Sciatica/Herniated Disc, Emergency Medicine

Basics

Description

Pain that radiates from the back into buttocks and lower extremity distal to knee, with or without sensory or motor deficits:
- 95% sensitive, 88% specific for herniated disc (HD)
- 3 " 5% lifetime prevalence
- Peaks 4th to 5th decade
- 2 " 10% of low back pain
- 95% L5 or S1 nerve root
- 90% improve with conservative management
- Radicular symptoms usually resolve within 6 wk
- 5 " 10% require surgery

Etiology

Protrusion of colloidal gel (nucleus pulposus) through weakened surrounding fibrous capsule (annulus fibrosis)
Risk factors:
- Smoking
- Repetitive lifting/twisting
- Vehicular/machinery vibration
- Obesity
- Sedentary lifestyle

Diagnosis

Signs and Symptoms

History

Low back pain precedes onset of leg pain
Leg pain predominates with time
Sharp, well localized, radiates distal to knee
Exacerbated by activities that increase intradiscal pressure:
- Valsalva maneuver
- Cough
- Nerve-root tension (sitting, straight leg raise)
Relieved by decreasing pressure/tension:
- Lying supine
- Walking
Paresthesia is the most common sensory symptom

Physical Exam

Neurologic exam (motor, sensory, deep tendon reflexes)
L4 root/L3 " L4 disc:
- Knee extension/hip adduction
- Anteromedial leg/knee/medial malleolus
- Patellar reflex
L5 root/L4 " L5 disc:
- Great toe and foot dorsiflexion
- Dorsomedial foot/1st web space
- No reflex
S1 root/L5 " S1 disc:
- Foot plantarflexion
- Posterior leg/lateral malleolus/dorsolateral foot
- Achilles reflex
- Rectal exam (tone, sensation)
Straight leg raise:
- Elevate ipsilateral leg by heel 30 " 60 ° with or without dorsiflexing foot
- Reproduces radicular pain past knee
- 80% sensitive for HD
Crossed straight leg raise test (pathognomonic):
- Elevate contralateral leg
- Pain in involved leg
- Less sensitive but very specific for HD

Essential Workup

Complete history and physical exam
See below for test indications

Diagnosis Tests & Interpretation

Lab

Indicated if clinical suspicion for differential diagnoses (DDX), not limited to:
- CBC
- ESR/CRP
- UA

Imaging
PA/Lateral of LS spine

Helps to rule out some DDX
Indications:
- Extremes of age (<20, >55 yr)
- Unresolved back pain (>4 " 6 wk) despite conservative treatment
- Red flags on history and physical exam:
  - Trauma
  - Constitutional symptoms (fever, unexplained weight loss, malaise)
  - History of cancer
  - Immunocompromised
  - IV drug abuse
  - Recent bacterial infection
  - Worse at night/wakes patient from sleep
  - Fever
  - Midline point tenderness
  - Neurologic deficits

MRI (Criterion Standard)

Indications:
- Acute, severe neurologic deficits (order from ED)
- Suspicion of infectious etiology of back pain:
  - Epidural abscess
  - Osteomyelitis
  - Discitis
- 6 wk failed conservative therapy (order on outpatient basis)
- Disc disease (>25%):
  - Incidental finding on MRI in asymptomatic patients
  - No relationship between extent of protrusion and degree of symptoms

CT Myelogram

Rarely used alternative for MRI
CT better at bone details

Diagnostic Procedures/Surgery

Postvoid residual (PVR):
- Overflow incontinence = PVR >100 mL, suspect cauda equina syndrome

Differential Diagnosis

Lumbosacral strain
Degenerative joint disease
Spondylolisthesis
Hip/sacroiliac joint (infection, fracture, bursitis)
Pneumonia, pulmonary embolus
Pyelonephritis, renal calculi
Ectopic pregnancy, pelvic inflammatory disease
Abdominal aortic aneurysm (AAA)
Peripheral vascular disease (claudication)
Herpes zoster
Psychological: Functional or secondary gain (drug seeking, disability)
Irritating lesion affecting a lumbosacral nerve anywhere along its route:
- Brain:
  - Thalamic or spinothalamic tumor, hemorrhage
- Spinal cord (myelopathy):
  - Spinal stenosis, tumor, hematoma, infection (epidural abscess, discitis, osteomyelitis)
- Root (radiculopathy):
  - Intradural: Tumor, infection
  - Extradural: HD, lumbar spine/foraminal stenosis (pseudoclaudication), spondylolisthesis, cyst, tumor, infection
- Plexus (plexopathy):
  - Tumor, AAA, infection (iliopsoas abscess), hematoma (retroperitoneal)
- Peripheral nerve (neuropathy):
  - Toxic/metabolic/nutritional, infection, trauma, ischemia, infiltration, compression, entrapment

