GP - Back Pain and Fitness to Work Flashcards
What are the hallmark symptoms of Cauda Equina?
- Lower back pain
- Unilateral / bilateral leg pain / weakness
- Neurogenic bladder dysfunction - disruption to bladder sensation causes retention (bladder can’t tell brain it’s full) then overflow incontinence
- ↓ perianal sensation - saddle anaesthesia
- ↓ anal tone
What is the mechanism that causes cauda equina?
List some causes.
The spinal cord terminates at the conus medullaris (L1/2).
After this point spinal nerves continue as a bundle called the cauda equina. Compression of these nerves in the lumbro-sacral region causes the syndrome.
Causes:
- Disc herniation (most common)
- Spinal stenosis
- Tumour
- Trauma
- Spinal epidural haematoma (rare anaesthetic/surgical complication)
- Is collection of blood in space between dura and vertebrae periosteum
- Epidural abscess
What are the investigations of choice for
suspected Cauda equina syndrome?
MRI - best evaluates neurologic compression
CT myelography - investigation of choice if can’t have MRI
- Myuelography = form of fluoroscopy, inject contrast into spinal subarachnoid space
How is Cauda Equina syndrome treated?
Urgent surgical decompression within 48 hours
Discectomy or laminectomy
What is Sciatica?
The term used to describe symptoms of pain and paresthesia / numbness along the course of the sciatic nerve (i.e. buttocks, back of thigh, lateral calf, foot), due to lumbar radiculopathy
What are the most common causes of sciatica?
- Herniated intervertebral disc
- Spondylolisthesis
- Spinal Stenosis
What is the most common cause of ‘back pain’?
Simple / musculoskeletal back pain
In a Hx of back pain / sciatic pain, what ‘red-flag’ conditions need to be ruled out?
- Cauda equina syndrome
- Spinal fracture
- Cancer
- Infection e.g. discitis, vertebral osteomyelitis, or spinal epidural abscess
What are ‘red-flags’ for cauda equina syndrome?
- Bilateral sciatica
-
Severe or progressive bilateral neurological deficit of the legs
- e.g. significant motor weakness
-
Difficulty initiating micturition or impaired sensation of urinary flow
- if untreated this may lead to irreversible
- Urinary retention + overflow incontinence
- Faecal incontinence
- ↓ perianal sensation i.e. saddle anaesthesia
- ↓ anal tone
What are some ‘red-flags’ for spinal fracture?
- Sudden onset, severe spinal pain - relieved by lying down
- Hx of trauma (major or minor) or simply strenuous lifting in osteoporosis / steroids
- Structural spinal abnormality e.g. a step between vertebra
- Tenderness over specific vertebra
What are some ‘red-flags’ for cancer related back pain?
- Age > 50-yrs
- Gradual onset
- Weight loss
- Unremitting pain - continues when lying down, night pain disturbing sleep, pain exacerbated by straining (e.g. cough, stool)
- Hx or FHx of cancer - thyroid, breast, lung, renal, prostate
- Local spinal tenderness
-
No symptomatic improvement after 6-weeks of conservative management
*
What are some ‘red-flags’ for back pain due to infection?
- Fever
- TB or UTI
- Diabetes
- Hx of IV-drug use
- HIV infection OR immunosuppressant use OR immunocompromised
If a patient present with back pain, what conditions could cause back pain but not originate in the back?
- Pneumonia
- Peptic ulcer
- Acute pancreatitis
- Pancreatic cancer
- Ruptured AAA
- Fibromyalgia
- Pyelonephritis or ureteric colic
- Endometriosis
- Ovarian cyst
What are the initial / non-invasive treatments that come under conservative treatment of back pain / sciatica?
- Education - nature of lower back pain, red flags
- Avoid triggers
- Weight loss
- Local modalities: heat or ice
- Do not offer US, PENS or TENS for management
- Mobility devices + home modifications e.g. special chairs
-
Exercise / activity –> return to normal activities
- Avoid bed rest for > 2 days
-
Pain management:
- Paracetamol ineffective for back pain
- NSAIDs = 1st line - co-prescribe PPI in pts > 45 yrs and account for GI, liver and renal toxicity
- Weak opiods e.g. codeine
- Physiotherapy - once pain is controlled
What does the natural recovery in most patients
with lower back pain look like?
Natural recovery is favourable - most recover from acute episode in 6-12 weeks
- 50% recover in 2 weeks
- 70% recover in 1 month
- 90% recover by 4 months
- If pt fails to recover by 4 months then they are more likely to progress to long-term chronic back pain
Disc herniation and spinal stenosis are 2 common casues of back pain - at what ages are each more common?
