Assessment

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A thorough and structured initial history and physical examination is required to identify patients at risk of significant pathology that should prompt early senior doctor involvement and further investigation. Below is a list of red flag indicators that must be evaluated in the patient history and examination to alert us to potential serious diagnoses. If any of the red flag findings are identified, senior doctor input must be sought urgently to guide patient management and analgesia should be prescribed (see acute low back pain - treatment). The absence of red flag findings does not always exclude serious pathology.

Red Flags

• History of cancer
• Unexplained weight loss
• Severe pain when supine and/or at night
• Age <16 or >50 years
• History of significant trauma
• Intravenous drug abuse
• Recent bacterial infection or fever
• Immune suppression (HIV, transplant, corticosteroids)
• Saddle anaesthesia
• Bladder dysfunction (urinary retention or incontinence)
• Bowel dysfunction (faecal incontinence)
• Neurological deficit in either or both lower limbs (especially if progressive)
• Persistent symptoms for >4 weeks (recurrent presentations, worsening pain)
• Pregnancy
• Representation

After initial assessment it may be helpful to classify your patient into 1 of 4 broad categories to guide your decision making and management:

• Back pain with any red flags
  • Urgent senior doctor involvement required as described above.
• Back pain with associated radiculopathy
  • These patients have historical evidence of ‘sciatica type’ pain that radiates to either buttock or leg with no neurological abnormalities, indicating nerve root involvement.
  • Dermatomal distribution (9) of the pain may reflect the nerve routes involved.
  • Although the vast majority of these patients will experience symptomatic improvement or resolution within a month with appropriate analgesia and physiotherapy, earlier or more frequent re-evaluation by a general practitioner or spinal surgeon is advised.
• Non-specific musculoskeletal causes
  • More than 85% of patients who present to ED with low back pain will have no specific cause found and will recover symptomatically within a month with appropriate analgesia and physiotherapy.
• Back pain from a non-spinal cause
  • This category can be further subdivided into:
  • Non-spinal conditions requiring urgent attention. Early senior doctor involvement to expedite diagnosis and definitive management (e.g. suspected ruptured AAA or those conditions bolded above – (see causes of acute low back pain).
  • Non-spinal conditions requiring acute attention. The management of these conditions will not be discussed here, but will require appropriate care for the likely diagnosis (e.g. pyelonephritis or those conditions not in bold font above - (see causes of acute low back pain).

History

The history should aim to gather pertinent information to aid your diagnosis and guide management addressing the following key areas:

• Red flag symptoms (see above).
• Precipitating factor assessment (e.g. manual labour, heavy lifting, sudden movements etc.).
• Pain assessment (see below).
• Thorough neurological assessment.
• Thorough systems review to identify non-spinal causes of back pain (e.g. urinary frequency and dysuria preceding flank pain in pyelonephritis).
• Psychosocial history:
  • Alcohol and drug history
  • Work related injury and work duties
  • Emotional state – psychological distress such as depression, anxiety and job dissatisfaction are predictors for poorer outcomes and longer symptom duration.
• Don't forget to assess for Yellow Flags

Examination

Physical examination should further identify any red flag signs, any signs of non-spinal causes of back pain, any evidence of neurological or nerve root involvement and the severity of the symptoms.

• Red flag signs (see above).
• Fever.
• Signs of shock – tachycardia, hypotension.
• Mobility assessment:
  • Gait
  • Sit-to-stand, bed mobility, stairs.
• Straight leg raise testing(10)
  • Moderate sensitivity and positive predictive value for diagnosing herniated intervertebral disc.

Source: http://www.rheumatologynetwork.com/articles/10-minute-examination-low-back-pain/page/0/3

• Spinal examination:
  • Spinal range of motion – flexion, extension, lateral flexion and rotation
  • Palpating spinous processes for local pain and exacerbation of symptoms.
• Full lower limb neurological examination including:
  • Tone, power, sensation (pin prick and temperature) and reflexes
  • Bladder palpation (or bladder scan) and assessing for saddle anaesthesia.
• Systems review and examination to identify non-spinal causes of back pain.

