Intracranial suppuration: a clinical comparison of subdural empyemas and epidural abscesses

BACKGROUND

We compared the clinical features and therapeutic outcomes of intracranial suppurations (IEs) caused by sub-dural empyema (SDEs) and epidural abscesses (EAs).

METHODS

Twenty-four patients with IE were retrospectively identified at our institution over a period of 14 years. Therapeutic outcomes at 6 months were determined using the Glasgow Outcome Scale.

RESULTS

Among them, 15 had SDE and nine had EA with or without SDE. The three most frequently encountered clinical features Included fever (79%), disturbed consciousness(58%), and seizures (54%). Postneurosurgical or posttraumatic states (42%) and complication after meningitis (38%) were the two most common modes of infection. The overall mortality rate was 8% (2/24). However, if mortality and severe neurologic sequelae were included in the poor outcome group, then 29% (7/24) of our patients would be considered treatment failures.

CONCLUSION

In this study, SDE commonly arose following bacterial meningitis with a more fulminant course, but no deaths occurred. In contrast, EA commonly has a more Indolent course and is postoperatively or post-traumatically related, and therefore may have a higher mortality rate based on primary brain pathophysiology alone. Inpatients with meningitis or who undergo postneurosurgical procedures and develop fever, progressive disturbed consciousness, seizures, and focal neurologic signs, immediate neuroimaging studies should be per-formed to determine whether IE is present. Early surgical drainage and aggressive antimicrobial therapy are necessary.

[Complications of chronic subdural hematoma in the adult]

Chronic subdural hematoma is subject to post-operative fatal and non-fatal complications in 5 to 10% of the cases. Mortality ranges from 0 to 8%, depending on the preoperative clinical status. There is an average recurrence in 8% of the cases, chiefly linked to the absence of drainage. Empyema occurs in 2% of patients, especially when the drain is left in place more than 3 days. In most of the series, long-term epilepsy is a rare complication and patients do not require antiepileptic drugs. The lack of cortical reexpansion, postoperative intracerebral hematoma and tension hydrocephalus are, among others, complications occurring after surgery. Finally, 10% of the patients will have a permanent neurological impairment.

Brain abscess at the University Hospital of the West Indies

Surgical infections of the central nervous system are still attended by high rates of morbidity and mortality, although substantial progress has been made since the advent of computed tomography (CT) scanning technology. In this retrospective review of 25 surgically treated patients with either brain abscess or subdural empyema at the University Hospital of the West Indies, the majority of patients were male and between the ages of 10 and 30 years with a mean age of 16.9 years. Almost half the patients had a hemiparesis on presentation while 60% had fever. Subdural empyema was more common than a localized intracerebral abscess which was most frequently located in the frontal lobe. The most common predisposing factors were sinusitis and congenital heart disease. Streptococci spp and Staphylococci spp were the most frequently isolated organisms. All patients underwent CT scanning and surgical intervention. The mortality rate was 20%, and 21% of the survivors had late seizures. There must be a high index of clinical suspicion and early referral to specialist centres where neuroradiological investigation and prompt neurosurgical intervention can be carried out to minimize morbidity and mortality.

[Intracranial abscess and empyema: neurosurgical management]

Brain abscesses and empyemas are severe infections with lethal outcomes in the case of inappropriate treatment. The files of 34 patients with brain abscesses, and nine with intracranial empyemas treated over eight years (1990-1997) were analyzed retrospectively. Cases were evaluated for treatment and compared with data from the literature. Patients with brain abscess underwent either aspiration of the lesion through a burr hole (79.5% of the cases), or craniotomy and excision (8.8% of the cases); 11.7% were treated only with antibiotics. The operative mortality was 2.9% and the outcome was satisfactory in 85% of patients. These results are in agreement with data from the literature. Prognosis is strongly related to the initial clinical status. Current methods of treatment include surgical aspiration of large abscesses with a mass effect, and are usually associated with a poor clinical status. Excision is suggested whenever aspiration procedures have failed, or in the presence of foreign material or fungal abscess. Medical treatment is indicated for small and deeply located abscesses in patients with satisfactory clinical states. Empyemas in our series were treated with burr hole and pus aspiration. The mortality rate was 11%, and 62.5% of the patients made a good recovery. In agreement with other reported studies, the method of treating subdural empyema is much less significant than an aggressive early drainage of the infection. Although brain abscesses and empyema remain a significant neurosurgical concern, aggressive treatment can result in an excellent outcome in the majority of patients.

Treatment of subdural empyema by burr hole

Subdural empyema, a collection of pus in the space between the dura and arachnoid, is a rare type of intracranial infection. We report on 23 patients, aged 8 months to 70 years, with subdural empyema who were treated in our clinic between 1989 and 1994. The sources of subdural empyemas were meningitis in five patients, middle ear in five, trauma in four, paranasal sinus in three, complications of surgery and subdural tap in four, and unknown in two patients. The common presentations were headache, focal neurologic deficit, fever, vomiting, seizures, and neck stiffness. Diagnosis was achieved by computerized tomography and neurologic examinations in all cases. Treatment was effected by burr hole or small craniotomy with catheter drainage, and antibiotics were administered to all patients. The mortality rate was 8.7%; the remaining patients made a good recovery without sequelae. We therefore recommend burr hole with catheter drainage plus antibiotics as a method of treating subdural empyema.

