8.4 - Back pain Flashcards
What are the functions of the spine? (3)
- locomotor - capable of being both rigid and mobile
- bony armour - protects the spinal cord
- neurological - spinal cord transmission of signals between brain and periphery
What are the five parts of the spine?
- cervical (C1-7) - normal lordosis
- thoracic (T1-12) - normal kyphosis
- lumbar (L1-5) - normal lordosis
- sacral (S1-5)
- coccyx (Co1-4)
What are the key MSK structures of the spine?
- spinal column made up of:
- vertebrae - 24 bones (7 cervical, 12 thoracic, 5 lumbar)
- intervertebral discs - shock absorbers, allow segmentation and multi-directional movement
- facet joints - small synovial joints at posterior spinal column linking each vertebra
- muscles - move the spine
What are the key neurological structures of the spine?
- spinal cord - transmission of signals to/from brain
- ends at L2 vertebra
- nerve roots - exit the spinal cord bilaterally
- cauda equina - nerve bundle, runs distally
Where are lumbar punctures done?
Lumbar puncture is performed at L3/4 space to avoid the spinal cord (which ends at L2)
What are the movements of the spine? (3)
- flexion (forward bend) vs extension (backward bend)
- lateral flexion (side bend)
- rotation (twist)
What is back pain?
- very common: >50% of people will experience an episode
- acute back pain usually self-limiting (resolves by itself)
- most better in a few days, 96% better in six weeks
- chronic back pain (>12 weeks duration) also common - sedentary lifestyle
- need to distinguish mechanical back pain from serious pathology
What is mechanical back pain?
- reproduced or worse with movement
- better or not present at rest
What are some common causes of mechanical back pain? (4)
- muscular tension (e.g. chronic poor posture, weak muscles)
- acute muscle sprain/spasm
- degenerative disc disease
- osteoarthritis of facet joints
What is sciatica?
- pain radiating down one leg
- mechanical back pain may be accompanied by sciatica
What is sciatica typically caused by?
- typically due to disc herniation (‘slipped disc’) contacting the exiting lumbar nerve root
- tear in annulus fibrosis –> nucleus pulposus leaks out and can contact nerve root –> irritation and pain in corresponding dermatome
- location of the pain determined by the level of the herniated disc
What are some serious causes of back pain? (5 + 1)
- tumour - metastatic cancer or myeloma
- infection - discitis, vertebral osteomyelitis, paraspinal abscess
- inflammatory spondyloarthropathy - ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease (IBD)-associated
- fracture - traumatic or atraumatic
- large disc prolapse - causing neurological compromise
- NB referred pain (pancreas, kidneys, aortic aneurysm)
What are the common causes of infection (microbiology) of the back that cause back pain? (3)
- Staphylococcus (acute)
- Streptococcus (acute)
- tuberculosis (chronic)
What are the red flag symptoms for back pain? (10)
- pain at night or increased pain when supine
- constant or progressive pain
- thoracic pain (mechanical pain usually cervical/lumbar)
- weight loss
- previous malignancy
- fever/night sweats
- immunosuppressed
- bladder or bowel disturbance (sphincter dysfunction)
- leg weakness or sensory loss
- age <20 or >55 years
What is cauda equina syndrome?
- neurosurgical emergency
- untreated –> permanent lower limb paralysis and incontinence
What are the signs/symptoms of cauda equina syndrome? (5)
- saddle anaesthesia
- bladder/bowel incontinence
- loss of anal tone on PR
- radicular leg pain (pain radiates to legs)
- ankle jerks may be absent
What investigation is done for cauda equina syndrome?
Urgent MRI L spine
What are the causes of cauda equina syndrome? (5)
- large disc herniation
- bony metastases
- myeloma
- tuberculosis
- paraspinal abscess
- (anything that compresses cauda equina)
What is the treatment for cauda equina syndrome?
According to the cause - may require urgent surgery
What things do you ask about when taking a history for back pain? (7)
- SOCRATES
- prolonged morning stiffness?