Pain Assessment

An accurate pain assessment is essential during the medical evaluation of acute low back pain and can provide vital information to assist diagnosis and guide management. Some specific considerations when assessing the patient with acute back pain are listed below:

• Severity

Figure - National Institute of Clinical Studies (2011) Emergency Care Pain Management Manual

Pain Score Severity

• No pain = Pain Score of 0
• Mild pain = Pain Score of 1-3 (mild distress)
• Moderate pain = Pain Score of 4-6 (moderate distress)
• Severe pain = Pain Score ≥ 7 (severe distress - red flag)
• Radiation

Back pain with radiation to either buttock or leg indicates nerve root impingement due to a herniated intervertebral disc or lumbar spinal stenosis. On occasions you may get non-dermatomal referral patterns associated with back pain and this may or may not be nerve root associated pain^(9,11)

• Aggravating factors

Pseudoclaudication is the onset of leg pain during exercise or standing that is relieved by sitting or lying down in the absence of peripheral vascular disease. It is indicative of lumbar spinal stenosis.

• Duration

More serious spinal pathology is associated with pain that lasts for more than 4 weeks in duration or becomes acutely worse after a period of improvement (with appropriate management and no new aggravating factor).

Beware of the repeat ED presenters during the same episode of back pain!

• Analgesia history

Has the patient taken any analgesia?

If not – why not?!

If so – what drug, what dose, when, how often and what were the effects?

• Ankylosing spondylitis

This autoimmune condition is associated with a specific type of low back pain presentation that should alert the clinician to the diagnosis. Ankylosing spondylitis should be suspected in any patient who presents with the following symptoms so an early diagnosis can be made before the development of radiological abnormalities:

• Morning back stiffness
• Improved back pain / stiffness with exercise
• Alternating buttock pain (left and right)
• Awakening during the night due to back pain
• Younger age.

For a complete guide to emergency care acute pain management please click here.

Investigations

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Imaging

The vast majority of patients presenting to the ED with acute low back pain will require no imaging at all. Routine imaging is not indicated in patients presenting to ED with non-specific low back pain. Of the patients who require imaging only a minority require inpatient investigation with the remainder able to have imaging deferred until after a trial of analgesia and physiotherapy.

This is of particular concern when we consider that a single lumbar spine x-ray (2 views) or CT lumbar spine is equivalent to 100 and 250-500 chest x-rays respectively.

According to the RANZCR guidelines for medical imaging in acute low back pain the only recommended imaging modalities of the lumbar are x-ray and MRI, unless a vertebral fracture is the main or sole diagnosis in question (e.g. trauma) or an MRI is contra-indicated (e.g. pacemakers)

Below is an overview of the recommended imaging modalities in acute low back pain:

Urgent Imaging Recommended – Magnetic Resonance Imaging (MRI)

• Major risk factors for cancer

History of active cancer with back pain.

• Risk factors for or signs of cauda equina syndrome

Urinary retention, faecal incontinence, saddle anaesthesia.

• Risk factors for spinal infection

Fever, IVDU, recent infection, recent invasive procedure, elevated ESR, CRP or WBC, with high clinical suspicion in an at risk patient (immunocompromised, corticosteroids).

• Severe neurological deficits

Progressive motor weakness, motor deficits at multiple neurological levels.

If an MRI is contra-indicated or unavailable and the above diagnoses are suspected a CT lumbar spine may be indicated after discussion with a neurosurgeon and radiologist.

Imaging Recommended – CT Lumbar Spine

• Vertebral fracture suspected with significant trauma.

Imaging Recommended – X-ray Lumbar Spine

• Vertebral fracture suspected in:
  • Osteoporotic bone (elderly, corticosteroid use) with minimal or no trauma
  • Female (limit radiation).

Deferred Imaging until after a trial of therapy – MRI

• Risk factors for or signs of ankylosing spondylitis

See acute low back pain - assessment.

• Minor risk factors for cancer

Unexplained weight loss, age > 50 years, haematocrit 100.

• Risk factors or symptoms of spinal stenosis

Risk factors as listed above and patients are also a candidate for surgery.

• Signs and symptoms of radiculopathy
• Persistent back pain after 1 month of therapy

These patients will require imaging but not emergently.

