Lower back pain

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Background

  • Pain lasting >6wks is risk factor for more serious disease
  • Night pain and unrelenting pain are worrisome symptoms
  • Back pain in IV drug user is spinal infection until proven otherwise
  • 95% of herniated discs occur at L4-L5 or L5-S1 (for both pain extends below the knee)
  • Lumbago: acute, nonspecific back pain

Clinical Features

Lumbar nerve root distribution
  • Musculoskeletal pain
    • Located primarily in the back with possible radiation into the buttock/thighs
    • Pain worse with movement but improves with rest
  • Spinal stenosis
    • Bilateral sciatic pain worsened by walking (pseudo-claudication), prolonged standing
    • Pain relieved by forward flexion, especially sitting
  • Sciatica
    • Radicular back pain in the distribution of a lumbar or sacral nerve root
      • Anything that compresses the nerve roots, cauda equina, or cord can cause sciatica
    • Pain worsened by coughing, Valsalva, sitting; relieved by lying in supine position
    • Occurs in only 1% of patients with back pain
    • Present in 95% of patients who have a symptomatic herniated disk
  • Urinary/bowel disturbances, perineal anaesthesia
    • Cauda equina syndrome, due to compression of spinal nerve roots
    • Ortho emergency!
  • Inflammatory back pain
    • Morning stiffness >30minutes
    • Consider seronegative spondyloarthropathies, especially if in young adults (eg ankylosing spondylitis, psoriatic arthropathy, IBD arthropathy, Reiter's disease)
Back Pain Risk factors and probability of Fracture or Malignancy[1]
Factor Post Test Probability
Older Age (>65yo) 9%

(95% CI 3% to 25%)

Prolonged corticosteroid 33%

(95% CI 10% to 67%)

Severe trauma 11%

(95% CI 8% to 16%)

Presence of contusion or abrasion 62%

(95% CI 49% to 74%)

Multiple red flags 90%

(95% CI 34% to 99%)

Hx of malignancy 33%

(95% CI 22% to 46%)

Waddell's Signs of Non-Organic Back Pain

  • Assess for the following[2]:
    1. Over-reaction to the examination
    2. Widespread superficial tenderness not corresponding to any anatomical distribution
    3. Pain on axial loading of the skull or pain on rotation of the shoulders and pelvis together
    4. Severely limited straight leg raising on formal testing in a patient who can sit forwards with the legs extended
    5. Lower limb weakness or sensory loss not corresponding to a nerve root distribution
  • 3 or more positives suggest non-organic or alternative organic source

Differential Diagnosis

Differential diagnosis of back pain

Lower Back Pain

Evaluation

Exam

  • Straight leg raise testing
    • Screening exam for a herniated disk (Sn 68-80%)
    • Lifting leg causes radicular pain of affected leg radiating to BELOW the knee
    • Pain is worsened by ankle dorsiflexion
    • Pain may be relieved by pressing across biceps femoris and pes anserinus tendons behind knee ('bowstringing')
  • Crossed Straight leg raise testing (high Sp, low Sn)
    • Lifting the asymptomatic leg causes radicular pain down the affected leg
  • Nerve root compromise
  • Rectal exam, perineal sensation, palpable bladder?

Labs

  • Pregnancy test
  • Only necessary if concerned for infection, tumor, or rheumatologic cause
    • CBC, UA, ESR (90-98% Sn for infectious etiology)
  • Consider post void residual

Imaging

Management

Acute, Non-traumatic, Non-Radicular Back Pain

  • Instruct to continue daily activities using pain as limiting factor
  • Medications
    • Acetaminophen and/or NSAIDs
      • 1st line therapy
      • Consider gel/patch like diclofenac or ketoprofen (shown to be more effective than PO form and placebo in one study[3])
    • Lidocaine patch
    • Capsaicin or Cayenne
      • Skin desensitization upon repeated exposure
    • Opioids
      • Appropriate for moderate-severe pain but only for limited duration (<1 week)

Not Indicated

Acute, Radicular Back Pain (Sciatica)

80% of patients will ultimately improve without surgery

Spinal stenosis

  • Treatment is the same as for musculoskeletal back pain

Cauda equina syndrome

  • Immediate Ortho referral for spinal decompression to avoid permanent bowel/bladder injury

Disposition

  • Normally outpatient, as long as no signs of emergent pathology and able to ambulate

See Also

External Links

References

  1. Downie A, et al. Red flags to screen for malignancy and fracture in patients with low back pain: systematic review. BMJ. 2013; 347:f7095. [1]
  2. Waddell G, et al. Non-organic physical signs in low-back pain. Spine. 1980; 5:117-125.
  3. Mazières B, Rouanet S, Velicy J, et al. Topical ketoprofen patch (100 mg) for the treatment of ankle sprain: a randomized, double-blind, placebo-controlled study. Am J Sports Med. 2005;33:515-523
  4. Friedman BW, et al. "Diazepam is no better than placebo when added to Naproxen for acute low back pain." Annals of EM. August 2017. 70(2):169-176
  5. Holve, RL, et al. Oral steroids in initial treatment of acute sciatica. J Am Board Fam Med. 2008; 21(5):469-474.
  6. Goldberg H, et al. Oral steroids for acute radiculopathy due to a herniated lumbar disk: a randomized clinical trial. JAMA. 2015 May 19;313(19):1915-23. PMID 25988461.