What are the other Names for this Condition? (Also known as/Synonyms)

• Brain Actinomycosis
• CNS Actinomycosis
• Spinal Actinomycosis

What is Central Nervous System Actinomycosis? (Definition/Background Information)

• Central Nervous System (CNS) Actinomycosis is a rare and chronic infection, caused predominantly by the bacterium Actinomyces israelii, and to a lesser extent by other Actinomyces species
• They exist naturally in the mucous lining of the nose, throat, mouth, digestive tract, and female reproductive tract, and are not normally harmful. These anaerobic bacteria have the ability to grow in the absence of oxygen, or in reduced concentrations of oxygen
• However, any injury, trauma or surgical procedure can cause the bacterial cells to gain entry into deep tissues where they are not normally present. Since these bacteria can grow without oxygen, they can thrive in such environments, resulting in infection
• Central Nervous System Actinomycosis may result from infection, following a head injury or through spread of actinomycosis from other parts of the body, either through direct contact or blood
• The bacteria are slow-growing and the infection leads to the formation of hard, red or purple pus-filled abscess in the affected tissue. The abscess may drain and this can be accompanied by pain and fever. The condition can occur in all age groups and may be manifested as localized sensory loss, numbness, and seizures
• Examination of the fluid drainage under microscope and culture of affected tissue specimen and imaging techniques may be employed to diagnose CNS Actinomycosis. The pus or drainage is checked for “sulfur granules”
• Prolonged treatment with antibiotics is necessary to remove the infection. In some cases, the abscess may need to be surgically drained or removed
• With prompt diagnosis and sustained treatment, Central Nervous System Actinomycosis is curable. However, if the infection becomes generalized via spread of bacteria through the bloodstream, it can spread to other organs and tissues. In such cases, the recovery can be prolonged

Who gets Central Nervous System Actinomycosis? (Age and Sex Distribution)

• Central Nervous System Actinomycosis is an extremely rare infection. The condition has been reported from several parts of the world, although the exact prevalence is not known
• Individuals of all age groups and both genders are susceptible to the infection, although adult men are more vulnerable to CNS Actinomycosis

What are the Risk Factors for Central Nervous System Actinomycosis? (Predisposing Factors)

The following are some known risk factors for Central Nervous System Actinomycosis:

• Cervicofacial actinomycosis, when the neck, jaw, mouth, etc. are affected
• Thoracic actinomycosis that affects the lungs
• Male gender
• Malnutrition
• Alcoholism
• Penetrating trauma to the head
• Compromised immunity owing to HIV/AIDS, organ transplantation, chemotherapy or radiation therapy

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Central Nervous System Actinomycosis? (Etiology)

Central Nervous System Actinomycosis is caused by anaerobic bacteria belonging to the family Actinomycetaceae. These bacteria are gram-positive and can survive in very low concentrations of oxygen.

The following are some bacterial species known to cause Actinomycosis:

• Actinomyces israelii, which is responsible for majority of infections
• Actinomyces gerencseriae
• Actinomyces viscosus
• Actinomyces meyeri
• Actinomyces naeslundii

Under normal circumstances, the bacteria are present in the mucous lining of the mouth, throat, digestive system, and the female reproductive tract, without causing harm.

• However, when the mucous lining gets damaged owing to numerous factors, such as injury, trauma, or surgery, the bacteria enter the inner/deeper tissues
• Being anaerobic, they can survive and multiply in the low oxygen conditions of deep tissue, causing the development of scar tissue and fistula (or abnormal tracts)
• Abscess formation can take place with the accumulation of pus, which may drain when the tracts reach the surface of skin. This process may take months to years

In case of Central Nervous System Actinomycosis, the infection may occur owing to:

• Penetrating injury to the head and subsequent infection
• Spread of the bacteria from cervicofacial actinomycosis through contact of tissues
• Spread of bacteria from actinomycosis of lungs to the spine, through contact or via blood

Note: CNS Actinomycosis is not contagious and it does not spread from one individual to another.

