Acute non-traumatic back pain

Back pain may be due to 1. mechanical back pain 2. neurogenic pain, 3. pathological pain and 4. inorganic pain

Mechanical back pain

  • Is due to sprain of the spinal ligaments or arthritis in the facet joints.
  • Confined to the back (occasionally referred into the upper leg).
  • Exacerbated by movement.
  • Relieved by rest.
  • If pain at night, it is when they roll over.
  • PMHx of similar problem / previous injury making back more susceptible.

Red flags

  • Age >55 or <19
  • Night pain
  • Thoracic back pain
  • Bilateral neurological symptoms
  • Sphincter symptoms
  • Immunosuppression (or IVDU) Hx
  • Hx malignancy
  • Fever
  • Coagulopathy

Neurogenic pain

  • Nerve root is irritated by prolapsing lumbar disc, # or osteophyte.
  • Pain and paraesthesia.
  • Distribution consistent with that nerve root.
    • Paraesthesia is in the same distribution:
      • L4: pain extends into the medial malleolus.
      • L5: into the lateral malleolus and big toe.
      • S1: pain into the lateral border of the foot and little toe.
  • Worsening disease results in loss of sensation / power / reflex.
    • Distribution is characteristic for each nerve root.

Pathological pain

  • Nasty, unpleasant pain at rest.
  • Nocturnal pain prominent.
  • Due either to malignant disease or infection.
  • If neurological symptoms,may initially seem fluctuant / inconsistent.
  • Neurological dysfunction can rapidly result if it is not resolved.
  • Past History:
    • Thoracotomy.
    • Mastectomy.
    • Prostatectomy.
Sclerotic prostatic Secondary in Body of T12

Exam - non-traumatic back pain

Examine spine

  • History, history, history.
  • Look ( scoliosis, loss of lordosis, spasm).
  • Feel ( tender vertebra/rib, step betw spinous process).
  • Move - limitation and pain.

Please remember AAA and retroperitoneal pathology (pyelonephritsis, haematoma, pancreatitis) may present as back pain and consider appropriate tests (US AA in all older patients with back pain).


  • Sensation (including perianal pin prick).
  • Coordination (CNS/cord lesion).
  • Power and reflexes.
  • SLR/sciatic stretch test.
  • Femoral nerve stretch test.
  • FAIR (hip flex/add/int. rotation) - piriformis pathology.

Beware of stiffness in young people associated with sclerosis or obliteration of SI joints. Check viscosity/ESR.

Sciatic (L5 root) vs other pathology

Sciatic nerve (L5): weak ankle dorsiflexion/plantarflexion, foot inversion/eversion; absent ankle jerk. May have weak knee flexion. Weak hip abduction if L5 lesion (sup gluteal nerve)

Piriformis syndrome: Trigger point in buttock. Treat with physio.

Iliotibial band syndrome: Recent Δ activity or footwear (inversion). Trigger with Ober's test and weak popliteus.

Peroneal nerve pathology: Hx Local trauma (fibular neck), tender peroneal nerve, weak ankle dorsiflexion and foot eversion, but strong ankle plantarflexion and foot inversion, normal AJ, paraesthesia dorsum of the foot only.

Cortical lesion: +ve Babinski.

Cauda equina: bilateral symptons ± sphincter (see below).

Central disc prolapse - cauda equina

  • Leg signs are less clear.
  • Loss of perianal sensation (pin prick).
  • Lax anal sphincter.
  • Micturition difficulty.
  • It is a medical emergency.

X-rays required if:

  • Direct trauma.
  • Preceding back problems or relevant Hx.
  • Patients with neurological signs or unable to stand.
  • Elderly.
  • Referred for orthopaedic opinion! (They are not indicated but the team will insist anyway).

Content by Dr Íomhar O' Sullivan 23/06/2000. Reviewed byDr ÍOS 15/03/2004, 25/05/2005, 23/05/2006, 22/05/2007. Last reviewed Dr ÍO 4/06/21.