Makindo Medical Notes

Related Subjects: |Analgesia and Pain management |Sedation and Analgesia on ITU |Neuropathic Pain Management |Codeine |Dihydrocodeine |Diamorphine |Morphine |Paracetamol (Acetaminophen) |Osteoporosis

Do not perform imaging for low back pain in the first six weeks unless red flags are present. Red flags include, but are not limited to, severe or progressive neurologic deficits or suspected serious underlying conditions such as osteomyelitis

About

• Common and most are benign. Be on look out for malignancy, infection and fractures and neurology/cauda equina syndrome

Red flags: Inflammatory Malignancy Infective

• Age under 20 or over 50
• Night time pain
• Persists beyond 6 weeks
• Elevated ESR or CRP
• Signs of malignancy - weight loss or primary malignancy

Worrying diagnoses

• Multiple myeloma
• Metastases
• Tuberculosis osteomyelitis
• Bacterial osteomyelitis
• Spinal cord or root canal stenosis

Aetiology

• Mechanical: 90% of cases are mechanical in age 25-55 usually comes on with lifting or bending. Worse with activity and relieved by rest. usually asymmetrical pain. Usually lower back and buttocks. Normal neurology. Prognosis is good and 90% improve by 6 weeks.
• Malignancy: Young or over 50 years old. Constant progressive pain often worse at night. Not relieved by rest. Weight loss and cachexia. On steroids. Sweats, malaise. raised CRP. May have weakness of legs and cauda equina syndrome. Worsens over time.
• Inflammatory: Spondylitis usually seen in those under 40. often axial (midline) and symmetrical. Sacroiliitis can cause buttock pain. Morning stiffness.
• Degenerative disc disease: Can cause nerve root pain. Often affects L4/5. Can cause a cauda equina
• Fracture: Significant trauma relative to age (strong) Prolonged corticosteroid use (intermediate). Contusions or abrasions (intermediate). Age older than 70 years, osteoporosis (weak)
• Infection/Discitis/Osteomyelitis: Constant pain, Spinous process tender. Spinal procedure in the past 12 months (strong), Fever, wound in the spinal region (strong), Intravenous drug use, immunosuppression, distant lumbar spine surgery (intermediate), Localized pain and tenderness (weak

Table showing causes

Low back Pain Differentials

• Lumbosacral muscle strains/sprains (70%): post trauma or repetitive overuse; pain worse with movement, relieved by rest; examination may reveal restricted range of motion, muscle tenderness, or trigger points
• Lumbar spondylosis (10%): commoner age > 40. pain may be present in or radiate from the hips; pain is worse with activity; pain may worsen with lumbar spine extension or rotation; neurologic examination is usually normal
• Disk herniation Nucleus pulposus (5% to 10%): Most often involves the L5/S1 nerve root, at L4/L5 or L5/S1 in 90% to 95% of cases; symptoms may include pain, paraesthesia, sensory change, loss of strength or reflexes depending on affected nerve root
• Spondylolysis (5%): young athletes; symptoms often develop insidiously; pain with activities involving lumbar extension; imaging is diagnostic, but early imaging in the absence of red flags is typically not necessary; usually occurs in a lower lumbar vertebra, most often L5
• Spinal stenosis: Leg pain is greater than back pain; pain worsens with standing and walking, and improves with rest or when the spine is flexed; pain may be unilateral (foraminal stenosis) or bilateral (central or bilateral foraminal stenosis)
• Vertebral compression fracture (4%): Fracture may occur slowly over time or acutely with mild trauma. Acute episodes usually resolve in four to six weeks, but can cause chronic pain and functional impairment. Localised back pain that is worse with flexion and often point tenderness on palpation. Risk increased age, history of trauma, chronic steroid use, and osteoporosis; plain radiography should be obtained to confirm diagnosis
• Spondylolisthesis (3% to 4%): Pain radiates into the buttocks or posterior thigh; leg pain may be worse than back pain; often presents as paraesthesias, numbness, or weakness; occurs at L5 in 90% of cases
• Vertebral diskitis/ osteomyelitis: Constant pain, spinous process tenderness, often no fever, normal complete blood count, elevated ESR/CRP
• Inflammatory spondyloarthropathy: Intermittent pain at night, morning pain and stiffness, inability to reverse from lumbar lordosis to lumbar flexion
• Herpes zoster: Unilateral dermatomal pain, often allodynia, vesicular rash
• Abdominal aortic aneurysm: Abdominal discomfort, pulsatile abdominal mass
• Pancreatitis, peptic ulcer disease, cholecystitis: Abdominal discomfort, nausea\vomiting, symptoms often associated with eating

Clinical

• Assess back pain, tenderness, look for neurology
• Look for signs of malignancy
• Exclude cauda equina
  • Progressive motor or sensory loss
  • New urinary retention or overflow incontinence
  • New faecal incontinence (strong).
  • Saddle anesthesia
  • Loss of anal sphincter tone
  • Significant motor deficits encompassing multiple nerve roots (strong)

Neurologic Examination Findings in Patients with Acute Low Back Pain and disc prolapse with root compression

Investigations

• FBC, U&E, CRP/ESR (elevated in inflammation/infection)
• Calcium, phosphate, ALP, PPE, PSA for prostate cancer
• Imaging: Advice is do not order initial imaging studies unless there is concern for cauda equina syndrome, malignancy, fracture, or infection. Imaging of choice is MRI.
• Bone scans: infection or malignancy
• MRI: look at cord and disc lesions
• CT scan: better for seeing bone

Management of Non Red flag Back pain

• Patient education: Reassure the patient that the prognosis is often good, with most cases resolving with little intervention
• Advise the patient to stay active, avoiding bed rest as much as possible, and to return to normal activities as soon as possible
• Advise the patient to avoid twisting and bending
• Initiate trial of a nonsteroidal anti-inflammatory drug or acetaminophen (paracetamol)
• Consider a muscle relaxant based on pain severity
• Consider a short course of opioid therapy if pain is severe

References

• Mechanical Low Back Pain