How to Investigate Back Pain Facilitator notes: These notes aim to provide guidance to facilitators and accompany the presentations. This Back in Focus resource was developed for UK healthcare professionals only, organised and funded by AbbVie. Available to download at: www.axialspabackinfocus.co.uk Date of preparation: August 2017; AXHUR150807w(1)

Back pain: the challenge of differentiation Definitive diagnosis difficult – not made in up to 85%1 The majority of cases are mechanical; ~7% of back pain reported is inflammatory2,3 When does a patient need further investigation/referral to secondary care? Definitive diagnosis difficult – not made in 85%1 Therefore, it is important to identify those patients who require further investigation and to be aware of the appropriate referral pathway Reference: 1. Wong, L L-S. Hong Kong Bulletin on Rheumatic Diseases 2005;5:8–13 1. Wong, L L-S. Hong Kong Bulletin on Rheumatic Diseases 2005;5:8–13. 2 Dillon CF and Hirsch R. Am J Med Sci. 2011 Apr;341(4):281-3. 3. Hamilton et al. Rheumatology 2014;53;161-4

Inflammatory vs mechanical causes of back pain Possible causes of mechanical back pain Possible causes of inflammatory back pain2 Other possible causes of back pain Lumbar muscular strain/sprain1 Degenerative disc disease1,2 Facet arthropathy1 Fracture1,2 Herniated disc1,2 Osteoarthritis3 Congenital disease:2 Severe kyphosis Severe scoliosis Transitional vertebrae Spinal stenosis1 Spondylolysis and/or spondylolisthesis1,2 Axial spondyloarthritis including patients with ankylosing spondylitis (AS) Psoriatic arthritis (PsA)  Inflammatory bowel disease Psoriatic spondylitis Reiter’s syndrome Abdominal aortic aneurysm1,2 Disease of pelvic organs2 Fibromyalgia4 Gastrointestinal diseases2 Infections such as:2 Epidural abscess Osteomyelitis Septic discitis Paraspinous abscess Shingles Paget’s disease of bone2 Renal diseases1,2 Scheuermann’s disease (osteochondrosis)2 Tuberculous sacroiliitis5 Neoplasia2 Malignancy1 In addition to mechanical and inflammatory back pain, it is important to be aware that back pain may in some cases be caused by other conditions including: Tumours Gastrointestinal or renal diseases Infections Inflammatory back pain may be the result of PsA or IBD 1. BMJ. Assessment of Back Pain – Differential Diagnosis (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/differential-diagnosis/by-category.html (Accessed August 2017); 2. Deyo RA and Weinstein JN. N Eng J Med. 2001;344:363–70; 3. Goode AP, et al. Curr Rheumatol Rep. 2013;15(2):305 doi:10.1007/s11926-012-0305-z; 4. NHS Choices. Fibromyalgia – Symptoms (Last updated: March 2016). Available at: http://www.nhs.uk/Conditions/Fibromyalgia/Pages/Symptoms.aspx (Accessed August 2017); 5. Prakash J. J Clin Orthop Trauma. 2014;5(3):146-53.

Investigation and referral considerations Mechanical back pain Inflammatory back pain Red flags Symptoms/suspicions Lower back pain <3 months1 Degenerative disc disease/facet arthropathy2 Compression fracture2 Muscular sprain/strain2 Back pain >3 months1 Morning stiffness1 Good response to NSAIDs1 History of cancer2 Unexplained weight loss2 Significant trauma2 Fever/chills2 Bowel/bladder dysfunction with back pain2 Investigations to consider X-ray (for traumatic fracture only)3 ASAS criteria for IBP4 MRI/X-ray4 HLA-B27 blood test4 Ultrasound/MRI/X-ray/CT2,3 Blood tests: infection/tumour markers (only in a minority of cases)2,3 Urinalysis3 Referral possibilities Physiotherapy (if X-ray shows no abnormality) Orthopaedics Rheumatology Accident and Emergency (A&E) Urology Neurosurgery Different investigations are required for each of mechanical back pain, inflammatory back pain, and red flags The presence of any red flag symptom is an indication for urgent referral to Oncology/Gastroenterology/Urology/A&E as appropriate Red flag symptoms may be the result of any of the following: Abdominal aortic aneurysm Tumours Renal disease Gastrointestinal disease Infection 1. Sieper J, et al. Ann Rheum Dis. 2009;68:784–8; 2. BMJ. Assessment of Back Pain – Differential Diagnosis (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/differential-diagnosis/by-category.html (Accessed August 2017); 3. BMJ. Assessment of Back Pain – Diagnosis Approach (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/step-by-step.html (Accessed August 2017); 4. NICE. SpA in over 16s: diagnosis and management. NG65 (Last updated: June 2017). Available at: https://www.nice.org.uk/guidance/ng65. Accessed: August 2017.

