Musculoskeletal
Question 214 of 300
A 57 year old man presents to the Emergency Department with a 4 day history of back pain. He cannot recall any trauma. Whilst assessing the patient you are considering whether the patient has features suggestive of an inflammatory cause. Which of the following features would make you suspect an inflammatory cause for the patient's symptoms?
Answer:
- Inflammatory disease:
- Age < 40 years old
- Pain at night that is not relieved when the person is supine
- Stiffness in the morning that is relieved with movement/exercise
- Gradual onset of symptoms
- Symptoms that have lasted for more than three months
Back Pain
Musculoskeletal
Last Updated: 15th September 2022
Low back pain is common. Up to 60% of the adult population can expect to have low back pain at some time in their life.
Definitions
- Low back pain (LBP) is pain in the lumbosacral area of the back, between the bottom of the ribs and the top of the legs.
- Non-specific low back pain is diagnosed when the pain cannot be attributed to a specific cause, although in many cases, may be related to trauma, or musculoligamentous strain. Non-specific low back pain is often a chronic problem in which periods of little pain or disability are interrupted by acute episodes of severe pain.
- Sciatica describes symptoms of pain, tingling, and numbness which arise from impingement of lumbosacral nerve roots as they emerge from the spinal canal, and are felt in the distribution of the nerve root (dermatome). There may be accompanying motor weakness in a corresponding myotomal distribution. Symptoms of sciatica typically extend to below the knee from the buttocks, across the back of the thigh, to the outer calf, and often to the foot and toes.
Sciatica
Sciatica is caused by compression of one or more nerve roots in the lumbosacral spine. The compression can be caused by:
- Herniated intervertebral disc (about 90% of cases)
- Occurs most commonly at L4/L5 and L5/S1 levels
- Spondylolisthesis - when a proximal vertebra moves forward relative to a distal vertebra.
- Spinal stenosis - narrowing of the spinal canal (typically causes pain, which is relieved by forward flexion and worsened with extension)
- Infection (rare) - for example, discitis, vertebral osteomyelitis, or spinal epidural abscess.
- Malignancy (rare) - more often due to metastatic disease of the spine than a primary tumour.
Suspect sciatica if there is:
- Unilateral leg pain radiating below the knee to the foot or toes.
- Low back pain — if present, it is less severe than the leg pain.
- Numbness, paraesthesia, muscle weakness, or loss of tendon reflexes in the distribution of usually a single nerve root.
- An L4/L5 disc prolapse will tend to cause pressure on the L5 nerve root
- Involvement of the L5 nerve root presents with weakness of extension of the great toe, decreased sensation in the first web space, and normal reflexes.
- An L5/S1 disc prolapse will tend to cause pressure on the S1 nerve root
- An S1 radiculopathy is characterised by diminished sensation of the lateral small toe, impaired plantar flexion, and decreased or absent ankle jerk.
- An L4/L5 disc prolapse will tend to cause pressure on the L5 nerve root
- Positive straight leg raising test — raising the leg whilst it is straight causes greater pain radiation below the knee and/or more nerve compression symptoms. Dorsiflexion of the foot while the leg is raised will exacerbate pain (sciatic stretch test).
- Extensor plantar response — when the lateral part of the sole of the foot is stimulated, the toes extend and fan outwards.
Differential diagnosis of low back pain
- Non-specific low back pain
- Structural/degenerative disease:
- Vertebral fracture due to trauma or osteoporotic collapse
- Intervertebral disc prolapse
- Spinal stenosis
- Cauda equina syndrome (compression of the nerve roots below the termination of the spinal cord (conus medullaris)).
- Paget’s disease or other metabolic disease
- Spondylolysis or spondylolisthesis
- Inflammatory conditions:
- Ankylosing spondylitis
- Other spondyloarthropathies e.g. Reiter’s syndrome, psoriatic arthritis, enteropathic arthritis
- Polymyalgia rheumatica
- Sacroiliitis or sacroiliac dysfunction
- Infection:
- Discitis
- Vertebral osteomyelitis – bacterial or tuberculous (Pott’s disease)
- Spinal epidural abscess
- Malignancy
- Primary malignancy e.g. myeloma, osteosarcoma
- Secondary malignancy (most commonly: breast, lung, prostate, renal and thyroid)
- Causes outside the spine:
- Vascular
- Aortic dissection
- Ruptured/leaking aortic aneurysm
- Gastrointestinal
- Peptic ulcer disease
- Pancreatitis
- Retroperitoneal perforation of colon
- Genitourinary
- Pyelonephritis
- Renal calculi
- Prostatitis
- Pelvic infection
- Other
- Shingles
- Vascular
Red flag symptom and signs
- Cauda equina syndrome:
- Severe or progressive bilateral neurological deficit of the legs, such as major motor weakness with knee extension, ankle eversion, or foot dorsiflexion
- Perianal or perineal sensory loss (saddle anaesthesia or paraesthesia)
- Recent onset bladder dysfunction (urinary retention or overflow incontinence)
- Recent onset faecal incontinence (due to loss of sensation of rectal fullness)
- Laxity of anal sphincter on examination
- Spinal fracture:
- Sudden onset severe central spinal pain which is relieved by lying down
- Major trauma such as RTA or fall from a height
- Minor trauma, or even just strenuous lifting, in people with osteoporosis or those on corticosteroids
- Structural deformity of the spine
- Point tenderness over a vertebral body
- Malignancy:
- Person ≥ 50 years of age
- Gradual onset of symptoms
- Severe unremitting or progressive lumbar pain that remains when the person is supine
- Aching night pain that prevents or disturbs sleep
- Pain aggravated by straining
- Pain in the thoracic or cervical spine
- Localised spinal tenderness
- No symptomatic improvement after four to six weeks of conservative low back pain therapy
- Unexplained weight loss
- Past history of cancer (breast, lung, gastrointestinal, prostate, renal, and thyroid cancers are more likely to metastasise to the spine)
- Metastatic spinal cord compression in patient with cancer and pain suggestive of spinal metastases:
- Radicular pain
- Limb weakness
- Difficulty in walking
- Sensory loss, or bladder or bowel dysfunction
- Neurological signs of spinal cord or cauda equina compression
- Infection:
- Fever
- Tuberculosis, or recent urinary tract infection
- Diabetes
- History of intravenous drug use
- HIV infection, use of immunosuppressants, or the person is otherwise immunocompromised
- Inflammatory disease:
- Age < 40 years old
- Pain at night that is not relieved when the person is supine
- Stiffness in the morning that is relieved with movement/exercise
- Gradual onset of symptoms
- Symptoms that have lasted for more than three months
Investigations
No investigation is required for the vast majority of patients with non-specific back pain and sciatica.