No Imaging

• Previous imaging with no change in clinical status.
• No criteria for immediate imaging, less than 1 month of therapy.

RANZCR imaging decision flow chart for acute low back pain (Page 10 in below link).

For the RANZCR education module regarding current recommendations for imaging in acute low back pain please click here.

Pathology

A select group of patients will require pathology testing to assist with diagnosis and management. These requirements must be assessed on an individual patient basis.

• FBC – suspected infection, malignancy, non-spinal cause of back pain.
• ESR – suspected infection, malignancy, ankylosing spondylitis.
• Bloods cultures – febrile and suspected infection.
• Coagulation studies – neurosurgery anticipated.
• Other pathology tests including UECs, LFTs, lipase, urinalysis etc. should be considered when suspecting a non-spinal cause of back pain.

Treatment

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Pharmacological Treatment

It is essential that a clear analgesic plan is documented in the patient notes or discharge summary, prescribed on a medication chart or discharge prescription and communicated with medical staff, nursing staff, the patient and his/her carer.

¹ Caution with non-steroidal anti-inflammatory drug prescription in elderly (>75years), renal dysfunction, peptic ulcer disease, asthma.

Alternatively a COX-2 (cyclooxygenase 2) inhibitor may be used. Caution in patients with congestive cardiac failure in addition to the above cautions.

² Reduce dose to Oxycodone 2.5mg, orally, q4-6h, in elderly, > 75 years

• Neuropathic Pain

Neuropathic agents are not routinely prescribed for patients with a new presentation of acute low back pain.

Consider prescribing a medication for treating neuropathic pain in those who have pain refractory to standard analgesia (> 4 weeks) or are experiencing a considerable radicular component to their pain. These patients should have had imaging done or organised and a referral pathway commenced to investigate their pain.

Start at a low dosage and increase the dose incrementally until therapeutic effect is achieved (up to the maximum dose) or unacceptable side effects prevent further use. One example is:

Gabapentin – 100-300mg, orally, nocte; increase dose gradually over 3-7 day intervals according to response; usual range 1.8-3.6g daily in 3 divided doses

• Benzodiazepines

The routine use of benzodiazepines in the management of acute back pain is not recommended. However, for a select group of patients a small dose of oral diazepam (e.g. 2.5-5mg daily) may be prescribed for the sedative effects only, in the first 24-48 hours. Be aware and tell your patients that it does not change the pain but may make them feel better about it!

• Proton Pump Inhibitors (PPI)

Consider prescribing a PPI in those patients prescribed regular NSAIDs aged > 45 years or with a history of gastro-oesophageal reflux disease.

Non-Pharmacological Treatment

Before offering non-pharmacological therapies to patients who present to ED with acute low back pain, ensure their condition and in-particular their spine is stable. Any patient presenting with red flags should receive pharmacological treatment only, until they have been reviewed by a senior doctor.

Patients who have a confirmed diagnosis of non-specific mechanical back pain and those with symptoms of back pain with radiculopathy or spinal stenosis, have been proven to benefit from early integration of non-pharmacological therapies into their management plans. Examples of such therapy modalities include:

• Encourage early mobilisation and remaining physically active
• Early physiotherapy referral
  • Consideration of individually tailored structured exercise programmes
  • Aerobic activity
  • Movement instructions
  • Muscle strengthening
  • Postural control
  • Stretching
• Manual therapy (not recommended in the first 48 hours)
  • Spinal manipulation
  • Massage
  • Spinal mobilisation
  • Such therapies can be performed by physiotherapists, osteopaths or chiropractors
• Consider referral for a combined physical and psychological treatment programme to those with significant pre-existing disability or psychological distress

Other Treatment Options

• Nerve Root Injection

A CT guided lumbar or sacral nerve root or facet joint injection is not routinely offered to patients who present to ED with acute low back.

Nerve root injections are offered to patients with spinal stenosis or radicular pain from a prolapsed intervertebral disc, who have persistent and significant pain, despite completing an optimal combined physical and psychological (if required) treatment programme.

