Common problem w/broad differential. Majority of pts have musculoskeletal or mechanical causes that require only conservative management & most recover naturally. Goal: Identify causes that require further diagnostic workup & intervention.
Exam
General exam: Fever, rash, track marks, cachexia, new cardiac murmur (endocarditis), abdominal bruit (AAA), costovertebral tenderness (pyelonephritis, kidney stone), Grey-Turner or Cullen sign (retroperitoneal hemorrhage; pancreatitis), palpable abdominal mass, peripheral pulses (vascular claudication). Rectal exam for sphincter tone, palpable mass, prostate enlargement.
Spine examination: Inspect/assess deformities, ROM of spine. Palpate for vertebral tenderness, step-offs, paraspinal muscle spasm, paraspinal masses (tumor, TB cold abscess). Hip or SI joint pain: reproduced w/int & ext rotation of hip w/knee flexed (Patrick sign). Straight leg raise: reproduces radicular pain, buttock through posterior thigh; indicates nerve root compression. Crossed straight leg raise: in supine position, raising unaffected leg reproduces radicular pain in affected leg; indicates severe root compression from prolapsed disc. Neuro exam: eval for wkns, sensory loss, saddle or perianal anesthesia, hyper- or hyporeflexia.
Labs: CBC, ESR, CRP (helpful when infxn or malignancy considered). Other labs if indicated: UA, SPEP/UPEP, amylase/lipase, LFTs, Ca, blood cultures.
Neuroimaging: Unnecessary in many cases as pain is most likely 2/2 musculoskeletal etiologies & mild disc herniations & are usually self-limited. Indications: Strong suspicion for underlying systemic process, e.g., cancer or infxn; persistent or progressive neuro deterioration; unresponsive to conservative management for >4 wk; preoperative planning.
MRI: Sensitive & specific for multiple causes of back pain: disc herniation, spinal stenosis, osteomyelitis, discitis, epidural abscess, metastases, arachnoiditis, & myelopathies. MRI w/gado necessary if suspected infxn/inflam/neoplastic process.
CT: Rapid, useful for bony structures & fractures. CT myelogram: Contrast is injected intrathecally into subarachnoid space; eval lesions compressing cord & nerve roots; consider if MRI contraindicated.
Plain films: Rarely definitive; may be useful to assess for fracture & vertebral bony metastases such as from prostate ca; lateral of the LS spine are routine; flexionextension views in surgical fusion procedures or in spondylolisthesis; hip & pelvis when osteoarthritis is presenting as LBP.
EMG/NCS: Help r/o radiculopathy mimics such as plexopathy & entrapment neuropathy. Help localize radiculopathy in potential surg candidates w/multilevel dz or poor correlation between sx, exam, & imaging. Useful in cases w/give-way wkns or when pain limits exam. Usually unnecessary in pts where exam correlates clearly w/lesion on MRI. Pain or sensory sx w/o wkns often has nl EMG/NCS.
Conservative Rx: Indicated for most nonspecific causes of LBP. Key is early intervention.
General measures: Early ambulation, resumption of nl physical activity w/o heavy lifting; discourage bed rest >2 days; avoid activities that promote back pain.
Acute nonpharm Rx: Heat wrap therapy.
Chronic Rx: PT, cognitive-behavioral therapy, interdisciplinary rehab (
Ann Intern Med 2007;147:505); possible role for massage, yoga, acupuncture, spinal manipulation.
Medications:
First line: Acetaminophen, NSAIDs.
Second line: Short-term opioid analgesics, tramadol, benzos. Systemic corticosteroids, topiramate, muscle relaxants use controversial; consider TCAs in chronic LBP (>4 wk) & gabapentin (for radiculopathy) (
Neuromodulation 2014;17(Suppl 2):18-23). Epidural steroid injections may give short-term benefit for radiculopathy.
Prognosis: Most acute back pain resolves spontaneously; continuing poor function, unwillingness to remain active, psychiatric comorbidities, general poor health, & maladaptive coping strategies are predictors of chronicity.
