Contents

Search

actinomycosis

A chronic local or systemic granulomatous disease. Etiology: 1) Actinomyces israelii (most common) 2) other Actinomyces species Pathology: 1) Actinomyces species are commensals in the mouth & GI tract 2) portal of entry is through: a) aspiration b) a break in the integrity of the mucosa 3) poor dental hygiene & dental abscess predispose to cervico- facial lesions 4) within the GI tract, appendiceal abscesses are most common 5) infection spread a) direct extension b) hematogenous dissemination 6) pelvic actinomycosis a) may originate in the female reproductive tract or intestine b) IUDs left in place for more than 2 years increase risk 6) histopathology: a) grains (a few mm in diameter) surrounded by neutrophils b) adjacent tissue shows subacute or chronic inflammation with fibrosis & formation of sinus tracts Clinical manifestations: 1) General - multiple draining sinuses - pus contains 'sulfur granules' 2) cervicofacial actinomycosis - red or purplish, indurated, firm - subcutaneous mass typically submandibular (jaw mass) - one or more draining sinuses may be present - tenderness is minimal 3) pulmonary actinomycosis: - cough with purulent sputum - may present as subcutaneous abscess - weight loss, variable low-grade fever, lethargy 4) abdominal actinomycosis - pain &/or palpable mass - weight loss, variable low-grade fever, lethargy 5) cutaneous actinomycosis involving extremity (knee) [3] Laboratory: 1) complete blood count (CBC) - anemia & leukocytosis common in abdominal & thoracic actinomycosis 2) Actinomyces antibody in serum - Actinomyces israelii Ab in serum 3) microscopic examination of sulfur granules shows gram positive filaments 4) Actinomyces identified by culture a) growth in anaerobic culture b) isolation of Actinomyces often difficult because of mixed flora often present in actinomycotic abscesses 5) blood cultures are rarely positive Radiology: 1) chest X-ray a) dense pneumonitis may be seen b) fibrosis, empyema or cavitation may be seen 2) ultrasound may show abscess 3) computed tomography (CT) may show abscess 4) barium enema may show extrinsic mass Differential diagnosis: 1) botryomycosis 2) mycetoma 3) Nocardia Management: 1) mild cases - penicillin V 2-4 g/day - tetracycline - duration of therapy 2-4 months 2) severe cases - penicillin G 2-6 million units/day for 6 weeks - followed by prolonged oral penicillin V or tetracycline - total duration of therapy 6-12 months - surgical resection of necrotic tissue - draining of abscesses - cutaneous actinomycosis treated with amoxicillin clavulanate for 1 year resulted in clinical improvement, but not complete resolution [3] 3) in general, not necessary to treat secondary micro-organisms isolated with Actinomyces

Related

Actinomyces

General

bacterial infection

References

  1. DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 862
  2. Harrison's Principles of Internal Medicine, 12th ed. Wilson et al (eds), McGraw-Hill Inc. NY, 1991, pg 752
  3. Catano JC, Gomez Villegas SI. IMAGES IN CLINICAL MEDICINE. Cutaneous Actinomycosis. N Engl J Med. 2016 May 5;374(18):1773. PMID: 27144852 http://www.nejm.org/doi/full/10.1056/NEJMicm1511213
  4. Wong VK, Turmezei TD, Weston VC Actinomycosis. BMJ. 2011 Oct 11;343:d6099. PMID: 21990282 Review.