Managing low back pain in primary care

Dr Choo Chee Yong, pain specialist at Novena Pain Management Centre, speaks with Pearl Toh on the common ailment that is low back pain, and how to manage this in the primary care setting.

            

Back pain is one of the most common conditions encountered in primary care in Singapore. Up to 80 percent of the general population will experience low back pain at some point in their lives. It is the second most common complaint in general practice globally. In particular, elderly patients constitute a large proportion of the cases seen as they are susceptible to degenerative spine conditions due to reduced fluid content that lubricates the vertebrae in the spine.

Diagnosing low back pain

The common causes of low back pain include back strains/sprains and back contusions from trauma. Other causes of low back pain include prolapsed intervertebral discs, annular tears, facet joint arthropathy, neural foraminal or spinal stenosis.  Other less common causes include sacroiliac joint arthropathy and vertebral fractures due to osteoporosis.

We usually take a full history and clinical examination to look for red flags.  These may include, but are not limited to, focal neurological deficits such as persistent foot drop or cauda equina syndrome, significant loss of appetite or weight, persistent fever, history of drug abuse, and abdominal pain. 

If red flags are present, the patients may need early and timely referral for specialist pain management, or even surgical intervention.

For example, low back pain may be due to a sinister cause such as cauda equina syndrome. When there is significant disc prolapse causing compression of nerves in the lumbar spine, cauda equina syndrome can ensue. The signs and symptoms associated with the syndrome include numbness around the anus and loss of bladder and bowel control, which indicate a need for urgent surgery. Such patients will need an immediate surgical evaluation and urgent surgical decompression. If not detected early, permanent neurological deficit may be present even after surgery.

While most low back pain is caused by an injury (such as back strains), low back pain may also, though rarely, be the result of other diseases such as spinal infection, ankylosing spondylitis, sciatica, or cancer of the spinal cord.

To confirm a diagnosis, the best way to image the lumbar spine is by using magnetic resonance imaging (MRI). It provides a great resolution for looking at structures in the spine including the nerves, discs, paraspinal muscles, and vertebrate. However, MRI is costly and may not be readily accessible to all patients. GPs may want to treat low back pain empirically with analgesics first after eliminating red flags and send patients with persistent pain for MRI later.

What constitutes an emergency?

Pain situations that be taken seriously right away include incontinence and/or numbness around the saddle region (such as the groin and buttocks) or any accident that may cause fracture to the spine. Incontinence and numbness around the saddle area are indicators of spinal cord injury or compression which call for immediate medical attention.

Challenges

Some elderly patients may not be able to give a complete history of their pain symptoms. Therefore, it is important to talk to their family members or carers about the patient’s medical condition.  In addition, some patients see multiple doctors for their pain and GPs have to be careful to screen for polypharmacy and prevent overdose of common painkillers.  Last but not least, some patients may be multiple drug or opioid dependent.  These patients are best managed by the pain specialists.

Treating low back pain

The key aim of treatment is to restore function such that patient can return to their normal daily routine or work.  This would usually involve the use of analgesics, physiotherapy, modification of activities of daily living, and avoidance of prolonged bed rest.

The main treatments include use of simple analgesics such as paracetamol and NSAIDS.  Not all patients can tolerate strong analgesics like tramadol which can cause significant nausea.  Nerve pain medications such as gabapentin and pregabalin can cause drowsiness.  Patients should not drive or operate machinery while taking such medications.

Oral steroids are occasionally used to treat low back pain.  Long term use is associated with side effects of adrenal suppression, elevated blood pressure, suppressed immunity, osteoporosis, weight gain and glucose intolerance.  If started, they need to be slowly weaned and tapered.  Patients should be counselled appropriately.

GPs need to monitor the use of analgesics and eliminate those which are not efficacious or cause significant side effects.  They also need to encourage the patients to minimize bed rest and continue exercising once their pain has improved.  They may need to work closely with a physiotherapist or specialist to assist the patient in a faster recovery so that they can return to their daily function.

If there is no improvement after 4 weeks of treatment, they should be referred to a specialist for further assessment. Patients should also be referred urgently if red flags are present. 

The use of opioids for chronic low back pain is controversial and is best avoided or minimized unless clinically indicated.

Nonpharmacological interventions include, but are not limited to, acupuncture, TCM treatments, mindfulness meditation, physiotherapy, exercises and pilates. They can be used in conjunction with pharmacological treatments to get the best possible outcomes for pain relief.

Treating low back pain in primary care can be challenging.  It is not just about giving analgesics.  Frequently as doctors, we have to take a psychosocial history and understand the patient’s work and social functioning.  We try to encourage patients to return to work as soon as they can, under our supervised care.  In addition, poor sleep and mood disorders can exacerbate the pain that patients experience.

Summary

For diagnosis, thorough history taking together with physical examination are important to identify red flags. Clinical practice guidelines also recommend neurological testing in case of radicular pain syndrome, imaging of the spine if serious pathology is suspected, and evaluation of psychosocial factors. [Eur Spine J 2018;27:2791-2803]

For treatment, clinicians play a key role in reassuring their patients on the favourable prognosis and encouraging them to return to normal activities. Guidelines also recommend the use of NSAIDs for short periods and avoidance of bed rest. Patients should be referred to a specialist if specific pathology or radiculopathy is suspected, or if condition does not improve after 4 weeks of treatment.

Take-home message

It is important to not miss the red flags during diagnosis of low back pain. Psychosocial intervention is just as important as pharmacological management of low back pain.