Understanding Actinomycosis: Causes, Types, and Treatment Options

1. Actinomycosis

2. Definition It is the chronic suppurative, loculated ,non granulomatous disease, characterized by loculated foci of suppuration It is caused by anaerobic bacteria actinomyces israelli (in human beings) A.bovis ( in cattle) A. boudeti (in cats and dogs)

3. Actinomycetes israelli It is gram-positive, anaerobic organism with branching filaments that shows a tendency to break up into bacillary and twig forms (Actinomycetaceae family) The organisms are normal commensals in the oral cavity, alimentary tract and vagina A colony formed in tissue tends to surrounded by radially projecting fringe of club-shaped excrescences (clubs) These clubs are gram negative

4. These radiating fringe around colony gave rise to alternative name ray fungus The human pathogenic A.Israeli is anaerobic they grow at 370C on blood agar or glucose agar after few days Aerobic Actinomyces organism like A.graminis may be some time found in the lesion but they are contaminants

5. Types Depending upon the anatomic location of lesions, Actinomycosis is of four types Cervicofacial Actinomycosis – it is the commonest form and account for 60 % of cases. It has the best prognosis The infection enters from the tonsils, carious teeth, periodontal disease or trauma following tooth extraction. Initially, a firm swelling develops in the lower jaw With passage of time, the mass breaks down and abscesses/sinuses are formed. The discharging pus contains typical tiny yellow sulphur granules

6. Thoracic Actinomycosis – the infection in the lung is due to aspiration of the organism from oral cavity or extension of infection from abdominal or hepatic lesions Abdominal Actinomycosis – this type is common in appendix, ceacum and liver. It can extend from oral lesions or thoracic lesions Pelvic Actinomycosis – infection in the pelvis occurs as a complication of intrauterine contraceptive devices (IUCDs)

7. Pathogenesis After local trauma such as broken jaw or dental extraction, it may invade tissues, forming filaments surrounded by areas of inflammation. Hard, yellow granules (sulphur granules) composed of a mass of filaments are formed in pus. The typical actinomycotic lesion starts as an acute suppurative inflammation which then persists and progresses to chronicity.

8. As the organism spread by direct continuity, large numbers of abscesses are formed. Some of these fuse together but there is tendency for the individual foci of suppuration to remain discrete due to persistence of fibrous septa. This produces a characteristically loculated appearance. Honeycomb liver is the typical example of such loculation.

9. Spread About 65% of clinical Actinomycosis starts in Cervicofacial area, 20% is ileoceacal and the remainder commences in the lungs The main mode of spread is direct contact and heamatogeneous spread. Lymphatic spread does not occur as filaments are too large to be accommodated in the lymphatic channels. In case any regional lymphadenitis, secondary bacterial infections are responsible.

10. Histopathology Actinomyces colonies, purple, homogenous surrounded by ray fungus The narrow septa between abscesses are composed by fibrous tissue that is heavily infiltrated by polymorphs lymphocytes, macrophages and plasma cells These septa represent attempts at healing and the entire lesion is surrounded by a dense zone of fibrous tissue

11. Actinomycosis Microscopy

12. Actinomycosis Microscopy

13. Clinical features Actinomycosis appears as a hard, nontender swelling that develops slowly and eventually drains pus through sinus tract The appearance of a diffuse, indurated, painless area of suppuration in the region of the neck, discharging to the exterior through multiple sinuses, is the characteristic lesion of Actinomycosis

14. Diagnosis Identification of sulphur granules in the copious pus that exudes from the abscess sinus (direct microscopy) Anaerobic growth on the blood agar Biopsy of lesion No serologic tests available

15. Treatment Very sensitive to the commonly used drugs like penicillin and clindamycin Surgical drainage of pus from abscess

16. Prevention No vaccine No prophylactic drug

17. Prognosis Cervicofacial Actinomycosis – very good Abdominothoracic Actinomycosis sometimes fatal

19. Multiple sinus tracts in actinomycosis

20. Cutaneous actinomycosis

21. Actinomycosis of tongue

22. Cervicofacial actinomycosis

23. Lumpy jaw, actinomycosis

24. Actinomyces israelli, anaerobic gram+ve bacteria, filamentous branching

25. Sulfur granules

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