What investigations may assist differentiation? Laboratory analysis Blood tests: FBC (full blood count)1, U&Es (urea & electrolytes), LFTs (liver function tests) CRP (C-reactive protein),2 ESR (erythrocyte sedimentation rate)1 HLA-B27 (human leukocyte antigen-B27)2 Urinalysis:3 Can be done in GP surgery Tumour markers:4 E.g., Ca-125, AFP (alpha fetoprotein), PSA (prostate specific antigen) Imaging3 X-ray Magnetic Resonance Imaging (MRI) Computerised tomography (CT) Ultrasound (US) Laboratory and imaging investigations may be used to aid diagnosis Laboratory investigations (HLA-B27 and CRP) and imaging investigations (MRI) are part of the ASAS criteria for axial SpA1 Reference 1. Rudwaleit M, et al. Ann Rheum Dis 2009; 68:777-783 1. Castro C and Gourley M. J Allergy Clin Immunol. 2010;125(2 Suppl 2):S238–S247. 2. Sieper, J et al. Ann Rheum Dis. 2009; 68:784–8. 3. BMJ. Assessment of Back Pain – Differential Diagnosis (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/differential-diagnosis/by-category.html (Accessed August 2017); 4. Perkins GL, et al. Am Fam Physician. 2003 Sep 15;68:1075–1082.

HLA-B27 8-9% of UK population are HLA-B27 positive1 90-95% of UK patients with AS are HLA-B27 positive2 Useful in diagnosis Study showed that 58% of patients with IBP and HLA-B27 positivity were diagnosed with SpA3 Study showed a sensitivity of 66.1% and specificity of 79.9% for HLA-B27 for diagnosing axial SpA4 Useful for prognosis Study showed that severity of baseline MRI sacroiliitis and HLA-B27 positivity predicted radiographic AS at 8 years5 Study showed that HLA-B27 positivity at baseline had a larger effect of MRI inflammation on radiographic damage at 5 years when compared to HLA-B27 negativity6 HLA-B27 is one of the most predictive criteria for SpA;1 however, do not rule out a diagnosis of SpA solely on the basis of a negative HLA-B27 resullt.2 References: Sieper J, et al. Ann Rheum Dis. 2012;0:1–7 NICE. SpA in over 16s: diagnosis and management. NG65 (Last updated: June 2017). Available at: https://www.nice.org.uk/guidance/ng65. Accessed: August 2017 1. Orchard TR, et al. Aliment Pharmacol Ther. 2008;29:193-7; 2. Sheehan NJ. J R Soc Med. 2004;97:10-4; 3. Brandt, HC, et al. Ann Rheum Dis. 2007;66:1479–84. 4. Sieper J, et al. Ann Rheum Dis. 2012;0:1–7. 5. Bennett, AN et al. Arthritis & Rheum 2008; 58:3413–18; 6. Dougados M, et al. Ann Rheum Dis. 2017;0:1-6.

Radiological investigation of back pain Aim: Rule out serious spinal pathology and significant neurological involvement1 Not necessary in most cases of non-specific lower back pain2 ‘Red flags’ should suggest serious pathology and prompt early referral (not necessarily imaging) Generally detected on preliminary medical history and physical examination Imaging is not necessary in most cases of non-specific lower back pain and rapid improvements in pain and disability are seen within a few weeks to a few months1 However there are certain features or ‘red flags’ which may be the symptom of serious pathology and prompt early referral and additional tests where necessary Reference: 1. NICE. Low back pain and sciatica in over 16s: assessment and management. NG59 (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59. Accessed: August 2017. 1. BMJ. Assessment of Back Pain – Diagnosis Approach (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/step-by-step.html (Accessed August 2017); 2. NICE. Low back pain and sciatica in over 16s: assessment and management. NG59 (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59. Accessed: August 2017.

Lumbar X-ray Lumbar X-ray accounts for 12% of all requests for diagnostic radiology from GPs1 21% of all X-ray requests Limited value to osteoporotic fracture follow-up and post- treatment measurement of alignment and stability in trauma and deformity2 IBP suggestive of inflammatory disease may not always be associated with radiological features3 High rate of false positives4 Unnecessary radiation exposure1 Plain radiography (X-ray) is of limited value as degenerative changes are very common and pathology may easily be missed X-ray will only detect damage resulting from inflammation, but not the inflammation itself Unjustifiable use may lead to unnecessary exposure to potentially harmful radiation 1. Kerry S, et al. Health Technology Assessment. 2000; 4(20);1-119; 2. NICE. Low back pain and sciatica in over 16s: assessment and management. Assessment and non-invasive treatments. NG59: Methods, evidence and recommendations (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59/evidence/full-guideline-assessment-and-noninvasive-treatments-pdf-2726158003. Accessed: August 2017; 3. Rudwaleit M, et al. Ann Rheum Dis 2009;68:777–783; 4. Humphreys SG, et al. Am Fam Physician 2002;65:2299–306.

