Discitis

Question 1

What is the difference between discitis and vertebral osteomyelitis?

Answer 1

Vertebral osteomyelitis and spondylodiscitis = infection of the vertebrae and intervertebral disc

Discitis = infection of the intervertebral disc only

Question 2

Define discitis.

Answer 2

Discitis is an infection in the intervertebral disc space. It can lead to serious complications such as sepsis or an epidural abscess.

Question 3

How common is discitis?

Answer 3

Pyogenic infections of the spine are relatively rare
1 in 100,000
Common in males aged in their 50s

Question 4

What is the pathophysiology of discitis?

Answer 4

Usually associated with infection and haematogenous spread - S. aureus most common
Usually affects lumbar spine

Question 5

What are the causes of discitis?

Answer 5

Bacterial
* Staphylococcus aureus is the most common cause of discitis
Viral
TB
Aseptic

Question 6

What are the risk factors for discitis?

Answer 6

• Immunosuppression
• Diabetes
• Vascular disease
• IV drug use
• Surgery near disc space

Question 7

How does discitis present?

Answer 7

• Insidious onset neck or back pain
• Localised tenderness
• Pain worse on movement
• Restricted mobility
• +/- Fever
• +/- Weight loss
• Neurological deficit (rare)

Question 8

How do you diagnose discitis?

Answer 8

Conservative
* ESR and CRP
* WCC
* Blood cultures, sputum, urine - for source
Imaging
* XR spine - may be normal initially
* Nuclear medicine scans
* MRI - most sensitive and specific but CT can also be used
Surgical
* CT-guided or open biopsy - for culture
* Surgical debridement

Question 9

What is the management of discitis?

Answer 9

Analgesia
Immobilisation - brace and bed rest for 3-6 months

Antibiotics - 6-8 weeks IV; adjust when culture results come back

Surgical debridement - may be needed if there is deformity or lack of response to abx

Question 10

What are the complications of discitis?

Answer 10

Spread of infection into epidural space or paraspinal tissues -> sepsis, epidural abscess

Question 11

What is the prognosis with discitis?

Answer 11

Antibiotics usually successful in treating the condition
Mortality 2%
Minority will have permanent neurological deficits

Question 12

What other infections should you investigate for in discitis?

Answer 12

Endocarditis - TOE or TTE. Discitis is usually due to haematogenous seeding of the vertebrae implying that the patient has had a bacteraemia and seeding has occurred elsewhere