MEDICAL DECISION MAKING

History and physical exam along with a high index of

suspicion may be all that is required to make the diagnosis

of compartment syndrome. Measurement of compartment

pressures can serve as a diagnostic tool. Failure to make the

diagnosis and respond appropriately can lead to tissue

damage and long-term functional deficits (Figure 93-2).

TREATMENT

The definitive treatment for an acute compartment

syndrome is emergent fasciotomy. To minimize tissue damage, fasciotomy should be performed <8 hours and preferably <6 hours after the onset of symptoms. Emergency

department (ED) management involves early orthopedic

consultation as soon as the diagnosis is confirmed. The

patient should be hydrated and hypotension should be

avoided. The affected limb should be kept at the level of the

heart and not elevated. Elevation of the limb above the level

of the heart reduces the arterial pressure and may reduce

perfusion. Generous analgesia is often required.

Fasciotomy is performed by an orthopedic or general

surgeon in the operating room setting. A long incision is

made in the skin and fascia, allowing the contents of the

compartment to swell without increasing pressure. The

incision is usually closed several days later, when

the swelling has diminished. Sometimes skin grafting is

necessary.

COMPARTMENT SYNDROMES

Suspect compartment syndrome

High suspicion

Consult orthopedics for

fasciotomy

Low-moderate suspicion

· Norma l (< 10 mm Hg)

Discharge

• Elevated ( > 10 mm Hg)

Admit for observation

Figure 93-2. Compartment syndromes diagnostic algorithm.

DISPOSITION

..... Admission

Patients with acute compartment syndrome require

hospital admission and urgent surgical intervention.

Patients with a high clinical concern for the development

of compartment syndrome should receive orthopedic

consultation in the ED, with consideration for admission

and observation.

..... Discharge

Patients who are being discharged with long bone fractures

or blunt extremity trauma should be educated about the

signs and symptoms of compartment syndrome and be

given instructions to return if they develop worsening

swelling, numbness, or pain that is not responsive to pain

medications.

SUGGESTED READING

Gourgioutis S, Villas C, Germanos S, et al. Acute limb compartment

syndrome: A review. l Surg Educ. 2007;64:1 78.

Haller PR. Compartment syndrome. In: Tintinalli JE, Stapczynski

JS, Ma OJ, Clince DM, Cydulka RK, Meckler GD. Tintinalli's

Emergency Medicine: A Comprehensive Study Guide. 7tb ed .

New York, NY: McGraw-Hill, 20 11, pp. 1 880--1 884.

Reichman EF, Simon RR. Compartment pressure measurement.

In: Emergency Medicine Procedures. New York, NY: McGrawHill, 2004.

Septic Arthritis

Kim L. Askew, MD

Key Points

• Septic arthritis can lead to significant morbidity if not

treated in a timely manner.

• Because the history and physical examination has limitations, arthrocentesis should be performed in anyone

suspected of having a septic arthritis.

INTRODUCTION

Emergency physicians' greatest concern and diagnostic

dilemma when faced with patients presenting with

nontraumatic acute joint pain is septic arthritis. The invasion

by bacteria and the associated immune response can lead to

rapid joint destruction and irreversible loss of function. Yet,

despite the severity of the condition, misconceptions about

patient presentations and the evaluation of patients with

possible septic joints persist in all aspects of health care.

Septic arthritis affects approximately 2-10 people per

100,000 annually and is frequently encountered in the emergency department (ED) setting. Once infected, the joint

cartilage is rapidly injured, with up to 30% of patients experiencing residual damage and up to 1 0% dying as a result of

the septic joint. Septic arthritis typically affects young children and adults older than 55 years; however, any age group

can be affected. The microbiology of septic joints can be

divided into 2 groups: nongonococcal and gonococcal.

