Family Medicine 10: 45-year-old with low back pain User: Monica Morales Email: [email protected] Date: February 8, 2024 6:38 PM

Learning Objectives

The student should be able to:

Recognize the societal and personal costs of acute and chronic back pain.

Conduct a focused history and physical exam appropriate for differentiating between common etiologies of a patient presenting with low back pain.

List risk factors for the development of low back pain.

Recognize “don’t miss” conditions that may present with low back pain.

Summarize the key features of a patient presenting with low back pain, capturing the information essential for differentiating between the common and “don’t miss” etiologies.

Describe an evidence-based management plan that includes pharmacological and non-pharmacological treatment of acute LBP.

Find and apply a cost-effective diagnostic approach for common and "don't miss" conditions in acute low back pain.

Knowledge

Low Back Pain Prevalence, Duration, and Burden

Low back pain (LBP) is one of the most common reasons for doctor visits. In the U.S., the lifetime prevalence of LBP is up to to 80%. LBP is often described by its duration: acute LBP is defined as lasting less than 4 weeks; sub-acute LBP lasts between 4 and 12 weeks, and chronic LBP lasts longer than this. (Chronic nonspecific LBP is a diagnosis of exclusion after ensuring that a pathologic cause is not identified).

Most episodes of acute LBP resolve within days to weeks with self-care: the spontaneous recovery rate is reported to be up to 75% at 4 weeks and more than 90% at six months. However, one year after initial acute onset and resolution of low back pain, up to one-third of patients report continued chronic low back pain of at least moderate intensity and one-fifth report continued functional limitations.

Common Causes of Back Pain

Musculoskeletal (MSK) causes: Also known as mechanical causes (intrinsic pain, directly associated with the spine)

Axial:

Degenerative disc disease

Facet arthritis

Sacroiliitis

Ankylosing spondylitis

Spondylolyis & Spondylolisthesis

Discitis

Paraspinal muscular issues

Sacroiliac joint dysfunction

Radicular:

Disc prolapse

Spinal stenosis

Trauma:

Lumbar strain

Compression fracture

Non-MSK causes: Also known as nonmechanical causes (systemic causes of pain)

Neoplastic:

Lymphoma/leukemia

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Metastatic disease

Multiple myeloma

Osteosarcoma

Inflammatory:

Rheumatoid Arthritis

Visceral: pain related to internal organs

Endometriosis

Prostatitis

Renal lithiasis

Infection:

Discitis

Herpes zoster

Osteomyelitis

Pyelonephritis

Prostatitis

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

The three most common causes of back pain are all mechanical/MSK causes, which account for 95-97% of back pain. Non-mechanical (systemic, and visceral) causes account for only 3-5%.

1. Lumbar strain/sprain: 70%

2. Age-related degenerative joint changes in the discs and facets: 10%.

3. Herniated disc: 4%

Acute sciatica is a diagnosis of lower back pain with pain radiating down the back of the leg, usually below the knee. Sciatica is caused by a variety of conditions: disc herniation, lumbar spinal stenosis, facet joint osteoarthritis or other arthropathies, spinal cord infection or tumor, or spondylolisthesis. Symptoms resolve without treatment within two weeks in about a third of patients, and within three months in about 75% of patients. Severe cases or cases with a neurologic deficit may have prolonged recovery, but the prognosis is still good.

Less common causes of mechanical back pain:

Osteoporotic fracture: 4%

Spinal stenosis: 3%

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

Risk Factors for Low Back Pain

Age > 30

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Certain occupations: Truck drivers (mainly due to vibration, ergonomics, and risk for deconditioning) have the highest rate of LBP, followed by people with desk jobs. People with jobs that support active lifestyles are less likely to have back pain, but those who were previously sedentary and become more active (at work or otherwise) can be at risk for LBP.

Prolonged sitting and deconditioning

Suboptimal lifting and carrying habits

Repetitive bending and lifting

Spondylolysis, disc-space narrowing, spinal instability, and spina bifida occulta

Obesity

Prolonged use of steroids

Smoking

Diabetes mellitus

Education and socioeconomic status: lower levels of income and education are associated with prolonged pain, potentially due to structural issues related to work, (lack of) support, and other factors

Mental health diagnoses, including anxiety and depression, can contribute to pain

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 deficits

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 (vertebrae)

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 improving 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

Foot drop (difficulty lifting the front part of the foot)

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 imaging tests and/or referral are progressive neurological deficits, nonresponse to conservative treatment, or red flags signaling serious medical conditions such as fracture, cancer, infection, and cauda equina syndrome.

