Epidural abscess natural history, complications and prognosis: Difference between revisions
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An epidural abscess is a rare suppurative infection of the [[central nervous system]], a collection of [[pus]] localised in the [[epidural space]] lying outside the [[dura mater]], which accounts for less than 2% of focal [[CNS]] infections. <ref>{{Cite book | last1 = Longo | first1 = Dan L. (Dan Louis) | title = Harrison's principles of internal medici | date = 2012 | publisher = McGraw-Hill | location = New York | isbn = 978-0-07-174889-6 | pages = }}</ref> It may occur in two different places: [[intracranial space|intracranially]] or in the [[spinal canal]]. Due to the fact that the initial symptoms and clinical characteristics are not always identical and are similar to other diseases, along with the fact that they are both rare conditions, the final diagnosis might be delayed in time. This late diagnosis comes at great cost to the patient, since it is usually accompanied by a bad prognosis and severe complications, with a potential fatal outcome. According to the location of the collection, the [[abscess]] may have different origins, different organisms involved, symptoms, evolutions, complications and therapeutical techniques. <ref name="DannerHartman1987">{{cite journal|last1=Danner|first1=R. L.|last2=Hartman|first2=B. J.|title=Update of Spinal Epidural Abscess: 35 Cases and Review of the Literature|journal=Clinical Infectious Diseases|volume=9|issue=2|year=1987|pages=265–274|issn=1058-4838|doi=10.1093/clinids/9.2.265}}</ref> | An epidural abscess is a rare suppurative infection of the [[central nervous system]], a collection of [[pus]] localised in the [[epidural space]] lying outside the [[dura mater]], which accounts for less than 2% of focal [[CNS]] infections. <ref>{{Cite book | last1 = Longo | first1 = Dan L. (Dan Louis) | title = Harrison's principles of internal medici | date = 2012 | publisher = McGraw-Hill | location = New York | isbn = 978-0-07-174889-6 | pages = }}</ref> It may occur in two different places: [[intracranial space|intracranially]] or in the [[spinal canal]]. Due to the fact that the initial symptoms and clinical characteristics are not always identical and are similar to other diseases, along with the fact that they are both rare conditions, the final diagnosis might be delayed in time. This late diagnosis comes at great cost to the patient, since it is usually accompanied by a bad prognosis and severe complications, with a potential fatal outcome. According to the location of the collection, the [[abscess]] may have different origins, different organisms involved, symptoms, evolutions, complications and therapeutical techniques. <ref name="DannerHartman1987">{{cite journal|last1=Danner|first1=R. L.|last2=Hartman|first2=B. J.|title=Update of Spinal Epidural Abscess: 35 Cases and Review of the Literature|journal=Clinical Infectious Diseases|volume=9|issue=2|year=1987|pages=265–274|issn=1058-4838|doi=10.1093/clinids/9.2.265}}</ref> | ||
==Natural History== | |||
Depending on the location of the epidural abscess, its natural history and related symptoms will invariably change. Therefore, it is important to distinguish the two: | Depending on the location of the epidural abscess, its natural history and related symptoms will invariably change. Therefore, it is important to distinguish the two: | ||
===Intracranial Epidural Abscess=== | ===Intracranial Epidural Abscess=== | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
An epidural abscess is a rare suppurative infection of the central nervous system, a collection of pus localised in the epidural space lying outside the dura mater, which accounts for less than 2% of focal CNS infections. [1] It may occur in two different places: intracranially or in the spinal canal. Due to the fact that the initial symptoms and clinical characteristics are not always identical and are similar to other diseases, along with the fact that they are both rare conditions, the final diagnosis might be delayed in time. This late diagnosis comes at great cost to the patient, since it is usually accompanied by a bad prognosis and severe complications, with a potential fatal outcome. According to the location of the collection, the abscess may have different origins, different organisms involved, symptoms, evolutions, complications and therapeutical techniques. [2]
Natural History
Depending on the location of the epidural abscess, its natural history and related symptoms will invariably change. Therefore, it is important to distinguish the two:
Intracranial Epidural Abscess
The less common of the three main focal suppurative central nervous system infections (brain abscess and subdural empyema). It may have several origins, however the more common are: complication of sinusitis or following neurosurgical procedures or head trauma. Since the dura mater is tightly adherent to the bone surface of the skull, making the epidural space a virtual space, the abscess tends to have an indolent evolution, usually creating small, round collections of purulent material. Since this infected material is able to cross the dura mater, along the emissary veins, the epidural abscess is usually accompanied by a subdural empyema. This explains the fact that these two entities share common etiologies. In the case of the abscess originating from sinusitis, the responsible organisms are usually similar to the ones causing subdural empyema, such as streptococci and anaerobes, while if the abscess originates on a trauma or a neurosurgical procedure, the responsible organisms are usually staphylococci or gram-negatives. At the time of presentation, patients usually complain of headache, fever and seizures and present with nuchal rigidity and focal neurologic deficits. Since the abscess develops slowly, the signs and symptoms may develop insidiously. A particular situation may arise, when the abscess is located near the petrous bone, compressing the nearby structures, being responsible for the so called Gradenigo’s syndrome, in which compression of the cranial nerves V and VI, results in unilateral facial pain and lateral rectus muscle weakness. [3][4] If left untreated the condition will aggravate and severe complications will arise, possibly leading to a fatal outcome. Proper diagnosis and treatment are therefore mandatory. Treatment usually involves aggressive antibiotic therapy and surgical drainage.
