The Journal of Emergency Medicine, Vol. 6, pp 391-396, 1968 Prlnted an the USA ??Copyright 0 1968 Pergamon Press plc

SPINAL EPIDURAL ABSCESS

Peter Siao T. C., MD, and Pratap Yagnik, MD

Veterans Administration Medical Center and The Medical College of Pennsylvania, Philadelphia, PA Reprint address: Pratap Yagnik, MD, Neurology Service, University and Woodland Avenues, Philadelphta, PA 19104

0 Abstract-We present three cases of spinal epidural ab- scess. Initial presentation of localized spinal pain and ten- derness along with fever should lead one to suspect the diagnosis. An emergency myelography and prompt treat- ment with appropriate antibiotics is necessary to prevent catastrophic neurologic deficit.

0 Keywords - spinal epidural abscess; myelography; spine pain; fever; paraparesis; antibiotics

Spinal epidural abscess is said to have been described in the literature as early as 1762.’ Scattered cases, retrospective studies, and reviews of this subject have been published.z-8 Recently, modern diagnostic imag- ing modalities like computed tomography (CT scan) and magnetic resonance (NMR) have been shown to be helpful in establishing the diagnosis of spinal epi- dural abscess.+1’ Yet, time and again, patients with this rather uncommon but well described clinical enti- ty are not recognized early enough to prevent perma- nent and severe neurological sequelae. At the Phila- delphia Veterans Administration Hospital, with an average of 7,000 admissions per year, we saw three patients with spinal epidural abscess within a four- month period. This unusual clustering of cases prompted us to report and to review the subject so as to heighten awareness of the clinical entity leading to earlier diagnosis and treatment.

Case One

CASE REPORT

A 55year-old man was in good health until nine days prior to admission when he aspirated while eating and had to cough out forcefully. Related to this event,

the patient thought he had pulled one of his neck muscles. The next morning he noted pain and stiff- ness on the right side of his neck and behind the right ear. A physician gave him analgesics and antibiotics but the neck pain did not improve. Instead he noted exacerbation with coughing, and constipation devel- oped. Five days prior to admission, he noted a tem- perature of 39.4”C (103°F) and difficulty emptying his bladder. The patient had to go to an emergency department twice for urinary retention necessitating urinary straight catheterization. One day prior to ad- mission, he developed right lower extremity weakness which progressed to right hemiparesis.

Upon presentation to our emergency department, the patient had a temperature of 38.4”C (101.2”F), a stiff neck and an area of warmth and swelling behind his right ear. He had a right hemiparesis and a slight weakness of his left deltoid and iliopsoas muscles. The biceps reflex on the right and the patellar and ankle reflexes on both sides were absent. Plantar re- flexes were downgoing bilaterally. Sensory examina- tion revealed decreased pain sensation over the CS to C8 dermatomal distributions on the right side. An emergency myelogram demonstrated a complete block at the C6-C7 level. (Figure lA, 1B). Postmyelo- gram CT of the cervical spine showed a soft tissue mass in the epidural space extending from the C7 level to the C2 level with some skipped areas (Figure l-C, 1-D). The patient then underwent an emergency laminectomy from the 3rd to 7th cervical levels. Granulation tissue was noted in the epidural space and a Gram’s stain of this tissue revealed Gram-posi- tive cocci. A culture of the same material, however, was negative. Preoperative blood cultures grew out Staphylococcus aureus. Immediately following sur- gery, the patient was noted to be paraplegic with in- creased right upper extremity weakness. His motor

RECEIVED: 22 December 1987; ACCEPTED: 9 March 1988

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392 Peter Siao T. C. and Pratap Yagnik

Figure 1. Myelographic images demonstrate non-specific extradural block at the level of C6-C7. (a) AP view; (b) LPO view.

strength gradually improved over a period of two months. The patient was found to need insulin thera- py for persistent hyperglycemia.