MRI First choice if available but expensive No known radiation risk1 Extremely good at showing soft tissue and pathology of the cord, disc and ligaments1 Remember specific sequences need to be considered – consult radiologist Not suitable for all patients2 E.g., ferromagnetic implants, cardiac pacemaker, intracranial clips MRI is good for showing soft tissue and pathology of the cord, disc and ligaments. NICE. Low back pain and sciatica in over 16s: assessment and management. Assessment and non-invasive treatments. NG59: Methods, evidence and recommendations (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59/evidence/full-guideline-assessment-and-noninvasive-treatments-pdf-2726158003. Accessed: August 2017. 1. NICE. Low back pain and sciatica in over 16s: assessment and management. Assessment and non-invasive treatments. NG59: Methods, evidence and recommendations (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59/evidence/full-guideline-assessment-and-noninvasive-treatments-pdf-2726158003. Accessed: August 2017; 2. Humphreys SG, et al. Am Fam Physician. 2002;65:2299–306.

Reassurance from a normal X-ray 31-year-old patient with IBP: Images courtesy of Dr Raj Sengupta

CT scan Computerised tomography (CT) Useful in diagnosing bony pathology, assessing trauma, deformity and planning surgery1 Not as useful in soft tissue conditions e.g., disc infection2 Limitations Radiation exposure1 Less detailed images compared with MRI2 Results are adversely affected by patient motion2 CT images are less detailed than MRI1 Useful in diagnosing bony pathology, assessing trauma, deformity and planning surgery2 CT may be used to complement information from other diagnostic imaging studies Reference: 1. Humphreys SG, et al. Am Fam Physician 2002;65:2299–306. 2. NICE. Low back pain and sciatica in over 16s: assessment and management. Assessment and non-invasive treatments. NG59: Methods, evidence and recommendations (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59/evidence/full-guideline-assessment-and-noninvasive-treatments-pdf-2726158003. Accessed: August 2017 1. NICE. Low back pain and sciatica in over 16s: assessment and management. Assessment and non-invasive treatments. NG59: Methods, evidence and recommendations (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59/evidence/full-guideline-assessment-and-noninvasive-treatments-pdf-2726158003. Accessed: August 2017; 2. Humphreys SG, et al. Am Fam Physician. 2002;65:2299–306.

Ultrasound Occasional first-line diagnostic tool to evaluate the urinary tract in patients with symptoms of pyelonephritis1,2 May visualise signs of renal enlargement, oedema or haemorrhage1 Not all patients with suspected pyelonephritis are ultrasound- positive1 As few as 20% of patients Ultrasound may be used to evaluate the urinary tract in patients with symptoms of pyelonephritis1 Ultrasound may also be used to visualise signs of renal enlargement, oedema or haemorrhage1 Reference: 1. Craig WD et al. RadioGraphics. 2008; 28:255–276. 1. Craig WD et al. RadioGraphics. 2008; 28:255–76; 2. BMJ. Assessment of Back Pain – Differential Diagnosis (Last updated: June 2017). Available at: http://bestpractice.bmj.com/best-practice/monograph/189/diagnosis/differential-diagnosis/by-category.html (Accessed August 2017).

Summary: Recommendations for assessment and imaging of low back pain Think about alternative diagnoses when examining or reviewing people with non-specific low back pain, particularly if they develop new or changed symptoms. Exclude specific causes of low back pain, for example, cancer, infection, trauma or inflammatory disease such as SpA1 Please refer to NICE guideline NG65 for recommendations on the assessment and imaging of patients with suspected SpA. Available at: https://www.nice.org.uk/guidance/ng65 Do not routinely offer imaging in a non-specialist setting for people with non-specific low back pain with or without sciatica1 Consider imaging in specialist settings of care (for example, a musculoskeletal interface clinic or hospital) for people with non-specific low back pain with or without sciatica only if the result is likely to change management1 Think about alternative diagnoses when examining or reviewing people with non-specific low back pain, particularly if they develop new or changed symptoms Consider imaging in specialist settings of care (for example, a musculoskeletal interface clinic or hospital) for people with non-specific low back pain with or without sciatica only if the result is likely to change management NICE. Low back pain and sciatica in over 16s: assessment and management. NG59 (Last updated: November 2016). Available at: https://www.nice.org.uk/guidance/ng59. Accessed: August 2017.