Intracranial epidural abscess

John E Greenlee MD (Dr. Greenlee of the University of Utah School of Medicine has no relevant financial relationships to disclose.)
Originally released July 26, 1995; last updated October 15, 2019; expires September 15, 2022

This article includes discussion of intracranial epidural abscess, epidural empyema, pachymeningitis externa, and Pott's puffy tumor. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


Intracranial epidural abscess is a potentially life-threatening complication of pericranial infection, particularly sinusitis. The condition may also develop after cranial trauma or neurosurgical procedures. The condition is often accompanied by osteomyelitis of the frontal bone with associated subperiosteal abscess (Pott's puffy tumor), but it may also present without localizing symptoms or signs. Intracranial epidural abscess itself is rarely fatal but may progress to much more serious conditions, including intracranial subdural empyema, meningitis, brain abscess, or venous sinus thrombosis. In this article, the author discusses the pathogenesis and clinical presentation of intracranial epidural abscess and provides an approach to diagnosis and treatment of the disorder.

Key points


• Intracranial epidural abscess represents loculated infection between the skull and the outermost layer of the cranial meninges, the dura mater.


• The condition is usually a complication of frontal sinusitis. Less frequently, the condition may occur as a complication of otitis or mastoiditis.


• Symptoms of epidural abscess are fever, focal pain, and, at times, subcutaneous swelling over the affected area indicating a subperiosteal abscess (Pott's puffy tumor).


• The condition is important in its own right but may also spread inward to cause much more dangerous conditions, including intracranial subdural empyema, meningitis, brain abscess, or septic venous thrombophlebitis.


• Diagnosis may be made by MRI or, less optimally, CT. Treatment involves antibiotics and often requires surgical drainage.

Historical note and terminology

Epidural abscess represents infection between the outermost layer of the meninges (the dura), and the overlying skull. Focal osteomyelitis (following cranial trauma, with separation of the frontal bone from the underlying dura) was described in 1771 by Percival Pott. The literature concerning cranial epidural abscess, however, is comprised for the most part of individual case reports over much of the past century (Leopold 1916; Skillern 1922; Koenig and Craigmile 1956; Handel et al 1974; Harris et al 1987). Intracranial epidural abscess was initially a condition diagnosed by burr holes and subsequently (with varying degrees of accuracy) by radionuclide imaging or angiography (Koenig and Craigmile 1956; Norrell and Wilson 1967). CT provided the first noninvasive method of detecting intracranial epidural abscess (Kaufman and Leeds 1977). However, MRI has provided a more precise technique for imaging intracranial infection and has demonstrated its ability to identify infections not yet visible by CT (Sze and Zimmerman 1988; Younis et al 2002; Nickerson et al 2012). Improved imaging techniques have made it apparent that certain early epidural infections in neurologically stable patients may be treated with antibiotics alone.

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