Usually secondary to trauma or serious underlying medical disease (e.g., leukemia); consider complete workup
<10 yr:
- Infection
- Tumor
- Arteriovenous malformation
≥10 yr:
- Traumatic HD
- Spondylolisthesis
- Scheuermann disease
- Tumor

Ectopic pregnancy
Labor
Pyelonephritis
Musculoskeletal

Treatment

Pre-Hospital

Full spine precautions for trauma victims

Initial Stabilization/Therapy

Evaluate for neurosurgical emergency

Ed Treatment/Procedures

Pain relief:

NSAIDs 1st line
Muscle relaxants, opioids as needed in acute phase

Medication

NSAIDs:
- Ibuprofen (Motrin, Advil): 600 " 800 mg (peds: 5 " 10 mg/kg/dose) PO TID " QID
- Naproxen (Naprosyn, Aleve): 500 mg PO BID
Muscle relaxants (short term):
- Cyclobenzaprine (Flexeril): 5 " 10 mg TID
- Diazepam (Valium): 2 " 10 mg (peds: 0.1 mg/kg/dose) PO TID " QID
- Methocarbamol (Robaxin): 1,000 " 1,500 mg PO QID
Opioids (short term):
- Hydromorphone (Dilaudid): 2 " 4 mg PO/0.5 " 2 mg IM/IV q4 " 6h PRN
- Morphine sulfate: 2 " 10 mg (peds: 0.1 mg/kg/dose) IM/IV q2 " 4h PRN
- Codeine 30 mg + acetaminophen 300 mg; do not exceed acetaminophen4 g/24 h
- Hydrocodone 5 mg + acetaminophen 300 mg; do not exceedacetaminophen 4 g/24 h

Follow-Up

Disposition

Admission Criteria

Severe neurologic deficit (cauda equina syndrome, inability to walk)
Progressive neurologic deficit
Multiple root involvement
Unstable fracture, infection, neoplasm
Inability to manage as outpatient (social situation/pain)

Discharge Criteria
Patient able to ambulate, follow instructions, has reliable home situation and planned follow-up
Issues for Referral
Abnormal workup that does not warrant immediate admission. Where and when depend on results (large DDX)

Follow-Up Recommendations

Consultant (orthopedic spine surgeon or neurosurgeon) or PCP within 1 wk
Conservative treatment (4 " 6 wk):
- Medication as noted
- Avoid complete bed rest, 2 days at most
- Limited activity in acute phase but gradually increase activity/exercise as tolerated
- Avoid movements that load lower back or exacerbate pain:
  - Heavy lifting, twisting, bending, stooping, bodily vibration
Therapies of unproven benefit:
- Chiropractic care
- Transcutaneous electrical nerve stimulation
- Traction
- Back brace/corset
- Ultrasound
- Diathermy
- Acupuncture, acupressure
- Massage
- Systemic glucocorticoids

Additional Reading

Haas M, Sharma R, Stano M. Cost-effectiveness of medical and chiropractic care for acute and chronic low back pain. J Manipulative Physiol Ther. 2005;28(8):555 " 563.
Jegede KA, Ndu A, Grauer JN. Contemporary management of symptomatic lumbar disc herniations. Orthop Clin North Am. 2010;41(2):217 " 224.
Schoenfeld AJ, Weiner BK. Treatment of lumbar disc herniation: Evidence-based practice. Int J Gen Med. 2010;3:209 " 214.
Tarulli AW, Raynor EM. Lumbosacral radiculopathy. Neurol Clin. 2007;25:387 " 405.
van der Windt DA, Simons E, Riphagen II, et al. Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain. Cochrane Database Syst Rev. 2010;(2):CD007431.

Codes

ICD9

722.10 Displacement of lumbar intervertebral disc without myelopathy
724.3 Sciatica
724.4 Thoracic or lumbosacral neuritis or radiculitis, unspecified

ICD10

G57.00 Lesion of sciatic nerve, unspecified lower limb
M51.16 Intervertebral disc disorders w radiculopathy, lumbar region
M54.30 Sciatica, unspecified side

SNOMED

23056005 Sciatica (disorder)
311804006 Prolapsed lumbar intervertebral disc with sciatica (disorder)
299967007 Compression of sacral nerve root (disorder)

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