eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Actinomycosis

Author: Jorge M Quinonez, MD, Medical Director of Pediatrics, Chief Medical Officer, Family Health Centers of South West Florida, Inc
Contributor Information and Disclosures

Updated: Jun 27, 2008

Introduction

Background

Actinomycosis is a chronic bacterial disease. Localized swelling with suppuration, abscess formation, tissue fibrosis, and draining sinuses characterize this disease. Gram-positive, pleomorphic non–spore-forming, non–acid-fast anaerobic or microaerophilic bacilli of the genus Actinomyces and the order Actinomycetales cause actinomycosis. Actinomyces are very closely related to Nocardia species; both were once considered to be fungal organisms.

Infections of the oral and cervicofacial regions are the most commonly recognized infections; however, the thoracic region, abdominopelvic region, and the CNS are also frequently involved. Actinomyces israelii, Actinomyces naeslundii, Actinomyces odontolyticus, Actinomyces viscosus, and  Actinomyces meyeri most frequently cause human actinomycosis. Actinomyces gerencseriae may also cause disease in humans. Three former Centers for Disease Control and Prevention (CDC) coryneform bacteria now have been added to the Actinomyces group and are thought to be potential causes for disease; these include Actinomyces neuii,¹ Actinomyces radingae, and Actinomyces turicensis. Actinomyces radicidentis, a recently described species, has been isolated with polymerase chain reaction from patients with endodontic infections.²

Actinomyces species grow well in enriched media with brain-heart infusion and may be aided in growth by an atmosphere of 6-10% ambient carbon dioxide. They grow best at 37°C. Colonies can appear at 3-7 days, but, to ensure that no growth is missed, observe cultures for 21 days.

Propionibacterium propionicus and related species of bacteria can also cause actinomycosislike disease. Other bacteria that are frequently isolated from clinical specimens concomitantly with Actinomyces in human infection include Actinobacillus actinomycetemcomitans, Eikenella corrodens, and species of Fusobacterium, Bacteroides, Capnocytophaga, Staphylococcus, Streptococcus, and Enterococcus.

Pathophysiology

Actinomyces species that cause human disease are not found in nature but are normal flora of the oropharynx, GI tract, and female genital tract. This is not an exogenous infection; therefore, no person-to-person spread of the pathogen occurs.

In general, Actinomyces species, being members of the normal flora, are agents of low pathogenicity and require disruption of the mucosal barrier to cause disease. Oral and cervicofacial diseases are commonly associated with dental procedures, trauma, oral surgery, or dental sepsis. Pulmonary infections usually arise after aspiration of oropharyngeal or GI secretions. GI infection frequently follows loss of mucosal integrity, such as with surgery, appendicitis, diverticulitis, trauma, or foreign bodies. Numerous reports have linked the use of intrauterine contraceptive devices to the development of actinomycosis of the female genital tract.³ The presence of a foreign body in this setting appears to trigger infection.

Other bacterial species that often are copathogens to Actinomyces species may aid spread of infection by inhibiting host defenses and reducing local oxygen tension. Once the organism is established locally, it spreads to surrounding tissues in a progressive manner, leading to a chronic, indurated, suppurative infection often with draining sinuses and fibrosis. In tissues, Actinomyces grow in microscopic or macroscopic clusters of tangled filaments surrounded by neutrophils. When visible, these clusters are pale yellow and exude through sinus tracts; they are called sulfur granules. This is not an exclusive finding of actinomycosis, and its absence does not rule out the diagnosis. Other conditions, such as eumycetoma and nocardiosis, have been linked to the production of sulfur granules.

Frequency

United States

The disease is uncommon. Studies in the Cleveland area in the 1970s showed incidence to be about 1 per 300,000 persons.

International

Studies in Germany and the Netherlands in the 1960s showed incidence of 1 per 100,000 persons. No data are available on the incidence of disease in developing nations.

Sex

A male-to-female infection ratio of 3:1 is encountered in most series. Unconfirmed explanations for this comprise poorer oral hygiene and augmented oral trauma in males.

Age

Infection can develop in individuals of all ages; however, it is rare in the pediatric population and in patients older than 60 years. Most cases are encountered in individuals in the mid decades of life.

Clinical

History

History is specific to the type of actinomycosis infection encountered.

