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Acute back pain

Last updated: June 21, 2021

Summarytoggle arrow icon

Acute back pain, typically defined as lasting less than 4–6 weeks, is experienced by most adults. The majority of cases are benign, nonspecific back pain (pain that is not attributable to a specific pathology). Spinal causes of acute back pain are conditions of the spinal column or surrounding muscles and soft tissue. Spinal causes include conditions that require urgent management to prevent or minimize permanent neurological dysfunction (e.g., spinal cord compression, spinal infections) and nonurgent causes (e.g., inflammatory arthritis, bone metastases without cord compression or unstable vertebral fracture). In rare cases, back pain may be referred pain resulting from thoracic, abdominal, pelvic, retroperitoneal, or cardiovascular causes. Serious and life-threatening nonspinal causes, such as myocardial infarction and aortic pathology, should be considered particularly in patients with abnormal vital signs and no neurological abnormalities. Assessment for red flag features of acute back pain and a focused neurological examination is required in all patients. Initial diagnostics and management should be guided by the pretest probability of the underlying condition. Patients with new neurological findings other than isolated unilateral radiculopathy require immediate imaging, typically MRI, and urgent spinal surgery consultation. Neurologically intact patients without red flags do not require urgent imaging and typically improve with nonpharmacological treatment options (e.g., superficial application of heat, massage), symptomatic treatment with NSAIDs, and early mobilization.

  • Up to 8 out of 10 individuals experience low back pain in their lifetime. [1]
  • 2–3% of visits to the ED are for acute nontraumatic back pain. [2]
  • 85% of patients with acute low back pain have nonspecific back pain. [3]
  • Approx. 2% of patients presenting with acute back pain have an underlying etiology that requires urgent management. [3]

Epidemiological data refers to the US, unless otherwise specified.

  • Spinal causes of acute back pain are conditions of the spinal column or surrounding muscles and soft tissue; these can be divided into:
    • Urgent spinal causes: conditions that cause, or have the potential to cause, permanent neurological damage or life-threatening complications
    • Nonurgent spinal causes: conditions that require specific (but not immediate) treatment
  • Nonspinal causes include thoracic, abdominal, pelvic, retroperitoneal, or cardiovascular conditions that can manifest with referred pain to the back.

Red flag features on history or clinical examination should guide further diagnostics. Patients with no red flag features and normal neurological examination are unlikely to have a serious underlying etiology. Patients with red flag features but normal neurological examination are unlikely to need urgent spinal surgery. [2]

Common red flags for acute back pain [2][3][4]
Features
Patient characteristics
Relevant medical history
Medication use
Pain characteristics
  • Pain that does not improve with rest and/or worsens at night
  • Persistent or progressive pain and/or neurological findings despite > 4 weeks conservative therapy
Examination findings

Hypertension, hypotension, and/or tachycardia in a patient with a normal neurological examination should raise suspicion for an urgent nonspinal pathology. Hypotension and bradycardia in a patient with signs of spinal cord compression are likely indications of spinal shock.

Focused history and clinical examination [4][9][10]

Assess for red flag features of acute back pain in all patients. A thorough neurological examination is essential to adequately triage patients who need urgent imaging and neurosurgery consult.

Administer analgesics (preferably NSAIDs) after baseline neurological function and pain severity are documented (see “Pain management”). [2][10]

Because irreversible damage to the spinal cord occurs within 6 hours of compression, a thorough neurological examination is essential to detect damage early and minimize long-term disability. [11]

Pretest probability of the underlying etiology [9][10]

Estimate the pretest probability (PTP) of the underlying etiology based on the patient history and clinical features.

Pathological fractures, bone metastases, or referred pain (e.g., myocardial infarction, abdominal aortic aneurysm, aortic dissection) are more likely in older individuals with acute back pain.

Suspect inflammatory arthritis (detailed in “Nonurgent spinal causes of acute back pain”) in young adults with back pain that does not improve with rest or medication and/or worsens at night.

