Intracranial Epidural Abscess Clinical Presentation

Updated: Nov 12, 2014
  • Author: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
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Presentation

History

An intracranial epidural abscess often has an insidious onset, with symptoms developing over several weeks to months. Symptoms of the initiating infection might dominate the picture. Signs and symptoms are as follows:

  • Usually, the patient presents with headache that is either diffuse or localized to one side with scalp tenderness. Headache may be the only presenting symptom. The patient may have persistent fever that develops during or after treatment for sinus or middle ear infection. Purulent discharge from the ears or sinuses, periorbital swelling, and brawny edema of the scalp might accompany.
  • Because the epidural abscess usually enlarges slowly, the following signs do not develop until the infection has reached the subdural space, resulting in subdural empyema, at which time the patient might present with neck stiffness, nausea, vomiting, lethargy, and hemiparesis. Seizures might very well be the first presenting symptom in some cases.
  • Symptoms and signs of increased intracranial pressure (ICP) include nausea, vomiting, and papilledema. Rarely, when the epidural abscess develops near the petrous bone and involves the fifth and sixth cranial nerves, the patient may present with ipsilateral facial pain and weakness of the lateral rectus muscle (ie, the so-called Gradenigo syndrome). Many times, scalp cellulitis, sinusitis, or skull fracture may draw the attention of the physician to such an extent that the diagnosis of epidural abscess may be missed.
  • One should consider the diagnosis of intracranial epidural abscess when a patient presents with unresolving frontal sinus symptoms. Also consider this diagnosis in patients with new neurologic symptoms after trauma or cranial surgery, even if months or years have elapsed since operation or trauma.
  • Onset can be acute, especially in patients without any history of previous cranial neurosurgery. They often present with acute symptoms of encephalopathy and focal neurological deficits.
  • Mittal et al present the case of an 11-year-old girl who presented with typical features of meningitis, suggesting that sinusitis can rarely be latent and present directly with intracranial complications. She underwent neuroimaging because of slow improvement and concern for a brain abscess. Although no history or examination findings were suggestive of sinusitis, the patient was found to have pansinusitis with intracranial extension causing meningitis and epidural abscess. [9]
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Causes

Because the intracranial epidural space is only a potential space and the dura is essentially adherent to the inner table of the skull, infection in the epidural space can result from the following:

Sinusitis (mastoid, ethmoid, sphenoid, and frontal sinusitis); trauma associated with skull fracture; and following craniotomy, orbital cellulitis, cranial osteomyelitis, sagittal sinus phlebitis, fetal monitoring, and mucormycosis. [10]

The risk of infection is increased when multiple neurosurgical operations are performed or if the operation also involves implantation of foreign material. Even though hematogenous spread to the epidural space from a remote site of infection is a common cause of spinal epidural abscess, it is a rare cause of cranial epidural abscess.

Mallur et al reported on 11 children with acute mastoiditis. Complications in these children were as follows: 4 cases of cranial epidural abscess, 4 cases of sigmoid sinus thrombosis, 2 cases of perisigmoid abscess or bony erosion, and 1 case of tegmen mastoideum dehiscence). The authors claim that, although uncommon, intracranial complications of acute mastoiditis may present without clinical signs or symptoms. Computed tomography of the temporal bone with contrast is essential for identifying asymptomatic complications. [11]

Bacteriology

Epidural abscess usually occurs as a result of infection caused by Staphylococcus aureus, Staphylococcus epidermidis, enteric gram-negative bacilli (especially Escherichia coli), Pseudomonas species, Bacteroides species, and other anaerobes. Aerobic and microaerophilic streptococci are usually responsible for infection that has spread from the paranasal sinuses. Rarely, Salmonella species, Eikenella corrodens, and Mucor species have been isolated. Haemophilus influenzae may also be the responsible organism, in addition to Mycobacterium tuberculosis, Proteus penneri, Actinomyces species, Blastomyces species, Aspergillus fumigatus, and Cladosporium species.

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