When a radiculopathy is suspected, perform the straightleg raise and reverse straight -leg raise tests. A positive

straight-leg raise (reproduction of the patient's radicular

symptoms between 30 and 70 degrees of leg elevation) has

a relatively high sensitivity ( 9 1%), but a low specificity

(26%) for diagnosing a herniated disc. The reverse straightleg raise is more specific (88%) but less sensitive (26%).

Evaluate strength for nerve root dysfunction by testing knee

strength (IA nerve root), great toe/foot dorsiflexion (LS

nerve root), and foot plantartlexion (S1 nerve root). Sensory

deficits in radiculopathy include decreased sensation

between the first and second toes (LS nerve root) and

decreased sensation on the lateral aspect of the foot (S1

nerve root).

Lastly, assess the pulses and palpate the abdomen for

possible vascular causes of the pain, including aortic

aneurysm.

DIAGNOSTI C STUDI ES

� Laboratory

Laboratory testing generally plays a limited role in the

evaluation of low back pain. Obtain a urine pregnancy test

in females of reproductive age to exclude ectopic pregnancy

and guide future decisions regarding imaging. A urinalysis

may also be helpful to evaluate for nephrolithiasis or

pyelonephritis as potential causes of low back pain.

Although erythrocyte sedimentation rates and C-reactive

protein may be elevated in some patients with back pain

( eg, epidural abscess, malignancy), these studies are

nonspecific and should not be routinely ordered as part of

the work-up.

� Imaging

Patients presenting with nonspecific low back pain with

none of the high-risk features discussed previously do not

warrant routine radiographic evaluation. Prompt

evaluation with magnetic resonance imaging (MRI) or

computed tomography (CT) is recommended when severe

or progressive neurologic deficits are present or when

serious underlying conditions are suspected on the basis of

history and physical exam. If available, MRI is preferred

over CT because it provides better visualization of soft

tissues, vertebral marrow, and the spinal canal.

In patients suspected of a vertebral compression

fracture (eg, osteoporosis, chronic steroid use), plain

radiography is recommended (Figure 92-1). A CT should

be considered if there is significant loss of height of the

vertebral body or if any neurologic symptoms are present.

Patients with an underlying malignancy with acute back

pain should have an MRI on an urgent basis (within

24 hours) when no neurologic deficits are present. When

neurologic deficits are present, the MRI is performed

emergently. For patients with low back pain associated

with radiculopathy, MRI (preferred) or CT are only

recommended if the patient is a candidate for surgery or

LOW BACK PAIN

Figure 92-1. T1 2 compression fracture.

epidural steroid injection, as the natural course of lumbar

disc herniation with radiculopathy is improvement within

4 weeks.

MEDICAL DECISION MAKING

The history and physical exam serve as the cornerstones in

the evaluation of low back pain. Eliciting risk factors

indicative of a serious underlying condition ( eg, urinary

retention concerning for cauda equina syndrome) or

identifying neurologic deficits on exam should prompt

advanced imaging. In the absence of risk factors, neurologic

deficits, or symptoms suggestive of a potentially serious

cause, the source of the low back pain is most likely benign,

and reassurance and symptomatic management with

outpatient follow-up is recommended (Figure 92-2).

TREATMENT

The treatment of low back pain varies depending on the

identified etiology. For those patients with nonspecific low

back pain, symptomatic therapy should include advice to

remain active and application of heat as needed.

Acetaminophen and nonsteroidal anti-inflammatory drugs

(NSAIDs) have shown short-term benefits. One must weigh

the potential analgesic benefit from NSAIDs with the known

risks of their use. Opioid analgesics or tramadol are an

option for patients with severe, debilitating pain that is not

controlled with acetaminophen or NSAIDs, but again, they

should be prescribed judiciously and for very limited periods given the risk of medication interactions and potential

for abuse. Musculoskeletal relaxants are approved by the

Lower back pai n/trauma

Perform a focused history & physical exam for:

• Duration of symptoms

• Risk factors for potentially serious cond itions

• Symptoms suggestive of radiculopathy or spinal stenosis

• Presence & severity of neurologic deficits

Risk factors and/or

neurologic deficits

PRESENT

Perform diagnostic studies (x-ray,

CT, MRI) to identify specific cause

Risk factors and/or

neurologic deficits

ABSENT

Symptomatic management,

outpatient follow-up

No specific cause identifiedsymptomatic treatment with

close outpatient follow-up

Figure 92-2. Low back pain diagnostic algorithm. CT, computed tomography; MRI,

magnetic resonance imaging.

CHAPTER 92

Food and Drug Administration for treatment of musculoskeletal conditions or spasticity and are another option for

short-term use in acute low back pain.