• Cervicofacial actinomycosis
  • This is the most common and recognized presentation of the disease.
  • Actinomyces species are commonly present in high concentrations in tonsillar crypts and gingivodental crevices. Many patients have a history of poor dentition, oral surgery or dental procedures, or trauma to the oral cavity.
  • Chronic tonsillitis, mastoiditis, and otitis are also important risk factors for actinomycosis.
  • Periostitis or osteomyelitis can develop if the infection extends to facial and maxillary bones. The mandible appears to be one of the most common osteomyelitis sites.
  • Meningitis can also develop if the process extends into the cranial bones through sinus tracts.
• Thoracic actinomycosis
  • Diagnosis of this condition requires a high index of suspicion.
  • The most common route for infection is aspiration of oropharyngeal or GI secretions.
  • Patients may have a history or risk factors for aspiration.
  • Other less common routes of infection include extensions from cervicofacial disease or spread from the abdomen and, rarely, dissemination through blood from other sites of infection.
  • The most common clinical presentation is a chronic, indolent, slowly progressing pneumonia with or without pleural involvement. Patients present with a productive cough, fever, chest pain, and weight loss. The condition can mimic tuberculosis or malignancy.
  • The disease can spread to the mediastinum and cause tracheoesophageal fistulas, pericarditis, myocarditis, or endocarditis.
  • Posterior mediastinal involvement can lead to vertebral infection with bone destruction or disease of paraspinal muscles and soft tissues.
• Abdominal actinomycosis
  • Abdominal actinomycosis is the most covert and indolent of all forms of the disease.
  • Diagnosis is rarely suspected or made on clinical grounds. Usually, the laboratory or the pathologist provides diagnosis.
  • The infection usually develops after GI mucosal integrity is broken from surgical procedures or trauma, although, on many occasions, the inciting conditions may not be apparent.
  • Conditions such as typhoid fever, amebic dysentery, and the presence of foreign bodies, such as chicken and fish bones, have precluded the development of actinomycosis.
  • Appendicitis with perforation is the most common predisposing event, and, as a result, right-sided abdominal infection is far more common than left-sided abdominal infection. The inciting event can precede the diagnosis by months to years.
  • Patients present with nonspecific symptoms and findings, such as fever, weight loss, diarrhea or constipation, and abdominal pain. Extension to the perirectal space is not uncommon and these patients present with defecation symptoms.
  • Hepatic, renal, and splenic disseminations are uncommon complications of abdominal actinomycosis.
• CNS disease
  • Clinical features are indistinguishable from those of other infections of the CNS.
  • The findings in those patients without meningeal involvement are typically those of a space-occupying lesion with focal neurologic defects and increased intracranial pressure.
  • The specific signs and symptoms are attributed to the anatomic location of the abscess, empyema, or actinomycoma.
  • Patients with chronic meningitis have an indolent picture that is no different from other chronic meningitides with headaches, low toxicity, and subtle neurologic findings dominating the picture.
• Pelvic actinomycosis
  • This condition is extremely rare in the pediatric population and is almost exclusively is observed in patients who present with prolonged use of intrauterine contraception devices, usually for longer than 2 years.
  • Pelvic actinomycosis may develop from extension of intestinal infection, commonly from indolent ileocecal disease.
  • Patients present with an indolent history of vaginal discharge, abdominal or pelvic pain, menorrhagia, fever, weight loss, and prolonged use of an intrauterine contraceptive device.

Physical

Physical findings are specific to the type of actinomycosis infection encountered.

• Cervical actinomycosis
  • Patients may present with an acute form of disease characterized by the formation of a painful pyogenic abscess with trismus and fistulas that drain the characteristic sulfur containing granules.
  • More commonly, patients present with a painless indurated mass at the angle of the jaw or submandibular region with 1 or several draining sinus tracts that discharge sulfur granules.
  • Although infection of the mandible is the most often encountered presentation, include actinomycosis in the differential of any mass lesion encountered in the head and neck regions.
• Thoracic actinomycosis
  • Specific clinical or radiologic findings are not recognized.
  • Physical examination reveals diffuse rales and rhonchi. Decreased breath sounds can be appreciated if a pleural empyema is present.
  • The patient appears chronically ill.
  • Radiographic findings have the appearance of pneumonitis or a mass lesion, and, frequently, a pleural effusion is present.
  • Hilar adenopathy can often be observed.
  • Extension to adjacent tissues with involvement of chest wall muscles and soft tissues may lead to the formation of sinus tracts extending to the skin. This finding should always raise the possibility of actinomycosis.
• Abdominal actinomycosis
  • An abscess or a hard, firm mass fixed to underlying tissue can be palpated in all quadrants, more commonly in the right lower quadrant.
  • Sinus tracts that extend to the abdominal wall or perirectal tissues may be found sporadically. Patients experience localized or diffuse abdominal tenderness.
  • Hepatomegaly and jaundice can be found with liver involvement. Appearance of symptoms is indolent, and the patient may have had symptoms for months before seeking attention.
• Pelvic disease: Upon physical examination, a pelvic mass can be felt on the adnexa and a vaginal or cervical discharge can be observed with speculum examination.

Causes

Predisposing risk factors are specific to the type of infection encountered.

• Cervicofacial actinomycosis
  • Poor dental hygiene
  • Oral surgery
  • Dental work
  • Oral trauma
  • Chronic mastoiditis
  • Chronic otitis
  • Chronic tonsillitis
• Thoracic actinomycosis
  • Any risk factor for aspiration
  • Alcohol or drug intoxication
  • Altered mental status
  • Neurologically devastated patients
• Abdominal actinomycosis
  • Previous GI surgery
  • Perforation of the bowel, appendix, or colon
  • Abdominal trauma
  • Foreign bodies
  • Typhoid fever
  • Amebic dysentery
• CNS actinomycosis
  • Prior Actinomyces infection at a distant site, such as lungs, abdomen, or pelvis
  • Extension from contiguous source, such as cervicofacial actinomycosis, paranasal infection, or middle ear infection
• Pelvic actinomycosis
  • Prolonged use of intrauterine contraception devices
  • Spread from intestinal infection

• Search for CME/CE on This Topic »

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