eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Back Pain, Mechanical

Debra G Perina, MD, Associate Professor, Director of Prehospital Care Division, Department of Emergency Medicine, University of Virginia Health Sciences Center

Updated: Jul 16, 2009

Introduction

Background

Mechanical low back pain is one of the most common patient complaints expressed to emergency physicians in the United States accounting for more than 6 million cases annually. Approximately two thirds of adults are affected by mechanical low back pain at some point in their lives, making it the second most common complaint in ambulatory medicine and the third most expensive disorder in terms of health care dollars spent surpassed only by cancer and heart disease.¹

Low back pain reportedly occurs at least once in 85% of adults younger than 50 years, and 15-20% of Americans have at least one episode of back pain per year. Of these patients, only 20% can be given a precise pathoanatomic diagnosis. Low back pain affects men and women equally. The onset most frequently occurs in people aged 30-50 years. Low back pain is the most common and most expensive cause of work-related disability in the United States.² Low back pain is not a common complaint in children and, when present, is more likely to have a serious etiology, such as infection or malignancy.³

Pathophysiology

Many causes of mechanical low back pain exist. The most common causes are age-related degenerative disc and facet processes and muscle- or ligament-related injuries. Discussion in this article is limited to musculoskeletal causes. These can be divided into nerve root syndromes, musculoskeletal pain syndromes, and skeletal causes.

Nerve root syndromes

Classic nerve root syndrome is characterized by radicular pain arising from nerve root impingement due to herniated discs. A similar syndrome can also be produced by inflammation and irritation, which may explain why patients whose presentation is consistent with this diagnosis respond to conservative therapies.

Impingement pain tends to be sharp, well localized, and can be associated with paresthesia, whereas irritation pain tends to be dull, poorly localized, and without paresthesia. Impingement is associated with a positive straight leg raising sign (ie, shooting pain down contralateral leg with leg raising), while irritation is not. Neurologic deficits and pain radiation below the knee are rarely seen in irritation alone and are most commonly found with impingement.⁴

The cause of impingement syndrome is most commonly herniated discs, but it may also be caused by spinal stenosis, spinal degeneration, or cauda equina syndrome.

Herniated discs are produced as spinal discs degenerate. After growing thinner, the nucleus pulposus herniates out of the central cavity against a nerve root. Intervertebral discs begin to degenerate by the third decade of life, and herniated discs are found on autopsy in one third of adults older than 20 years. Only 3% of these, however, are symptomatic.⁵ The most common locations for herniation are L4, L5, and S1.⁶

Spinal stenosis occurs when disc spaces decrease as intervertebral discs lose moisture and volume with age. Even minor trauma under these circumstances can cause inflammation or nerve root impingement, which can produce classic sciatica pain without disc rupture. The pain can often be bilateral.⁷

Spinal degeneration is caused by alterations in the hygroscopic quality of the nucleus pulposus. This process progresses to annular degeneration. Coupled with progressive posterior facet disease, this process leads to spinal canal or foraminal encroachment. These retrogressive and proliferative changes in the disc anteriorly and the joints posteriorly produce clinical symptoms and radiographic findings termed 3-joint complex degeneration. Spinal degeneration has 3 distinct stages, as follows:

• Dysfunction with complaints of pain only
• Instability with advanced degeneration, pseudospondylolisthesis, and neurologic abnormalities
• Stabilization with morning stiffness and with prolonged standing or walking, producing radicular pain

Cauda equina syndrome is produced by massive midline extrusion of nuclear material or tumor into the spinal canal, which compresses the caudal sac. The classic presentation is bilateral sciatica, with lower extremity bowel or bladder dysfunction present in 90% of patients. Urinary retention is initially observed and followed by overflow incontinence. Perineal or perianal anesthesia is present in 60-80% of patients.⁸

Musculoskeletal pain syndromes

Musculoskeletal pain syndromes that produce low back pain include myofascial pain syndromes and fibromyalgia.

Myofascial pain is characterized by pain and tenderness over localized areas (trigger points), loss of range of motion in the involved muscle groups, and pain radiating in a characteristic distribution but restricted to a peripheral nerve. Relief of pain is often reported when the involved muscle group is stretched.

Fibromyalgia results in pain and tenderness on palpation of 11 of 18 trigger points, one of which is the low back area, as classified by the American College of Rheumatology. Generalized stiffness, fatigue, and muscle ache are reported.

