|Year : 2014 | Volume
| Issue : 2 | Page : 122-124
Department of Radiology and Imaging, Prathima Institute of Medical Sciences, Nagunur, Karimnagar District, Andhra Pradesh, India
|Date of Web Publication||20-Jun-2014|
Department of Radiology and Imaging, Prathima Institute of Medical Sciences, Nagunur, Karimnagar District, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Actinomycosis is a subacute to chronic bacterial infection caused by Actinomyces species. Most common form of actinomycosis is cervicofacial type. We report a rare case of spinal actinomycosis with subcutaneous abscesses illustrated by magnetic resonance imaging and computed tomography findings.
Keywords: Computed tomography, magnetic resonance imaging, spinal actinomycosis
|How to cite this article:|
Vikas C. Spinal actinomycosis. J NTR Univ Health Sci 2014;3:122-4
| Introduction|| |
Human actinomycosis is caused predominantly by Actinomyces israelii, a slow growing, filamentous, anaerobic, Gram-positive bacterium, susceptible to penicillin. Any site of the body can be involved by actinomycosis, but cervicofacial region is most commonly involved region. Actinomycosis presents with vague clinical manifestations. Vertebral actinomycosis is a rare manifestation of actinomycosis. We describe a case of spinal actinomycosis with subcutaneous abscesses illustrated by computed tomography (CT) and magnetic resonance imaging (MRI). Review of the literature shows very rare descriptions of both CT and MRI findings in a case of spinal actinomycosis.
| Case report|| |
Here we present a case of a 55-year-old male patient presented with back pain of 5 months duration. He denied any history of trauma or fever. He gave a history of below knee amputation of left leg. His old case sheets revealed that he was suffering from actinomycosis of the left leg, which was amputated. Investigations were revealed elevated erythrocyte sedimentation rate. MRI was advised, which revealed moth eaten appearance of lumbosacral vertebrae with the multiple small lytic lesions surrounded by sclerotic margins and paravertebral and subcutaneous hyperintense collections [Figure 1] and [Figure 2]. L4, L5, S1, S2 vertebral bodies were involved. There was the involvement of posterior elements of the fore mentioned vertebral bodies. Post-contrast there was heterogenous enhancement of involved vertebra, enhancement lumbosacral dura matter suggestive of meningeal involvement and multiple paraspinal and subcutaneous peripherally enhancing lesions were noted, suggestive of abscesses [Figure 3]. CT scan of the lumbosacral spine showed mixed lytic and sclerotic moth eaten appearance of involved vertebrae [Figure 4]. Excisional biopsy was performed on one of the subcutaneous nodules, which drained pus with sulfur granules and on microscopy there was a characteristic sunray appearance and further examination revealed Gram-positive, beaded and branching filamentous bacteria [Figure 5]. Diagnosis of actinomycosis was considered as based on these findings.
|Figure 1: Sagittal T1W image show hypointense appearance of involved vertebra thecal sac (large arrow) and subcutaneous abscess (small arrow)|
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|Figure 2: Sagittal short TI inversion recovery image shows heterogenous hyperintensity of involved vertebra (large arrow) and prevertebral collection (small arrow)|
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|Figure 3: Sagittal contrast enhanced magnetic resonance imaging shows heterogenous enhancement of involved vertebra (large arrow) and peripheral enhancement of subcutaneous nodules (arrow)|
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|Figure 4: Sagittal reconstructed computed tomography image of the lumbosacral region of the spine shows typical moth-eaten type of destruction with adjacent sclerosis of vertebrae (arrow)|
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|Figure 5: Microscopy of crushed sulfur granule shows the characteristic appearance of actinomycosis|
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Parenteral penicillin was started in a dose of 20 million units/day for 4 weeks followed-up by oral amoxicillin for 6 months. Monthly follow-up until 6 months was undertaken. Good response to treatment was suggested by reduction of the clinical symptoms, reduction of edema and soft-tissue collections on MRI studies at follow-up intervals. There was no recurrence after the completion of treatment.
| Discussion|| |
Actinomycosis is a slowly progressive subacute to chronic bacterial infection caused by filamentous, gram-positive, anaerobic bacteria. Most common species isolated is Actinomycosis israelii. These organisms are normal commensals in the oral cavity, gastrointestinal and female genital tract.  Mucosal or cutaneous disruption by trauma leads to infection at any site in the body. It is characterized by contiguous spread, suppurative and granulomatous inflammation and formation of multiple abscesses and sinus tracts that may discharge sulfur granules.
Actinomycosis can affect people at all ages, but is more commonly seen in middle aged people.  Men are affected more commonly than females. Actinomycosis in humans manifests predominantly in three forms, i.e., cervicofacial, thoracic and abdominopelvic. Other forms occur less frequently in central nervous system and musculoskeletal system (5%). Cervicofacial actinomycosis is the most common manifestation. , Precipitating factor such as dental caries, dental manipulation and maxillofacial trauma leads to disease in the cervicofacial region. Thoracic actinomycosis commonly presents as pulmonary infiltrate, mass, pleural effusion, hilar adenopathy, pericardial and chest wall disease ultimately leading to formation of sinus tract that discharge sulfur granules.  Actinomycosis of abdomen and pelvis is difficult to diagnose.  Hematogenous spread occurs to liver kidney and can present as liver abscess, periphrenic abscess and fistulas to bowel, uterus and skin. Actinomycosis of pelvis in women is associated with intrauterine contraceptive device usage. Mycetoma is common manifestation in India. It is slow progressive disease of foot in farmers and those walking barefoot.
Vertebral actinomycosis is usually due to adjacent spread of soft-tissue infection but the infection may occur following trauma or it can be hematogenous spread. As the progression of the disease is slow, both bone destruction and new bone formation can be seen. As the disease progresses, the initial erosions become deeper causing destruction of the cancellous bone resulting in multiple intercommunicating cystic spaces. , Along with the bony destruction there invariably occurs new bone formation around the cystic cavities giving a mottled or lattice like appearance on imaging. One or several successive vertebrae may be involved. There may be paraspinal and subcutaneous abscesses. , Meningitis, epidural abscess and spinal cord compression are the possible complications of vertebral actinomycosis. ,, Actinomycosis usually spares the discs, but unlike tuberculosis invariably affects the adjacent pedicles, transverse processes and corresponding heads of the ribs. As a result of the abundant new bone formation, vertebral collapse and angular deformities are uncommon. , Actinomycosis needs to be differentiated from tuberculosis, mycosis, granulomatous diseases or malignancy. Imaging helps in knowing the location and extent of the disease. Demonstration of sulfur granules in discharge and histopathology are diagnostic. A culture of tissue or fluid may show actinomycosis species. ,
Actinomycosis responds well to penicillin therapy. Parenteral penicillin in a dose of 20 million units/day until the initial response suggestive of healing of disease followed by oral penicillin or amoxicillin for several months is advised. Newer drugs such as ceftriaxone, ceftizoxime, imipenem and ciprofloaxacin are successful in clearing the disease. Medical treatment may be sufficient for patients without any neurological deficits  and surgery may be considered in patients with neurological deficits.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]