Bone TB

What is Bone Tuberculosis?
When tuberculosis involves the skeleton, the following joints are affected-(in the order of frequency as shown below)-
  • Spine
  • Hips
  • Knees
  • Feet
  • Elbows
  • Wrists
  • Shoulders
  • Sometimes other joints also

Spinal TB is the most known and common form of bone TB.
It is also known as TB Spondylitis or Pott ‘s disease.
What are the causes of Bone Tuberculosis?
  • Bacilli reach the joints from some focus elsewhere, from lesions in lungs, travel by blood stream
  • Spread from infected lymph nodes.
  • From other visceral organs

What is Synovial joint TB?
  • The disease starts in synovium,grows slowly over cartilage.
  • Then extends via the cartilage into underlying bone, which then decalcifies.
Symptoms of Bone TB?
  • Spinal tuberculosis (Pott’s disease) usually affects the thoracic part of the spine.

    • Causes constant back pain as the virus degrades the discs cushioning the vertebrae.
    • In spine, disease starts in the disc-
    • If treated before cartilage destroyed, joint recovers fully.
    • Treated late stops disease but joint develops ankylosis.
    • Sometimes-abscesses and sinuses lead to secondarily infection.

  • Patient is usually a young adult or a child above 6 years.
  • (Although even a year old child & older people can get infected
  • Progressively painful one or more joints.
  • Stiffness in joints during previous weeks.

  • If leg is involved, limping is the first complaint.

  • A constant pain in the bone can cause complications carpal tunnel syndrome (wrist).
  • The infected joint gets filled with fluid, and there is wasting of muscles round it.
  • There is mild to moderate pain, but more on forced movement.
  • Skin over infected joint is same temperature as normal skin.(‘cold’)
  • In septic arthritis it is ”hot’, temperature is more than surrounding skin.
  • Sometimes there can be mild fever, night sweats, or loss of weight or appetite.
  • Pain and fever may be quite marked.
  • He may also have signs of tuberculosis in his chest, or a family history of it.
  • The affected bone may also be weakened and may fracture easily

Treatment of Bone TB
CHEMOTHERAPY

  • Ideally a 4-drug regimen is advised which can be adjusted as per susceptibility reports.
  • Isoniazid and Rifampin to be given during the whole course of therapy.
  • Additional drugs administered during first 2 months of therapy –chosen from streptomycin, pyrazinamide and ethambutol.
  • A 3-drug regimen usually includes isoniazid, rifampin, and pyrazinamide.
  • When there is drug resistance, then second-line medications used.
Duration of Treatment-
  • Somewhat controversial.
  • Most favour a 6-9 months course.
  • Traditional courses are from 9 months to one year or even longer.
  • Usually individualized, based on resolution of symptoms and clinical status.
  • Resting the joint by sling or otherwise
  • To admit if required.
  • Application of traction
  • Major surgical operations to drain or remove lesion.

The prognosis of Bone TB-
Tuberculous joints can be successfully and cheaply treated if diagnosed early enough, within first few weeks.

How to confirm diagnosis?
  • Be suspicious as there are no certain diagnostic signs.

    • Seeing any chronic bone or joint disease, ask: ”If this Might be tuberculous?” If so, it can be treated

  • Biopsying a node or synovium confirms diagnosis in 50% cases.

    • When joint swollen aspirate and examine fluid.
    • When lymph nodes enlarged, get biopsy done.
    • Biopsy from spine is difficult, take same from hip joint.
    • Biopsies are fallible-accept them with caution.

  • In Tubercular arthritis, the X-rays show –

    • Generalized rarefaction
    • Lack of sharpness of joint
    • Some Localized areas of erosion or decreased density/erosion.
    • Joint space abnormally narrow or wide or irregular.

  • (CAUTION! Joint destruction in TB always more severe than seen in X-ray.)
  • Get X-ray of lungs to know extent of infection
  • Get X-ray of lungs to know extent of infection
  • CT scan gives very favourable clarity on the quality of bone/joint destruction
  • Many diagnostic specialists make use of MRI scan for sharp assessment.

Differential Diagnosis of Bone TB
  • to distinguish from Septic arthritis

Septic Arthritis

Quality

Bone TB

History of Hours and days

ONSET

History of Weeks

Acutely painful in any direction

PAIN

Progressively painful

‘hot joint’

TEMPERATURE OF JOINT

‘cold’ joint

High fever and leucocytosis

FEVER

Mild fever

Severely affected

MOVEMENT

Limitedly affected

High fever and leucocytosis

FEVER

Mild fever

Severely affected

MOVEMENT

Limitedly affected
  • History of Trauma/injury.
  • Haemarthrosis
  • Other forms of arthritis with history of infections like gonorrhoea/dysentery
  • Rheumatoid arthritis
  • If child and hip involved- could be – Perthes’ disease/ slipped epiphysis
  • If old, with history of previous injury, consider osteoarthritis.
  • History of Trauma/injury.
  • Haemarthrosis
  • Other forms of arthritis with history of infections like gonorrhoea/dysentery
  • Rheumatoid arthritis
  • If child and hip involved- could be – Perthes’ disease/ slipped epiphysis
  • If old, with history of previous injury, consider osteoarthritis.