see also:

• back pain in the ED
• see also interscapular thoracic back pain

• back pain can be a very deceptive presentation, all too easily put down to muscle strain while missing potentially time critical diagnoses.
• watch for red flags in the presentation and specifically search for and exclude the main differentials.
• patients with chronic back pain can be difficult to manage in the ED and requires a degree of experience to avoid traps
• avoid opiates and tramadol in chronic back pain as evidence suggests they are of little benefit over non-steroidal anti-inflammatory drugs (NSAIDs) and do more harm
• most patients DO NOT warrant a thoracic spine Xray as these are high radiation procedures and usually have a low pick up rate
  • consider plain XR or CT scan if acute low back pain and not pregnant, and either:
    • high impact trauma
    • osteoporotic or over 50yrs age with a fall
    • fall from a height

• one of the first steps in assessing these patients in ED is to determine the pain pattern to better direct you down the correct path:
  • cutaneous pain such as herpes zoster (shingles)
  • muscular pain (eg. strain) - paravertebral or intercostal
  • rib pain - fractured ribs (pathologic or otherwise)
  • vertebral pain - eg. crush fracture, vertebral osteomyelitis / discitis, tumour, tuberculosis (TB), osteomyelitis, Diffuse idiopathic skeletal hyperostosis (DISH), ankylosing spondylitis (AS), etc
  • neuropathic pain:
    • nerve root impingement
    • thoracic disc prolapse
      • ~15% of adult population have incidental Tx disc prolapses on MRI, 75% are T8-12 (lower Tx spine is more mobile than upper Tx spine), mostly at T11 and T12
      • the far majority are asymptomatic, symptomatic Tx disc prolapses ones are said to be rare
      • central ones generally cause spinal cord compression which may not be associated with pain
        • rare upper Tx prolapses may also compress the arterial supply to the spinal cord
      • post-lateral ones may cause nerve root impingement
  • Spinal cord syndromes and lesions or acute spinal cord compression - epidural abscess, spinal ischaemia, tumour, etc (usually have neurologic features)
  • intrathoracic pain:
    • pleural - pulmonary embolism (PE), pneumonia, pleurisy, tumour, etc
    • vascular - aortic dissection
  • retroperitoneal / subdiaphragmatic pain: abdominal aortic aneurysm (AAA), PU, pancreatitis, retroperitoneal haemorrhage, biliary colic, acute pyelonephritis (see RUQ abdo pain)
  • could it be referred shoulder pain from haemoperitoneum (eg. ruptured ectopic pregnancy) or other subdiaphragmatic causes?
  • is it a more chronic pain due to spondyloarthopathies

• manage according to red flag such as:
  • trauma to thoracic spine - manage as per thoracic spine trauma
  • presenting features suggestive of aortic dissection or abdominal aortic aneurysm (AAA) (eg. severe pain radiating to back which is not clearly biliary, or hypotension)
  • acute neurology - spinal precautions and emergent imaging
  • fever or sepsis - manage as per sepsis / septicaemia and search for cause
    • tender abdomen - consider abdominal CT scan if not biliary (in which case fasting biliary USS may be better if time allows)
    • CXR +/- thoracic spine views
    • urinalysis +/- MSU m/c/s
    • if midline vertebral tenderness or neurology - emergent MRI

• emergent MRI scan if
  • clinical features of cauda equina syndrome (CES)
  • unexplained new neurology
  • unexplained pain/neurology in context of coagulopathy/warfarin Rx - may be retroperitonal haemorrhage or a spinal epidural haematoma
  • unexplained raised CRP esp. if IVDU with back pain

• detailed history and exam to search for likely cause and best approach to investigation, in particular:
  • history of the pain and was there trauma?
  • could the patient be pregnant? (this will affect analgesia options, radiology, and raise possibility of PE or ruptured ectopic as causes)
  • is there a history of fevers or chills, cough, SOB, calf pain, dissection risk factors
  • overseas travel
  • VTE risk factors
  • past history tuberculosis (TB), neoplasia / cancer / tumours, recent sepsis / septicaemia, surgery to spine or thorax
  • is there an obvious herpes zoster (shingles) rash, or could it be post-zoster neuralgia
  • where is the tenderness?
  • double check for acute neurology
  • double check it is not referred pain from abdomen
  • urinalysis to exclude acute pyelonephritis, esp. if there is flank tenderness
  • immunocompromised, IVDU or recent staphylococcal infection - consider inflammatory markers

• see sensory & motor testing including dermatomes, myotomes, reflexes, coordination & balance