Nongonococcal pathogens include Staphylococcus aureus

(SO%), Streptococcus pneumoniae, Streptococcus pyogenes

(25%), and gram-negative bacilli (20%). Hematogenous

spread is more common than contiguous extension from a

local cellulitis or penetrating injury. Although the incidence

of gonococcal arthritis has declined over the past 2 decades,

it is the leading cause of septic arthritis among sexually

active individuals and causes 5% of all septic joints.

• A combination of the patient's presentation, risk factors,

and synovial fluid tests determine appropriate management decisions.

CLINICAL PRESENTATION

� History

Nongonococcal Septic Arthritis

Patients typically develop symptoms over the span of

hours to days. Symptoms present in more than half of

patients with septic arthritis include joint pain, joint

swelling, and fever. Sweats and rigors are less common

findings. Patients will typically splint the joint and resist

any active or passive range of motion. If patients have a

history of similar episodes, the likelihood of septic arthritis

decreases and the likelihood of other forms of arthritis

increase. Although typically monoarticular and affecting

the knee, polyarticular involvement occurs in 10% of cases.

Risk factors for septic arthritis include immunosuppression

(eg, diabetes), injection drug use, elderly, prosthetic joint,

and previous joint injury (eg, rheumatoid arthritis).

Gonococcal Septic Arthritis

Gonococcal septic arthritis typically has a slightly different presentation. A prodromal phase with migratory

arthritis and tenosynovitis is the major feature before one

or more joints become involved. Patients may describe

features of gonococcal disease such as vaginal discharge,

pelvic pain, penile discharge, or pustules on the hands.

41 0

SEPTIC ARTHRITIS

� Physical Examination

Although patients can appear toxic, most patients will not

have vital sign abnormalities, including fever. The goal of the

examination is to attempt to distinguish a joint infection

from inflammation or infection of the surrounding struc ­

tures (bursa, tendons, skin). A septic joint typically has diffuse swelling, redness, and warmth. Pain severely limits

both active and passive range of motion. This is in contradistinction to inflammation or infection of surrounding

structures, in which pain is more severe with a ctive range of

motion.

Gonococcal arthritis may have more subtle signs. It

commonly affects the wrist, knee, and/or ankle and is associated with tenosynovitis, rash, and migratory arthritis.

Immunocompromised patients and those with prosthetic

joints also have more subtle exam findings. In these patients,

less of an immune response is generated with invasion of the

joint. Therefore, the classic teaching of a red, hot, swollen,

painful joint does not always predict septic arthritis.

DIAGNOSTIC STUDIES

� Laboratory

There is no one laboratory test that can rule in or out a septic

joint. Frequently ordered tests in the evaluation of patients

with painful joints include a complete blood count, erythrocyte sedimentation rate, and C-reactive protein. However,

these tests lack sensitivity and specificity and should not be

used in determining the need for arthrocentesis.

Synovial Fluid Analysis

The synovial white blood cell (WBC) count has been shown

to have a wide variety of sensitivity and specificity. Although

one specific number cannot be used as a cutoff, patients with

counts >50,000/!lL should be considered septic until proven

otherwise. The likelihood of a septic joint can be reduced

with counts <25,000/!lL (Table 94-1). Nonetheless, 10% of

patients with septic arthritis have synovial fluid leukocyte

counts < 10,000/!lL. A lower synovial WBC count is more

common in immunocompromised patients and those with

prosthetic joints. In prosthetic joints, a synovial WBC count

> 1,1 00/!lL is concerning for an infectious etiology. Although

the number of WBCs can be helpful, the type of WBCs is

less helpful. Some reference a synovial polymorphonuclear

cells count >90% as a rule-out criteria; however, its sensitivity

has ranged from 60% to 70% in several studies.

Synovial lactate and lactate dehydrogenase (LDH) have

been shown to be predictive of septic arthritis if their levels

are greater than >5.6 mmol!L and >250 U/L, respectively.

Gram stain and culture should always be performed;

however, negative results can occur in septic arthritis,