TB in bone

Question 1

How do we classify TB bone infections? [3]

Answer 1

By site of infection:

• Extra-articular (epiphyseal plate)
• Intra-articular (large joints)
• Vertebral body

1/3rd of patients have it in multiple sites

Question 2

How does TB bone infection present? [5]

Answer 2

Pain, swelling and weight loss
Low grade fever
Decreased ROM
~Ankylosis and deformity

Look for a TB history with an insidious onset

Question 3

Whats the most common form of TB bone infection and how does it present? [3]

Answer 3

Spinal TB

• psoas abscess
• kyphosis of the spine
• Little pain or illness until they reach the point of vertebral body collapse, which can be seen on X-ray and is normally either TB or cancer

Question 4

What tests would we use for dx TB with bone involvement? [4]

Answer 4

X-ray
Sputum/urine cultures, Mantoux Test
FBC, ESR
Joint aspiration & biopsy

Question 5

How would bony TB show up on X-ray? [3]

Answer 5

• Periarticular Osteoporosis
• Synovium thickening –> narrowed articular space
• Soft tissue swelling

Question 6

DDX for TB? [5]

Answer 6

Transient synovitis
Monoarticular RA
Haemorrhagic Arthritis
Pyogenic Arthritis
Tumour

Question 7

How do we treat TB in the bone? [2]

Answer 7

Rest and splintage
Rarely operative drainage
Anti-tb eradication therapy

Question 8

Describe the drug regimen to clear TB from the bone? [2]

Answer 8

8 wks of Rifampicin + Isoniazid + Ethambutol

then 6-12 months of Rifampicin + Isoniazid

Question 9

What is Pott’s disease

Epidemiology

Answer 9

Spinal TB

Ep: young patients

Question 10

Indications of operative drainage (rarely necessary)

Answer 10

Indicated in spine when causes compression to prevent continuous collapse