Skeletal tuberculosis: The challenges

April 9, 2019 0 By FM

Mycobacterium tuberculosis is an organism that causes multi-systemic involvement. Although pulmonary tuberculosis is the major manifestation of the disease, multifocal and extra pulmonary tuberculosis has gained medical attention since the emergence of HIV. In the late 1980s, the world was on its way to control tuberculosis. However, an increase in the incidence of diabetes mellitus, HIV etc. led to a comeback of tuberculosis. The world experienced a rising trend in the occurrence of extra-pulmonary tuberculosis crossing all socio-economic barriers. Lymphadenopathy and tuberculosis of the spine account for the lion’s share of extra pulmonary tuberculosis. Then comes tuberculosis of the hip, the knee and the foot, in that order. In the foot, the decreasing order of occurrence are calcaneum, talus, 1st metatarsal and naviculum. The evolution of MDR and XDR TB have led to further challenges in the management of tuberculosis. XDR –TB is a rare type of multi drug resistant TB that is resistant to isoniazid and rifampicin, plus fluoroquinolones and at least one of three injectable second line drugs such as amikacin, kanamycin or capreomycin.

X- ray misses early lesions, and any obvious bony destruction may not be apparent for up to 3 months from the time of occurrence of the disease. The advantage of X- ray is that it can be taken in vertical as well as a load-bearing position, as against MRI. Even though MRI is the gold standard in the diagnosis, its over-sensitivity is an issue. However, it is quite efficient in early diagnosis, assessing the progression and finding out the skip-lesions. CT scan is the choice in occipito-cervical and sacroiliac TB lesions and in defining the extent of bony destruction.

Diagnosing extra-pulmonary TB
Tuberculosis is the ninth leading cause of death as far as the global burden of diseases is concerned. In 2016, an estimated 1.3 million TB deaths were reported among HIV-negative people (1.7 million in 2000) and an additional 374,000 deaths were seen among HIV-positive people. (Global incidence – 10,400,000, Indian incidence – 2,790,000, Indian Deaths – 435,000.) The revised national tuberculosis control programme suggests a daily regime, instead of the DOTS regime.

If you suspect extra pulmonary tuberculosis in a patient and if the disease tissue is available, it is advisable to do a CBNAAT (Cartridge Based Nucleic Acid Amplification Test). CBNAAT is a polymerase chain reaction which also detects rifampicin resistance as it targets an rpoB gene of mycobacterium. Another test, MGIT (Micobacteria Growth Indicator Tube) is also preferred. It is a test to isolate mycobacterium from all types of clinical specimens, pulmonary as well as extra pulmonary, except those from blood and urine. After the processed specimen is inoculated, the MGIT tube is monitored until positive or till the end of the testing protocol. If MTB is detected, we may start anti-TB drugs after evaluation for drug resistance and liver and kidney function tests.

Spinal tuberculosis
The other major developments are in the management of spinal tuberculosis.

  • A course of 6 to 12 months of ATT instead of the old practice of 18-24 months.
  • Hong Kong operation, the “Middle Path Regime’’ of a great Indian orthopaedic surgeon, Prof. Tuli, and the newer “Millennium Doctrine’’ based on the cardinal principles for the management of spinal tuberculosis.
  • Nonsurgical treatments that yield good results as elective surgeries in spinal instability, para-spinal abscess and spinal cord compression in place of surgical intervention.
  • Posterior surgical approaches which are less morbid to the patients and more surgeon-friendly gaining more acceptance than anterior approaches that better anterior reconstruction and neurological decompression.

Culture of MTB in clinical specimens using TB MGIT, the current gold standard, is more sensitive than smear biopsy. The drawback is a longer incubation period of 10-14 days. If it turns out to be MDR TB, it would have caused more destruction by the time the results are in. Newer, ultra-fast modalities of GeneXpert test and Line Probe Assay have revolutionized the management of tuberculosis. The Xpert MTB RIF Assay detects DNA of mycobacterium and rifampicin resistance in 2 hours. LPA also detects resistance to isoniazid, quinolones and second-line injectables, thus detecting MDR as wells as XDR TB in 48 hrs. These tests are to be done on biopsy specimens in addition to TB MGIT culture and histopathology.

The emergence of MDR and atypical lesions made biopsy and culture mandatory procedures. The biopsy specimen should be from granulation tissue rather than from an abscess to make a prompt diagnosis. Biopsy with a 11 G needle instead of fine needle aspiration cytology is advised in the present practice to diagnose tuberculosis.

Here, I am describing a case which was really challenging for me to manage: An 80-year-old grandma came with complaints of inability to walk and back pain in a devastated condition at our OP clinic. Clinically, she had loss of sleep and appetite, chills and fever due to UTI, a neurogenic bladder and extensor plantar response. She was posted for surgical decompression and instrumentation at another hospital for ‘? Tuberculosis/Tumour spine’. Clinical examination, blood investigation, Mantoux test, X-ray evaluation, ultrasound evaluation and MRI scan had revealed left renal calculus, cystitis / pyelonephritis, destruction at D6/7, end plate destruction and normal pedicles. It was clinically and radiologically diagnosed as tuberculosis of the spine.

The grandma and her bystanders were not willing for any type of surgery, even a CT guided biopsy. After getting well informed consent, ATT was started. A therapeutic trial of ATT based on clinical and radiological evidence is legitimate only in a population setting treating large numbers of tuberculosis cases under a national programme. After starting ATT (DOTS regime), she was mobilized in wheel chair with the help of spinal brace and rehabilitation within two weeks of starting the treatment.

