Gross Pathologies of the Vertebral Column Flashcards
Describe spinal tuberculosis
- Vertebral column is the most common loaction for musculoskeletal tuberculosis.
- Spinal TB = Mycobacterium TB
- Accounts for 11% of extra-pulmonary TB
- Affects 2 or more adjacent vertebral bodies
- Average number of vertebrae affected = 2.6
- Progression of disease is slow
- Can be associated with HIV:
- TB in HIV negative patients = 3-5% spinal
- TB in HIV positive patients = 60% spinal
- Usually secondary to an extraspinal source of infection
What spinal deformity can be caused by spinal tuberculosis and why?
- Severe kyphosis
- Due to vertebral body destruction during childhood
Where does spinal tuberculosis most commonly start?
Usually begins in anterior spine and surrounding soft tissue structures then proceeds posteriorly.
Relatively sparing of the disc space.
What are the causes of spinal tuberculosis?
- Poverty
- Overcrowding
- Malnutrition
- Alcoholism
- Diabetes
- HIV infection
- Genetic
- Zhang et al. (2010) found that polymorphism in the vitamin-D receptor gene was related to spinal TB.
List the effects of spinal tuberculosis
- Destruction of vertebral bodies and IV discs
- Formation of abscesses / lesion
- Anterior wedging
- Functional disability
- Spinal cord compression
- Back pain
What is stage 1 in the spread of spinal tuberculosis?
Hematogenous spread via arterial / venous route from a pulmonary lesion or a genitourinary infection.
What is stage 2 in the spread of spinal tuberculosis?
Pre-pus inflammatory reaction with Langerhans giant cells, epitheloid cells and lymphocytes.
What is stage 3 in the spread of spinal tuberculosis?
Granulation tissue proliferates, and thrombosis of blood vessels occurs.
What is stage 4 in the spread of spinal tuberculosis?
Tissue necrosis and / or breakdown of inflammatory cells = paraspinal abscess. Produces pus.
What is stage 5 in the spread of spinal tuberculosis?
Continued necrosis leads to kyphosis.
What is stage 6 in the spread of spinal tuberculosis?
Spread to other vertebral bodies via longitudinal ligaments.
What does hematogenous mean?
To spread via blood
Describe the process of diagnosis of spinal TB
- Patients are often wrongly prescribed anti-inflammatories and physical therapy.
- Slow disease progression so difficult to diagnose initially.
- MRI and CT used for diagnosis.
- BUT, histopathological diagnosis is ESSENTIAL.
- Adults and children differ (primary and secondary)
Explain the difference between spinal tuberculosis in adults and spinal tuberculosis in children
- As intervertebral discs are vascularised in children, infection can spread to the discs and start there as a primary infection.
- In adults, disc involvement is secondary following spread of infection from adjacent vertebrae.
What are the 2 main treatment options for spinal tubrculosis?
- Antituberculosis drugs
- Surgery
Describe drug treatmnt of spinal tuberculosis
- Chemotherapy remains the gold standard for spinal TB treatment.
- 3 main treatment drugs:
- Rifampin
- Isoniazid
- Pyrazinamide
- Early onset chemotherapy can minimise further risks
- All 3 drugs are typically administered every day for 2 months.
- Then, switch to only Rifampin and Isoniazid for a minimum of 4-8 months.
- Potential problems - drug resistance.
Describe the surgical treatment of spinal tuberculosis
- Can be anterior, posterior or combined
- First, use MRI to identify affected area(s)
- Insertion of screws to correct deformity
- Bone grafts (spinal fusion)
- Draining of abscess using needle
Secondary postoperative deformity can develop from incorrect choice of method to fixate the affected area, fusing unsuitable segments or a resultant poor balance following surgery.
What are the outcomes of treating spinal TB (one hopes)?
- Relieving spinal nerve compression
- Regaining spinal stability
- Correcting spinal deformity
- Eliminating sites of tuberculosis
Describe Scheuermann’s disease
- Characterised by juvenile thoracic kyphosis
- Usually occurs at 10-16 years
- Reported prevalence between 0.4 and 8.3%
- Typically seen at mid-thoracic level, lower thoracic level or at the thoracolumbar junction.
- No sex difference
- Geographical variations
- Common reason for hyperkyphosis following idiopathic scoliosis.
Describe the clinical presentation of Scheuermann’s disease
- Painless kyphotic deformity = most common symptom
- Painful kyphosis = more severe symptoms
- Compensatory cervical and lumbar lordosis
- Cutaneous pigmentation
- Hip and shoulder flexion contractures
- Hamstring spasm
What is a flexion contracture?
- Joint motion limitation
- Results from muscle shortening / fibrosis
- Named for the opposite action, so flexion contracture lacks full extension and vice versa.
List the pathologies caused by Scheuermann’s disease
- Vertebral body wedging (>5°) - sometimes whole body can appear flattened.
- Premature degeneration of IV discs - linked to loss of water in nucleus pulposus, proteoglycan content decrease.