Other skeletal causes

Other skeletal causes of low back pain include osteomyelitis, sacroiliitis, and malignancy.

Osteomyelitis results from infectious processes involving the bones of the spine, while sacroiliitis results from inflammatory changes in the sacroiliac joints. This pain presents over the sacroiliac joints and radiates to the anterior and posterior thighs. This pain is usually worse at night and is exacerbated by prolonged sitting or standing.

Malignant tumors of the spine can be primary or metastatic. Most primary spinal tumors are found in patients younger than 30 years and usually involve the posterior vertebral elements. Metastatic tumors are found mostly in patients older than 50 years and tend to occur in the anterior aspects of the vertebral body.⁹

Frequency

United States

Mechanical low back pain is one of the most common patient complaints expressed to emergency physicians in the United States accounting for more than 6 million cases annually.

Mortality/Morbidity

• Most etiologies of mechanical low back pain are not life threatening; however, significant morbidity is associated with chronic low back pain syndromes.
• A significant number of patients are unable to return to their normal daily routines or function in a productive work environment secondary to low back pain.²
• Most cases of back pain treated in the emergency department are not true emergencies, with the exception of cauda equina syndrome. Patients who have cauda equina syndrome must undergo surgical decompression as soon as possible or face permanent neurologic damage.

Race

No differences exist in incidence of back pain between racial groups.

Sex

Both male and female populations are affected; however, there is a tendency towards a higher incidence in male patients.

Age

Low back pain is a common complaint in adults of all ages.

Low back pain is not a common complaint in children and, when present, is more likely to have a serious etiology, such as infection or malignancy.

Clinical

History

A thorough history and physical examination is paramount to arrive at a diagnosis, and initially imaging is often unnecessary.⁴

• Patients most often complain of pain in the lumbosacral area.
  • Determine whether pain is exacerbated by movement or by prolonged sitting or standing.
  • Determine the duration of pain.
  • Determine if pain is relieved by lying down.
  • Establish if pain was sudden in onset or gradual over days or months.
  • Determine if pain is worse in the morning or at night.
  • Find out if the patient can identify a precipitating event such as lifting or moving furniture.
• Explore the presence of systemic symptoms such as fever, weight loss, dysuria, cough, and bowel or bladder problems.
• Inquire about current medications that may produce symptomatology.
  • Chronic steroids may predispose to infection or compression fractures.
  • Anticoagulants may result in a bleed or hematoma.
• Any history of new-onset bowel or bladder dysfunction (eg, urinary hesitancy, overflow incontinence) with back pain is suggestive of cauda equina syndrome. This is particularly true if other, new neurologic deficits are also present.

Physical

• Physical examination of a patient with back pain should include range of motion and a thorough neurologic examination, including assessment of peripheral motor function, sensation, and deep tendon reflexes.¹⁰
  • Perform straight leg testing with the patient in a supine position. Record response to raising each leg. An approximation of the test may also be performed with the patient sitting and each leg straightened at the knee. An elevation of the leg to less than 60° is abnormal. The straight leg test result is positive only if the pain radiates to below the knee and not merely in the back or the hamstrings.
  • Perform an abdominal examination to exclude intra-abdominal pathology.
  • Perform a rectal examination on men older than 50 years to assess prostate size and exclude prostatitis. Also perform a rectal examination on any patient who may have cauda equina syndrome to assess rectal tone and perineal sensation. If cauda equina syndrome is suspected, urinary catheterization for a postvoid residual or bedside ultrasonography of the bladder may be helpful to assess for urinary retention.
  • Perform a rectal examination, if necessary, in younger males who are febrile and have urinary complaints.
  • Perform a pelvic examination, if necessary, in females complaining of menstrual abnormalities or vaginal discharge.
• Patients with true herniated discs may not present with any findings other than a positive straight leg raising test. Classic presentation includes numbness in a dermatomal distribution corresponding to the level of disc involved, with findings of motor weakness and reflex loss as described below. Herniated discs have different presentations depending on the location as follows:
  • At L4: Pain along the front of the leg; weak extension of the leg at the knee; sensory loss about the knee; loss of knee-jerk reflex
  • At L5: Pain along the side of the leg; weak dorsiflexion of the foot; sensory loss in the web of the big toe; no reflexes lost
  • At S1: Pain along the back of the leg; weak plantar flexion of the foot; sensory loss along the back of the calf and the lateral aspect of the foot; loss of ankle jerk
  • L5 and S1: These nerve roots are involved in approximately 95% of all disc herniations.
• Spinal stenosis may be present when evidence of degenerative joint disease is present on radiographic studies.
  • Patients with this disease process often complain of progressive pain down the lateral aspect of the leg during ambulation (pseudoclaudication). This pain results from neurologic compression rather than actual arterial insufficiency, which produces true claudication. In cases of spinal stenosis, the straight leg test result is often negative.
  • The stoop test helps distinguish true claudication from pseudoclaudication. Patients with true claudication sit down to rest when pain occurs, while patients with pseudoclaudication attempt to keep walking by stooping or flexing the spine to relieve the stretch on the sciatic nerve.
• Sacroiliitis usually presents with pain over the involved joints and no peripheral neurologic findings.
• Osteomyelitis may be subacute or acute.
  • Clinical findings are nonspecific, and the patient may be afebrile on presentation.
  • Classic presentation includes pain on palpation of the vertebral body, elevated sedimentation rate, and complaints of pain out of proportion to physical findings.
  • Patients particularly at risk for development of osteomyelitis include patients who have undergone recent back surgery, intravenous (IV) drug users, patients with immunosuppression, and those with a history of chronic pelvic inflammatory disease (PID).

