Actinomycosis

Last reviewed: March 2019

Last updated: February 2019

Summary

A rare, pyogenic, granulomatous, subacute to chronic infection caused by actinomycetes. Actinomycetes are a group of anaerobic gram-positive bacteria with high guanine-cytosine content found as natural flora of the oral cavity.

The most frequent features are ulcer and granuloma formation, and the presence of multiple abscesses and sinus tracts that may discharge sulfur granules. The pathogens often spread into neighbouring tissues.

Actinomycetes often invade the body by microfissures, and the most common clinical form of actinomycosis is cervicofacial, either after oral surgery or caused by poor dental hygiene. Thoracic and abdominal actinomycoses also occur frequently, and pelvic actinomycosis is possible in women.

Prolonged antibiotic treatment is necessary.

Definition

Actinomycosis is an infectious disease caused by anaerobic, gram-positive actinomycetes. The most common clinical forms of actinomycosis are cervicofacial and abdominal. [1] In women, pelvic actinomycosis is possible. [2] Many other sites of infection have been described, although less frequently than cervicofacial and abdominal actinomycoses. Because the disease is rare and most physicians have not seen a patient with actinomycosis, diagnosis is often delayed.

Whipple's disease, which may be interpreted as a special form of actinomycosis, since it is caused by Tropheryma whipplei , a pathogen from the clade of actinomycetes, is not discussed here.

History and exam

Key diagnostic factors

presence of risk factors
soft-tissue swelling

Full details

Other diagnostic factors

multiple sinuses
skin discoloration
chewing difficulties
constitutional symptoms
change in bowel habits
abdominal discomfort
nausea and vomiting
sensation of abdominal mass
vaginal bleeding or discharge
dry or productive cough
blood-streaked sputum
shortness of breath
chest pain
focal neurological defects

Full details

Risk factors

male gender
injury or inflammation of the oral cavity
diabetes mellitus
immunosuppression
malnutrition
local tissue damage by neoplasia, trauma, or irradiation
intra-uterine device
aspiration

Full details

Diagnostic investigations

1st investigations to order

culture of pus or affected tissue
histology of affected tissue
immunohistology
FBC
CT or MRI of abdomen

Full details

Emerging tests

PCR of affected tissue
serology

Full details

Treatment algorithm

ACUTE

non-penicillin-allergic

penicillin-allergic

Contributors

Authors VIEW ALL 

Thomas Schneider, MD, PhD

Professor

Medical Department I

Charité - University Medicine Berlin

CBF

Berlin

Germany

Disclosures

TS is an author of a number of references cited in this topic.

Verena Moos, PhD

Scientist

Medical Department I

Charité - University Medicine Berlin

CBF

Berlin

Germany

Disclosures

VM is an author of a number of references cited in this topic.

Peer reviewers VIEW ALL 

Johannes R. Bogner, MD

Professor of Internal Medicine

Department of Infectious Diseases

Medical Polyclinic

University Hospital Munich

Munich

Germany

Disclosures

JRB declares that he has no competing interests.

Chris Huston, MD

Assistant Professor of Medicine

Division of Infectious Diseases

University of Vermont

Burlington

Disclosures

CH declares that he has no competing interests.

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Actinomycosis

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Emerging tests

Treatment algorithm

non-penicillin-allergic

penicillin-allergic

Contributors

Authors VIEW ALL 

Thomas Schneider, MD, PhD

Disclosures

Verena Moos, PhD

Disclosures

Peer reviewers VIEW ALL 

Johannes R. Bogner, MD

Disclosures

Chris Huston, MD

Disclosures

Differentials

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