Case Two

A 61-year-old insulin dependent diabetic man came in with fever and chills that started eight days prior to admission. This was followed by low back pain with radiation down both of his lower extremities. On ex- amination, he was febrile to 38.4”C (lOl.l”F) and was ambulatory, though in great pain. There was marked tenderness of the L3-L4 region with para- spinal muscle spasm and warmth. Minimal movement of both lower extremities would precipitate excruciat- ing pain. The knee, ankle, and plantar reflexes were

absent bilaterally. A spinal epidural abscess was sus- pected because of the combination of fever, back pain, and neurological dysfunction in a compromised host. A myelogram was therefore performed revealing complete block to caudal flow of contrast dye at the level of L3 (Figure 2-A, 2B). A postmyelogram CT of the lumbar spine showed an epidural soft tissue densi- ty on the right poster0 lateral aspect of the thecal sac at the level of L3. Marked spinal stenosis from L3 through Sl was also seen.

Initially, the patient refused surgery to evacuate the abscess. The rapid progression of marked weak- ness of his lower extremities, however, prompted him to consent. Purulent material was aspirated from the paraspinous muscles at the level of L3. Laminectomy was performed at the level of L3 and L4, and granula- tion tissue was evacuated. Both abscess culture and

Spinal Epidural Abscess 393

Figure 1 (c). Transverse CT imaging thru C6 vertebra dem- onstrates right sided extradural compression displacing opacified dural sac to the left.

the preoperative blood culture grew Staphylococcus aureus. Postoperatively, the patient improved remark- ably and was ambulatory on discharge.

Figure 1 (d). Transverse CT image at C2 vertebra demon- strates similar findings to those in figure 1-C.

and the preoperative blood culture grew methicillin resistant Staphylococcus aureus. Postoperatively, the patient’s left iliopsoas strength improved markedly and he became ambulatory.

Case Three

DISCUSSION A 44-year-old man, a known intravenous drug abuser, had a draining abscess on his left buttock, and com- plained of intermittent back pain that he had noted for one year. The patient, who was brought to the emergency department by the police after he passed out on the street, apparently had taken heroin and cocaine intravenously before losing consciousness. On admission, the patient was lethargic, febrile, and noted low back pain radiating down his left lower extremity. The patient was moving all of his extremi- ties. Two days later, the patient became more alert and was able to follow commands. Examination at that time revealed exquisite tenderness of the lumbar spinous processes with a weak iliopsoas muscle on the left. The patient was unable to lift his left lower ex- tremity off the bed. An emergency myelogram showed a ventral epidural defect starting from the lower border of L3 down to the midportion of the L5 vertebra (Figure 3-a, 3b). Laminectomy at the level of L3 to L5 was performed, and pus was evacuated from the lumbar epidural space. The culture of the abscess

In 1948, Heusner described the following four phases of spinal epidural abscess: phase 1, local spine pain; phase 2, root pain, fever, leukocytosis; phase 3, the onset of neurological deficits; and phase 4, the onset of paralysis.‘* The incidence of nontuberculous spi- nal epidural abscess has been reported to be 0.2 to 1.2 per 10,000 hospital admissions per year.4s’2 Recently, Danner and Hartman noted an incidence of 2.8 cases per 10,000 admissions to the New York Hospital.6 Blunt trauma,z~4J~‘2 skin infection,4-6 diabetes melli- tus,4s6 intravenous drug abuse,5 alcohol abuse,hJ3 pre- vious spine surgery, 4.6 and spinal anesthesia14-I6 have all been implicated as predisposing factors. A review of five hospital series of spinal epidural abscess showed the etiologic bacteria to be Staphylococcus aureus in 62%; aerobic gram-negative rods in 18%; aerobic Streptococci 8 %; Staphylococcus epidermidis 2%; anaerobes 2%; unknown 1O%.6 Infection proba- bly enters the spinal epidural space by direct exten- sion or hematogenous spread. The Batson’s plexus of

394 Peter Siao T. C. and Pratap Yagnik

Figure 2. Demonstrates a extradural block to the inferior flow of contrast media at the L3 level. (a) AP view; (b) Lat view.