Intracranial suppuration: a modern decade of postoperative subdural empyema and epidural abscess

A retrospective study of subdural empyema and epidural abscess spanning 11 years and encompassing 41 patients was performed, demonstrating that the clinical characteristics of intracranial suppuration have changed over time. Sinusitis and otitis media, previously the predominant etiologies, were predisposing factors in only 29% of patients. A prior craniotomy had been performed in 66% of cases and was the most common risk factor for abscess development. The postoperative patients were subjected to detailed analysis. Patients who had undergone a prior craniotomy were notable for the following features: older age, lack of fever, evidence of wound infection, frequent false-negative computed tomographic scans, and a high percentage of Gram negative aerobic organisms or skin flora as pathogens. The population at highest risk for abscess development ranged from 50 to 60 years old, older than in previous series. Older age and an advanced degree of encephalopathy were indicative of a poor prognosis. Patients with subdural empyema had a worse prognosis as well. Hyponatremia was a frequent complicating factor. A much greater percentage of Gram-negative aerobic bacteria were isolated than in previous studies. Computed tomographic scans, half of which were performed with intravenous contrast material, were nondiagnostic in 30% of patients. The mortality rate was 18.5%, and delay in treatment correlated with increased risk of poor outcome. All patients were treated with a craniotomy. Repeated operations were required in three patients and were associated with the development of intraparenchymal abscess.

The management of cerebellar abscess since the introduction of CT scanning

Sixteen patients with surgical infection of the posterior fossa are presented. There were 14 patients with cerebellar abscess, one patient with a solitary posterior fossa subdural empyema, and another with a combined cerebellar abscess and subdural empyema. Two of the cerebellar abscess patients also had supratentorial infections. The presenting features, aetiology, radiology and bacteriology are discussed with particular reference to differences in abscess re-accumulation, and outcome between those managed by aspiration and excision. We have been unable to show that either method of treatment is superior to the other. An overall mortality rate of 19% was achieved; however, for those with parenchymal cerebellar abscesses this was reduced to 13%. We conclude that burr hole aspiration with regular CT is a satisfactory method of treatment for cerebellar abscess.

[Clinical course and the results of the treatment of unilateral chronic subdural hematoma]

The authors analysed the clinical and surgical results in 131 patients treated for unilateral chronic subdural haematoma. 71% of patients had a history of head trauma, 34% were addicted to alcohol. In 18% of cases the clinical course mimicked cerebral stroke. All patients were treated by burr holes and closed-system drainage lasting for 24-48 hours. There were 4 deaths, 3 from ischaemic stroke, and 1 from subdural empyema. 19 patients revealed postoperative complications--intracranial hypotension, cerebral oedema, and haematoma recurrence being the commonest. Follow-up revealed that 83% of patients were healthy, 10% had stable neurological deficit, and 7% presented epileptic fits.

Management of subdural empyema: a series of 24 cases

Twenty four cases of subdural empyema are reviewed. The overall mortality was 17%, 18 patients were managed by burr hole and five by craniotomy or craniectomy. Antibiotic therapy was commenced once pus had been evacuated. Infection of the paranasal and mastoid sinuses was the commonest aetiological factor. Aspiration of pus through burr holes is the recommended surgical procedure with low mortality and morbidity, when combined with early diagnosis and aggressive chemotherapy.

Subdural empyema: a rational management plan. The case against craniotomy

A review of the management of 34 patients with subdural empyema treated at the Derbyshire Royal Infirmary has been undertaken. It is concluded that craniotomy has little part to play in the management of patients with this condition. With modern, improved antimicrobials and prompt burr hole lavage complete recovery should be obtained in the majority of cases. The treatment of the severely ill patient is discussed.

Intracranial suppuration 1968-1982--a 15 year review

The CT scanner and the recognition of anaerobic organisms has altered the investigation and management of intracranial suppuration. Improved treatment of acute and chronic middle ear infection has also occurred. A 15 year retrospective review was undertaken to assess the effects of these changes. The ears and sinuses were confirmed as the major source of intracranial suppuration (69%) although initial presentation to ENT surgeons was less common (14%). Ear complications occur in childhood and in the fifth and sixth decades; sinus complications predominantly in the second and third decades. The incidence of sinus infection appears to be rising. With the introduction on the CT scanner cerebral abscess mortality declined from 27.5% to 6.5% and subdural abscess mortality halved. The introduction of metronidazole contributed to a drop in mortality. The use of the CT scanner and more accurate antibacterial treatment, including metronidazole, gives hope for a more successful outcome than was previously possible.

Surgical management of subdural empyema

The methods and results of surgical management in 42 patients under 20 years of age with subdural empyema are described. Based on this experience and on a review of the literature, primary craniotomy with radical removal of pus has increasingly become the authors' preferred method of treatment, in addition to appropriate antibiotic treatment with survival figures of around 90% expected.