A small number of patients with the above conditions may present with severe symptoms that are refractory to standard treatment. After appropriate imaging and consultation with a spinal surgeon, this small group of patients may be referred for an in-patient CT guided nerve root injection.

• Surgery

Any patient presenting with red flag signs or symptoms will almost certainly require a spinal surgical referral after senior ED doctor review. Some patients will require a more urgent referral than others, for example those with signs of cauda equina syndrome (urinary retention, faecal incontinence, saddle anaesthesia) need an urgent referral. This process will be guided by the senior doctor.

The majority of patients presenting to ED with acute low back pain will not require surgery. Referral to a spinal surgeon should be reserved for patients who still have significant pain having completed an optimal treatment programme.

Disposition

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Admission

Any patient presenting with red flag signs or symptoms will require a hospital admission whilst appropriate investigations and management plans are implemented. Senior ED clinician review is essential to ascertain the most appropriate admission pathway. For example, if red flags are present but the senior doctor has a low index of suspicion of serious pathology, it may be appropriate to admit the patient to an ED short stay unit (EDSSU) or medical ward whilst investigations are pending. However, if there is immediate concern for significant spinal pathology, urgent spinal surgical referral with expedited investigations is imperative.

Patients presenting with acute non-specific low back or back pain with sciatica symptoms only, who fail an initial trial of therapy in the ED may require a brief hospital admission. Such failure of therapy may include ongoing pain despite adequate analgesia or poor mobility despite efforts and encouragement for early mobilisation.

The vast majority of these patients can be safely admitted to an EDSSU or medical ward and will experience sufficient symptom improvement to be discharged within the next 24 hours, if an appropriate management plan has been implemented. For the minority of patients who have ongoing symptoms negating safe discharge; re-evaluation with appropriate investigation and spinal surgery referral is required.

Discharge

Patients with no red flag criteria or those who have had serious pathology ruled out by appropriate investigations and review may be considered for discharge. Pain must be adequately controlled and they must be able to mobilise safely and independently. Social factors must also be considered including ability to climb stairs if required and necessary family or carer support.

Patient Education

Patient and carer education is paramount is ensuring successful and timely recovery. A patient factsheet should be provided. Key areas to discuss with the patient include:

• Recovery

Likely substantial recovery within 4 week with a favourable prognosis

Concerning signs and symptoms (red flags) that should prompt re-presentation

Advice regarding activities to avoid that will hinder or delay recovery

• Pharmacological Therapy

A clear explanation to the patient is required (verbally and documented). Which medications to take, how many and how often. Provide a patient factsheet to explain this.

If you assume your patient has never taken a medication before and has no previous experience managing pain you won’t go wrong!

Provide adequate prescriptions for your patient. If they present in the evening or night ensure they have an appropriate ‘take home’ pack to get them through the night.

• Non-pharmacological Therapy

Ensure physiotherapy referrals have been made or appropriate information has been provided to the patient to arrange their own physiotherapy appointment. Early mobilisation and exercise is key to their recovery.

Physiotherapy is the preferred referral process and should be encouraged, but individual preference for an osteopath or chiropractor can be accepted as an alternative.

Appropriate psychological follow-up (via the general practitioner) is encouraged when required.

• Work Cover

Ensure all relevant documentation is completed by the medical practitioner if this is a work related injury.

Discharge Letter

The discharge letter should be completed including the relevant clinical information, investigations and discharge plan specifics as stated above.

Acute Low Back Pain Patient Factsheets

Provide the patient with the above acute low back pain patient factsheet.

Follow-up

All patients who are discharged from ED after an episode of acute low back pain should follow-up with a physiotherapist (osteopath or chiropractor if the patient prefers) within the next week. However, the sooner the better, to re-enforce the exercises and strategies taught whilst in the ED.

Most patients who are discharged from ED after an episode of acute low back pain will not require medical follow-up. Exceptions to this include:

• Development of any red flag signs or symptoms – represent to the ED emergently
• Sudden deterioration in symptoms during recovery
• No improvement in symptoms despite appropriate recovery management plan
• Persistent symptoms for > 4 weeks
• Consider GP review within 4 weeks if radicular or sciatica pain is significant or not improving
• Work related injury – require a GP or specialist review within 72 hours of injury.