veins could easily be a route of infection.” The actual mechanism of spinal cord injury is probably is- chemic, leading to infarction secondary to the epi- dural mass occluding the vascular supply of the cord. This is suggested by the fact that damage to the cord is often out of proportion to the degree of cord com- pression. Symptoms and signs usually include a combination of fever, localized spine pain, and subse- quent neurological dysfunction, eg radiculopathy, paraparesis, quadriparesis, hemiparesis, urinary and bowel incontinence, and sensory deficits.z-5 The rate of progression of the different phases of spinal epi- dural abscess is highly variable. The onset of paraly- sis can occur suddenly in spite of the chronicity of the patient’s previous symptoms. This is the main reason why it is so important to make the diagnosis as soon as possible. Of particular note, the series from New York Hospital included 15 out of 35 patients with spinal epidural abscess who had no fever or other signs of sepsis upon presentation, and 64% who had

no neurological deficits at the time of admission.6 In children, one may only see irritability, excessive cry- ing, or symptoms of an acute abdomen.17 The prog- nosis is related to the rate of progression of neurologi- cal dysfunction rather than to the time interval between the onset of the symptoms and the onset of abnormal neurological signs.* Sensory loss has been associated with poor prognosis.3

Spinal epidural abscess is most commonly found in the thoracic and lumbar regions where the epidural space is the widest. Our first patient was unusual because of the cervical location of his spinal epidural abscess. In a recent report, the incidence of cervical spinal epidural abscess was estimated to be between 1 in 70,000 and 1 in 400,000 admissions.7 The epidural abscess is usually located posterolaterally because the anterior surface of the dura is adherent to the posteri- or surface of the vertebral bodies.8 There are no ana- tomical barriers to the rostro-caudal spread of the infection in the spinal epidural space, therefore it

Spinal Epidural Abscess 395

Figure 3. Demonstrates an anterior and left lateral extradural impression on the contrast media column at the level of L3 to L5. (a) AP view (b) Lat view.

usually involves three to five vertebral bodies. The diagnosis is confirmed by myelography. A postmyelo- graphic CT scan of the spine may help to delineate the extent of involvement as we have shown in case one. Magnetic resonance imaging of the spine has been shown to localize the crania-caudal extent of an epidural abscess in a patient who was known to have allergy to contrast dye.” However, the value of NMR imaging in the diagnosis of spinal epidural abscess is not well established.‘* Patients with fever and severe local spine pain should be highly suspect for spinal epidural abscess. In addition, known predisposing factors such as the immunocompromised host, diabe- tes mellitus, intravenous drug abuse, alcohol abuse, and spinal surgery and trauma should further in- crease suspicion for spinal epidural abscess. It is im- perative that a myelogram be performed as soon as possible to establish the diagnosis. Therapy involves

the early use of broad spectrum antibiotics, which should include coverage for Staphylococcus aureus, and an emergency laminectomy with decompression and drainage, Once the results of the cultures are obtained, then a more appropriate antibiotic can be administered. Antibiotics alone without lami- nectomy have been shown to be effective in selected cases, primarily for patients who are poor surgical candidates.6.93’9

The correct diagnosis of spinal epidural abscess was made at initial presentation only in a quarter of the cases reported from Massachusetts General Hos- pital. Our first patient presented twice to the emer- gency department for urinary retention. Even though he had fever and neck pain at that time, the diagnosis of spinal epidural abscess was entertained only after he developed right hemiparesis. Our second patient was a fairly typical case of spinal epidural abscess.

396 Peter Siao T. C. and Pratap Yagnik

The third patient was confused and lethargic on ad- mission. He complained of back pain, but the diag- nosis of spinal epidural abscess was not entertained until two days later when he became more alert and was found to be weak.

one cannot over-emphasize the importance of early recognition of this potentially devastating but treata- ble condition.

SUMMARY

Since the neurological deficits caused by spinal epi- dural abscess can progress rapidly and irreversibly,

Acknowledgmenls-The authors are grateful to Dr. Rosalie A. Burns for her helpful comments during the preparation of the manuscript, to Dr. Joel Swartz for reviewing the myelogram and the CT scan, and to Ms. Barbara Kucowski for typing the manuscript.

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