Causes

• Mechanical low back pain is a common complaint in patients with functional disorders. In addition, a functional overlay or component of secondary gain may be present in some patients with true organic pathology.¹¹ The degree of psychosocial issues affecting the patient's condition may be assessed by the following:
  • Patient may receive compensation for injury.
  • Patient has pending litigation.
  • Patient dislikes job.
  • Patient has symptoms of depression.
  • Patient caused the accident resulting in back pain.
• Physical clues that help identify patients with significant functional overlay or component of secondary gain include the following:
  • Findings of nonanatomic motor or sensory loss
  • Nonspecific tenderness or generalized tenderness over the entire back
  • Overly dramatic behavior and loss of positive straight leg raising test when patient is distracted
• A particularly useful test is to have patients hold their wrists next to their hips and turn their body from side to side. This test gives the illusion that you are testing spinal rotation, but no actual stress is placed on any muscles or ligaments. Any complaint of pain during this maneuver is strongly suggestive of a functional overlay or component of secondary gain in the presentation.

Differential Diagnoses

Other Problems to Be Considered

Perforated viscous
Pancreatitis
Large bowel obstruction

Workup

Laboratory Studies

• Consider performing urinalysis if the problem is not clearly musculoskeletal or an exacerbation of chronic back pain.
• Perform a complete blood count (CBC) and erythrocyte sedimentation rate (ESR) if the patient is febrile or if an epidural or spinal abscess, or osteomyelitis is suspected. While ESR has moderate specificity, the sensitivity is relatively high in cases of abscess, and it can be used as a screening test.
• Other laboratory studies are rarely needed unless a disorder other than back pain is strongly suspected.

Imaging Studies

• Radiography
  • Lumbosacral spine series are expensive and expose the reproductive organs to significant radiation. Annually, 7-8 million such tests are obtained, but most have little value in directing therapy, particularly among adults younger than 50 years.
  • Unless a history of traumatic injury or systemic illness is present, such films should be obtained only for suspicion of malignancy or infection. Malignant involvement of vertebral bodies can be evident on plain film when as little as 30% of the vertebral body has been replaced.
  • Other indications that suggest the need for radiographic imaging include chronic steroid use and acute onset of pain in patients older than 50 years or in the pediatric age group.
  • The physician may also consider obtaining radiographs in patients whose cases involve (or potentially involve) litigation or for patients seeking compensation.
• CT and MRI¹²
  • CT and MRI are generally considered the studies of choice for more precise imaging of the vertebrae, paraspinal soft tissues, discs, or spinal cord. CT images cortical bone with higher resolution and can delineate some fractures better than MRI.
  • MRI is generally the preferred imaging modality for detecting disc, cord, or soft tissue abnormalities.
• Ultrasonography may be useful if the differential diagnosis includes appendicitis, a pathologic pelvic process, or abdominal aneurysm.
• True emergencies that necessitate imaging include the following:
  • Patients with a history of malignancy and new evidence of nerve entrapment
  • Patients with back pain associated with paralysis or gross muscle weakness
  • Patients with bilateral neurologic deficits associated with bowel or bladder function loss
  • Patients in whom an epidural hematoma or epidural abscess is suspected
  • Postoperative patients with a recent lumbar laminectomy or hip replacement

