This post is part of the St Emlyn’s induction series and accompanies the podcast below.
Firstly, when seeing patients with back pain take a deep breath and try to leave the baggage at the consultation room door.
There are lots of things that cause back pain which are nothing to do with the chronic back pain cohort who can be tricky to look after. Back pain is a mixed bag presentation: there are some life-threatening diagnoses we have to consider all the way through to patients who have chronic disease and hard-to-manage pain.
So we need a system to manage these patients. What do we do at St Emlyn’s?
Ask yourself: is this something other than musculoskeletal back pain?
Leave musculoskeletal diagnoses at the bottom of the list and ensure you are happy you’re not facing the big stuff before anything else.
The big diagnosis – ruptured/leaking abdominal aortic aneurysm (AAA) – usually elderly patients (depending on literature aged 55+) – in these patients examine the abdomen as well as the back and consider ED ultrasound (being aware of its limitations). Beware the diagnosis of first time renal colic in anyone over 50 without ED imaging!
Think about key history features: the chronology of pain is important – rest pain, night pain, and long term evolving pain are concerning for neoplastic disease and occult infectious processes.
Fever plus back pain should mandate a need for further investigation. Think about, identify and treat sepsis. Septic foci causing back pain include pyelonephritis. Be particularly cautious to seek out infection in immunocompromised patients (IVDU, diabetes, steroid use, alcoholics, chemotherapy, HIV) who may not mount a febrile response but are at increased risk of infections such as osteomyelitis or spinal epidural abscesses.
We advocate a quick review of systems for these patients (I also ask “is anything else unusual going on?”)
Actively ask about and seek red flag symptoms
Other concerning features include bilateral pain, neurological symptoms (especially altered sensation, disturbance of bladder and bowel function), patients older than 55 (some literature suggests 65) or younger than 19 [mechanical back pain is not impossible but is less likely in these age groups], weight loss, known cancer (especially those which commonly metastatise to bone), night sweats (consider infection especially TB), coagulopathy including patients on warfarin (we have seen spontaneous retroperitoneal haemorrhage and spontaneous epidural haematoma in anticoagulated patients – rare but important to pick up if present).
Is it Cauda Equina syndrome?
Generally, the syndrome is present when a protruding disc squashes nerve roots. The patient may lose motor and sensory function to lower limbs and perianal area and have altered bladder and bowel control. Cauda equine can just affect sacral roots (perianal sensation, bladder and bowel control) without leg symptoms. This is a highly litigious area. Cauda equina is serious as it can lead to permanent irreversible disability and the diagnosis is missed not infrequently.
Be aware that altered sensation in the perianal area is a late sign – so any abnormal findings should trigger a consideration of cauda equine syndrome and discussion with your senior colleagues.
These patients may require an MR scan.
Examine carefully and document well!
In all patients with back pain, document a full neuro exam (myotomes and dermatomes) esp lower legs. Consider post-void scanning for incomplete emptying (which may be present before full urinary retention) but self-reported urinary dysfunction lacks sensitivity and specificity in diagnosing cauda equina syndrome . Examine perineum for anal tone and ask the patient whether they can feel your finger on PR examination!
Serial examinations of neurological function can be helpful; it can be difficult to differentiate between restriction in function due to pain, a patient’s feeling that something is not quite right, and a true neurological deficit. Treat pain and re-examine – true neurological findings won’t disappear with analgesia!
Image and investigate wisely
Most patients with atraumatic back pain don’t require lumbar spine x-rays. They carry a high radiation exposure and are of limited diagnostic utility except in the very elderly patients when osteoporotic fractures or metastatic disease might be apparent.
If imaging is warranted, discuss with a senior doctor whether CT (for AAA, renal pathology, suggestion of infective spinal pathologies like TB) or MR (cauda equine, soft tissue pathologies like osteomyelitis, epidural haematoma) is more appropriate given the ease of access to each in your facility and what it is you are looking for. Nuclear medicine (bone scans) might also be indicated – subsequent discussion with a friendly radiologist about your diagnostic concerns can provide excellent advice on the most appropriate imaging modality.
Bloods – if red flags present, think about FBC, inflammatory markers, bone profile and calcium
Treating musculoskeletal back pain
The best management for these patients is to get up and get moving but they don’t want to do that because it hurts! Breaking the cycle of muscle spasm and immobility perpetuating one another is important.
Get on top of pain early!
Simple analgesia may be sufficient (paracetamol, codeine, ibuprofen)
Benzodiazepines can improve lower back pain to get patients mobilising but be careful; this shouldn’t be standard practice for all back pain. In these patients benzodiazepines aren’t used as analgesia or as muscle relaxants but to relax the patient who can become quite distressed by the pain.
Analgesia doesn’t occur in isolation – keeping moving is key to recovering from musculoskeletal back pain and enhancing core stability can help too.
As for amitriptyline and gabapentin? It’s probably not our role to start these in the ED. Good communication with primary care colleagues is key including articulation of what advice and guidance you’ve given the patient.
Expectation management is also really important as patients often expect imaging if back pain isn’t getting better – expectations are best managed in conjunction with the patient’s primary care physician (GP).
Chronic Back pain
Check out Iain’s talk for an approach to the patient with chronic pain which involves different pathways altogether.