- effect of movement vs inactivity
- buttock pain
- leg weakness (/pain)
- sensory loss/paraesthesia
- lower limb claudication (peripheral vascular disease, spinal stenosis)
What do we do when examining the spine? (6)
- look
- feel
- move
- straight leg test (SLR) - sciatica = pins and needles felt (tests lumbar nerve root related pain)
- lower limb neurological exam
- general exam (signs of malignancy, AAA)
What do we do if there are no red flag symptoms of back pain?
- in the absence of red flags, investigation usually not required
- do not routinely arrange a spinal X-ray or other imaging to diagnose non-specific low back pain in primary care
- arrange review if symptoms persist/worsen after 3-4 weeks and reassess for underlying cause
What are the treatments for low back pain without red flags? (4)
- time
- analgesia (NSAIDs e.g. ibuprofen, paracetamol, codeine)
- AVOID bed rest - keep moving
- physiotherapy - soft tissue work, corrective exercises (especially core)
What blood tests can be done for back pain, and what abnormalities can they show? (6)
- erythrocyte sedimentation rate (ESR) - high in myeloma, chronic inflammation, TB
- CRP - high in infection or inflammation
- FBC - anaemia in myeloma + chronic disease, WCC in infection
- alkaline phosphatase (ALP) - high with bony mets
- calcium - may be high in myeloma, bone mets
- PSA - prostate cancer with bony mets
What imaging modalities can be used to investigate back pain? (3)
- radiographs (X-rays)
- computed tomography (CT)
- magnetic resonance imaging (MRI) - best test for back
What is a pro and a con of using radiographs (X-rays) for investigating back pain?
- +: cheap, widely available
- -: poor sensitivity, radiation
What is a pro and a con of using CT scans for investigating back pain?
- +: good for bony pathology
- -: larger radiation dose than X-ray
What are pros and a con of using MRIs for investigating back pain?
- +: best visualisation of soft tissue structures like tendons and ligaments
- +: best for spinal imaging - can see SC and exiting nerve roots
- -: expensive and time-consuming, claustrophobic
Back pain case 1:
- 70-year-old woman
- Acute onset thoracic spine pain with radiation through to the chest wall
- Focally tender over thoracic spine
Does she need investigation?
What is the diagnosis?
Yes as she has red-flag symptoms:
- age 55+
- thoracic pain
- radiation to chest wall
Diagnosis: osteoporotic vertebral collapse ‘wedge fracture’
What would you see on X-ray of osteoporotic vertebral collapse ‘wedge fracture’?
Affected vertebra is triangular/wedge-shaped instead of a usual rectangle
Back pain case 2:
- 25 year old man originally from Nepal
- Worsening low back pain for 8 weeks
- Worse in the morning but present at all times
- Weight loss
- Night sweats
Does he need investigation?
What is the diagnosis?
Yes due to red-flag symptoms:
- weight loss
- night sweats
- worsening pain
Diagnosis: TB with paraspinal abscess
What might you see on MRI spine of TB with paraspinal abscess?
- T1 (CSF black) - L4/5 endplate destruction, soft tissue mass encroaching spinal canal
- T2 (CSF white) - altered signal in sacral segments
- generally murky/gunky area of the MRI indicates paraspinal abscess
- confirm with aspiration sample
Back pain case 3:
- A 45-year-old man complains of acute back pain and sciatica extending down the R leg into the foot associated with paresthesia
- No incontinence of bladder/bowel
- Examination: no weakness, sensation intact
- He has been off work for two weeks and wants to know when he can get back to work
Does he need investigation? What is his diagnosis?
- no investigation required as no red-flag symptoms
- diagnosis: herniated disc
What is herniated disc natural history/outlook like?
