subdural empyema

What is Subdural Empyema?

Subdural empyema, also known as a subdural abscess, is a rare but serious infection that occurs between the dura mater and the arachnoid mater in the brain. This condition is characterized by a collection of pus in the subdural space, which can cause severe symptoms and potentially life-threatening complications if left untreated.

Causes and Risk Factors

Subdural empyema can develop as a complication of various conditions, including:

• Sinusitis (inflammation of the sinuses)
• Otitis (infection of the middle ear)
• Mastoiditis (infection of the mastoid bone)
• Cranial surgery or trauma
• Secondary infection of a subdural effusion or hematoma

Symptoms

The symptoms of subdural empyema can vary depending on the severity and location of the infection. Common symptoms include:

• Fever
• Headache
• Sleepiness
• Vomiting
• Seizures
• Stiff neck
• Confusion or altered mental status

Complications and Mortality

If left untreated, subdural empyema can lead to severe complications, including direct brain compression and injury due to the confined cavity of the skull. The mortality rate for subdural empyema is approximately 10-13%, despite aggressive neurosurgical management.

Prompt Diagnosis and Treatment

Early diagnosis and treatment are crucial in preventing these complications and improving outcomes. History and physical examination should guide the clinician to suspect this condition, and prompt surgical intervention can often prevent severe consequences.

References:

• [1] (Result 10) - Intracranial subdural empyema is a loculated pus collection in the intracranial subdural space...
• [2] (Result 13) - Subdural empyema can develop after a cranial surgery or after a trauma, particularly in cases where there is a compound depressed fracture.
• [3] (Result 14) - The pathogenesis of subdural empyema is similar to those of brain abscess: direct extension from a contiguous infection.
• [4] (Result 15) - Intracranial subdural empyema can lead to severe symptoms, or even death, by direct brain compression and injury due to the skull being a confined cavity.

Common Signs and Symptoms of Subdural Empyema

Subdural empyema, a rare but serious infection of the subdural space between the arachnoid mater and the dura mater, can manifest in various ways. The symptoms often reflect the raised intracranial pressure, meningitis, and the source of infection.

• Fever: A persistent high temperature is often reported at the outset.
• Headache: A severe headache that worsens over time is a common symptom.
• Nausea and Vomiting: Patients may experience nausea and vomiting due to increased intracranial pressure.
• Malaise: A general feeling of being unwell or weak is also reported.

Neurological Symptoms

In addition to the above symptoms, subdural empyema can cause various neurological symptoms, including:

• Seizures: Focal or generalized seizures are a common neurologic manifestation.
• Changes in Mental Status: Confusion, drowsiness, stupor, and coma are possible signs of altered mental status.
• Hemiparesis: Weakness or paralysis on one side of the body is another neurological symptom.

Other Possible Symptoms

In some cases, subdural empyema can cause other symptoms, such as:

• Periorbital Swelling: Swelling around the eyes may indicate a high likelihood of empyema expanding into the intracranial space.
• Diplopia: Double vision or blurred vision can be a symptom of subdural empyema.
• Facial Swelling: Swelling on one side of the face may also occur.

References

[11] Subdural empyema is a rare but serious infection of the subdural space between the arachnoid mater and the dura mater. It can be caused by bacterial, fungal or protozoal infection and can lead to brain damage, coma and death if not treated. [12] Signs and Symptoms of a Subdural Empyema. Symptoms of a subdural empyema are usually a consequence of the raised intracranial pressure, meningitis and the source of infection. It can be more distressing if a cerebral infarction occurs. [14] What Are the Signs and Symptoms of Subdural Empyema? Patients present with the signs and symptoms of infection. Few cases are asymptomatic. Common symptoms are fever, headache, vomiting, and neurological symptoms like seizures and changes in the patient's mental status. [15] Hemiparesis, seizures, and altered mental status are the most common neurologic signs when the intracranial space is involved.