- Disc herniations = more common in patients < 50-yrs
- Spinal stenosis = more common in patients > 60-yrs
A prolapsed lumber disc tends to have the main features:
- leg pain usually > than back
- pain often worse when sitting
A prolapsed lumbar disc produces clear dermatomal leg pain + neurlogical deficits depending on the level of the prolapse.
For the following describe the pattern of leg pain + neurological deficit:
- L3 nerve root compression
- L4 nerve root compression
- L5 nerve root compression
- S1 nerve root compression
-
L3 nerve root compression
- Sensory loss over anterior thigh
- Weak quadriceps
- Reduced knee reflex
- Positive femoral stretch test (lie prone, knee flexed to thigh, thigh extended –> pain = +ve)
-
L4 nerve root compression
- Sensory loss anterior aspect of knee
- Weak quadriceps
- Reduced knee reflex
- Positive femoral stretch test
-
L5 nerve root compression
- Sensory loss dorsum of foot
- Weakness in foot and big toe dorsiflexion
- Reflexes intact
- Positive sciatic nerve stretch test (straight leg raise pain = +ve)
-
S1 nerve root compression
- Sensory loss posterolateral aspect of leg and lateral aspect of foot
- Weakness in plantar flexion of foot
- Reduced ankle reflex
- Positive sciatic nerve stretch test
For pts with lower back pain resistant to inital conservative management, what alternative non-surgical approaches can be used?
Pain Clinic
- MDT
- Physiotherapy
- Occupational therapy
- Phsychotherapy
- Address complex issues related to pain behaviours
- Identify psychosocial barriers to treatment
- Different medication called ‘pain modifying medication’:
- Gabapentin
- Amitryptiline
TENS is often used by pain clinics in the treatment of resistant lower back pain.
What is TENS?
Transcutaneous electrical nerve stimulation
- Small electrodes on superficial skin
- Gate theory of pain: stimulation of large myelinated fibres at the level of the spinal cord blocks transmission of pain by small unmyelinated fibres (pain fibres) at the level of the spinal cord
What invasive, non-surgical interventions can be considered for back pain?
-
Radiofrequency denervation when:
- Non-surgical treatments not working AND
- Main pain source comes from structures supplied by medial branch nerve AND
- Pain score > 5/10
- Only use after a +ve response to diagnostic medial branch block
- Medial branch nerve = small nerves that carry pain signals from spinal facet joints (see pic)
-
Epidural - acute / severe sciatica
- Local anaesthetic + steorid
- Don’t use in spinal stenosis
What is spondylolysis?
- Cogenital or acquired defect / stress fracture in pars interarticularis of the vertebral arch - often L4/L5
- Pars interarticularis = part of vertebra located between inferior and superior articular processes of the facet joint (lies between lamina and pedicle)
- Spondyolysis is the commonest cause of spondylolisthesis in children
- Asymptomatic cases = no treatment
- Features:
- Common in sports people (especially /w hyperextension)
-
Sudden onset (can be gradual), unilateral, lumbar pain (often mild)
- Pain worse on spinal extension & activity
- Pain better when resting / lying down
- Pain can radiate to buttock / thigh
- Normal neurological signs
- Excessive lumbar lordosis
- Unilateral local vertebrae tenderness
What is Spondylolisthesis?
When one vertebra is displaced relative to it’s immediate inferior vertebral body
- Features:
- Stiff back + tight hamstrings
- Lower back pain + shooting pain from buttocks to posterior thigh
- Abnormal posture + gait
- Guteal muscle atrophy due to lack of use in gait
- If pt has radicular symptoms / signs then will often require spinal decompression + stabilisation
What is spinal stenosis?
Condition in which central spinal canal is narrowed by:
- Space-occypying lesion
- Disk prolapse
- Arthritis
- Spondylolisthesis
-
Age
- progressive degeneration intervertebral discs (resulting in prolapse)
- stress transfer to posterior facets
- ligamentum flavum hypertrophy
- osteophyte formation
Often only occurs in the elderly.
How does neurogenic claudication (caused by lumbar spinal stenosis) differ from vascular claudication?
Neurogenic Claudication:
- Pain (back/legs) worse going down hill
- Sitting more comfortable than standing
- Pain worse on spinal extension
Vascular claudication:
- Pain (back/legs) worse going up hill
- Pain worse on flexion of spine / exertion