Improvement occurs in almost all patients within 4-6 weeks, except those with infection, occult malignancy, or systemic illness. If pain fails to significantly improve or resolve in this time frame, imaging is always indicated.¹³

Other Tests

• Perform the straight leg raising test with the patient in a supine position. Record the response to raising each leg. An approximation of the test may be performed with the patient sitting and each leg straightened at the knee. The examiner should take care to make sure that the quadriceps muscle is relaxed while passively raising the leg to ensure that the sciatic nerve is being adequately stretched during the testing. If the quadriceps is contracted, it will take the pressure off the sciatic nerve and may give a false-negative result.
• The stoop test helps distinguish true claudication from pseudoclaudication. Patients with true claudication sit down to rest when pain occurs, while patients with pseudoclaudication attempt to keep walking by stooping or flexing the spine to relieve the stretch on the sciatic nerve.

Treatment

Prehospital Care

• If the patient's back pain is from a traumatic injury, full spinal precautions using a long backboard for spinal immobilization should be used.
• If no history of trauma is present, spinal precautions is not necessary, as the patient may experience significant exacerbation of pain by lying on a rigid board. If the patient is brought into the emergency department on a rigid board, they should be removed from the board at the first opportunity.
• If a rigid board is necessary, the patient may be made more comfortable by supporting the lower extremities with a pillow or blanket.

Emergency Department Care

If new neurologic deficits are noted accompanied by bowel or bladder dysfunction one should suspect cauda equina syndrome. This is a true emergency, and emergency imaging is mandated. MRI is the preferred imaging modality in this situation. If cauda equina syndrome is strongly suspected, the practitioner should consider giving dexamethasone without delay to prevent further loss of neurologic function while pursuing confirmatory testing. 

Conservative therapy is the mainstay of treatment, as even those with true sciatica generally respond.¹⁴ Ultimately, only 2% of patients with sciatica and 4-6% of patients with true disc herniation require surgery. Conservative therapy traditionally includes the following:

• Bed rest, once the cornerstone of treatment, is no longer widely recommended.
  • A growing body of evidence suggests that even brief bed rest is not necessary except in patients with true sciatica. In this case, the supine position decreases pressure on the spinal cord itself, and is useful for the first 2-3 days.
  • Early mobilization with gentle range of motion and strengthening exercises are recommended for patients with nonsciatic back pain.¹⁵
  • Early return to work on light duty or restricted activity lead to better long-term outcomes.
• Pharmacologic therapy involves both anti-inflammatory medication and muscle relaxants.
  • Narcotics may be used initially to gain relief, but their long-term use is associated with increased functional impairment.
  • Steroids, while highly recommended by some practitioners, lack prospective confirmation of their value. Some physicians may prescribe a single burst or short course of oral steroids, which can be beneficial, particularly in those with a significant degree of inflammation.
  • Epidural steroid injection may also bring significant short-term relief, but this treatment is not without adverse effects and has not been shown to provide lasting benefit.¹⁶
• Unless the patient is allergic to the medicine or it is otherwise contraindicated, severe low back pain can be improved significantly with a combination of nonsteroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants.
• Use of hot or cold compresses has never been proven scientifically to speed symptom resolution, but some patients may experience brief relief.
• Gentle flexion/extension exercises are helpful.^17,18
• Spinal traction is ineffective.

Evidence-based clinical practice guidelines from the American Pain Society (APS) for patients with chronic low back pain describe the use of interventional diagnostic tests and therapies, surgeries, and interdisciplinary rehabilitation.¹⁹

• Practice guidelines for nonradicular pain
  • Interdisciplinary rehabilitation emphasizing cognitive-behavioral approaches should be considered for patients who do not respond to usual interventions.
  • Provocative discography (injecting material into a disc nucleus in an attempt to reproduce the patient's typical pain) is not recommended.
  • Facet joint corticosteroid injection, prolotherapy (repeated injections of irritant material to stimulate an inflammatory response), and intradiscal corticosteroid injection are not recommended.
  • Persistent disabling symptoms and degenerative spinal changes should prompt discussion and shared decision-making regarding surgery or interdisciplinary rehabilitation (evidence is insufficient to weigh the risks and benefits of vertebral disc replacement in these patients).
• Practice guidelines for persistent radiculopathy
  • For patients with herniated discs, the use of epidural steroid injection should be discussed.
  • For patients with herniated discs and disabling leg pain from spinal stenosis, surgical options should be discussed.
  • For patients with persistent pain after surgery, the risks and benefits of spinal cord stimulation should be discussed.