- Spinal x-ray
- History of trauma
- Suspicion of malignancy, fracture or metabolic bone disease
- MRI
- Suspected cauda equina syndrome
- Suspected spinal cord compression
- Suspected infection
- Suspected inflammatory disease
- Suspected malignancy
- FAST
- Suspected AAA or aortic dissection
- Bloods – CRP, WCC
- Suspected infection
Management of non-specific low back pain and sciatica
- If there are red flag symptoms and signs that may suggest a serious underlying cause, admit or refer urgently for specialist assessment, or imaging, using clinical judgement.
- If an underlying cause for the low back pain has been identified, manage according to the specific diagnosis.
- Offer patient self-management advice.
- Provide information and advice on the natural history of LBP and sciatica, to encourage realistic expectations:
- Advise that acute non-specific LBP is not caused by serious structural damage and most people recover within a period of a few weeks with self-care.
- Sciatica symptoms usually settle within 4–6 weeks, but may persist for longer in some people.
- Address any specific concerns the person has about the cause of their pain and their expectations of treatment.
- Provide information on self-help measures to relieve symptoms (e.g. exercises, local heat).
- Encourage the person to stay active, resume normal activities, and return to work as soon as possible.
- Provide information and advice on the natural history of LBP and sciatica, to encourage realistic expectations:
- Offer analgesia to manage pain.
- Offer a nonsteroidal anti-inflammatory drug (NSAID) such as ibuprofen or naproxen first-line, if there are no contraindications. An NSAID should be used at the lowest effective dose for the shortest possible time. Gastroprotective treatment should also be offered while an NSAID is being used.
- If an NSAID is contraindicated, not tolerated, or ineffective, offer codeine with or without paracetamol, taking into account the risk of opioid dependence and adverse effects such as constipation.
- If the person has muscle spasm, consider offering a short course of a benzodiazepine, such as diazepam 2 mg up to three times a day for up to 5 days, if not contraindicated.
- If nerve pain remains uncontrolled, consider offering a drug to treat neuropathic pain, such as amitriptyline, duloxetine, gabapentin, or pregabalin, depending on local prescribing policies, and titrate the dosage according to response and tolerability.
- Consider referral to a specialist low back pain and sciatica service for assessment for an epidural corticosteroid/local anaesthetic injection.
- Advise the person to seek follow-up if symptoms persist or are worsening after 3–4 weeks.
- Advise the person to report any red flag symptoms and signs.
- If there is progressive, persistent, or severe neurological deficit, admit or refer urgently to neurosurgery or orthopaedics for specialist assessment, depending on clinical judgment and local referral pathways.
Suspected cauda equina syndrome
- Cauda equina syndrome (CES) is a medical emergency and requires immediate referral for investigation. Early diagnosis is essential. Early surgical decompression is crucial for a favourable outcome in most patients with CES.
- The cauda equina is formed by nerve roots caudal to the level of spinal cord termination. Cauda equina syndrome (CES) is caused by compression of the nerves, causing one or more of the following: bladder and/or bowel dysfunction, reduced sensation in the saddle (perineal) area, sexual dysfunction, and neurological deficit in the lower limb (motor/sensory loss, reflex change).
- Causes include:
- Herniation of a lumbar disc (most commonly L4/L5 and L5/S1 level) - most common cause
- Tumours e.g. metastases, lymphoma, spinal tumours
- Trauma
- Infection e.g. epidural abscess
- Spondylolisthesis
- Late-stage ankylosing spondylitis
- Spinal haematoma
- The diagnosis of CES is primarily based on a thorough history and clinical examination, assisted by appropriate radiological investigation. MRI scan is the preferred investigation to confirm the diagnosis and determine the level of the compression and any underlying cause.
- Patients should be referred immediately for a neurosurgical consultation. Urgent surgical spinal decompression is indicated for most patients to prevent permanent neurological damage.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
