Actinomycotic brain infection: registered diffusion, perfusion MR imaging and MR spectroscopy

Management strategy in actinomycosis brain abscess

We reported herein a case of isolated cerebral actinomycosis in a 54-year-old immunocompetent man. Brain MRI showed a left frontal intra-axial lesion and perilesional edema. We performed an open biopsy of the left frontal enhancing lesion. Intraoperative findings showed a yellowish, malleable, and capsulated lesion that was well defined with surrounding normal tissue within pus inside and lacked any necrotic content. MR spectroscopy showed a high level of choline, lactate, and lipid peaks with a choline/N-Acetylaspartic acid ratio of 1.8. The diagnosis was confirmed histologically, and the patient was treated successfully for 3 months after surgical aspiration. Surgical management allowed to confirm the diagnosis with a shorten antibiotics, a rapid resolution of symptoms, and a complete recovery.

Wolf in Sheep's clothing: Intracranial actinomycosis masquerading as en-plaque meningioma

Background:

Actinomycosis israeli is a gram-positive non-acid-fast bacterium and is the most common causative agent of actinomycosis. It usually presents as a brain abscess via a secondary spread from the cervicofacial region or lungs. However, presentation as an en-plaque lesion with bone involvement out of proportion to brain parenchyma is rare and needs to be acknowledged.

Case Description:

We report a case of intracranial en-plaque lesion in a 47-year-old female with restriction of mouth opening and right third nerve palsy for 1 year. Imaging showed hyperostosis of the maxilla, temporal base, sphenoid, and zygoma with dural thickening suggestive of a meningioma. Surgical decompression yielded a granulomatous lesion along with empirical antitubercular therapy. However, patient succumbed to the infection and final histopathology revealed actinomycosis infection.

Conclusion:

Adequate knowledge along with clinical suspicion are the pillars to treating this unfortunate disease. Cheek swelling with bone involvement should be actively sought as risk factors. This case presents a unique opportunity to identify the fox among the sheep by elucidating the characteristic imaging findings and intraoperative view of this rare entity.

Intracranial actinomycosis: case report and review of literature

Actinomycosis infection is a slow progressing disease, in which involvment of the central nervous system by Actinomyces israelii is uncommon (less than 5%). Clinical picture is non-specific and is often misdiagnosed with neoplasia; some clinical clues my arise suspicion. The case of a 59 year-old female is reported who presented headache and focal neurologic signs and in whom a out-of the hospital diagnosis of a neuroepitelial dysembryoplastic tumor was made; nonetheless after careful interview and physical exploration, a spectroscopy magnetic resonance of the brain and hystopathological description of the lesion was made and yielded the definitive diagnosis of intracranial actinomyces infection. Treatment and progression were uneventful.

Actinomycotic brain abscess

Actinomycosis is caused by Gram-positive filamentous anaerobic organisms of genus Actinomyces, which are commensals of mucosal membranes of the oropharyngeal cavity, and gastrointestinal and genitourinary tracts. Central nervous system involvement is rare and may present as cerebral abscess, meningitis, meningoencephalitis, subdural empyema or epidural abscess. The radiological appearances of actinomycotic brain abscesses are not well recognized. Here, we present the characteristic imaging features of an actinomycotic brain abscess.

Infections Caused by Actinomyces neuii: A Case Series and Review of an Unusual Bacterium

Background. Actinomyces neuii is a Gram-positive bacillus rarely implicated in human infections. However, its occurrence is being increasingly recognized with the use of improved identification systems. Objective. To analyse A. neuii infections in Alberta, Canada, and review the literature regarding this unusual pathogen. Methods. Cases of A. neuii were identified in 2013-2014 in Alberta. Samples were cultured aerobically and anaerobically. A predominant catalase positive Gram-positive coryneform bacillus with no branching was isolated in each case. Testing was initially done with API-CORYNE® (bioMérieux) and isolates were sent to the Provincial Laboratory for Public Health for further testing. Isolates' identities were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry microbial identification system (MALDI-TOF MS MIS; bioMérieux) and/or DNA sequencing. Results. Six cases of A. neuii infection were identified. All patients had soft tissue infections; typically, incision and drainage were done followed by a course of antibiotics. Agents used included cephalexin, ertapenem, ciprofloxacin, and clindamycin. All had favourable outcomes. Conclusions. While A. neuii is infrequently recognized, it can cause a diverse array of infections. Increased use of MALDI-TOF MS MIS is leading to increased detection; thus, understanding the pathogenicity of this bacterium and its typical susceptibility profile will aid clinical decision-making.

Cerebral actinomycosis : unusual clinical and radiological findings of an abscess

We report a case of cerebral actinomycosis in a 69-year-old immunocompetent woman. The patient showed a progressive worsened mental status for one week. MRI examination showed an increased size of multiple enhancing nodular lesions associated with mild perilesional edema. We performed an open biopsy for the right frontal enhancing lesion. The intraoperative finding showed a yellowish friable lesion that was not demarcated with normal tissue. Pathologically, an actinomycotic lesion with sulfur granules and inflammatory cells was diagnosed. We report an unusual case of diffuse involvement of cerebral actinomycosis. The presence of the uncapsulated friable lesion that consisted mainly of foamy macrophages and lymphocytes could explain the unusual radiological features.

Differentiation between glioblastomas and solitary brain metastases using diffusion tensor imaging

The purpose of this study is to determine whether diffusion tensor imaging (DTI) metrics including tensor shape measures such as linear and planar anisotropy coefficients (CL and CP) can help differentiate glioblastomas from solitary brain metastases. Sixty-three patients with histopathologic diagnosis of glioblastomas (22 men, 16 women, mean age 58.4 years) and brain metastases (13 men, 12 women, mean age 56.3 years) were included in this study. Contrast-enhanced T1-weighted, fluid-attenuated inversion recovery (FLAIR) images, fractional anisotropy (FA), apparent diffusion coefficient (ADC), CL and CP maps were co-registered and each lesion was semi-automatically subdivided into four regions: central, enhancing, immediate peritumoral and distant peritumoral. DTI metrics as well as the normalized signal intensity from the contrast-enhanced T1-weighted images were measured from each region. Univariate and multivariate logistic regression analyses were employed to determine the best model for classification. The results demonstrated that FA, CL and CP from glioblastomas were significantly higher than those of brain metastases from all segmented regions (p<0.05), and the differences from the enhancing regions were most significant (p<0.001). FA and CL from the enhancing region had the highest prediction accuracy when used alone with an area under the curve of 0.90. The best logistic regression model included three parameters (ADC, FA and CP) from the enhancing part, resulting in 92% sensitivity, 100% specificity and area under the curve of 0.98. We conclude that DTI metrics, used individually or combined, have a potential as a non-invasive measure to differentiate glioblastomas from metastases.

[Actinomycosis: an unusual cause of spinal cord compression. Case report and review of the literature]

Actinomycosis is an unusual and unrecognized cause of spinal cord compression of infectious origin. We report the case of a 57-year-old immunocompetent woman admitted for sub-acute lower limb ataxia. The diagnosis of spinal cord compression secondary to actinomyces infectious arthritis was established. Surgical decompression and long-term antibiotic treatment enabled complete recovery. Data from the literature indicate that actinomycosis is a potential cause of several neurological manifestations. Unusual but treatable, actinomycosis is a potential alternative when the main etiologies have been ruled out.