Consultations

• ED consultation with a specialist is necessary for patients who present with acute cauda equina syndrome, demonstrate intractable pain, have evidence of a serious etiology (eg, epidural abscess, tumor), or where a social situation makes hospitalization necessary.
• Whether orthopedic or neurosurgical consultation is chosen depends on local custom and resources.
• Other medical consultation may be needed if the cause of back pain is not mechanical.

Medication

The goal of pharmacotherapy is to reduce pain and inflammation.

Nonsteroidal anti-inflammatory agents (NSAIDs)

NSAIDs are most commonly used to relieve mild to moderate pain. Although the effectiveness of NSAIDs tends to be patient specific, ibuprofen is usually the DOC for initial therapy. Other options include flurbiprofen, ketoprofen, and naproxen.

Ibuprofen (Ibuprin, Advil, Motrin)

DOC to treat mild to moderate pain if no contraindications exist.
Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Dosing

Adult

600 mg PO tid

Pediatric

<6 months: Not established
6 months to 12 years: 20-40 mg/kg/d PO divided tid/qid
>12 years: Administer as in adults

Interactions

Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Contraindications

Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency; high risk of bleeding

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy

Ketoprofen (Oruvail, Orudis, Actron)

For relief of mild to moderate pain and inflammation.
Small dosages initially are indicated in patients who are small or elderly and in those with renal or liver disease. Doses over 75 mg do not increase therapeutic effects. Administer high doses with caution, and closely observe patient for response.

Dosing

Adult

25-50 mg PO q6-8h prn; not to exceed 300 mg/d

Pediatric

<3 months: Not established
3 months to 12 years: 0.1–1 mg/kg PO q6-8h
>12 years: Administer as in adults

Interactions

Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy

Naproxen (Anaprox, Naprelan, and Naprosyn)

For relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing activity of cyclooxygenase, which results in a decrease of prostaglandin synthesis.

Dosing

Adult

500 mg PO initial, followed by 250 mg q6-8h; not to exceed 1.25 g/d

Pediatric

<2 years: Not established
>2 years: 2.5 mg/kg/dose PO; not to exceed 10 mg/kg/d

Interactions

Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Contraindications

Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency; high risk of bleeding

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Acute renal insufficiency, interstitial nephritis, hyperkalemia, hyponatremia, and renal papillary necrosis may occur; patients with preexisting renal disease or compromised renal perfusion risk acute renal failure; leukopenia occurs rarely, is transient, and usually returns to normal during therapy; persistent leukopenia, granulocytopenia, or thrombocytopenia warrants further evaluation and may require discontinuation of drug

Muscle relaxants

These agents reduce tonic somatic motor activity of the muscle.

Carisoprodol (Soma)

Short-acting medication that may have depressant effects at spinal cord level.
Skeletal muscle relaxants have modest short-term benefit as adjunctive therapy for nociceptive pain associated with muscle strains and, used intermittently, for diffuse and certain regional chronic pain syndromes. Long-term improvement over placebo has not been established.

Dosing

Adult

350 mg PO tid/qid

Pediatric

Not established

Interactions

Increases toxicity of alcohol, CNS depressants, MAO inhibitors, clindamycin, phenothiazines

Contraindications

Documented hypersensitivity; acute intermittent porphyria

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in renal and hepatic impairment

Cyclobenzaprine (Flexeril)

Skeletal muscle relaxant that acts centrally and reduces motor activity of tonic somatic origins influencing both alpha and gamma motor neurons.
Structurally related to tricyclic antidepressants and thus carries some of the same liabilities.

