A Case of CNS Actinomycosis: Rarer than Rare!
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.314572
Source of Support: None, Conflict of Interest: None
Keywords: Actinomycosis, cerebral infections, CNS actinomycosisKey Message: Actinomycosis is often called the great masquerader. It can cause an uncommon presentation, mimicking a common condition and therefore clinical suspicion is key to diagnosis. Early diagnosis and treatment can lead to good treatment outcomes.
Actinomycosis is an uncommon, chronic, suppurative infection that rarely affects the central nervous system (CNS). Actinomyces are Gram positive, anaerobic, non-spore forming, filamentous branching bacteria (except A. meyeri). They are commensals of the mouth, gastrointestinal tract and urogenital tract. The hallmark of actinomycosis is abscess formation and chronic progression of infection irrespective of anatomic barriers. Of the 47 species and two subspecies recognized so far, Actinomyces israelii is most commonly isolated.
In cerebral actinomycosis, the clinical presentation and radiological findings are like typical findings in parenchymal pyogenic abscesses, but may also present as meningitis, meningoencephalitis, epidural abscess and subdural empyema.
We report a rare case of a 62-year-old immunocompetent male with cerebral actinomycosis, who presented as an acute onset focal neurological deficit without systemic symptoms, mimicking a stroke.
An 62-year-old hypertensive male presented with 12 hours of mild weakness in right hand and upper limb, focal convulsions one hour prior to presentation, followed by slurring of speech and worsening of right sided weakness. There was no history of loss of consciousness, headache, altered sensorium, stool or urinary incontinence. In the Emergency Department, on examination, he was conscious, co-operative and well oriented. Right sided UMN (Upper Motor Neuron) facial palsy was present. Right upper limb and lower limb had power of 2/5 with depressed reflexes. No meningeal signs were present. Other systemic examination was normal. The patient was loaded with anti-convulsant and underwent MRI, which showed a solitary intra-axial space occupying lesion in the left frontal parenchyma in the peri-rolandic region involving the pre-central gyrus. The lesion had a T2 hypointense rim and hyperintense center. It exhibited restricted diffusion. Moderate perilesional edema was also identified [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d. The lesion was hypo perfused on MR perfusion, exhibited a prominent Lipid-Lactate and non-specific Amino Acid peaks on MR spectroscopy and was seen displacing the adjoining white matter tracts on Diffusion Tensor Imaging [Figure 2]a, [Figure 2]b, [Figure 2]c. Based on the MRI findings, the possibility of an intra-axial abscess was considered. However, possibility of neoplastic etiology could not be completely ruled out.
On admission, complete blood count, electrolytes, liver function tests, X-ray and ECG were within normal limits. ESR was mildly elevated (was 32). HIV combo was negative.
Neurosurgery team advised immediate surgical intervention. PET-CT scan is done to rule out neoplasia revealed, an abnormal signal in the left maxillary alveolus suggestive of possible dental infection. There was history of dental extraction done elsewhere few weeks back, but local tissue was not sent for culture then.
By the time the patient was taken up for surgery, the patient's neurological status had deteriorated to complete right-sided hemiplegia (power – 0/5). Left parietal craniotomy with intra-op USG guided aspiration and excision of the mass was done. Actinomyces israelii was isolated from the frank pus collected. No granules seen on gross examination. Histopathology examination with special stains as mentioned in figures [Figure 3]a, [Figure 3]b, [Figure 3]c revealed findings consistent with actinomycosis. Identification done on VITEK 2 compact analyzer: showed Actinomyces israelii. The patient was treated with intravenous Ceftriaxone 1 gm twice a day and oral Clindamycin 600 mg three times a day. Physiotherapy and anti-epileptic drugs were continued. There were no further episodes of convulsions. On subsequent follow-up visit at 6 weeks, his power had improved to 5/5 in lower limb, 4/5 in proximal upper limb, 2/5 in distal upper limb. The clinical status remained the same at 12 weeks and repeat MRI did not reveal significant findings. The treatment was stopped after 12 weeks, and patient continued to stay asymptomatic on later follow-ups. The patient was investigated for possible immunodeficiency; only significant finding was absolute CD4 count of 295. Lymphocyte subset assay for CD3, CD4, CD8, CD16 for NK cells, CD19, CD20 and Nitro blue Tetrazolium dye test for Chronic Granulomatous Disease were within normal limits.
Actinomycosis is a rare, chronic and slowly progressive granulomatous disease that is easily treatable. It is often misdiagnosed because it can mimic other conditions such as malignancy and tuberculosis, and a high level of clinical suspicion is needed for early diagnosis. Smego RA reviewed and reported 70 cases of CNS Actinomyces over 40 years. As per the review, CNS lesions included brain abscess (67%), meningitis or meningoencephalitis (13%), actinomycoma (7%), subdural empyema (6%), and epidural abscess (6%). Actinomycotic CNS lesions most frequently resulted from primary sources of infection in the lungs (27%) or the cervicofacial region (20%). Abdominal and pelvic primary foci were less common. In 23 instances (33%) the site of primary infection could not be identified. For non-meningitic infection, signs and symptoms were generally those of a space-occupying lesion and were indistinguishable from the manifestations of other pyogenic infections except for a longer interval before diagnosis. Risk factors included dental caries; recent tooth extraction; head trauma; gastrointestinal tract surgery; chronic otitis, mastoiditis, or sinusitis; chronic osteomyelitis; tetralogy of Fallot; and actinomyces infection of an intrauterine device.
Common differential for CNS actinomycosis includes tuberculosis (cold abscess formation), nocardiosis, pyogenic abscess and neoplasia/metastasis.
Previously, the use of high dose antimicrobial therapy was advocated, with treatment extending up to one year (or even longer). Surgical intervention was routinely encouraged for treatment of antimycotic lesions. However, the current trend is to limit invasive procedures and to rely on a targeted antibiotic regimen instead., Treatment of abscesses usually requires drainage, whereas surgery may be indicated only in cases with extensive necrotic lesions or when antimicrobial therapy fails or for obtaining samples for definitive diagnosis.
In a 2010-2011 survey on antimicrobial susceptibilities of anaerobic bacteria was conducted in laboratories in Ontario, Canada, nearly 400 Actinomyces strains were tested against six antimicrobial agents., Except for high rates of resistance to metronidazole (>80%), the strains were fully susceptible to the other antimicrobial agents examined which were penicillin, piperacillin-tazobactam, meropenem, cefoxitin and clindamycin. Moreover, it is noteworthy that there are considerable differences in MICs among Actinomyces species, with A. europaeus and A. turicensis being the most resistant., In the review of 70 patients with CNS Actinomycosis, the overall mortality from treated infection was 28%; 54% of the survivors had neurologic sequelae.
Actinomyces can cause diverse clinical manifestations and therefore clinical suspicion is key to diagnosis. CNS actinomycosis can mimic Tuberculosis, neoplasms, and can also co-exist with them. Current treatment guidelines include basic antibiotics for long duration, and at times, surgical intervention.
Health care is always about team work. Likewise, the management and diagnosis of this case was possible due to the wonderful team at Dr. Balabhai Nanavati Hospital, Mumbai. We would like to specially thank Dr. Ami Variaya (HOD Microbiology Department ) and the entire microbiological team for their help and support without whom the diagnosis of this case would not have been possible. We would like to thank the Emergency department, Critical care department, Neurosurgery department and Nuclear Medicine department at Dr. Balabhai Nanavati Hospital, Mumbai for their contribution to the management of this case. A special thanks to Dr Aniruddha Dutta for his support towards this case.
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Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3]