When a specific etiology for low back pain is identified, the

treatment varies depending on the underlying pathology. Low

back pain with radiculopathy (in the absence of focal neurologic deficits) can be treated symptomatically, as most patients

recover without surgery. Patients diagnosed with vertebral

osteomyelitis require intravenous (N) antibiotics, whereas an

epidural abscess is treated with neurosurgical evaluation

for potential drainage as well as parenteral antibiotics.

Neurosurgical consultation should also be obtained immedi ­

ately for patients with cauda equina syndrome. In patients

with vertebral malignancy with new neurologic deficits, e mergent radiation to shrink the tumor and relieve cord

compression is advised. The administration of corticosteroids

(dexamethasone 10 mg N) for acute spinal cord compression

should also be considered in consultation with neurosurgery.

DISPOSITION

� Admission

The patient disposition depends primarily on the etiology

of the back pain as well as analgesic control of symptoms.

Patients found to have a serious underlying etiology of low

back pain (eg, cauda equina syndrome, epidural abscess)

should be admitted in consultation with neurosurgery. It is

also reasonable to consider observation for patients with

nonspecific low back pain (with or without radiculopathy)

when pain control cannot be achieved in the ED.

� Discharge

Patients with nonspecific low back pain or back pain with

radiculopathy in whom pain is reasonably controlled can

be discharged with outpatient follow-up. All patients

should receive patient education regarding self-care and

treatment for low back pain as well as indications to

return to the emergency department ( eg, development of

neurologic deficit, change in urinary or bowel functions) .

SUGGESTED READING

Chou R, Huffman LH. Medications for acute and chronic lower

back pain: A review of evidence for an American Pain Society/

American College of Physicians clinical practice guideline. Ann

Intern Med. 2007;147:505-5 14.

Chou R, Qaseem A, Snow V, et al. Diagnosis and treatment of low

back pain: A joint clinical practice guideline from the American

College of Physicians and the American Pain Society. Ann

Intern Med. 2007;147:478-491.

Frohna WJ, Della-Giustina D. Neck and back pain. In: Tintinalli

JE, Stapczynski JS, Ma OJ, Cline DM, Cydulka RK, Meckler GD.

Tintinalli's Emergency Medicine: A Comprehensive Study Guide.

7th ed. New York, NY: McGraw-Hill, 20 11, pp. 1885-1 893.

Com partment Syndromes

Marc Doucette, MD

Key Points

• Compartment syndrome occurs when tissue pressure in

a closed space rises, compromising perfusion to nerves

and muscles.

• The leg and forearm compartments are most commonly

involved, but compartment syndrome can also occur in the

upper arm, thigh, hand, foot, gluteal region, or abdomen.

INTRODUCTION

Acute compartment syndrome is a surgical emergency. If

unrecognized and untreated, it can lead to tissue ischemia,

necrosis, and long-term functional impairment. Volkmann

ischemic contracture is the end result of an ischemic injury

to the muscles and nerves of a limb. Compartment syndrome

is seen most commonly in the setting of trauma, including

long bone fractures, crush injuries, and circumferential

burns to the extremities. Males and young people are

affected more commonly than females and elderly.

The pathophysiology of compartment syndrome

involves increased pressure in a muscle compartment that is

enclosed by a fascial structure with limited ability to expand.

This increased pressure is caused by edema or bleeding,

from compression of the compartment by a circumferential

burn or a constricting cast, or a combination of both.

Increased pressure leads to decreased venous outflow from

the compartment, causing a decrease in the arteriovenous

pressure gradient and ultimately cellular ischemia and tissue

necrosis.

Cardinal signs and symptoms include severe pain over

the involved area, pain with passive stretch of the muscles

in the affected compartment, weakness, and paresthesias.

Although commercially available devices can be used to

• Compartment syndrome is usually associated with long

bone fracture, crush injuries, circumferential burn, or

cast.

• Acute compa rtment syndrome is a surgical emergency,

treated by fasciotomy to relieve pressure and restore

circulation.

measure compartment pressures, the diagnosis is often

made on clinical grounds alone. Early recognition and

orthopedic consultation are essential in preventing t issue

necrosis and adverse outcome.

CLINICAL PRESENTATION

..... History

Acute compartment syndrome is seen most commonly in

the setting of trauma or long bone fracture. Significant

blunt trauma or crush injury can lead to compartment

syndrome, even in the absence of fracture. Symptom onset

is usually within hours of injury, but can pres

ical consultation should also be obtained immedi ­

ately for patients with cauda equina syndrome. In patients

with vertebral malignancy with new neurologic deficits, e mergent radiation to shrink the tumor and relieve cord

compression is advised. The administration of corticosteroids

(dexamethasone 10 mg N) for acute spinal cord compression

should also be considered in consultation with neurosurgery.