Back Pain OSCE - Sciatica / Disc Herniation

Case Overview

• Age/Sex: 43-year-old female
• Occupation: Office worker (administrative assistant)
• Setting: Primary care / urgent clinic
• Chief complaint: "Back pain"

Patient Script

Who I Am

I'm 43 and I sit at a desk most days working as an administrative assistant.

What Brings Me In

My lower back pain has been getting worse and now shoots down my left leg so I thought I should get it checked.

My Story

About 10 days ago I started with a dull ache in my lower back after I lifted a heavy box at home. Over the next few days it changed into a sharp, shooting pain down the back and outside of my left leg and I get a lot of numbness and tingling on the outside of my left foot, especially the little toe. Sitting for long periods, coughing or bending forward makes it worse. Walking seems to help a bit. I tried ibuprofen and heat which helped a little but I still rate the pain around 7/10 when it flares and it keeps me awake at night. I had one similar episode years ago that got better after a couple of weeks on its own, but this feels worse and the numbness is new.

My Medical Background

• Past medical history: occasional migraine headaches; no diabetes or arthritis
• Medications: over-the-counter ibuprofen as needed; the combined oral contraceptive pill
• Allergies: none known
• Social: non-smoker, drinks alcohol socially (1–2 glasses wine at weekend), sedentary job, tries to walk at lunch
• Family history: mother has osteoporosis (older age)

What I Think & Worry About

• I worry that this might be something serious that won't get better on its own.
• I'm worried I might need an operation or that I won't be able to work.
• I think it might be a slipped disc because I remember someone mentioning that when my cousin had similar symptoms.

If You Ask Me About Other Symptoms...

• Fever/night sweats/weight loss: I have none.
• Bowel or bladder problems: none, I haven’t noticed any difficulty passing urine or bowel control.
• Leg swelling/redness: none.
• Recent infections: I had a bad cold about a month ago but nothing recent.
• Other pain: I have occasional neck stiffness and headaches (migraines), but not related to this.
• Mobility: I can walk but I limp a bit and avoid stairs because it hurts.

---

Clinical Summary

Examination

• General: afebrile, comfortable at rest, vital signs: BP 124/78 mmHg, HR 78 bpm, RR 14/min
• Inspection: no spinal deformity, mild antalgic gait favouring the left side
• Palpation: tenderness and mild spasm over the left paraspinal muscles at L4–S1
• Range of motion: forward flexion limited by pain; extension painful
• Neurological examination (lower limbs):
  • Straight leg raise (SLR): positive on the left at ~40° reproducing radicular pain down posterior-lateral thigh to lateral foot
  • Sensation: decreased pin-prick sensation over the lateral aspect of the left foot and little toe (S1 dermatome)
  • Motor: left plantarflexion 4/5 (S1), dorsiflexion 5/5
  • Reflexes: left ankle (Achilles) reflex reduced compared with right
• Saddle sensation: preserved
• Bladder/bowel: no retention, normal anal tone on brief exam

Investigations

• Full blood count: Hb 13.2 g/dL, WCC 6.5 x10^9/L (no infection)
• CRP: 2 mg/L (normal) (low likelihood of inflammatory/infective cause)
• Lumbar spine X-ray: mild L5–S1 disc space narrowing and early degenerative changes (age-appropriate)
• MRI lumbosacral spine: left posterolateral disc extrusion at L5–S1 impinging the left S1 nerve root (correlates with clinical radiculopathy)

Diagnosis

• Primary: Left L5–S1 intervertebral disc herniation causing left S1 radiculopathy.
  • Evidence: acute onset after heavy lifting, shooting pain down posterior/ lateral left leg, sensory loss in lateral foot (S1), reduced left ankle reflex, positive SLR, and MRI showing left L5–S1 disc extrusion compressing the left S1 nerve root.
• Differentials:
  • Lumbar muscle strain — less likely given dermatomal sensory change and positive SLR.
  • Piriformis syndrome — can mimic sciatica but less likely with clear S1 dermatomal signs and MRI nerve-root compression.
  • Spinal stenosis — usually older with neurogenic claudication rather than acute post-lift radiculopathy.
  • Peripheral neuropathy (e.g., diabetic) — unlikely (no diabetes, focal dermatomal findings and acute onset).

Management

• Immediate:
  • Advise activity modification: remain as active as tolerated, avoid prolonged sitting and heavy lifting; short periods of rest if severe pain.
  • Analgesia: regular paracetamol plus an NSAID if no contraindication; consider a short course of oral opioids (e.g., codeine) only for severe breakthrough pain and for short duration.
  • Start a neuropathic pain agent if radicular symptoms are prominent (e.g., gabapentin or pregabalin) and titrate as tolerated.
  • Consider a short taper of oral corticosteroids for severe radicular pain on individual basis (local policy dependent).
• Rehabilitation:
  • Early referral to physiotherapy for supervised exercise program, core strengthening, and education on posture and ergonomics.
  • Provide employer fit note / modified duties for 1–2 weeks with advice on gradual return.
• If symptoms persist or worsen:
  • Offer epidural steroid injection if severe persistent radicular pain after 4–6 weeks despite conservative therapy.
  • Urgent neurosurgical referral if progressive motor weakness (e.g., worsening plantarflexion or new foot drop) or any signs of cauda equina (saddle anaesthesia, new bowel/bladder dysfunction).
• Follow-up:
  • Review in 4–6 weeks to assess symptom progression and response to conservative measures; sooner if neurological deterioration.

Key Learning Points

• Sciatica due to lumbar disc herniation typically presents with acute radicular pain after a precipitant, dermatomal sensory loss, a positive straight leg raise, and may show nerve-root compression on MRI.

• Neurological examination (motor strength, sensation, reflexes) and red-flag screening (saddle anaesthesia, bladder/bowel dysfunction, severe progressive weakness) guide urgency of imaging and referral.

• Initial management is conservative (analgesia, physiotherapy, activity modification); consider epidural injection or surgical referral for persistent severe pain or progressive neurological deficits.