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.

Bahrain Med Bull 2000;22(4):193-95.

Actinomycosis is a chronic granulomatous suppurative disease characterized by peripheral spread with extension to contiguous tissue in the formation of multiple draining sinus tract.  The infection usually involves the cervico facial, thoracic, abdominal or pelvic region. Actinomycosis israeli is the predominant organism causing disease in humans.  Other implicated species in order of importance include:   Arachriapropionica,   A. Odontolyticus,  A. meyeri, A. naeslundii, A. viscous and Bifido bacterium eriksonii1,2.  The three important sites of actinomycosis infection in order of frequency are cervicofacial, abdominal and thoracic.  A British epidemiological survey 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 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 a febrile, pale asthenic girl, not in respiratory distress, with diminished air entry on the right side of the chest and bronchial breathing. No lymphadenopathy or hepatosplenemegaly was detected. Laboratory  investigations revealed the Hemoglobin of 8 g/dl, 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 (Fig 1)  showed a mass in 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 (Fig 2).  Tuberculin cold agglutination tests were negative.  Fine needle aspiration revealed the presence of non-specific inflammatory lesion.  Thoractomy was done which demonstrated a vascular mass extending from the posterior to anterior mediastinum.  Biopsy  demonstrated the presence of colonies of fungi surrounded by neutrophils which are combined with the actinomycosis laying over vascular malformation.  Patient was treated with intravenous penicillin G 200,000 unit / kg/day until the sedimentation rate returned to normal.

Following which patient 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.  The last chest radiograph (Fig 3) showed complete resolution of upper mediastinal mass and her ESR  was normal.

DISCUSSION

Actinomycosis is usually not included in the differential diagnosis of mediastinal and pulmonary masses in children4,5.  As demonstrated by our case, actinomycosis  should be considered whenever there is a slowly progressive pulmonary or mediastinal mass accompanied by symptoms, clinical 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 is no clear evidence to support the pathogenesis of pulmonary actinomycosis but dental manipulation, immunodeficiency and foreign body could favour  actinomycosis infection7,8.  The 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 natural course of thoracic actinomycosis was described in details by Bates and Cruick Shank9. Of  85 patients, 67% had primary disease and 7% had primary mediastinal involvement.  Children between the age 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 symptom was pleuritic chest pain, cough, fever, sputum production and weight loss.  Retrosternal and back pain occurs with mediastinal involvement.  Pulmonary actinomycosis should be considered in the differential diagnosis of pulmonary and mediastinal mass lesion in children10,11.  The early roentgenographic manifestation of actinomycosis include patchy pulmonary infiltrates and cavitatory or mass lesion12.

The main stay of treatment for pulmonary actinomycosis is prolonged  antibiotic therapy and an appropriate surgical approach to the sinus tract disease 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 this 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 lesions.   Surgical resection of the mass lesion and prompt  treatment with  appropriate antibiotics could result  in a high cure rate.

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