This Back in Focus resource was developed and funded by AbbVie Ltd. Date of preparation: June 2015; AXHUR150807o

How to Investigate Back Pain

• 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?

Back pain: the challenge of differentiation

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

1. Deyo, RA and Weinstein, JN. N Eng J Med 2001;344:363–370. 2.http://www.nhs.uk/Conditions/Fibromyalgia/Pages/Symptoms.aspx. Date accessed May 2015. 3. Papagelopoulos PJ. Eur Spine J (2005) 14: 683–688.

Possible causes of mechanical back pain1

Possible causes of inflammatory back pain1

Other possible causes of back pain1,2,3

• Degenerative disc diseases

• Facet joint derangement

• Fracture

• Herniated disc

• Muscle imbalance

• Osteoarthritis

• Severe kyphosis

• Severe scoliosis

• Spinal stenosis

• Spondylolisthesis

• Transitional vertebrae

• Axial spondyloarthritis including patients with ankylosing spondylitis (AS)

• Psoriatic arthritis (PsA) 

• Inflammatory bowel disease

• Psoriatic spondylitis

• Reiter’s syndrome

• Abdominal aortic aneurysm

• Disease of pelvic organs

• Fibromyalgia

• Gastrointestinal diseases

• Infections such as: Epidural abscess Osteomyelitis Septic discitis Paraspinous abscess Shingles

• Paget’s disease of bone

• Renal diseases

• Scheuermann’s disease (osteochondrosis)

• Tuberculous sacroiliitis

• Tumours including metastases

Investigation and referral considerations1–3

Mechanical back pain Inflammatory back pain Red flags

Symptoms/ suspicions • Lower back pain <3 months

• Degenerative arthritis• Osteoporosis with

possible fracture• Muscular sprain/strain

• Back pain >3 months • Morning stiffness• Good response to

NSAIDs

• History of cancer• Unexplained weight

loss• Significant trauma• Fever/chills• Bowel/bladder

dysfunction with back pain

Investigations to consider

• X-ray (for traumatic fracture only)

• ASAS criteria for IBP• MRI/X-ray• HLA-B27 blood test

• Ultrasound/MRI/X-ray/CT

• Blood tests: infection/• Tumour markers (only

in a minority of cases)• Urinalysis

Referral possibilities • Physiotherapy (if X-ray shows no abnormality)

• Orthopaedics

• Rheumatology • Accident and Emergency (A&E)

• Urology• Orthopaedics• Neurosurgery

1. Adapted from BMJ Best Practice. Assessment of back pain. Accessed June 2015. 2. Bhangle SD et al. Cleveland Clinic Journal of Medicine. 2009;76:393–399. 3. Sieper et al. Ann Rheum Dis. 2009;68:784–788.

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), ESR (erythrocyte sedimentation rate)1

– HLA-B27 (human leukocyte antigen-B27)2

•Urine dipstick– Can be done in GP surgery

•Tumour markers: – E.g., Ca-125, AFP (alpha

fetoprotein), PSA (prostate specific antigen)3

Imaging

•X-ray

•Magnetic Resonance Imaging (MRI)

•Computerised tomography (CT)

•Ultrasound (US)

1. Castro C, Gourley M. J Allergy Clin Immunol. 2010; 125(2 Suppl 2):S238–S247. 2. Sieper, J et al. Ann Rheum Dis 2009; 68:784–788.. 3. Perkins GL, et al. Am Fam Physician. 2003 Sep 15;68:1075–1082.

• 9.5% of UK population are HLA-B27 positive1

• 88–94% of AS patients are HLA-B27 positive1,2

• Useful in diagnosis– Study showed that 58% of patients with IBP and HLA-B27

positivity were diagnosed with SpA2 – Study showed a sensitivity of 66.1% and specificity of 79.9%

for HLA-B27 for diagnosing axial SpA3

• Useful for prognosis– Study showed that severity of baseline MRI sacroiliitis and

HLA-B27 positivity predicted radiographic AS at 8 years4

HLA-B27

1. Brown, MA et al. Ann Rheum Dis 1996;55:268–270. 2. Brandt, HC et al. Ann Rheum Dis 2007;66:1479–84. 3. Sieper, J et al. Ann Rheum Dis 2012;0:1–7. 4. Bennett, AN et al. Arthritis & Rheum 2008; 58:3413–18.