Another challenge is in getting to the end point of treatment. Back pain can persist due to mechanical causes as well as deformity even after a healed status. MRI may show soft tissue image and sterile abscess after complete eradication of infection. Also, a late onset paraplegia (a delayed presentation of old healed TB spine) with progressive neurology and a high-grade kyphosis also poses challenges to the orthopedic surgeon.

Follow up Assessment
Hematological findings on 11/4/2016 showed ESR-60; Total Count -10300 polymorphs- 63 lymphocytes- 30 eosinophil- 7, HB-9.5, LFT/RFT-normal, GRBS-117, urine – severe UTI, uric acid- 6.5, Mantoux test – positive 14 mms. X-ray showed: D6/7, end plate disease with pedicle intact.
Catheterized since there was neurogenic bladder and UTI.

21.7.2016: Hemetologically – HB=10.4, ESR-20

23.9.2016: HB- 11.8

26/5/2016: Catheter removal done. Her urination became normal.

Tuberculosis of hip
A 38-year-old gentle man presented with severe hip pain, true shortening, all movements painfully restricted. ESR was at 70, Mantoux test positive, CBNAAT test positive, Histopathology also positive. He was on bed rest with traction for 2 months and on ATT. Now he is undergoing ATT.

Tuberculosis of the knee
32-year-old gentleman, welder by profession, presented with right knee pain since 3 yrs. According to his words the complaint started after a hit to his knee with an iron bar while working. In the last one-year period he could do work only for 4 months (the other 8 months were spent on treatment from various other health facilities). His personal history revealed that he has no diabetes, jaundice, hypertension, recurrent fever or HIV. The complaint stated as a sudden onset of pain 3 years back following hit to an iron rod, with a swelling disproportionate to the pain. Now presented with swelling around right knee. O/E: Patient walks with antalgic gait, horse shoe swelling around knee with increased temperature, patellar tap was present along with synovial thickening. Fixed flexion deformity of 20 degrees then flexion possible up to 90 degrees but with pain. Clinically a diagnosis of chronic synovitis was made. The case is interesting for its 3-year duration, and the MRI report of pigmented villo-nodular synovitis.

HB: 11.7, TC-4200, P-69%, L-23%, E-6%, M-2%. ESR-80. RBS: 143mgs, HBS Ag, HCV, HIV – negative X-ray showed osteoporosis.

MRI report indicated synovial thickening, 2 punched out lesions at the femoral condyles, pigmented villo nodular synovitis to be considered. After proper preoperative checkup partial synovectomy and biopsy done under spinal anesthesia.

Medial para- patellar incision, synovium was thickened with increase in vascularity. Synovial fluid sent for culture and sensitivity – the result after 72 hours was sterile. Drain removed after 24 hours; collection was 50 ml only. Wound inspection done on 3rd day which was clean. Patient was discharged on 3rd day. Suture removal was done after 14 days. Quadriceps exercises started from second day onwards. The biopsy report came after 2 weeks and it was a typical tuberculous granuloma. Liver function test and renal function test was normal. He was registered in government DOTS regime.

By 2 months, the pain and swelling disappeared. By 6 months, ESR become 25. Completed chemotherapy by 9 months. Rejoined in his company at Ernakulam after 7 months post op.

2yrs follow up
Patient has no complaints. On examination terminal 10 degrees of flexion limited. Otherwise healthy.

Differential diagnosis
1. Tuberculosis. 2. Pigmented villo-nodular synovitis 3. Rheumatoid arthritis 4. Sero-negative arthropathy.

Tuberculosis of the knee causes triple dislocation due to hamstring spasm and contracture. These are flexion, posterior dislocation, lateral rotation and adduction of tibia. In advance cases in adults, arthrodesis is done by using Charnley’s compression arthrodesis. Other causes of triple deformity are polio and rheumatoid arthritis. DOTS treatment was for 6 months with 2 months of four-drug regime and 4 months two-drug regime. At my request, the medical officer in charge of DOTs programme extended treatment up to 9 months.

Tuberculosis of calcaneum
Tuberculosis affecting this bone is a rare occurrence even though infections are not uncommon in calcaneum, especially in compound injuries. Co-morbid conditions like diabetes, arterial diseases, smoking, alcoholism etc. are other contributing factors.

A 35-year-old gentleman presented with a non-healing ulcer at the lateral aspect of foot. Two years back, he had a swelling at the same region; for which he underwent an incision and drainage (I &D) in a local hospital. At that time the ulcer was healed in 2 weeks. The 2nd recurrence occurred after 8 months, but at that time there was no ulcer, only pain, which was cured by NSAIDs and footwear modification (micronized rubber shoes). Now he presented with a non-healing ulcer at the lateral aspect of foot at the same region of I&D. It started 1 month back with a swelling at the lateral aspect of the foot. An I&D was done at a local hospital for the same. Culture and sensitivity of pus yielded heavy growth of coagulase positive staphylococci sensitive to cloxacillin and gentamicin. X-ray showed a lytic lesion at the antero-lateral portion of the calcaneum.

With the help of C-Arm, we identified the lytic lesion, thorough debridement was done, and the specimen was sent for histopathology. The lytic space was filled with vancomycin impregnated purified Ca SO4 (Stimulan). Suture removal was done at 10 days post operatively, then a below-knee plaster cast was given.

After 6 weeks it was converted to a walking cast for six more weeks and then he was allowed full weight bearing.

The case was managed with the DOTS regime protocol. Follow up X-ray and clinical picture at 3 months shows well healed scar and consolidating lesion.

The author is additional professor in Orthopedics, Govt. Medical College, Kollam, India.