Actinomycosis & Nocardiosis

• • Actinomycosis and nocardiosis are not communicable

Actinomycosis

• • Actinomyces israelii

  • -Gram-positive, non-acid-fast, filamentous organism that usually shows branching and may break up into short bacterial forms

    -Anaerobe, part of the normal flora of the human oropharynx and upper intestinal tract

  • Chronic, slowly progressive infection that may involve many tissues, resulting in the formation of granulomas and abscesses that drain through sinuses and fistulas

  • Lesions resemble those produced by mycobacteria, fungi, and cancer, although the causative organisms are bacteria

  • Sinus tracts or fistulas usually become secondarily infected with other bacteria

  • Abdominal infection may produce an abdominal mass mimicking a malignant process or may give rise to appendicitis

Nocardiosis

• • Nocardiae are gram-positive, aerobic, branching, filamentous organisms that may be acid-fast

  • Nocardia asteroides is the most common isolate

  • May present in 2 forms:

  • 1. Localized, chronic granuloma with suppuration, abscess, and sinus tract formation resembling actinomycosis

    2. Systemic infection, usually beginning as pneumonitis with suppuration and progressing via the bloodstream to involvement of other organs

Epidemiology

Actinomycosis

• • Inflammatory nodular masses, abscesses, and draining sinuses occur most commonly in the head and neck (50%)

  • 20% of patients have primary lesions in the chest and an equal proportion in the abdomen, most commonly involving the appendix and cecum

  • Pelvic actinomycosis can occur in women with prolonged use of an intrauterine device

Nocardiosis

• • More apt to occur as a complication of immunodeficiency in patients with chronic obstructive pulmonary disease, cancer, HIV-associated disease, or corticosteroid-induced immunosuppression

Symptoms and Signs

Actinomycosis

• • Multiple draining sinuses with pus containing "sulfur granules"

  • Lesions are often hard and relatively painless and nontender

  • Systemic symptoms, including fever, are variably present

  • Abdominal actinomycosis may mimic appendicitis

  • Thoracic actinomycosis may give rise to cough, pleural pain, fever, and weight loss

Nocardiosis

• • Systemic nocardiosis produces fever, cough, and weight loss and resembles mycobacterial or mycotic infections

Laboratory Findings

Actinomycosis

• • Culture reveals gram-positive branching rods, with sulfur granules

  • Organisms may be identified by immunofluoresence

Nocardiosis

• • Culture reveals branching rods or filaments that are gram-positive or acid-fast

Actinomycosis

• • Abdominal neoplasm

  • Appendicitis

  • Mycobacterial or mycotic infection

Nocardiosis

• • Systemic infection resembles mycobacterial or mycotic infections

Rule Out

• • Mycobacterial and mycotic infection

  • Appendicitis

  • Neoplasms

• • Complete history and physical exam

  • Culture draining sinus tracts

  • CT scanning and needle aspiration may be helpful diagnostically