Isolated Tuberculosis of Sacrum with Monoparesis: An Atypical Presentation
A 20-year-old male presented with complaint of weakness in right lower limb and loss of sensation. He was having low back pain for past two months for which he was being treated by analgesics and rest. There was history of low-grade fever, malaise, and significant weight loss in the last 2 months. Neurological examination revealed that findings were localized to the right lower limb. Bulk and tone of right calf were less than the left calf. There were no neurological deficits in the left lower limb. Nevertheless, in the right lower limb, the motor powers were of 4/5 grade around hip, 3/5 at knee joint, and 2/5 at ankle joint. Knee jerk was sluggish and ankle jerk was absent on the right side. Superficial abdominal reflexes were present bilaterally. Plantar reflex was absent on the right side. Pain and temperature sensation was impaired in the L4, L5, and S1 distribution in right lower limb. Perianal and perineal sensation were present. Urinary bladder was not distended and bowel habits were normal. No gibbus or kyphosis was found on examination of the spine. Straight-leg raising test was positive on the right side. Clinical presentation suggested, lesion of some compressive etiology in region of lumbosacral spine, which was giving lower motor neuron type of clinical picture.\nOn laboratory investigation, hemoglobin level was 8.7 g/dL, erythrocyte sedimentation rate (ESR) was 60 mm/1 hour and; C-reactive protein (CRP) was 40 mg/L; other biochemical parameters were normal. The human immunodeficiency virus (HIV) and enzyme-linked immunosorbent assay were negative. Mantoux test was positive with an induration of 20×15 mm. X-ray of lumbosacral spine lateral and anteroposterior views and X-ray chest posteroanerior view were normal. The non contrast computerized tomogram (NCCT) showed a large lobulated hypodence mass with destruction of right sacral ala and posterior elements with spread of lesion to right piriformis muscle (). The magnetic resonance imaging (MRI) revealed large mass causing osseous destruction of all sacral vertebral segments and their posterior elements. Mass was extended to presacral area anteriorly and sacral canal posteriorly along with contagious spread to right piriformis muscle. Intervertebral disc of L5-S1 was intact with normal lumbar vertebrae. Lesion showed hyperintence signals in T2W images and mild hypointence signals in T1W images (). Finding were suggestive of a mitotic bony lesion; chordoma; Ewing sarcoma; tuberculosis.\nFine needle aspiration cytology (FNAC) from posterior part of mass was performed to define the nature of lesion. Smear showed scattered spindle cells and fibro collagenous tissue. No features of any malignant lesion were observed. Staining of material by zeal-nelson stain was negative for acid fast bacilli (AFB). A computed tomography (CT) guided biopsy was planned to confirm histopathological diagnosis. Biopsy was taken from peripheral margins of lesion under CT guidance. Histopathological examination of tissue showed presence of tuberculous granuloma. Central caseous necrosis was surrounded by epithelioid cells and Langhans type giant cells. This finding was consistence with tuberculosis as a cause of bony destruction.\nTreatment was initiated with a four-drug antibiotic regimen (isoniazid, rifampicin, pyrazinamide, ethambutol) for initial intensive phase of three month followed by continuation phase with two drug regimen (isoniazid, rifampicin) for next 15 months. Improvement in symptoms and laboratory marker (ESR, CRP) were assessed periodically, at monthly intervals for initial 6 months when value of these specific markers returned to normal levels (ESR=6 mm/1st hour; CRP=5 mg/L). The patient was found to gradually recovered from monoparesis. At the latest follow up, after 2 years of starting antibiotics, patient was ambulatory with no symptoms of residual disease.