Osteoarticular tuberculosis with involvement of multiple sites (a case report).
Tuberculosis of bone may evade diagnosis for a long time, as it usually remains silent till either involvement of a neighbouring joint or development of a soft tissue swelling due to cold abscess formation. The osteolytic lesions of tuberculosis may closely mimic those due to multiple myeloma or secondary malignant deposits.
LRG, a 20-years-old female, mentally retarded and epileptic since early childhood, presented with insiduous onset of low backache and generalised weakness of 6 months' duration. There was no history suggestive of any myelopathy or radiculopathy in terms of shooting pains, difficulty in walking, and sensory or bladder/bowel disturbances; nor were there any constitutional symptoms like anorexia, fever or weight loss to point any chronic disease like tuberculosis or malignancy.
On clinical examination, the patient had averagely built nutrition with normal vital parameters. The only significant clinical finding was prominence of lumbar spine at L3 level with tenderness on touch.
There was no bone tenderness at any other sites and the movements of spine were free. She had a minimal restriction of straight leg raising on right side. There was no objective evidence of any neurological deficit, and other systems were normal.
In view of the patient having backache and generalised weakness while on therapy with antiepileptic drugs, and having spinal deformity, the patient was investigated to exclude metabolic bone disease and Pott's spine.
Her haemogram, E.S.R. and routine urine examination were normal. Radiojaphs of the lumbosacral spine (see [Figure - 1]) revealed a lytic lesion in the centre of third lumbar vertebra with compression of its body. The superior end plate was irregular with niininial reduction of disc space between the second and third lumbar vertebrae. There was no soft tissue swelling adjacent to this. There was arthritis of right sacroiliac joint with reduction in joint space and irregularity of articular surfaces. The lateral view of lumbar spine showed anterior wedging of L3 vertebra. The chest radiograph (see [Figure - 2]) showed multiple osteolytic lesions in the niedial end of right clavicle and in the left 5th and 6th ribs. There was fracture of the left 5th rib. This was associated with a soft tissue swelling adjacent to it. The lung fields were normal. In view of these multiple osteolytic lesions, a skeletal survey was performed which was normal except for the above mentioned lesions.
Calcium studies were unremarkable (serum calcium 9.3 mg/dl, serum phosphorus 2.3 mg/dl and alkaline phosphatase 2.9 Bodansky Units). Urine examination for Bence Jone's proteins was negative. Technitium 99m bone scan showed increased uptake of the isotope at the site of above mentioned lesions and also in the pelvic bones. Renal chemistry and liver function tests were normal.
To arrive at the tissue diagnosis, aspiration biopsy of the left 6th rib was performed under fluoroscopic guidance. An 18G lumbar puncture needle was used for the aspiration. The smear showed a cluster of cells consisting of multiple lyniphocytes, epitheloid like cells and 2 giant cells consistent with tuberculosis. The smear was negative for malignant cells. (see [Figure - 3] )
As the aspiration biopsy was suggestive of tuberculosis, the patient was put on 4 anti-tuberculous drugs. (I.N.H., rifampicin, pyrazinamide and streptomycin) for the initial 2 months, followed by I.N.H. and rifampicin for the remaining period. The treatment was continued for 2 years. During the 2 years' follow up, the patient's health improved remarkably with considerable weight gain. Patient is being followed for more than 2 ½ years and the serial X-rays taken during that period showed considerable stable lesion of spine and sacroiliac joint (see [Figure - 4], [Figure - 5]).
Osteoarticular tuberculosis may frequently pose diagnostic problems. A delay in diagnosis in our country is usually due to the patients presenting late while in the Western countries it may be due to lack of awareness and its insidious onset.
About 50% of cases of skeletal tuberculosis are extra-spinal. Multiple sites of involvement in an individual are not common. Pure bone lesions tend to be silent until there is some complication such as compression fracture of the bone, involvement of a neighbouring joint or formation of a cold abscess, which approaches the skin surface.
Bone lesions alone are most commonly seen as periosteal new bone formation or cystic lesions. The osteolytic lesions of tuberculosis at multiple sites need to be differentiated from multiple myeloma, secondary metastasis and bacterial osteomyelitis. Other less common causes of such lesions include gout, actinomycosis, coccidioidomycosis, maduromycosis, cryptococcosis, syphilis etc.
A positive Mantoux test and raised E.S.R. give important diagnostic clue for tuberculosis. However, Mantoux test may be negative in 10% patients, while the E.S.R. may be normal in a similar number of patients,.
Definitive diagnosis depends upon needle aspiration of the bone lesions under fluoroscopic guidance. Histopathological examination yields a high percentage of positive results ,, and the use of histopathology, culture and guinea pig inoculation together may confirm the diagnosis in all the cases of skeletal tuberculosis .
The authors are thankful to the Dean, Seth, GS Medical College and King Edward Memorial Hospital for giving the permission to publish this case report.