History
Clinical presentation may be quite variable. The clinical triad of fever, back pain, and neurologic deficit is not present in most patients. [6, 8] Early presentations may be subtle, and atypical presentations are not unusual. A 4-phase sequential evolution has been described, with (1) localized spinal pain, (2) radicular pain and paresthesias, (3) muscular weakness, sensory loss, and sphincter dysfunction, and finally (4) paralysis. [1]
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The virulence of the infecting organism and the mode of infection contribute to the tempo of this progression. Abscesses from hematogenous spread tend to progress rapidly, while abscesses from osteomyelitis or discitis may evolve over weeks or months with slow progression of symptoms.
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Frequently the patient gives a history of back strain or mild injury.
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An evident source of infection in skin or soft tissue may be found.
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IV drug users are a high-risk group. Occurrences have been cited even in patients with a remote history of IV drug abuse. [7]
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Cases are frequently reported in patients with diabetes mellitus, which is a risk factor in 50% of reported patients; alcoholism; and conditions involving chronic immunosuppression.
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Hematogenous seeding of the epidural space with abscess formation may stem from intravenous lines, urinary catheters, or implantable devices. Direct inoculation of the epidural space may follow spinal surgery, epidural catheter placement, or epidural injections.
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Symptoms may include the following:
Fever, present in only about one third of patients
Localized back pain in most patients, often the first symptom
Radiculopathy with radiating or lancinating pain, including chest or abdominal pain (At times this may simulate myocardial infarction or other causes of chest or abdominal pain.)
Spinal cord syndromes, typically involving paraparesis with prospective progression to paraplegia (Epidural abscesses at the level of the cauda equina cause symptoms consistent with cauda equina syndrome rather than a spinal cord syndrome.)
Central cord syndrome from epidural abscess has also been reported. [9]
Sphincter dysfunction, including incontinence or increased residual urine volumes
Headache and neck pain may be present, especially with cervical epidural abscesses. (Of course, these symptoms might also suggest meningitis.)
Physical
See the list below:
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In some patients, fever is found at presentation.
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Physical findings vary with the degree of spinal cord compression or dysfunction.
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In the most advanced cases, a transverse cord syndrome is seen with motor and sensory levels found with neurologic examination.
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Localized tenderness to percussion or palpation at the site of the abscess may be noted. Paraspinal muscle spasm may be present.
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Reflexes may vary from absent to hyperreflexia with clonus and extensor plantar (Babinski) responses. Areflexia may indicate spinal shock with transient inhibition of spinal reflexes.
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Nuchal stiffness or rigidity may be present, notably with cervical epidural abscesses.
Causes
See the list below:
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Most cases arise from hematogenous seeding of the epidural space from a distant source of infection.
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A few cases are the result of direct extension of infection from the spine or paraspinal tissues.
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Sources of hematogenous infection
Skin and soft tissue
Infected catheter
Bacterial endocarditis
Respiratory tract infection
Urinary tract infection
Dental abscess
Others
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Sources of contiguous spread
Vertebral osteomyelitis
Retropharyngeal abscess
Dermal sinus tract
Psoas abscess
Penetrating injury
Epidural injections or catheters
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Cervical epidural abscess with spinal cord compression and spinal cord edema.
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Spinal epidural abscess lumbar area.
