Acute non-traumatic back 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

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

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:

See below. Bilateral symptons ± sphincter.

Central "disc" prolapse - cauda equina

• Is a medical emergency requiring urgent MRI
• Bilateral radicular pain
• Δ perianal (pin prick) sensation or genital dysaesthesia
• Bilateral motor weakness (esp. knee extension, anle eversion, foot dosiflexion)
• Lax anal sphincter (late, unreliable sign)
• New (<14/7) micturition difficulty (post void residual vol. >200ml)
• If unable to micturate, check bladder vol:
  • If > 600ml, catheterise (to avoid distension injury)
  • Document if sensate and catheter tug
  • Contact your senior now