body aches. Physical examination revealed febrile, pale asthenic girl, not in respiratory distress, with diminished air entry by ausculation on the right side of the chest and bronchial breathing. There were no lymphadenopathy neither hepatosplenemegaly. Investigation showed the Hemoglobin of 8 g%, platelets 827 x 10⁹/L, white blood cells 21.3 x 10 ⁹/L (polymorph 66%, Lymphocytes 25%). ESR was 115 mm in 1 hr, chest radiograph (figure 1) showed a mass on the anterior mediastinum. CT scan of chest confirmed the presence of a large mass in the upper mediastinum extending anterio posteriorly to the paravertebral region (Figure 2). Tubercurbin, cold agglutination tests were negative. Fine needle aspiration revealed the presence of inflammatory lesion, not malignant or tuberculous. Thoractomy done which demonstrate a vascular mass extending from the posterior to anterior mediastinum, biopsy taken demonstrated the presence of colonies of fungi surrounded by neutrophills which is combined with the actinomycosis laying over vascular malformation. She was treated with intravenous penicilline G 200,000 unit / kg/day until the sedimentation rate returned to normal, and then she was maintained on oral pencillin G 500 mg 4 times daily for 6 months. She showed a dramatic improvement in her physical and general condition and the last chest radiograph (figure 3) showed complete resolution of upper mediastinal mass and her ESR was normal.

Figure 1. Chest x-ray showing mass in the anterior mediastinum

Figure 2. CT Scan of chest showing the presence of a large mass

Figure 3. Chest x-ray showing complete resolution of upper mediastinal mass

• Discussion

Actinomycosis is usually not included in the differential diagnosis of mediastinal and pulmonary masses in children^4,5. As demonstrated by our case, actinomycosis should be considered whenever there is a slowly progressive pulmonary or mediastinal mass accompanied by symptoms, sign and laboratory evidence of chronic infection. Of the four species of actinomyces capable of producing infections in man, A. Israelii is the primary pathogen. A. Israelii is a normal saprophyte of the oral cavity and nasopharynx and can be cultured from carious teeth, periodontal tissue, tonsillar crypts and para nasal sinuses⁶.

There was no clear evidence to support the pathogenisis of pulmonary actinomycosis but dental manipulation immunodeficiency and foreign body could be favoured actinomycosis infection^7,8. mediastinal involvement probably is the result of direct extention from lungs or may result from spread via lymphatic channels connecting the mediastum and oral pharynx⁹.

The nature course of thoracic actinomycosis was described in details by Bates and Cruick Shank⁹ Of their 85 patients, 67% had primary disease and 7% had primary mediastinal involvement. Children between the ages of 3 and 20 years accounted for 27% of the cases. This was thought to be secondary to the prevalence of dental caries in this age group.

The most common symptoms were pleuritic pain, cough, fever, sputum production and weight loss. Retrosternal and back pain occurred with mediastinal involvement. Pulmonary actinomycosis should be considered in the differential diagnosis of pulmonary and mediastinal mass lesion in children^10,11. The early roentgenographic manifestation of actinomycosis include patchy pulmonary infiltrates, and cavitory or mass lesion¹².

The main stay of treatment for pulmonary actinomycosis is prolonged antibiotics and an appropriate surgical approach to sinus tract and abscesses. The drug of choice for treatment is penicillin, a recommended treatment schedule is 12 - 18 month of 2 - 5 million units of oral penicillin daily and should be tailored to each clinical situation¹³.

• Conclusion

Mediastinal actinomycosis is a rare disease in children. It should be considered in the differential diagnosis of pulmonary and mediastinal lesion. Surgical resection of the mass lesion and prompt treatment with appropriate antibiotics could result in a high cure rate.

• References

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