- Vertebral endplate irregularity - main gateway for nutrient supply to IV disc so irregularities = less nutrients reach disc.
- Schmorl’s nodes
- Narrowing of space between IV discs
- Reduced anterior vertebral growth - increased stress on anterior part of growth plate. Greater weight = greater compressive force (also uneven distribution of force).
What are the 3 types of treatment for Scheuermann’s disease?
- Rehabilitation
- Orthopaedic treatment
- Surgical treatment
Mild cases can be left alone and unmanaged.
Patients should avoid all sports involving excess spinal load bearing.
Describe the rehabilitation of patients with Scheuermann’s disease
- Physiotherapy and bracing - gold standard.
- Exercise techniques include:
- Strengthening and stretching the trunk
- Postural control
- Musculotendinous stretching
Describe orthopaedic treatment of Scheuermann’s disease
- Most effective for lower thoracic and lumbar regions
- 42-92% success in stabilisation (depends on compliance)
- Reduction of coronal deviating / limiting rotation
- 2 main types of brace:
- Static - constant pressure; rigid
- Dynamic - movement opposes spinal movement; uses flexible bands
Describe the surgical treatment of Scheuermann’s disease
- Very uncommon in this disease
- Only for very severe kyphosis (>70°)
- Spinal fusion with instrumentation (use of bone graft to joint 2 opposing bony surfaces)
- Fusion typically extends from just above to just below kyphosis
- Curves of 55° or less treated with posterior spinal fusion
Describe ankylosing spondylitis
- Chronic inflammatory disease related to rheumatoid arthritis and the spondylopathies disease family.
- Incidence at 0.2-0.8% in Caucasian populations.
- More common in males than females.
What are the symptoms of ankylosing spondylitis?
- Chronic back pain
- Increased stiffening of the spine
- Stooped or hunchback posture
- Difficulty expanding chest
What are the conditions which often manifest in conjunction with ankylosing spondylitis (AS)?
- 1/3 of patients will also experience arthritis in the hip or shoulder.
- 1/2 of patients will also experience peripheral joint synovitis.
- 25-40% of AS patients will also develop acute anterior uveitis (inflammation of the iris and ciliary body) at some point in their lifetime.
- 2-10% of AS patients will develop aortic regurgitation caused by weakening heart valves; the valve may need to be replaced.
- Long life (prolonged AS) increases the risk of conduction system disturbances in the heart. It occurs in 3% of patients who’ve had AS for 15 years and 9% of patients who’ve had it for 30 years. It is corrected by fitting a pacemaker.
- 2-3% of patients with AS may develop secondary amyloiditis (accumulation of amyloid protein in the kidney).
- Nerve subluxation and caud equina syndrome.
- Inflammatory bowel disease (6%).
Describe peripheral synovitis
- Inflammation similar to rheumatoid arthritis found in hips, knees, ankles, fingers and toes.
- Unlike rhumatoid arthritis it affects the joint capsule, enthesis attachments and even bone lining, not just the synovial membrane.
- Can also affect an entire digit, not just one joint.
Describe cauda equina syndrome
- Fibrous tissue constricts the cauda equina and can result in loss of:
- Continence
- Sensation to the lower body
- Motor function to the lower body
Which genes are associated with the aetiology of ankylosing spondylitis?
- Human leukocyte antigens (HLA)
- HLAs are a family of proteins derived from the HLA complex which consists of around 200 genes on chromosome 6.
- Particularly HLA-B27
Describe HLA-B27 misfolding
- Subtypes of HLA-B27 have different binding specificities.
- Insufficient binding of peptides and interaction with the chaperone protein results in misfolding.
- Results in endoplasmic reticulum associated protein degradation and autophagy, but also cytokine production which promotes inflammation.
What results from abnormal HLA-B27 and KIR3DL2 interaction?
- Cytokine production
- Helper T cell proliferation
Describe sacroiliitis secondary to ankylosing spondylitis
- SI joint is usually the first area affected by AS.
- Pathology:
- Inflammation
- Cartilage and subchondral bone degradation
- Remodelling and osteoproliferation leading to joint fusion
Describe facet joint fusion secondary to ankylosing spondylitis
- Inflammation and joint space narrowing
- Cartilage and subchondral bone degradation
- Articular cartilage fusion
- Remodelling and osteoproliferation - bone fusion
- Restricted motion
Thought to occur before syndesmophyte formation.
Describe syndesmophytes secondary to ankylosing spondylitis
- Inflammation where the vertebrae meets the annulus fibrosus.
- Syndesmophytes begin as inflammation which leads to a build-up of granulose tissue at the point where the annulus fibrosus meets the vertebral body.
- Remodelling and osteoproliferation causes bony bridges to form between vertebrae - fibrous tissue forms over the affected area, repairing the lesions.
- Restricted motion.
What are the treatments for ankylosing spondylitis?
- Physiotherapy and exercise
- Non-steroidal anti-inflammatory drugs
- Tumour necrosis factor antagonists
- Bisphosphonates
- Disease-modifying antirheumatic drugs
