CNS involvement may take the form of:
(1) one or more brain abscesses, especially in the frontal and/or temporal lobes
(2) meningitis, which may be basilar
(3) meningoencephalitis
(4) subdural empyema
(5) epidural abscess around the brainstem or spinal cord
(6) actinomycoma
Sources:
(1) paranasal sinuses
(2) ears
(3) other cervicofacial sites of involvement
(4) hematogenous spread from focus of actinomycosis within the thorax or abdomen
(5) disseminated actinomycosis
Culture of a focus of CNS actinomycosis may show pure growth of an Actinomycosis species or mixed isolates including an Actinomycosis species.
The diagnosis may be delayed if:
(1) the patient is afebrile
(2) indolent or nonspecific clinical findings
Differential diagnosis:
(1) tuberculous meningitis
(2) other causes of brain abscess
(3) brain tumor
(4) intracranial aneurysm
(5) cholesteatoma
