Skills in diagnosis and treatment of low back pain.

The student should be able to:

Discuss the differential diagnosis for low back pain. Develop physical exam skills in evaluating low back pain. Develop the skills in diagnosis and treatment of low back pain. Recognize red flags for possible serious causes of low back pain. List the indications for imaging studies for low back pain. Propose appropriate treatment for back pain. Discuss the management of refractory back pain with consultation and surgical intervention.

Knowledge

Low Back Pain Prevalence, Cost, & Duration

Low back pain (LBP) is the fifth most common reason for all doctor visits. In the U.S., lifetime prevalence of LBP is 60% to 80%. The direct and indirect costs for treatment of LBP are estimated to be $100 billion annually. Fortunately, most LBP resolves in two to four weeks.

Common Causes of Back Pain

Musculoskeletal (MSK) and Non-MSK Causes of Back Pain

MSK Causes

Axial: Degenerative disc disease Facet arthritis Sacroiliitis Ankylosing spondylitis Discitis Paraspinal muscular issues SI dysfunction

Radicular: Disc prolapse Spinal stenosis

Trauma: Lumbar strain Compression fracture

Non-MSK Causes

Neoplastic: Lymphoma/leukemia Metastatic disease Multiple myeloma Osteosarcoma

Inflammatory: Rheumatoid Arthritis

Visceral: Endometriosis Prostatitis Renal lithiasis

Infection: Discitis

Herpes zoster Osteomyelitis Pyelonephritis Spinal or epidural abscess

Vascular: Aortic aneurysm

Endocrine: Hyperparathyroidism Osteomalacia Osteoporotic vertebral fracture Paget disease

Gastrointestinal: Pancreatitis Peptic ulcer disease Cholecystitis

Gynecological: Endometriosis Pelvic inflammatory disease

Most Common Causes of Back Pain

There are three major categories of back pain: mechanical, visceral, and non-mechanical. Mechanical

97% of back pain no primary inflammatory or neoplastic cause

Visceral

2% of back pain no primary involvement of the spine, usually from internal organs

Non-mechanical

1% of back pain other

The three most common causes of back pain are all mechanical: 1. lumbar strain/sprain – 70% 2. age-related degenerative joint changes in the discs and facets – 10%. 3. herniated disc – 4% Acute sciatica is lower back pain with radiculopathy below the knee and symptoms lasting up to six weeks. Sciatica is a common and costly problem, caused by a variety of conditions: disc herniation, lumbar spinal stenosis, facet joint osteoarthritis or other arthropathies, spinal cord infection or tumor, or spondylolisthesis. Less common causes of mechanical back pain: Skills in diagnosis and treatment of low back pain.

osteoporotic fracture – 4% spinal stenosis – 3%

Uncommon causes of back pain: Pyelonephritis, a visceral cause, accounts for 0.4% of back pain.

Risk Factors for Low Back Pain

Prolonged sitting, with truck driving having the highest rate of LBP, followed by desk jobs Deconditioning Sub-optimal lifting and carrying habits Repetitive bending and lifting Spondylolysis, disc-space narrowing, spinal instability, and spina bifida occulta Obesity Prolonged use of steroids Intravenous drug use Education status: low education is associated with prolonged illness Psycho-social factors: anxiety, depression, stressors in life Occupation: Job dissatisfaction, increased manual demands, and compensation claims

Red Flags For Serious Illness or Neurologic Impairment with Back Pain

Fever Unexplained weight loss Pain at night Bowel or bladder incontinence Urinary retention Neurologic symptoms Saddle anesthesia Trauma

Anatomy of Mechanical Lower Back Pain

Mechanical lower back pain generally involves one or more of the following: 1. bones of the spine 2. muscles and ligaments surrounding the spine 3. nerves (the nerves entering and exiting the spinal cord or problems with the cord itself)

Symptoms of Disc Herniation

When disc herniation is suspected, a very important historical point is the position of comfort or worsening of symptoms. Classically, disc herniation is associated with exacerbation when sitting or bending; and relief while lying or standing. Other symptoms of disc herniation include:

increased pain with coughing and sneezing pain radiating down the leg and sometimes the foot paresthesias muscle weakness, such as foot drop

Red Flags for Serious Underlying Causes of Back Pain

While the majority of back pain has a benign course and resolves within a month, a small number of cases are associated with serious underlying pathology. Timely treatment of these conditions is important to avoid serious consequences. Indications for early diagnostic testing such as x-rays and other imaging and referral are patients with progressive neurological deficits, patients not responding to conservative treatment, and patients with red flags signaling serious medical conditions such as fracture, cancer, infection, and cauda equina syndrome. Knowing this would also help guide the evaluation and treatment of the back pain. While the worst pain a patient has ever had is concerning and needs to be addressed, it is not by itself indicative of a more serious condition. Numbness can be part of cauda equina, but is also common with a simple disc herniation, therefore by itself it is not a red flag. Red Flags by Serious Condition

Cancer

1. History of cancer 2. Unexplained weight loss >10 kg within 6 months 3. Age over 50 years or under 17 years old 4. Failure to improve with therapy 5. Pain persists for more than 4 to 6 weeks 6. Night pain or pain at rest

Infection

1. Persistent fever (temperature over 100.4 F) 2. History of intravenous drug abuse 3. Recent bacterial infection, particularly bacteremia (UTI, cellulitis, pneumonia, pelvic inflammatory disease) 4. Immunocompromised states (chronic steroid use, diabetes, HIV, taking chemotherapeutic or biologic medications)

Cauda Equina Syndrome

1. Urinary incontinence or retention 2. Saddle anesthesia 3. Anal sphincter tone decreased or fecal incontinence 4. Bilateral lower extremity weakness or numbness 5. Progressive neurologic deficits

Significant Herniated Nucleus Pulposus

1. Major muscle weakness (strength 3 of 5 or less) 2. Foot drop

Vertebral Fracture

1. Prolonged use of corticosteroids 2. Mild trauma over age 50 years 3. Age greater than 70 years 4. History of osteoporosis

5. Recent significant trauma at any age (car accident, fall from substantial height) 6. Previous vertebral fracture Skills in diagnosis and treatment of low back pain.

Acute Low Back Pain Prognosis

Most cases of low back pain are acute in onset and resolution, with 90% resolving within one month and only 5% remain disabled longer than three months. For patients who are out of work greater than six months, there is only 50% chance of them returning to work; this drops to almost zero chance if greater than two years. Patients who are older (>45) and patients who have psychosocial stress take longer to recover. Recurrence rate for back pain is high at 35 to 75%.