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For Primary Care| Differential diagnosis

Low Back Pain: What's the Diagnosis?

Dr Simon Somerville Considers Some Possible Causes of Low Back Pain and Explains that Self-management is Key to Improved Quality of Life for Patients

Read This Article to Learn More About:
  • tools that can help stratify a patient’s risk of disability
  • key points about the management of low back pain
  • when specialist care is required.

Low back pain is the commonest cause for years lived with disability.NICE Guideline (NG) 59 on Low back pain and sciatica in over 16s: assessment and management, published in November 2016, recommends a number of changes in the approach to care of patients with low back pain.2 The guideline marks a departure from the traditional classification of back pain by symptom duration (acute, sub-acute, and chronic) and instead states that the risk of poor outcome at any time point is almost always more important than the duration of symptoms. Perhaps the biggest difference in NG59 is the move away from passive treatments such as medication and injections to a more active approach involving activity promotion and self-management.2 It can be difficult to pick out clinically who is at increased risk of ongoing disability; however, the use of risk stratification tools can help clinicians identify at-risk patients so that they can be referred at an earlier stage for more intensive treatment.

This article presents four case histories on low back pain and discusses the likely diagnosis and how to manage the problem, reflecting the key messages from NG59.

Case 1

A 37-year-old teacher presents with acute onset low back pain after lifting a desk at work 2 weeks ago. She is finding walking and sitting difficult and painful, which is preventing her from working, but is reasonably comfortable at rest. She has no leg pain, no urinary or bowel symptoms, and is otherwise well with no significant past medical history. You find tenderness of her paraspinal muscles, a straight-leg raise (SLR) is negative, and lower limb neurological examination is unremarkable.


From the clinical presentation, this is likely to be non-specific low back pain (NSLBP), the key features of which are:3

  • no previous medical history of note or presence of ‘red flags’ that might point to a serious spinal pathology (see Box 1)
  • no leg pain that might suggest sciatica.
Box 1: Red Flags for Serious Potential Pathology4

It should be noted that the red flags do not perform well as predictors of serious disease and use of clinical judgment is paramount in interpreting them. There are several different examples of lists, but a memorable version is ‘TUNAFISH’:

  • Trauma
  • Unexplained weight loss
  • Neurological symptoms
  • Age <20 or >55 years old
  • Fever
  • Intravenous drug abuse
  • Steroids
  • HIV.


Most patients with NSLBP make a good recovery and can be managed with confidence in primary care. There are, however, some patients whose symptoms persist and NG59 recommends considering the use of a risk stratification tool, such as STarT Back (SB),5,6 to identify such patients so that they can be referred for more intensive treatment at an earlier stage.2 In Case 1 above, the SB score indicated that the patient was at low risk of ongoing disability and that referral was not necessary.

The key points for management are:2

  • advice­—explain that although the patient is currently experiencing pain, it is very unlikely that she will have developed an ongoing back problem, and that you expect her pain to improve significantly over the next few weeks. Reinforce this message with an appropriate patient leaflet
  • activity—explain that it is important to resume normal activities as soon as possible and to avoid prolonged rest. In the author’s experience, it is best practice to reassure the patient that ‘hurt does not mean harm’ and to expect some discomfort with exercise
  • work—advise that the best approach is to remain at work if possible but to ask for amended duties, which can be supported with a fit note
  • medication—a non-steroidal anti-inflammatory drug or alternatively a weak opioid (with or without paracetamol) may help with pain, but the main objective is to support return to activity


With the aid of an informative fit note the patient was able to return to work with reduced hours and fewer duties. This gave her the chance to do the back exercises recommended by the patient advice leaflet provided by her GP. Two weeks later she returned to teaching a full timetable.

Case 2

A 45-year-old man presents with low back pain and left leg pain radiating down to the foot. He describes the pain as burning and tingling. He has tried taking ibuprofen but it has not helped. There are no features of cauda equina syndrome. His SB score indicates a medium risk of disability. You find that SLR is reduced on the affected side and he has an absent ankle reflex, but otherwise the myotomes are preserved.


The diagnosis here is likely to be sciatica. Compression or irritation of the sciatic nerve leads to typical neuropathic-type pain. The SLR test is positive if it increases the leg pain rather than the back pain.7


Sciatica can be managed, at least initially, in the same way as NSLBP (described in Case 1); however, it often does not respond to simple analgesia, so it is appropriate to offer specific neuropathic pain medication. NICE Clinical Guideline 173 on Neuropathic pain in adults recommends trying the following therapies in any order: amitriptyline, duloxetine, gabapentin, or pregabalin according to patient profile, tolerability, and effectiveness.8 Tramadol should be considered only if short-term rescue therapy is needed.8

The decision to use medical imaging techniques (most commonly magnetic resonance imaging [MRI]) should be made in a specialist setting only where the result is likely to alter management. Therefore, rather than request a scan in primary care, it is a better option to consider referral according to the local spinal pathway.