• Not necessary in most cases of non-specific lower back pain1

• ‘Red flags’ should suggest serious pathology and prompt early referral (not necessarily imaging)– Generally detected on preliminary medical history and

physical examination

Radiological investigation of back pain

1. Teh, J. Investigation of back pain. The British Institute of Radiology. 2012. Available at http://imaging.birjournals.org/content/early/2012/01/26/imaging.22537980.full.pdf. Accessed 15.01.2013.

Aim: Rule out serious spinal pathology and significant neurological involvement1

• Lumbar X-ray accounts for 12% of all requests for diagnostic radiology from GPs1

– 21% of all X-ray requests1

• Limited value in absence of trauma or suspecting fracture– IBP suggestive of inflammatory disease may not always

be associated with radiological features2

– May miss early fractures in osteoporosis3

• High rate of false positives4

• Unnecessary radiation exposure1

Lumbar X-ray

1. Kerry S, et al. Health Technology Assessment. 2000; 4(20). 2. Rudwaleit M, et al. Ann Rheum Dis 2009;68:777–783. 3. Teh, J. Investigation of back pain. The British Institute of Radiology. 2012. Available at http://imaging.birjournals.org/content/early/2012/01/26/imaging.22537980.full.pdf. Accessed January 2013; 4. Humphreys SG, et al. Am Fam Physician 2002;65:2299–306.

• First choice if available but expensive

• No known radiation risk1

• Consider MRI if suspicious of:

– Spinal malignancy

– Infection

– Fracture

– Disc lesion

– AS or other inflammatory disorders2

• Remember specific sequences need to be considered – consult radiologist

• Not suitable for all patients

– E.g., ferromagnetic implants, cardiac pacemaker, intracranial clips1

MRI

1. Humphreys SG, et al. Am Fam Physician 2002;65:2299–306.. 2. Savigny P, et al. Low Back Pain: early management of persistent non-specific low back pain. National Collaborating Centre for Primary Care and Royal College of General Practitioners. 2009. Available at http://www.nice.org.uk/nicemedia/pdf/CG88fullguideline.pdf. Accessed June 2015.

31-year-old patient with IBP:

Reassurance from a normal X-ray

Images courtesy of Dr Raj Sengupta

• Computerised tomography (CT)

• Helpful in diagnosing fractures, partial/complete dislocation and certain tumours 1

– Not as useful in soft tissue conditions e.g., disc infection

• Limitations1

– Radiation exposure

– Less detailed images compared with MRI

– Results are adversely affected by patient motion

CT scan

1. Humphreys SG, et al. Am Fam Physician 2002;65:2299–306.

• Occasional first-line diagnostic tool to evaluate the urinary tract in patients with symptoms of pyelonephritis1

• May visualise signs of renal enlargement, oedema or haemorrhage1

• Not all patients with suspected pyelonephritis are ultrasound-positive

– As few as 20% of patients1

Ultrasound

1. Craig WD et al. RadioGraphics. 2008; 28:255–276

• A combination of laboratory and imaging tests can aid differentiation

• Do not offer X-ray of the lumbar spine for management of non-specific low back pain

• Consider MRI when spinal malignancy, infection, fracture, cauda equina syndrome or ankylosing spondylitis (or other inflammatory disorders) are suspected

• Only offer an MRI for non-specific low back pain within the context of referral for possible surgical intervention

Summary: Recommendations for assessment and imaging1

1. Savigny P et al. Low Back Pain: early management of persistent non-specific low back pain. London: National Collaborating Centre for Primary Care and Royal College of General Practitioners. NICE guideline CG88. May 2009.