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 syndrome, but is also common with a simple disc herniation, therefore by itself, it is not a red flag.

Red Flags by Serious Condition

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1. History of cancer

2. Unexplained weight loss > 10 kg within 6 months

3. Age over 50 years or under 17 years old

4. Lack of improvement 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 38 °C (100.4 °F))

2. History of intravenous drug use

3. Recent bacterial infection, particularly with bacteremia (UTI, cellulitis, osteomyelitis, endocarditis, pneumonia, or 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

Severe herniated nucleus pulposus

A herniated nucleus pulposus occurs when the soft, central portion of an intervertebral disc prolapses through the disc itself. Mild cases can be managed conservatively as with other disc herniations, but severe cases may require immediate surgery.

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

2. Foot drop

Vertebral fracture

Recent significant trauma at any age (motor vehicle crash, fall from substantial height) can result in a traumatic vertebral fracture.

Vertebral compression fractures can be atraumatic or a result of mild trauma and are most common in people of older age.

Other risk factors for vertebral compression fractures include:

1. Prolonged use of corticosteroids or other medications that decrease bone density

2. Osteoporosis or osteopenia

3. Previous vertebral fracture

4. Inactivity

5. Female sex

6. Alcohol or tobacco use

Acute Low Back Pain Prognosis

Most episodes of acute LBP resolve within a month with conservative management, with spontaneous recovery rates reported to be up to 75% at four weeks and > 90% at six months, regardless of treatment. Most patients with low back pain can return to work quickly, even if pain has not completely subsided: complete pain relief usually occurs after the resumption of normal activities.

Severe cases or cases with neurologic deficit may have prolonged recovery, but prognosis is still overall promising. Recurrence of low back pain is common—some studies show that up to 70% of patients may experience a recurrence within a year, though estimates are quite variable. Risk factors for recurrence include exposure to awkward posture, prolonged sitting (> 5 hours a day), and more than two previous episodes.

Clinical Skills

Approach to the Physical Exam for Back Pain

Throughout the exam, make certain to note how your patient is sitting, standing, and walking in general, asking yourself, "What is the degree of impairment?" and "How uncomfortable are they?"

Perform the back exam systematically in sequential order with the patient:

1. Standing

2. Sitting

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3. Supine

Physical Exam for Back Pain—Standing

1. Inspection: Look at posture, contour, and symmetry. Also, inspect overlying skin to check for any lesions or abnormalities.

Check for lordosis (excessive curvature of the lower back towards front of body)

Check for kyphosis (rounding of the spine on the upper back, like a hump)

Check for scoliosis (curvature laterally like an "S" or "C")

Slight scoliosis may be more easily visualized during lumbar flexion. This is performed by having the patient stand with their feet and hands together, like they are about to dive off a diving board, bending forward toward their toes. Look out across the back to see if the shoulders are level.

2. Palpation: Check for any tenderness, tightness, rope-like tension, or inflammation in the paraspinal muscles or tenderness over bony prominences.

3. Range of motion (ROM):

Lumbar Flexion: Restriction and pain during flexion are suggestive of herniation, osteoarthritis, or muscle spasm (generally, mechanical causes).

Lumbar Extension: Pain with extension is suggestive of spinal stenosis.

Lateral Bending: Most patients should be able to touch the proximal fibular head of the knee. Pain on the same side as bending is suggestive of bony pathology, such as osteoarthritis. Pain on the opposite side of bending is suggestive of a muscle strain.

Rotation to the left and rotation to the right. Compare side to side.

Range of motion varies and may be of limited diagnostic use, but can be helpful in planning and monitoring treatment.

4. Gait: Ask the patient to walk on heels and toes.

Difficulty with heel walk is associated with L3-L4 disc herniation/L4 nerve root

Difficulty with toe walk is associated with L5-S1 disc herniation/S1 nerve root

5. Stoop test: Have the patient go from a standing to squatting position.

In patients with central spinal stenosis, squatting will reduce the pain.

Asking the patient to jump is not part of a back exam and may cause discomfort to a patient who is already in pain.

