Topic 8

Question 0

What are the risk factors for spinal infection

Answer 0

Smoking
Obesity
Malnutrition 
Immunosuppressed/ compromised- immunodeficient or undergoing treatment
Drug addicts
Diabetics
Urinary tract instrumentation

Question 1

What is the most reliable imaging for spinal infections

Answer 1

MRI when diagnosis is expected
Bone scans are too sensitive and therefore not specific, also infection has a latency period so may not show up for at least a week

Question 2

What can look like Pyogenic infections

Answer 2

Degenerative endplate changes, dialysis arthropathy, Charcot joint, ankylosing spondylitis etc

Question 3

What is the most common site for Pyogenic infections

Answer 3

Axial skeleton, lumbar spine is most common followed by cervical vertebrae
Thoracic is least common, can occur, but more common in non-Pyogenic infections such as tuberculosis

Question 4

When pedicle, laminae and spinous process are involved what would you susoect

Answer 4

Uncommon for Pyogenic infections so suspect tuberculosis

Question 5

When does Pyogenic infections occur and who does it affect

Answer 5

M>F 1.5-3.1

Two peak prominent ages fifth decade and second decade

Question 6

What can cause Pyogenic infections

Answer 6

Bacteria, fungal and parasitic organisms

Staphylococcus aereus 60%, enterobacter 30% are most common infections

Question 7

How does infection spread

Answer 7

Hematogeneous spread: directly through circulation and lymphatics
Non-hematogeneous spread: direct trauma (implantation), postoperative and contiguous source

Question 8

What are the clinical features of Pyogenic infection

Answer 8

Signs precede film findings by 7-10days (appendicular) and 21days (axial)
Young patients present with acute systemic symptoms
Adults vary and tend to be chronic, may have persistent back pain for months-years with anorexia, malaise and fever
Affects large tubular bones eg femur mc
May have hx of infection, infection spread may have neuro deficits

Question 9

What are the lab findings for Pyogenic infections

Answer 9

Lab findings are not always helpful depends on the grade and causative agent of infection
Elevated erythrocyte sedimentation rate
White blood cell count
C-reaction protein values or normal values may or may not be elevated

Question 10

What is the rule of 50’s

Answer 10

50% are 50yo or older
Fever only present 50% patients
WCC normal 50% patients
Urinary tract infection is the primary source of infections in 50% of patients
Staphylococcus aereus causative agent in 50% lumbar spine infections
No primary site is found in 50%
Symptoms are present >3 months in 50%

Question 11

What are the radiologic findings for Pyogenic infections

Answer 11

Moth-eaten bone destruction, usually metaphyseal
Periosteal new bone formation
Joint space destruction
Epiphysis often spared
Loss of disc height, vertebral destruction and collapse

Question 12

What is the treatment and prognosis of Pyogenic infections

Answer 12

Treatment: antibiotics, surgical debridement (late)
Prognosis: good when early, but 18-31% mortality

Question 13

General info of facet joint Infections

Answer 13

Isolated Pyogenic arthritis is rare
Non-hematogeneous spread is usual, eg cortisone injection
Pain increased by extension and lateral bending but not forward flexion

Question 14

What would CT show for a facet joint infection

Answer 14

Abnormalities include loss of subchondral bone associated with the facet joint and loss of density of ligament flavum
MRI may show swelling, and may have pus or joint effusion

Question 15

What would be differential diagnosis for facet joint infection

Answer 15

Neoplastic disease
Erosive arthritis
Hystiocytosis
Scleroderma

Question 16

What patients usually have non-pyogenic infections (tuberculosis spondylitis)

Answer 16

Rising with rising AIDS
Generally fourth and fifth decade
Found in immunosuppressed - aids sufferers, silicosis, lymphoma, alcoholics, corticosteroid, debilitated geriatrics
No sex predilection rare in <1 yo

Question 17

What is the etiology of non-Pyogenic infections

Answer 17

Mycobacterium tuberculosis

Spread by inhalation and ingestion

Question 18

What are the clinical features of non-Pyogenic infections

Answer 18

Regional joint pain, decreased ROM, focal tenderness and swelling common symptoms 
Abscess formation produces soft tissue swelling
Psoas abscess (5%) request lay have snowflake calcification

Question 19

Radiographic features of TB

Answer 19

Most common at L1, lower thoracic and upper lumbar also favoured sites
Latency 3weeks
Early sign: lytic endplate destruction, loss of disc height, anterior gauge defects, paraspinal swelling
Late: vertebral body collapse, gibbus formation (acute angular thoracic spine) , obliteration of the disc

Question 20

What is the treatment and prognosis of Potts disease

Answer 20

Chemotherapy somewhat resistant to modern drug therapy

Surgery is seldom necessary