Acute low back pain part 1 clinical assessment - Issue 7 (Feb 2004)

Issue 7 February 2004

General points

exclusion of cauda equina syndrome and other risk factors for serious disease or trauma (Red Flags) is essential at the initial clinical assessment
giving patients a clear message about the natural history of pain without the use of inappropriate labels that may cause anxiety or fear of activity are important
in the absence of Red Flags, investigations such as MRI, X-rays and CT scans in the first 4-6 weeks are inappropriate
ongoing assessment is required to identify patients whose recovery may be impeded by psychosocial (Yellow Flags) or other co-morbid factors

Background

Acute low back pain (ALBP) affects many New Zealanders. Although, in a few cases there may be a serious cause that requires urgent referral or more in depth investigation, most acute episodes are characterised by non-specific pain and precise diagnosis is not possible or necessary. ALBP is classified as an episode that lasts less than three months and chronic pain as episodes extending beyond three months. After an acute episode there may be persistent or fluctuating pain for a few weeks or months. Prompt effective assessment and management will reduce the likelihood of a chronic pain syndrome developing. The aim of initial assessment is to exclude Red Flags, particularly neurological deficit that requires urgent specialist management, assess functional limitations and determine clinical management options. Ongoing patient assessment is required to identify patients whose recovery is impeded by external, psychosocial (Yellow Flags) or other comorbid factors. Recently ACC has published an evidence-based ALBP guideline, the recommendations for initial and ongoing assessment are summarised.*

Initial Clinical Assessment

The patient’s history may indicate the need for a more extensive clinical examination, particularly if Red Flags for more serious systemic disease (e.g. cancer) or injury are suspected. It is not usually necessary at the time of the initial clinical assessment to screen for psychosocial factors unless problems with the patient's response to pain, or barriers to recovery are evident. The initial assessment should, via a careful and thorough patient history, identify and determine:

any risk factors for serious disease (Red Flags)
the history of the acute episode
activities that may be associated with pain
how limiting the symptoms are
if there have been similar episodes before
any factors that might limit recovery and early return to usual activities, including paid work (this includes assessing possible Yellow Flags)
the level of activity required for return to normal work, recreation and daily living activities.

Risk of serious disease or injury (Red Flags)

Red Flags and/or abnormal test results may be indicative of serious physical disease or injury and the need for urgent referral to an appropriate specialist or at least fuller investigation.

Neurological deficit and cauda equina syndrome

Significant neurological deficits require urgent referral for specialist management. The most important condition is cauda equine syndrome, a clinical emergency that requires urgent hospital referral. Symptoms for cauda equina syndrome include some or all of urinary retention, faecal incontinence, widespread neurological symptoms and signs in the lower limb, including gait abnormality, ‘saddle area’ numbness and a lax anal sphincter.

Other Red Flags

Other Red Flags for serious disease or injury include:

significant trauma
history of cancer
weight loss
intravenous drug use
fever
patient aged >50 years
severe, unremitting night-time pain
steroid use
pain that gets worse when lying down

Red Flags such as severe pain at night or weight loss should lead to full investigation and/or referral even if test results are normal. Some patients will describe a trauma that may have caused a serious bony or soft tissue injury (e.g. fracture or dislocation) requiring appropriate investigation or specialist opinion.

Patient reassurance

It is important that the patient is given a simple and clear explanation about the natural history and diagnosis of non-specific ALBP. Inappropriate labelling of pain that promotes medicalisation in the absence of Red Flags should be avoided.

Ongoing Clinical Assessment

Patient follow-up and review is required at appropriate intervals (usually weekly) until symptoms have mostly resolved and normal activity is achieved.

Investigations

In the first 4-6weeks investigations do not provide clinical benefit unless Red Flags are present or surgery is anticipated. A full blood count and ESR should usually be performed only if there are Red Flags. Other tests may be indicated depending on the clinical situation. MRI scans are not indicated for early non-specific ALBP. Radiological investigations (X-rays and CT scans) can cause harm from radiation-related effects and should be avoided unless necessary. Many people without symptoms show abnormalities on X-rays and scans. The chances of finding coincidental disc prolapse increase with age. It is important to correlate MRI findings with age and clinical signs before advising surgery.

Psychosocial barriers to recovery (Yellow Flags)

At follow-up the need to screen for psychosocial factors should be considered if there are problems noted with the patient's response to pain or recovery. The goal is to identify factors that increase the probability of long-term disability and work loss and areas where specific intervention is required. The following factors are predictive of poor outcomes:

Belief that back pain is harmful or potentially disabling
Fear-avoidance behaviour and reduced activity levels
Tendency to low mood and withdrawal from social interaction
Expectation of passive treatment(s) rather than a belief that active participation will help

Reference

*The full guideline “New Zealand Acute Low Back Pain Guide, Incorporating the Guide to Assessing Psychosocial Yellow Flags in Acute Low Back Pain” June 2003 (including references and evidence tables) can be obtained at www.nzgg.org.nz.