Dosing

Adult

10 mg PO tid with a range of 20-40 mg/d in divided doses; not to exceed 60 mg/d

Pediatric

Not established

Interactions

Coadministration with MAOIs and tricyclic antidepressants may increase toxicity; cyclobenzaprine may have additive effect when used concurrently with anticholinergics; effects of alcohol, CNS depressants, and barbiturates may be enhanced with cyclobenzaprine

Contraindications

Documented hypersensitivity; patients who have taken MAOIs within the last 14 d

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in angle-closure glaucoma, urinary hesitance

Analgesics

Pain control is essential to ensure patient comfort, to promote pulmonary toilet, and to aid physical therapy regimens. Many analgesics have sedating properties that benefit patients who have sustained injuries.

Acetaminophen (Tylenol, Panadol, Aspirin Free Anacin)

DOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, in those with upper GI disease, or in those who are taking oral anticoagulants.

Dosing

Adult

325-650 mg PO q4-6h or 1000 mg tid/qid; not to exceed 4 g/d

Pediatric

<12 years: 10-15 mg/kg/dose PO q4-6h prn; not to exceed 2.6 g/d
>12 years: 325-650 mg PO q4h; not to exceed 5 doses/d

Interactions

Rifampin can reduce analgesic effects of acetaminophen; coadministration with barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity

Contraindications

Documented hypersensitivity; known G-6-PD deficiency

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate a serious illness; acetaminophen is contained in many OTC products, and combined use with these products may result in cumulative acetaminophen doses exceeding recommended maximum dose

Acetaminophen and codeine (Tylenol #3)

A drug combination indicated for the treatment of mild to moderate pain.

Dosing

Adult

30-60 mg/dose based on codeine content PO q4-6h or 1-2 tabs q4h; not to exceed 12 tabs/d

Pediatric

0.5-1 mg/kg/dose based on codeine content PO q4-6h; 10-15 mg/kg/dose based on acetaminophen content; not to exceed 2.6 g/d of acetaminophen

Interactions

Toxicity increases with CNS depressants or tricyclic antidepressants

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in patients dependent on opiates because this substitution may result in acute opiate-withdrawal symptoms; caution in severe renal or hepatic dysfunction

Hydrocodone bitartrate and acetaminophen (Vicodin ES)

A drug combination indicated for the relief of moderate to severe pain.

Dosing

Adult

1-2 tab or cap PO q4-6h prn

Pediatric

<12 years: 10-15 mg/kg/dose acetaminophen q4-6h PO prn; not to exceed 2.6 g/d acetaminophen
>12 years: 750 mg acetaminophen PO q4h; not to exceed 10 mg hydrocodone bitartrate in single dose; not to exceed 5 doses/d

Interactions

Coadministration with phenothiazines may decrease analgesic effects; toxicity increases with CNS depressants or tricyclic antidepressants

Contraindications

Documented hypersensitivity; elevated intracranial pressure

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Tablets contain metabisulfite, which may cause hypersensitivity; caution in patients dependent on opiates because this substitution may result in acute opiate-withdrawal symptoms; caution in severe renal or hepatic dysfunction

Follow-up

Further Inpatient Care

• Inpatient care for low back pain is typically not required.
• Patients with cauda equina syndrome, epidural abscess, spinal tumor, systemic illnesses, or those with poor social support should be admitted for further evaluation and management.
  • Referral to an orthopedist or a neurosurgeon may be necessary. Whether an orthopedist or a neurosurgeon is selected for referral depends on local resources and customs.
  • The patient's primary physician should be contacted regarding the referral.

Further Outpatient Care

• Outpatient follow-up is generally managed by the patient's private physician. Patients with true sciatica or nerve root findings may also require consultation with an orthopedic surgeon or a neurosurgeon.
• Short-term physical therapy with gentle exercises may be of some benefit.
  • Short-term physical therapy has not been proven significantly more effective than self-care with instructions by the physician. However, patients appear to prefer therapy to self-care when surveyed.
  • Sertpoyraz et al compared isokinetic and standard exercise programs for chronic low back pain. Pain, mobility, disability, psychological status, and muscle strength was measured. Forty patients were randomly assigned to a program that took place in an outpatient rehabilitation clinic. Results showed an equal effect in the treatment of low back pain, with no statistically significant difference found between the two programs.¹⁸
  • Cost-benefit ratio should be considered prior to physical therapy referral from the ED.