What are the Signs and Symptoms of Central Nervous System Actinomycosis?

The signs and symptoms of Central Nervous System Actinomycosis may vary depending on the site of infection and may include the following:

• Abscess formation, which is commonly present in all types of actinomycosis
• Headache
• Vomiting
• Weakness of some specific body regions (focal weakness)
• Numbness/loss of sensation
• Seizures

How is Central Nervous System Actinomycosis Diagnosed?

The diagnosis of Central Nervous System Actinomycosis is made on the basis of the following test and exams:

• A thorough physical examination and assessment of symptoms
• Evaluation of the affected individual’s medical history
• Microscopic observation of pus or tissue samples, to check for the presence of sulfur granules (these are named for their characteristic yellow and round appearance; they do not contain sulfur). The tissue samples may have to be obtained surgically
• Culture of fluid (after stereotaxic aspiration) or tissue from infected area: These bacteria are slow to grow in culture, and it may take over 3 weeks to obtain a (positive) culture result
• X-ray or computed tomography (CT) imaging to ascertain location and number of abscesses, as well as differentiate inflammatory masses due to infection from the tumors

Note: CNS Actinomycosis may mimic some malignant conditions, and therefore, ruling-out other health conditions may often be necessary to arrive at a final diagnosis.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Central Nervous System Actinomycosis?

The potential complications of Central Nervous System Actinomycosis may include:

• Seizures
• Paralysis of one side of the body (hemiplegia)
• Inability to articulate or understand speech (aphasia)

How is Central Nervous System Actinomycosis Treated?

The treatment for Central Nervous System Actinomycosis may include the following:

• Prolonged use of antibiotics (anywhere from 2 months to over 12 months); typically, β-lactam (such as penicillin, amoxicillin) or tetracycline family of antibiotics are used
• Surgical drainage of abscess through aspiration
• Surgical removal of infected tissue:
  • Surgery is sometimes necessary for cases in which large abscesses have developed, the infection has spread to organs and bones, and antibiotics alone are unsatisfactory
  • Surgery creates an aerobic environment, which is detrimental to bacterial growth. It also allows for the excision of lesions, drainage of sinuses, as well as containment and elimination of the disease
• Hyperoxygen therapy to eliminate bacteria:
  • This therapy helps increase the concentration of oxygen in the infected tissues
  • The presence of oxygen results in higher amounts of oxygen-derived radicals that harm, and are specifically drawn to anaerobic organisms, such as Actinomyces
  • This method has only been approved as an adjunct to other forms of treatment

How can Central Nervous System Actinomycosis be Prevented?

Central Nervous System Actinomycosis can be prevented through adherence to the following factors:

• Practicing proper dental hygiene: Maintaining proper dental hygiene always, and particularly, following a dental procedure, surgery, or tooth extraction, so that chances of cervicofacial actinomycosis are minimized
• Seeking medical attention for any abscess or lung infection
• Educating oneself or monitoring self for any signs of discomfort following a surgery, and promptly reporting to the attending healthcare provider, so that infections may be detected early and treated appropriately

Completing the full course of prescribed antibiotics regimen, to eliminate the infection causing bacteria from deep tissue, as well as to prevent relapse of infection and development of drug-resistant bacterial species.

What is the Prognosis of Central Nervous System Actinomycosis? (Outcomes/Resolutions)

The prognosis of Central Nervous System Actinomycosis is positive with early diagnosis and prompt treatment in individuals with good overall health status.

• The outcomes may be influenced by underlying medical conditions and/or compromised immunity
• Additionally, lack of treatment may allow the infection to spread to other organs and tissues, which may prolong the treatment and recovery process

Additional and Relevant Useful Information for Central Nervous System Actinomycosis:

Actinomycosis commonly occurs in animals (mostly cattle) and rarely in humans. In cattle, the bacteria target areas around the head, especially the jaw, which gives rise to the name “big/lumpy jaw”.