Symptom To Diagnosis - Low Back Pain Flashcards
Back pain due to disorders of the musculoskeletal structures - Non specific back pain:
- In general, a specific anatomic diagnosis cannot be made, and there is no definite relationship between anatomic findings and symptoms.
- No neurologic signs and symptoms.
- Non progressive.
Examples of non specific musculoskeletal back pain:
- Lumbar strain and sprain.
- Degenerative processes of disks and facets.
- Spondylolisthesis (anterior displacement of a vertebra on the one beneath it).
- Spondylolysis (defect in the pars interarticularis of the vertebra).
- Scoliosis.
Specific musculoskeletal back pain:
- A specific anatomic diagnosis can often be made.
- Neurologic signs and symptoms.
- Can be progressive.
Examples of specific musculoskeletal back pain:
- Herniated disk.
- Spinal stenosis.
- Cauda equina syndrome.
Back pain due to SYSTEMIC disease affecting the spina - Serious, requiring specific and often rapid treatment:
- Neoplasia - MM, metastasis, lymphoma/leukemia, spinal cord tumors, primary vertebral tumors.
- Infection - Osteomyelitis, septic diskitis, paraspinal abscess, epidural abscess.
Back pain due to SYSTEMIC disease affecting the spine - Serious, requiring treatment but not immediately:
- Osteoporotic compression fracture.
2. Inflammatory arthritis - Ank. spondylitis, psoriatic arthritis, IBD arthritis, Reiter.
Back pain due to VISCERAL disease is serious and often requires specific and rapid diagnosis and treatment:
- Retroperitoneal - Aortic aneurysm, retroperitoneal adenopathy or mass.
- Pelvic - Prostatitis, endometriosis, PID.
- Renal - Nephrolithiasis, pyelonephritis, perinephric abscess.
- GI - Pancreatitis, cholecystitis, penetrating ulcer.
Hip flexion:
Ilio-psoas L2, L3.
Direct nerve supply and femoral twigs.
Knee extension:
Quadriceps - L2, L3, L4
Femoral nerve.
Hip extension:
Glutei L4, L5
Gluteal nerves.
Knee flexion:
Hamstrings L5, S1
Tibial nerve, peroneal nerve. Lateral head of biceps femoris only.
Hip adduction:
Glutei and tensor fascia lata L4, L5.
Hip adduction:
Adductor group L2, L3, L4
Obturator nerve.
Plantar flexion:
S1, S2 tibial nerve - gastrocnemii (tibialis posterior).
Inversion of the foot:
L4 - Tibial and peroneal nerves. (Tibialis anterior, an anterior compartment muscle, and tibialis posterior, a posterior compartment muscle, work together).
Dorsiflexion:
L4, L5 - Peroneal nerve (Tibialis anterior, long extensors, peroneus tertius, extensor digitorum brevis).
Eversion of the foot:
S1 - Peroneal nerve (peronei longus and brevis, long extensors assist, extensor digitorum brevis).
Low back pain evaluation - 1st step:
Is there any: 1. Urinary retention/incontinence. 2. Leg weakness. 3. Saddle anesthesia. IF YES --> IMMEDIATE MRI TO RULE OUT CAUDA EQUINA SYNDROME.
Low back pain approach - If there is NO symptoms/signs of cauda equina syndrome - 2nd step:
- Sciatica.
- History of cancer.
- Osteoporosis risk factors.
- Fever/IVDA/Immunosuppression/Skin infection/Instrumentation.
- Wide-based gait, thigh pain/ older patient.
IF NOT any of the above –> Mechanical low back pain –> Treat conservatively.
Low back pain approach - If sciatica?
Consider herniated disk; treat conservatively –> If NO RESPONSE –> MRI; consider epidural injection or surgery.
Low back pain approach - If history of cancer:
Spine radiograph or MRI to look for vertebral metastasis.
Low back pain approach - Osteoporosis risk factors:
Spine radiograph to look for osteoporotic compression fracture.
Low back pain approach - Fever/IVDA/Immunosuppression/Skin infection/instrumentation?
MRI to look for spinal epidural abscess or vertebral osteomyelitis.
Low back pain approach - Wide-based gait, thigh pain, older patient:
Vascular risk factors?
YES –> Conservative therapy for presumed spinal stenosis/ Consider MRI to confirm diagnosis/ perform ABIs to look for PAD.
NO –> Conservative therapy for presumed spinal stenosis/ Consider MRI to confirm diagnosis.
Mechanical low back pain - Textbook presentation:
The classic presentation is non radiating pain and stiffness in the lower back, often precipitated by heavy lifting.
Mechanical low back pain - Disease highlights:
- May have pain and stiffness in the buttocks and hips.
- Generally occurs hours to days after a new or unusual exertion and improves when the patient is supine.
- Can rarely make a specific anatomic diagnosis.
Mechanical low back pain - Prognosis:
75-90% of patients improve within 1 month.
25-50% have additional episodes over the next year.
Mechanical low back pain - Risk factors for persistent low back pain:
- History of previous back pain.
- Depression.
- Substance abuse.
- Pending or past litigation or disability compensation.
- Low socioeconomic status.
- Work dissatisfaction.
What is important to keep in mind about imaging studies in the approach of low back pain?
Many ASYMPTOMATIC patients will have anatomic abnormalities on imaging studies.