Suspect spinal epidural abscess or vertebral osteomyelitis (detailed in “Urgent spinal causes of acute back pain”) in patients with acute back pain, fever, and risk factors for spinal infections.

Approach to imaging [12][13]

Imaging is not routinely required for acute back pain. Indications for imaging include suspicion for a serious underlying etiology (e.g., severe or progressive neurological findings, red flag features of underlying malignancy or spinal infection) or pain that persists despite at least 4 weeks of conservative management.

Approach to imaging in acute back pain
See the relevant sections below for information on preferred initial imaging modalities and alternatives for specific suspected etiologies.
Suspected spinal causes Isolated radiculopathy, no red flag features for acute back pain
  • Urgent imaging is typically not required.
New or rapidly progressive neurological symptoms
Suspected vertebral fracture (traumatic/pathological)
or ankylosing spondylitis in a patient with no neurological symptoms apart from isolated radiculopathy

Suspected nonspinal causes

Nonspecific back pain

Nonspinal causes of back pain can be life-threatening; consider alternative diagnoses such as abdominal aortic aneurysm!

In the acute setting, imaging is not indicated when no red flags for back pain and no neurologic deficits are present. [10]

Laboratory studies

Laboratory studies are not routinely required for acute back pain. Consider obtaining laboratory studies based on the presence of red flag features for acute back pain. Examples include:

Immediate management of back pain with new neurological symptoms [2][3][8]

  • Obtain urgent spinal surgery or neurosurgery consult (e.g., for surgical decompression).
  • If there is concern for unstable vertebral fractures :
  • All other suspected causes: Order urgent MRI or transfer to an appropriate facility.
  • Clearly document the patient's current neurological deficits and reassess frequently. [15]
  • Administer analgesics (preferably NSAIDs) after baseline neurological function and pain severity are documented (see “Pain management”). [2][10]
  • Catheterize patients with bladder dysfunction.
  • Patients with neurological abnormalities are at high risk of pressure sores: See “Prevention” in “Decubitus ulcer.”

Spinal boards should only be used for transport; remove patients from them on arrival at the hospital to reduce pain and prevent the development of pressure ulcers!

Urgent spinal causes include conditions that cause, or have the potential to cause, permanent neurological damage or life-threatening complications. Patients with significant new neurological findings (e.g., bilateral neurological abnormalities, bladder or bowel dysfunction, saddle anesthesia) should be managed as an urgent priority to prevent worsening of spinal cord injury or the development of complications. [2]

Urgent spinal causes of acute back pain [8]
Common etiologies Characteristic clinical features Diagnostics [14] Acute management
Spinal cord compression [8]
  • Preferred initial imaging modality: urgent MRI with or without IV contrast
  • Alternative: CT myelography; similar findings to MRI

Conus medullaris and cauda equina syndrome [18]

  • Urinary catheter if the patient has retention
  • Urgent neurosurgery consult for surgical decompression.

Vertebral fractures [19]

Spinal epidural abscess

Vertebral osteomyelitis [25]

Spinal epidural hematoma [27]


Acute spinal cord compression is a surgical emergency. Obtain immediate MRI or CT myelography, give IV steroids for malignant compression, and decompress the cord (e.g., with surgery) as soon as possible!

Acute urinary retention in a patient with sudden back pain and neurological deficits is strongly suggestive of cauda equina syndrome (90% sensitivity). [10]

Patients with unilateral neurological symptoms resulting from radiculopathy do not require urgent spinal surgical management.

Nonurgent spinal causes refers to conditions that require specific (but not immediate) treatment.