Failure of conservative management (i.e. non-surgical treatment options) or severe pain levels are indicators for the spinal specialist to consider an epidural injection, but only in the first 3 months.2,3 It is important to realise that epidurals act as short-term pain relief and do not affect the natural history. A surgical opinion about possible decompression is another valid option in the case of failure of conservative management.2


The patient was referred to physiotherapy as his SB medium-risk score suggested a referral for additional treatment was appropriate. He made slow but steady progress over 8 weeks. After this his leg pain had reduced significantly but he continued to have low back pain for the next year. He found both walking and pilates to be helpful in managing his pain, and this will hopefully prevent recurrence of his sciatica.

Case 3

A 52-year-old woman comes to see you about her chronic low back pain, which has significantly affected her quality of life, including her ability to work. Her medical notes show that over the years she has been seen and investigated on several occasions by rheumatology and orthopaedic specialists. She has other co-morbidities including chronic obstructive pulmonary disease and hypertension. After examining her you decide that her clinical picture has not changed. She is clearly distressed and you find on using the SB tool that she is at high risk of disability.


Chronic low back pain can be challenging for the affected individual and the healthcare professional(s) treating them. An assessment should take a biopsychosocial approach, which considers the interaction of physical, psychological, and social factors that shape how chronic back pain affects the individual. This information can then be used to focus management on the factors identified, with the aim of reducing the impact so that the person can ‘live well’ with their problem. A biopsychosocial assessment should cover:

  • a review of the patient’s history—could pathology have been missed?
  • consideration of what other factors might be at play:9
    • distress
    • depression
    • social and work issues.


There is often pressure on practitioners to prescribe ever-increasing strength analgesia. Opioids are no longer recommended for chronic back pain due to lack of efficacy and attendant risks of dependency and side-effects.2 A supportive biopsychosocial approach is the mainstay of management, particularly in this case given the high SB score, and aims to support the patient in managing their long-term condition.2


It was a difficult consultation and although the patient appreciated that you had listened to her story, she remained distressed and keen to pursue treatment options. You were, however, able to help her understand that referring her back to the same specialities was unlikely to lead to a different outcome. Instead you referred the patient to a multidisciplinary biopsychosocial rehabilitation (MBR) service, who were better equipped to help address all the biopsychosocial issues affecting her.

Multidisciplinary biopsychosocial rehabilitation services may not currently be available to all GPs; however, NICE Quality Standard 15510 states that commissioners should ensure that the services they commission for back pain have an approach to risk stratification, and so MBR services should become available in the future. Until then, consider using local physiotherapy services, which may already have staff trained in this approach.

Case 4

A 29-year-old man comes to see you with a 3-year history of low back pain. He has seen a number of your colleagues over the years but no specific diagnosis has been made. He describes that his back is very stiff in the morning, but the stiffness eases off with activity. Recently he has also developed pain in the buttocks. He has a history of psoriasis, but is otherwise well.


The patient’s clinical history (presence of back pain for more than 3 months, pain with an inflammatory pattern [worse after rest, easier with exercise], buttock pain, and history of psoriasis) points to possible ankylosing spondylitis (AS) or other inflammatory arthritis.11 It can be difficult to diagnose AS, and diagnostic delays of 8–11 years from the initial onset of symptoms are typical.12

See NG65 on Spondyloarthritis in over 16s: diagnosis and management for further details about referral for suspected AS.11


The most important thing is to refer the patient to a specialist to confirm the diagnosis. It is, however, appropriate to request a full blood count, erythrocyte sedimentation rate, and C-reactive protein to accompany the referral. These tests can produce normal results in people with AS, and therefore normal values should not be used to rule out AS.11


The patient was seen by a rheumatology specialist and an MRI scan of the sacro-iliac joints appeared normal, as is often the case with AS. However, given the clinical presentation and rapid response to treatment with NSAID within 48 hours, the specialist concluded that AS was highly likely. The specialist arranged physiotherapy for the patient as back exercises are an important part of management.11 Ankylosing spondylitis can significantly affect quality of life, and it is good practice to direct the patient towards sources of support, such as the National Ankylosing Spondylitis Society (

The specialist arranged ongoing follow up in secondary care as some patients require treatment with disease-modifying anti-rheumatic drugs (DMARDs) and/or treatment for osteoporosis. People with AS are more likely to develop cardiovascular disease, so primary care has a definite role in the assessment and management of cardiovascular risk factors for this patient group.2


Low back pain presents a considerable challenge to patients, healthcare systems, and society in general. The most recent NICE guideline on back pain, NG59, represents the paradigm shift needed to address this issue. Rather than focusing on passive treatments with little evidence of efficacy, it is better for practitioners to support and encourage patients to self-manage, especially in cases where the condition is chronic.

Dr Simon Somerville

GPwSI musculoskeletal medicine, Staffordshire

GP researcher, Arthritis Research UK Primary Care Centre, Keele University

Member of the Guideline Development Group for NICE Guideline 59