…% of patients aged 14-25 have degenerative disks on plain radiographs:
20%.
…-…% of patients <50 have herniated disks on MRI:
20-75%.
…-…% of patients have bulging disks on MRI.
40-80%.
Over …% of patients >50 have degenerative disks on MRI:
90%.
Up to …% of patients >50 have spinal stenosis:
20%.
Bottom line about imaging studies in low back pain:
Patients who have none of the clinical clues should NOT have any diagnostic testing done.
ACUTE low back pain - Treatment:
- NSAIDS + muscle relaxants are effective.
- Heat and spinal modulation have been shown to reduce ACUTE low back pain.
- Best approach - NSAIDs and heat during the acute phase and activity as tolerated until the pain resolves.
ACUTE low back pain and bed rest:
Does NOT help acute pain and may prolong duration of pain.
Subacute or chronic low back pain - Treatment:
- TCAs.
- Tramadol.
- Opioids.
- Gabapentin.
- Benzodiazepines.
Best evidence is for TCAs.
Herniated disk - Textbook presentation:
Moderate to severe pain radiating from the back down the buttock and leg, usually to the foot or ankle, with associated numbness or paresthesias –> Called sciatica.
Sciatica is classically precipitated by?
A sudden increase in pressure on the disk, such as after coughing or lifting.
Herniated disk - Disk disease is frequently?
ASYMPTOMATIC.
Herniated disk - MC site of weakness:
Foot plantar or dorsiflexion.
Proximal weakness suggests a femoral neuropathy or compression of the lumbar plexus.
Herniated disk - Highest prevalence:
In the 45-64yrs old age group.
Herniated disk - Risk factors:
- Sedentary activities, especially driving.
- Chronic cough.
- Lack of physical exercise.
- Possibly pregnancy.
- -> Jobs involving lifting and pulling have NOT been associated with increased risk.
Herniated disk - Prognosis:
50% –> Recover in 2 weeks.
70% –> Recover in 6 weeks.
Which spinal levels are involved in herniated disks:
L4-L5 and L5-S1 cause 98% of clinically important disk herniations, so pain and paresthesias are often seen in these distributions.
What is important to keep in mind regarding UNILATERAL disk?
There are NO bowel or bladder symptoms with UNILATERAL disk herniations.
Herniated disk - What may aggravate pain?
Coughing, sneezing, or prolonged sitting.
BILATERAL midline herniations can cause the?
Cauda equina syndrome.
Cauda equina syndrome - Features:
- Urinary retention - Sens 90%, spec 95%, LR+=18, LR-=0.1.
- Urinary incontinence.
- Decr. anal sphincter tone (80%).
- Sensory loss in a saddle distribution (75%).
- Bilateral sciatica.
- Leg weakness.
Suspected cauda equina syndrome is?
A MEDICAL EMERGENCY - Requires immediate imaging and decompression.
Sciatica has an LR+ of … for the diagnosis of L4-L5 or L5-S1 herniated disk.
7.9
A positive straight leg test reproduces patients sciatica when the leg is elevated between … and … degrees.
30 and 60 degrees.
Sciatica pain description:
Shooting down the leg, not just a pulling sensation in the hamstring muscle.
Crossed straight leg test:
Is performed by lifting the contralateral leg; a positive test reproduces sciatica in the affected leg.
A straight leg test that elicits back pain is:
NEGATIVE.
Physical exam findings for the diagnosis of disk herniation - Sciatica:
Sens - 95%.
Spec - 88%.
LR+: 7.9.
LR-: 0.06.
Positive crossed straight leg raise for the diagnosis of disk herniation:
Sens - 25%.
Spec - 90%.
LR+ 2.5.
LR- 0.83.
Positive ipsilateral straight leg raise for the diagnosis of herniated disk:
Sens - 91%.
Spec - 26%.
LR+: 1.2.
LR-: 0.3.
Ankle dorsiflexion weakness for the diagnosis of herniated disk:
Sens - 35%.
Spec - 70%.
LR+: 1.2.
LR-: 0.93.
Great toe extensor weakness for the diagnosis of disk herniation:
Sens - 50%.
Spec - 70%.
LR+: 1.7.
LR-: 0.71.
Impaired ankle reflex for the diagnosis of disk herniation:
Sens - 50%.
Spec - 60%.
LR+: 1.3.
LR-: 0.83.
Ankle plantar flexion weakness for the diagnosis of disk herniation:
Sens - 6%.
Spec - 95%.
LR+: 1.2.
LR-: 0.99.
Herniated disk - Plain radiographs:
Do NOT image the disks and are USELESS for diagnosing herniations.
CT and MRI scans for diagnosing herniated disks:
CT –> Sens 62-90%, spec 70-87%, LR+ 2.1-6.9, LR- 0.11-0.54.
MRI –> Sens 60-100%, spec 43-97%, LR+ 1.1-33, LR- 0-0.93.
Herniated disk - In the absence of cauda equina syndrome or progressive neurologic dysfunction, what should be tried?
Conservative therapy for 1 month.
- NSAIDs are the 1st choice.
- Opioids are necessary.
- Bed rest does NOT accelerate recovery.
- Epidural corticosteroid injections may provide temporary pain relief.
Herniated disk - Surgery indications include:
- Impairment of bowel and bladder function (cauda equina syndrome).
- Gross motor weakness.
- Progressive neurologic symptoms or signs.