Physical Exam for Back Pain—Seated Position

Check reflexes, muscle strength, and sensation of the lower extremities. Focus on the L4, L5, and S1 nerve roots because most neuropathic back pain is due to impingement of these. Therefore, check the patellar reflex (L2-4) and Achilles reflex (S1). Check muscle strength for hip flexion, abduction, and adduction; knee extension and flexion; as well as ankle dorsiflexion and plantar flexion. Also, test for sharp and light touch along the dermatomal distribution of the great toe (L5), lateral malleolus, and posterolateral foot (S1).

Overview of the neurologic exam

Deep tendon reflexes

Grading reflexes:

0 No evidence of contraction

1+ Decreased, but still present (hyporeflexic)

2+ Normal

3+ Increased (hyperreflexic)

4+ Clonus: Repetitive shortening of the muscle after a single stimulation

Decreased patellar reflex implies nerve impingement at the L3-L4 level/L4 nerve root. Decreased Achilles reflex implies nerve impingement of L5-S1 level/S1 nerve root. Hyperreflexia can be a sign of upper motor neuron syndrome associated with spinal cord compression.

Muscle strength

Rating scale:

0/5 No movement

1/5 Barest flicker of movement of the muscle, though not enough to move the structure to which the muscle is attached

2/5 Voluntary movement which is not sufficient to overcome the force of gravity. For example, the patient would be able to slide their hand across a table but not lift it from the surface.

3/5 Voluntary movement capable of overcoming gravity, but not any applied resistance. For example, the patient could raise their hand off a table, but not if any additional resistance were applied.

4/5 Voluntary movement capable of overcoming "some" resistance

5/5 Normal strength

i. Hip Flexion (L 2, 3, 4): Resist the movement of the patient lifting their thigh.

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ii. Hip Abduction (L 4, 5, S1): Resist the movement of the patient abducting (moving outward) their leg at the hip.

iii. Hip Adduction (L 2, 3, 4): Resist the movement of the patient adducting their leg (moving inward) at the hip.

iv. Knee Extension (L 2, 3, 4):

Resist the movement of the patient extending their knee.

v. Knee Flexion (L 5, S1, S2):

Resist the movement of the patient flexing their knee.

vi. Ankle Dorsiflexion (L 4, 5): Resist the movement of the patient dorsiflexing their ankle (pointing foot upward).

vii. Ankle Plantar Flexion (S 1, S 2): Resist the movement of the patient plantar flexing their ankle (pointing foot downward).

Decreased strength implies nerve impingement of the associated nerve.

Sensation

Test for sharp and light touch along a dermatomal distribution, great toe (L5), lateral malleolus, and posteriolateral foot (S1)

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Nerve root impingement syndromes

Nerve root Reflex Pin-prick sensation Motor examination Functional test

L3 Patellar tendon reflex Lateral thigh and medial femoral condyle Extend quadriceps Squat down and rise

L4 Patellar tendon reflex Medial leg and medial ankle Dorsiflex ankle Walk on heels

L5 Medial hamstring Lateral leg and dorsum of foot Dorsiflex great toe Walk on heels

S1 Achilles tendon reflex Posterior calf, sole of foot, and lateral ankle Stand on toes Walk on toes (plantarflex ankle)

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Disk L3-L4, Nerve root L4, Patellar Reflex, Motor examination: Ankle dorsiflexion

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Disk L3-L4, Nerve root L4, Patellar Reflex, Sensory loss signature zone: Medial malleolus

Disk L4-L5, Nerve root L5, Reflex: none, Motor examination: Great toe dorsiflexion

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Disk L4-L5, Nerve root L5, Reflex: none, Sensory loss signature zone: Dorsal third metatarsophalangeal joint

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Disk L5-S1, Nerve root S1, Reflex: Achilles, Motor examination: Ankle plantar flexion

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Disk L5-S1, Nerve root S1, Reflex: Achilles, Sensory loss signature zone: Lateral heel

Physical Exam for Back Pain—Supine

1. Abdominal exam

Auscultation: Check for abdominal bruit, looking for abdominal aortic aneurysm (AAA). These aneurysms are more common in people older than 65, especially those who have a smoking history.

Palpation: Check for abdominal and/or pelvic tenderness; palpate for a pulsatile mass (indicating a AAA).