Inpatient & Outpatient Medications

• Outpatient therapy generally consists of a combination of muscle relaxants and NSAIDs. In certain cases, a short course of prednisone may also be helpful.

Transfer

• Time-sensitive transfer to other facilities may be necessary in patients with suspected cauda equina syndrome if emergent MRI is not available at the treating hospital. All such patients should receive dexamethasone before transfer to avoid delays in treatment.
• Patients with compressive tumors or abscesses should be transferred to a center that has a spine surgeon who can provide decompression in a timely manner if unavailable at the treating hospital.

Deterrence/Prevention

• Back muscle strengthening exercises have value in preventing future episodes of low back strain.²⁰
• Weight loss in overweight patients results in less strain on back muscles.
• Practicing proper lifting techniques results in less back strain.
• General overall improvement of physical conditioning can decrease low back pain exacerbations.²¹

Prognosis

• The prognosis is good for most patients who present with mechanical back pain.^22,23
  • Overall, 70% of patients feel better in 1 week; 80%, in 2 weeks; and 90%, in 1 month.
  • Only 10% of all patients with low back pain have long-term problems.
  • A significant functional overlay or component of secondary gain is present in a subgroup of patients, who also account for the majority of office visits with low back pain complaints (see Causes section).
  • Recurrence is common and seen in up to 40% of patients within 6 months. Prevention methods should be discussed with patients with low back pain along with encouragement to monitor them when the acute period has resolved.
  • Psychosocial factors such as presence of posttraumatic stress disorder, use of a lawyer, presence of other chronic illnesses, and lower education levels appear to be positive predictors of development of chronic back pain in patients who sustain an initial injury to their back. Chronic back pain development was not associated with age, gender, occupation, or severity of original injury.

Patient Education

• Patient education focuses on prevention and includes the following:
  • Promoting weight loss where indicated
  • Performing back strengthening exercises
  • Teaching proper lifting technique
  • Increasing overall physical conditioning
• Back belts, which are commonly worn in occupations with heavy lifting, have not been proven to prevent back injury.
• For excellent patient education resources, visit eMedicine's Bone Health Center; Back, Ribs, Neck, and Head Center; and Muscle Disorders Center. Also, see eMedicine's patient education articles Back Pain, Chronic Pain, and Sciatica.

Miscellaneous

Medicolegal Pitfalls

• Work excuses deserve special mention
  • Most patients require some form of relief from work.
  • Prolonged work excuses often lead to functional disorders. It is generally recommended that excuses be limited to 2-3 days following an ED visit.
  • It is preferable that patients return to work as soon as possible. This may be facilitated by noting light or restricted duty upon their return for a short time period.
  • If work excuses are needed beyond this time, the patient's primary or referral physician should provide them.
  • When providing work excuses, patient confidentiality must always be protected. The only information employers are entitled to without explicit authorization by the patient is whether the work excuse is legitimate and whether the employee poses a health risk to others.
  • Be sure to include what activities the patient may engage in and the time period the restrictions are in effect.

Special Concerns

• Back pain is an uncommon complaint in children. The cause of back pain is most often infectious or malignant in these patients.
• Suspect malignancy if back pain has lasted for more than 1 month, is unrelieved by bed rest, and occurs at night (interrupting sleep in patients older than 50 years).

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Keywords

low back pain, mechanical low back pain, low back pain treatment, low back pain causes, musculoligamentous injury, classic nerve root syndrome, musculoskeletal pain syndrome, impingement syndrome, herniated disk, herniated disc, spinal degeneration, cauda equina syndrome, myofascial pain syndrome, fibromyalgia, osteomyelitis, sacroiliitis, spinal stenosis, degenerative joint disease, straight leg test

Contributor Information and Disclosures

Author

Debra G Perina, MD, Associate Professor, Director of Prehospital Care Division, Department of Emergency Medicine, University of Virginia Health Sciences Center
Debra G Perina, MD is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, National Association of EMS Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Edward Bessman, MD, Chairman, Department of Emergency Medicine, John Hopkins Bayview Medical Center; Assistant Professor, Department of Emergency Medicine, Johns Hopkins University
Edward Bessman, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Eric L Legome, MD, Chair, Department of Emergency Medicine, St Vincent's Hospital Manhattan; Associate Professor, Department of Emergency Medicine, New York Medical College
Eric L Legome, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: WebMD Salary Employment

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