Lower back pain red flags

Red Flags for Lower Back Pain

General Principles of Red Flags for Back Pain:

The UK Royal College of Emergency Medicine (RCEM) define Red Flags for back pain as:

• non-mechanical back pain
• past history of cancer, steroids, HIV
• generally unwell
• unexplained weight loss
• widespread neurological symptoms or signs
• structural deformity
• thoracic back pain

The RCEM note the TUNA FISH mnemonic for considering red flags for back pain:

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Red Flags can be considered in terms of presenting features or particular conditions

In terms of presenting features (1,2,3):

Factors in the history include:

• cancer
• unexplained weight loss
• history of immunosuppression
• history of HIV or tuberculosis
• prolonged use of steroids
• intravenous drug use
• urinary tract infection
• pain that is increased or unrelieved by rest
• fever
• history of atherosclerotic vascular disease
• significant trauma related to age (e.g. fall from a height or motor vehicle accident in young patient, minor fall or heavy lifting in potentially osteoporotic or older patient or a person with possible osteopororosis)
• bladder or bowel incontinence
• urinary retention (with overflow incontinence)
• consider age of patient in context of presentation of back pain - a review noted that back pain <20 years was significant (4); as is back pain in > 50 years old

Factors on examination:

• saddle anaesthesia
• loss of anal sphincter tone
• major motor weakness in lower extremities
• fever
• vertebral tenderness
• limited spinal range of motion
• neurological findings persisting for more than one month
• palpable pulsatile abdominal mass ? possible abdominal aortic aneurysm

Red Flag Symptoms with respect to possible underlying conditions:

Possible cancer red flags include:

• history of cancer - some cancers are known to metastasise to bone
  • primary tumours which give rise to metastases to bone are remembered by many students by the nonsense rule that they all begin with a B. Thus:
    • breast
    • bronchus
    • byroid (thyroid)
    • bidney (kidney)
    • bostate (prostate)
    • (rarely, bowel)
  • however note that pancreatic cancer can present with back pain (see below)
• unexplained weight loss
  • unintentional weight loss is loss of 10 pounds (4.5 kilograms) or 5% of your normal body weight over 6 to 12 months or less without knowing the reason (5)
• age over 50 years
• night pain that disturbs sleep
• no improvement in back pain symptom in a 4-6 week period despite conservative therapy
• back pain at rest

Possible infectious cause of back pain red flags include:

• persistent fever
• history of intravenous drug misuse
• history of lumbar spine surgery within the last 12 months
• recent bacterial infection e.g. pyelonephritis, cellulitis, pnemonia
• history of tuberculosis
• immunocompromised state e.g. history of use of systemic steroids, organ transplant, HIV, diabetes mellitus

Cauda Equina Syndrome Related Red Flags include:

• urinary incontinence (occurs because of loss of sensation that passing urine)
• urinary retention (occurs because loss of sensation of bladder fullness)
• saddle anaesthesia
• faecal incontinence
• decreased anal sphincter tone
• bilateral lower extremity weakness or numbness
• progressive neurological deficity
  • major motor weakness - such as major motor weakness with knee extension, ankle eversion, or foot dorsiflexion.
  • major sensory deficit

Vertebral Fracture related red flags include:

• prolonged use of systemic steroids
• history of trauma
  • the severity of trauma where a vertebral fracture may occur varies with various factors such as age, co-morbidities and use of corticosteroids. Thus in an elderly patient with osteoporosis then a vertebral fracture might occur with minimal trauma or even after heavy lifting. In a young patient with no osteoporosis and no corticosteroid use then a vertebral fracture might occur after a significant trauma such as falling from a height onto a hard surface
• localised vertebral tenderness
• a structural spinal deformity e.g. a step deformity

Also consider a possible abdominal aortic aneurysm or pancreatic cancer in the patient with back pain.

AAA possible features include:

• pulsating abdominal mass
• past history of atherosclerotic vascular disease
• pain at rest or nocturnal pain
• age greater than 60 years

Pancreatic cancer possible features include (6):

• typically patients complain of a deep epigastric pain, which in 60% of cases, radiates to the back
• unexplained weight loss - due to anorexia or malabsorption
• pain at rest
• nocturnal pain

Reference:

• https://www.rcemlearning.co.uk/ (RCEM learning accessed 15/6/22)
• NICE (October 2020). Low back pain and sciatica in over 16s: assessment and management
• Bratton RL. Assessment and Management of Acute Low Back Pain. Am Fam Physician. 1999 Nov 15;60(8):2299-2306
• ARC - Reports on Rheumatic Diseases (1999), 17, 1-4.
• National Library of Medicine - Medline Plus.Weight loss - unintentional (Accessed 23/4/2022).
• Bond-Smith G et al. Pancreatic adenocarcinoma. BMJ. 2012;344:e2476