Back pain - red flag symptoms

The signs and symptoms of potentially serious pathology in patients presenting with back pain.

(Photo: Rawpixel/Getty Images)
(Photo: Rawpixel/Getty Images)

Back pain is common, but it is crucial to be aware of signs and symptoms that could herald a more serious underlying pathology or where the cause is more complex than simple mechanical pain.

Red flag symptoms

  • Signs and symptoms of cauda equina or cord compression
  • Immunosuppression
  • Trauma
  • History of cancer
  • Nocturnal pain
  • Systemic upset – unintentional weight loss, fevers, night sweats
  • Thoracic pain
  • Abnormal gait
  • History of steroid use
  • Age under 20 years or age over 55 years
  • History of osteoporosis
  • Associated lightheadedness

A word of caution – NICE suggests that overall evidence for the use of red flags that may indicate serious spinal pathology in the primary care setting is not strongly established. The review suggests suspicion of spinal fracture or malignancy should not be made on the presence of a single red flag feature alone.

Differential diagnosis

  • Muscular/postural problems
  • Trauma/fracture
  • Inflammatory arthritis
  • Degenerative
  • Prolapsed disc
  • Paget's disease
  • Malignancy, such as myeloma or metastatic spread. Ovarian tumours can also present with back pain.
  • Referred pain
  • Infective causes such as pyelonephritis or discitis
  • Aortic dissection

Serious causes

It is vital not to miss cauda equina syndrome or spinal cord compression. The former is rare but with devastating consequences for the patient if missed. It can present with bladder, bowel or sexual disturbances.

There can be reduced sensation of the urinary system, lack of desire to void or poor stream or even new onset of faecal incontinence (caused by loss of sensation of a full rectum). There may be sensory changes in the perianal or saddle region with saddle anaesthesia or paraesthesia. Sensory changes and weakness can occur in the lower limbs so examination is crucial.

Back pain can sometimes be the symptom of malignant spread (lung, prostate, breast, thyroid or kidney), or myeloma. Often, the pain here remains on lying down, aching night time pain which disturbs sleep, and thoracic pain (which can also be a sign of other causes like aortic aneurysm).

Consider early investigation of patients who are generally unwell, with associated unexplained fevers, night sweats and weight loss; also, if they are immunocompromised, for example with HIV, diabetes or because of long-term steroid use.

Patient age

The age and sex of the patient should alert the clinician to other possible causes, such as ankylosing spondylitis in a young man. Elderly patients (and those with osteoporosis) fracture more easily, even from minor trauma.

Consider excluding inflammatory causes of pain if the patient is relatively young (<45 years), has pain which is improved with mobilising and has insidious onset with a chronic course. Ask whether there is any family history of inflammatory arthropathy.

Location of pain

Location of pain is important. Thoracic pain should alert the clinician to other causes, such as intra-abdominal or thoracic conditions (pancreatitis or aortic dissection, gastric, duodenal ulceration or retroperitoneal pathology, for example).

Paraspinal pain may be more pathognomonic of renal aetiology such as pyelonephritis or renal cell cancer.

It’s also worth establishing if there are any signs or symptoms of sciatica (or lumbar radiculopathy). This often presents with unilateral leg pain that radiates below the knee to the foot or toes (but not always). Usually in these cases the leg pain is much worse than the back pain; sometimes the back pain is minimal or absent.

Examination: face to face

For face-to-face examinations, ensure you wear appropriate PPE.

Abnormal gait as the patient walks in could suggest a serious pathology. Expose and inspect the back – do not miss shingles or psoriasis (indicating inflammatory arthritis).

Look for kyphosis, scoliosis or the 'question mark' appearance of ankylosing spondylitis.

Consider checking BP in both arms and other vital signs such as pulse and temperature. Check movements of the spine, and consider straight leg raise or Schober's test if clinically indicated. Also consider a slump test to establish if the sciatic nerve is being irritated.

Lower limb neurological examination is vital. Tone and reflexes can be increased and brisk or reduced and absent, depending on the site of the lesion. Any severe or progressive neurological deficit in the lower limbs in the context of back pain should be considered for immediate referral. Check power (look for foot drop) and plantar reflexes. Note the distribution of any sensory changes.

Consider checking perianal sensation and anal tone (reduced or lax) if cauda equina or cord compression is a possibility (offer a chaperone).

Consider lumbar radiculopathy if there are signs of nerve root compression (neurological disturbances in a nerve root pattern). If you suspect a non-muscular pathology then consider examining the system you feel is the likeliest cause of the pain from the history, for example, a gastrointestinal exam – is there a pulsatile aorta?

Examination: remote

If you are assessing a patient remotely via video you can consider the following points.

  • Observe the patient’s gait. How do they look?
  • Can the patient show you their back? If so, look for rashes.
  • Ask the patient to do some movements such as flexion extension and lateral flexion.

These remote examinations may help guide you on a management plan. But if you are unable to make a successful assessment then a face-to-face appointment will be needed.

Investigations

History and examination are the keystones of assessing back pain, but if serious pathology is suspected consider doing the following investigations:

  • FBC
  • Bone profile (abnormal in malignant spread or Paget's disease)
  • ESR
  • CRP (raised in malignancy, inflammatory or infective causes but often non-specifically raised so interpret results with caution)
  • PSA (if there is a risk of prostatic malignancy, but counsel the patient about the false positive and negative rates of the test)
  • Myeloma screen, including serum paraprotein and urinary bence jones protein
  • Urine dipstick
  • Renal ultrasound scan.

An X-ray may show fracture or infection (although evidence supporting X-ray use in non-specific back pain is limited and a request is likely to be rejected by your local radiology department), while an MRI, if indicated, may reveal spinal cord compression or other serious pathology more accurately.

Access to MRIs for GPs will vary nationally. Use caution MRIs with because they may reveal radiological changes that often do not correlate with symptoms.

Key learning points

    • Cauda equina can present with bladder, bowel or sexual disturbances.
    • Consider muscular and non-muscular causes.
    • Often, back pain as a symptom of malignant spread or myeloma remains on lying down.
    • Thoracic pain should alert to other causes, such as intra-abdominal or thoracic conditions.
    • Abnormal gait as the patient walks in could suggest a serious pathology.
    • Evidence supporting X-ray use in non-specific back pain is limited.
    • Severe or progressive neurological deficit in the lower limbs in the context of back pain should be considered for immediate referral.

Dr Adel Baluch is a portfolio GP in London.

  • This article was first published in 2012 and has been updated a number of times since then. This latest update was reviewed by Dr Pipin Singh, a GP in Northumberland and Dr Ravi Ramanathan a GP in London.

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