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 present up to

48 hours after the traumatic event.

Historically, the symptoms of compartment syndrome

have been described by the "the five Ps": pain, pallor,

paresthesias, pulselessness, and poikilothermia. However,

all of these are not typically present, and many are late

findings that signal irreversible injury. The primary

complaint in the alert patient is usually of severe pain in

the affected limb, often not controlled by opioid analgesics.

The pain is often worsened by passive stretch of the

muscles in the involved compartment. Nerve ischemia can

lead to a burning sensation or dysesthesia.

407

CHAPTER 93

..... Physical Examination

Detection of compartment syndrome requires a high

clinical suspicion and an attentive exam. The involved

compartment is swollen and tense. There is exquisite

tenderness to palpation. Pain is intensified if the examiner

passively stretches the muscles of the compartment.

Sensory deficits may be present, but motor weakness is

usually a later finding. Pulselessness is a rare and late

finding, as the arterial pressure usually exceeds the tissue

pressure. Thus, the limb often remains warm with normal

color, pulses, and capillary refill. In the alert patient, the

absence of pain, paresthesias, and pain with passive stretch

excludes the diagnosis of compartment syndrome.

DIAGNOSTIC STUDIES

..... Laboratory

Laboratory testing is not helpful in making the diagnosis of

compartment syndrome. In the setting of extensive muscle

damage, creatine phosphokinase or myoglobin may be elevated.

.... Imaging

Although diagnostic imaging studies are routinely used to

evaluate the traumatized limb for associated orthopedic

fracture, they are not required to make the diagnosis of

compartment syndrome. The presence of significant or

comminuted long bone fractures should heighten the

provider's concern for the development of compartment

syndrome.

PROCEDURES

When there is doubt about the clinical diagnosis of

compartment syndrome, such as in a patient with an unreliable exam due to altered mental status, compartment pressures should be measured. Pressures can be objectively

measured using a commercially available handheld manometer, such as the Stryker device (Figure 93- l). These instruments contain a needle connected to a pressure monitor.

The needle is inserted into the muscle compartment at the

most tense point, or near the fracture site. A small amount

of saline is injected into the compartment, and the manometer reads the resistance to injection created by the tissue.

Pressure should be checked at a minimum of 2 locations

within the affected compartment and can be checked in a

normal compartment for comparison.

Normal tissue pressure in a muscle compartment is

<10 mm Hg. Pressures up to 20 mm Hg are generally well

tolerated. Pressures between 20-30 mm Hg may cause

damage if they persist over multiple hours. Pressures

>30 mm Hg are generally considered an indication for an

emergent fasciotomy. More recent studies suggest that a

more important number is the difference between the

patient's diastolic blood pressure and the tissue pressure,

or "delta pressure." These studies suggest that a delta

Figure 93-1. Stryker STJC device. Repri nted with

permission from Hutson AM, Rovinsky D. Chapter 63.

Compartment Pressure Measurement. In: Reichman EF,

Simon RR, eds. Emergency Medicine Procedures. New

York: McGraw-Hill, 2004 .

pressure of >30 mm Hg is an indication for fasciotomy,

whereas patients with delta pressure <30 mm Hg have a

low likelihood of developing tissue damage if fasciotomy

is withheld.