- most prevalent in 30-50y/o
- good outlook
- normally spontaneous improvement, although typically slower than for low back pain alone (without sciatica)
What are the treatments for herniated disc? (3)
- conservative as for lower back pain without sciatica
- analgesia especially NSAIDs
- physiotherapy to improve core strength and treat associated muscle spasm
- nerve root injection (local anaesthetic and glucocorticoid) - CT-guided
- surgery if neurological compromise or symptoms persist
- trials of surgery vs conservative Rx show no long term advance/improvement for surgery
What do sequential MRIs show about prolapsed lumbar disc?
Sequential MRI studies reveal that the herniated portion of the disc tends to regress with time, with partial or complete resolution in 2/3 of cases after 6 months
Back pain case 4:
- 25 year old woman
- Presents with 1 year history of lumbar and buttock pain, with morning stiffness lasting 2 hours
- Ibuprofen helps
- Examination: reduced range of L spine movements
Does she need imaging? What is the likely diagnosis?
- yes - MRI and potentially bloods
- diagnosis: ankylosing spondylitis
- prolonged morning stiffness
- young
- ibuprofen helps
- reduced range of movement
What is inflammatory spondyloarthritis (SpA)?
- group of immune-mediated inflammatory diseases:
- ankylosing spondylitis (AS), psoriatic arthritis or IBD-associated
- primarily inflammation of the spine (spondylitis) and sacro-iliac joints (sacro-iliitis)
- peripheral joints, especially tendon insertions (entheses) can also be affected
What are the extra-articular manifestations of inflammatory spondyloarthritis? (4)
- Anterior uveitis (iritis) - ocular inflammation
- Apical lung fibrosis (top of lungs)
- Aortitis/aortic regurgitation
- Amyloidosis - due to chronically serum amyloid A (SAA) depositing in organs
How does ankylosing spondylitis manifest?
Loss of spinal movements (stiff and flat lumbar spine, neck held in fixed flexion, loss of curve of back)
What is ankylosing spondylitis characterised by?
Enthesitis (inflammation of the entheses - sites where tendon and ligaments join to bone)
Describe the genetic component of the pathophysiology of ankylosing spondylitis.
- large genetic component
- many gene variants associated with the disease (polygenic)
- HLA-B27 is the strongest genetic risk factor
- HLA-B27 is positive in 90% of AS patients versus 10% in general population
- used as a diagnostic biomarker but +ve HLA-B27 alone does not equal AS
What cytokines play important roles in the pathophysiology of ankylosing spondylitis? (3)
- tumour necrosis factor alpha (TNF-a) - targeted therapeutically
- IL-17
- IL-23
What about peptide processing pathways is important in the pathophysiology of ankylosing spondylitis?
Aberrant peptide processing pathways (aminopeptidases) in the endoplasmic reticulum
How can we see sacro-iliitis on an X-ray/MRI?
Increased whiteness around sacro-iliac joints show inflammation and bone marrow oedema (not seen in early disease)
What is the natural history of untreated ankylosing spondylitis?
Spinal enthesitis –> bridging syndesmophytes (new bone growth between adjacent vertebra, joints ossified instead of gaps) –> spinal fusion (loss of spinal movements)
Why do we use MRI in ankylosing spondylitis, and what would you see?
- MRI can detect spinal inflammation before X-ray changes develop
- ‘shiny corners’ sign at L4, L5 and S1 etc
What is the management of ankylosing spondylitis?
- physiotherapy and a life-long regular exercise programme
- pharmacological:
- 1st line: NSAIDs e.g. ibuprofen, naproxen, diclofenac
- mechanism: inhibit COX1&2
- risks: peptic ulcer, renal, asthma exacerbation, increased atherothrombosis risk
- selective COX2 inhibitors (e.g. celecoxib) reduce GI ulcer risk (but not CV risk)
- 2nd line: biological therapies - therapeutic monoclonal antibodies targeting specific molecules
- use if inadequate disease control after trying 2 NSAIDs
- anti-TNFalpha (e.g. adalimumab, certolizumab, infliximab, golimumab)
- anti-IL17 (e.g. secukinumab)