2. Rectal exam

Needed only in patients with symptoms suggesting acute prostatitis, or those with red flags or alarm symptoms (discussed further below).

If indicated, check for masses, bleeding, or abnormal rectal tone. Bleeding or rectal mass can be signs of cancer with metastasis to the spine causing back pain. Decreased tone can indicate disc herniation and/or cauda equina syndrome. Prostatitis can cause the prostate to be tender on examination.

3. Passive straight leg raise (SLR or Lasegue's sign)

The leg can usually be raised about 80 degrees.

If a patient can only raise their leg to < 80 degrees, they could have tight hamstrings or a sciatic nerve problem.

To differentiate between tight hamstrings and a sciatic nerve problem, raise the leg to the point of pain, lower slightly, then dorsiflex the foot. If there is no pain with dorsiflexion, the patient's hamstrings are tight.

The test is positive if pain radiates down the posterior/lateral thigh past the knee. This radiation indicates stretching of the nerve roots

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(specifically S1 or L5) over a herniated disc.

This pain will most likely occur between 30 and 70 degrees.

4. Crossed leg raise : asymptomatic leg is raised

Test is positive if pain is increased in the contralateral leg; this correlates with the degree of disc herniation. Such results imply a large central herniation.

A negative crossed leg raise test is nonspecific and does not rule out lumbar radiculopathy, but a positive test is virtually diagnostic of disc herniation.

5. FABER test : flexion, abduction, and external rotation

The Faber test evaluates for pathology of the hip joint, sacrum, or sacroiliac joint (e.g., sacroiliac pain from sacroiliitis).

The test is performed by flexing the hip and placing the foot of the tested leg on the opposite knee. Pressure is then placed on the tested knee while stabilizing the opposite hip.

The test is positive if there is pain at the hip or sacral joint and/or if the leg cannot lower to the point of being parallel to the tabletop. (see picture 4)

The FABER test should be performed in all patients suspected of having sacroiliac pain, not just in older adult patients. Sacroiliitis can occur in younger people as well.

6. Muscle atrophy: of quadriceps and calf muscles.

Management

Conservative Therapy for Acute Low Back Pain

Initial conservative therapy for acute low back pain includes:

Pharmacologic therapy: NSAIDs or skeletal muscle relaxants

Nonpharmacologic treament: Heat, massage, acupuncture, osteopathic spinal manipulation

Activity: Advice to stay active and/or participate in physical therapy

Pharmacologic therapy: The first-line medications for the treatment of LBP are nonsteroidal anti-inflammatory drugs (NSAIDs). There is moderate evidence that NSAIDs are helpful to reduce pain in the treatment of acute LBP. Non-benzodiazepine muscle relaxants such as cyclobenzaprine have also been found in some studies to provide short-term pain relief.

There is little evidence regarding the benefits of other medications including acetaminophen, though acetaminophen is sometimes used for its potential synergistic effects with other medications, or for patients who can not take other pain medications. Systemic corticosteroids have not been found to be beneficial for acute low back pain. While opioids may offer short-term pain relief, there is less evidence of any long-term benefits and significant concerns about side effects and the risks of misuse or dependence.

Nonpharmacologic Therapy: There is limited evidence that both acupuncture and massage can provide small decreases in the intensity of acute low back pain; massage may also help in the short-term with function. There is some evidence that osteopathic spinal manipulation may reduce pain and improve function. Heat wraps can help with pain in the short term.

Activity: Strict bed rest has been shown to prolong recovery. Patients should be encouraged to resume normal activities as soon as they are able to. Physical therapy can be helpful for the development of an individualized self-treatment plan.

Relatively few patients will benefit from surgery, so referral to a spine surgeon should be considered initially only if patients have an indication for urgent surgery, such as progressive motor weakness or cauda equina syndrome.

There is strong evidence that all patients should receive appropriate education on the treatment and recovery expectations for acute low back pain.

Effectiveness of Physical Therapy for Acute Back Pain

There is some data to show that tailored physical therapy is slightly more effective for acute back pain compared to recommendations that patients stay active. Physical therapy can be done by the patient, or as part of an active rehabilitation program with a therapist. The McKenzie method, which offers assessment by a trained physical therapist, followed by an individualized self-treatment program, has moderate evidence for improving acute low back pain. Early guideline-directed physical therapy has also been found to reduce the use of health care o

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