Spinal Epidural Abscess
This type of abscess usually develops following hematogenous dissemination of an infection, located elsewhere in the body or following neurosurgical procedure or trauma, particularly in patients with predisposing conditions, such as spinal deformities or bacteremia.[5] In this particular type of epidural abscess, its progression of symptoms and clinical findings, within hours to days or months in more chronicle settings, may be described according to 4 stages: [6][7]
- Stage 1 - back and focal vertebral pain, with tenderness on physical exam.
- Stage 2 - nerve root pain, radiating from affected areas, sometimes accompanied by paresthesia.
- Stage 3 - dysfunction of the spinal cord, presenting by motor and sensory deficits and sphincter incompetence.
- Stage 4 - Paralysis.
The typical triad of symptoms is: fever, back pain and neurologic deficits. However, these may not be present at all times on admission which, along with the vast differential diagnosis, may delay the final diagnosis. The progression of the disease from stage to stage and the duration of symptoms before admission (between 1 day to 2 months) are also highly variable. Along with these symptoms, others may be present, such as: weakness, urinary retention, and tenderness. Attending to the fact that the abscesses tend to form in larger epidural spaces, they will be more frequent in posterior and thoracolumbar areas, where is located fat, susceptible of being infected. [7][8][9]
Complications
The possible complications from this disease will depend on the severity and location of the abscess. The rate of complications rises with the increase of time to reach the diagnosis. The later the diagnosis is reached and proper therapy is started, worst the complications will be. These complications include:
It is important to remember that surgery is a vital part of the therapy of epidural abscess, along with the risks that are inherent to it, such as damage to the spinal cord, which may then be added to the list of complications. Following spinal cord injury, other complications arise:
Prognosis
The most important factor to predict the final outcome is the patients neurological status before the surgery:
- Patients undergoing surgery during stages 1 or 2 are expected to be neurologically intact with a possible decrease in risk of remaining radicular pain.
- Patients undergoing surgery in stage 3, may experience a some improvement of the weakness felt before the surgery.
- Patients undergoing surgery in stage 4 may experience some neurological function improvement.
In recent studies full recovery has been common among survivors and the mortality rate has been low (<5%). In the event of death, it is usually due to sepsis, secondary to prolonged immobility or evolution of sepsis. [10] Studies from Khanna and colleagues[11] revealed three factors associated with poor outcomes:
- age
- degree of thecal sac compression
- duration of symptoms
Other important factors include:
- absence of paralysis or its presence with less than 36 hours, is associated with better chances of returning to normal function and better chances or surviving;
- presence of purulent material, instead of granulation tissue, indicating a more acute scenario.
Considering that following treatment, neurological function improvements are reported during one year, with the help of rehabilitation, the final neurological outcome and functional capacity of these patients should only be fully assessed after one year. [7]
References
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Danner, R. L.; Hartman, B. J. (1987). "Update of Spinal Epidural Abscess: 35 Cases and Review of the Literature". Clinical Infectious Diseases. 9 (2): 265–274. doi:10.1093/clinids/9.2.265. ISSN 1058-4838.
- ↑ Mandell, Gerald L.; Bennett, John E. (John Eugene); Dolin, Raphael. (2010). Mandell, Douglas, and Bennett's principles and practice of infectious disease. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0-443-06839-9.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Mandell, Gerald L.; Bennett, John E. (John Eugene); Dolin, Raphael. (2010). Mandell, Douglas, and Bennett's principles and practice of infectious disease. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0-443-06839-9.
- ↑ Mandell, Gerald L.; Bennett, John E. (John Eugene); Dolin, Raphael. (2010). Mandell, Douglas, and Bennett's principles and practice of infectious disease. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0-443-06839-9.
- ↑ 7.0 7.1 7.2 Darouiche, Rabih O. (2006). "Spinal Epidural Abscess". New England Journal of Medicine. 355 (19): 2012–2020. doi:10.1056/NEJMra055111. ISSN 0028-4793.
- ↑ Mandell, Gerald L.; Bennett, John E. (John Eugene); Dolin, Raphael. (2010). Mandell, Douglas, and Bennett's principles and practice of infectious disease. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0-443-06839-9.
- ↑ Darouiche RO, Hamill RJ, Greenberg SB, Weathers SW, Musher DM (1992). "Bacterial spinal epidural abscess. Review of 43 cases and literature survey". Medicine (Baltimore). 71 (6): 369–85. PMID 1359381.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Khanna RK, Malik GM, Rock JP, Rosenblum ML (1996). "Spinal epidural abscess: evaluation of factors influencing outcome". Neurosurgery. 39 (5): 958–64. PMID 8905751.