Nonurgent spinal causes of acute back pain
Common etiologies Characteristic clinical features Diagnostics [14] Treatment

Spinal stenosis [30][31]

  • Risk factors: older patients (> 60 years of age)
  • Clinical features
    • Pain in buttocks and legs that worsens on walking or standing (neuropathic claudication)
    • Pain improves on sitting or bending forward
    • Low back pain (not always present)
    • Wide-based gait
    • Thigh pain after 30 seconds of lumbar extension

Intervertebral disk herniation [32]

  • Conservative
    • Continuation of activity (no bed rest)
    • NSAIDs
  • Surgical decompression: in cases of severe/progressive neurological deficits or evidence of spinal cord compression

Spondylolisthesis [35][36]

Bone metastases [3]

Inflammatory arthritis
(ankylosing spondylitis, reactive arthritis, psoriatic arthritis)

  • Risk factors: typically occur in teenagers and adults aged 20–40 years [3]
  • Clinical features
    • Pain mostly at rest
    • Symptoms improve with activity. [3]
    • Restricted spinal mobility (e.g., on Schober test)
    • Extra‑articular symptoms may be present.

Nonspinal causes of back pain include thoracic, abdominal, pelvic, retroperitoneal, or cardiovascular conditions that can manifest with referred pain to the back.

Nonspinal causes of acute back pain
Common etiologies Characteristic clinical features Diagnostic findings Acute management

Abdominal aortic aneurysm (AAA) [44]

  • Laboratory studies: Routine tests may show signs of hemorrhage in ruptured AAA.
  • Preferred initial imaging modality (only indicated in stable patients) : ultrasound abdomen [46]
    • Dilation of the aorta ≥ 3 cm
    • AAA rupture: periaortic fluid and intraabdominal free fluid
    • AAA thrombosis: intraluminal defect
  • Alternatives: CTA/MRA abdomen and pelvis
    • Similar findings to ultrasound
    • Localization of the ruptured/leaking site

Aortic dissection [48][49]

Retroperitoneal hematoma [51][52][53]

  • Laboratory studies: Routine tests may show signs of hemorrhage.
  • Preferred initial imaging modality: CT abdomen and pelvis with contrast [54][55]
  • Alternative: CTA with IV contrast; detects site of active bleeding [54]

Psoas abscess [56]

Pyelonephritis [59]

Nephrolithiasis
(ureteric colic) [62][63]

  • Treatment depends on the size of the stone.
  • Urgent urology consult in the following:
    • Stone ≥ 10 mm
    • Associated infection and/or obstruction
  • See “Treatment of nephrolithiasis” for details.

Acute pancreatitis [65][66][67]

Acute cholecystitis

[69][70][71]

Nonspecific back pain is one of the most common types of back pain; . It often occurs secondary to muscular or ligamentous strain and usually resolves spontaneously within 4–6 weeks.

Risk factors [3]

  • Obesity
  • Inactivity, smoking
  • Advanced age

Characteristic clinical features [3]

Diagnostics [10][12][13]

  • Not routinely required
  • Consider imaging for pain persisting for > 4 weeks despite conservative management.
  • Imaging findings are nonspecific.

Treatment [3][4][75]

  • Patient education
    • Recommend early mobilization and reassure patients that activity will not worsen their condition. [2]
    • Inform patients that most cases of acute back pain self-resolve in 4–6 weeks.
    • Set realistic expectations: Pain is likely to be improved but not eradicated by treatment.
  • Consider nonpharmacological treatment (e.g., local heat application, massage, spinal manipulation therapy, acupuncture) alone or as adjunctive therapy with pharmacological treatment. [75]
  • Pharmacological treatment

Opioids should only be prescribed if all other treatment options have been unsuccessful!

Prevention

  • Regular exercise
  • Education on how to correctly lift heavy items
    • Squatting down and keeping the back straight
    • Rising from the knees when lifting the load
    • Keeping the load close to the body

Significant trauma related to age [9]

Significant trauma related to age is a red flag feature of acute back pain; examples include:

  • Motor vehicle accidents, direct high-impact injuries, fall from a height in a young, otherwise healthy individual
  • Low-impact injuries, such as a minor fall or lifting heavy weights in individuals with risk factors for fragility fractures

Etiology of traumatic acute back pain

Acute management

Consider imaging the entire spine, as injuries may occur at multiple levels.

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