Subdural empyema, a serious medical condition characterized by a collection of pus in the space between the brain and its outermost membrane (subdural space), requires prompt diagnosis to initiate effective treatment. Various diagnostic tests can help identify this condition.

Imaging Studies

• Cranial MRI: Considered the imaging study of choice for diagnosing subdural empyema, as it provides detailed images of the brain and surrounding structures, allowing for accurate identification of the empyema and its extent [5].
• Magnetic Resonance Imaging (MRI) with contrast and DWI: This is the most sensitive test for diagnosing subdural empyema, especially when CT scans are not possible [2].
• CT scans: While less sensitive than MRI, CT scans can still be used to diagnose subdural empyema, particularly in emergency situations where MRI is not readily available [5].

Laboratory Tests

• Blood tests: Laboratory analysis of blood tests may show raised white cell count, C-reactive protein, and erythrocyte sedimentation rate, which are non-specific indicators of inflammation and infection [8].
• Cerebrospinal fluid (CSF) examination: CSF findings in subdural empyema include an increased WBC count (predominantly polymorphonuclear neutrophils), with a significant increase (> 50/µL) often seen [1].

Other Diagnostic Tests

• History and physical examination: A thorough medical history and physical examination can help tailor case evaluation and diagnosis, although cranial imaging should be performed in all patients suspected of having subdural empyema [3].
• Neuroimaging techniques: Advances in neuroimaging have improved the diagnosis and treatment of brain abscesses and subdural empyemas [4].

It is essential to note that a combination of these diagnostic tests may be necessary to confirm the diagnosis of subdural empyema. A prompt and accurate diagnosis is crucial for initiating effective treatment and improving patient outcomes.

References: [1] CSF examination in subdural empyema [2] MRI with contrast and DWI for diagnosing subdural empyema [3] History and physical examination in subdural empyema diagnosis [4] Advances in neuroimaging for brain abscesses and subdural empyemas [5] CT scans and MRI for diagnosing subdural empyema [8] Blood tests in subdural empyema

The drug treatment for subdural empyema typically involves antibiotics to cover the most likely causative organisms, as well as antiepileptic medication if seizures are present.

Antibiotics:

1. Vancomycin: This is often the first-line antibiotic due to its broad-spectrum coverage against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA).
2. Metronidazole: This antibiotic is effective against anaerobic bacteria, which are commonly found in subdural empyema.
3. Third-generation cephalosporins (e.g., ceftriaxone or cefotaxime): These antibiotics have broad-spectrum activity and are often used in combination with vancomycin and metronidazole.

Antiepileptic medication:

1. Levetiracetam: This is a commonly used antiepileptic medication for treating seizures associated with subdural empyema.
2. Phenytoin: This medication may be used if levetiracetam is not effective or tolerated.

Other medications:

1. Dexamethasone: This corticosteroid may be used to reduce inflammation and swelling in the brain.
2. Pain management: Medications like acetaminophen, ibuprofen, or opioids may be prescribed to manage pain and discomfort.

Duration of antibiotic treatment:

The duration of antibiotic treatment typically ranges from 3 to 6 weeks, depending on the severity of the infection and the patient's response to treatment.

Differential Diagnoses of Subdural Empyema

Subdural empyema, a life-threatening infection, requires prompt diagnosis and treatment to prevent severe symptoms or death. The differential diagnoses for subdural empyema include:

• Bacterial Meningitis: A bacterial infection that inflames the meninges, the protective membranes surrounding the brain and spinal cord.
• Superior Sagittal Sinus Thrombosis: A blood clot in the superior sagittal sinus, a vein that drains blood from the brain.
• Epidural Abscess: A collection of pus between the dura mater and the inner surface of the skull.
• Cerebral Abscess: A collection of pus within the brain tissue itself.

These conditions can be distinguished by their clinical presentation, imaging findings, and laboratory results. For example:

• Bacterial meningitis is often characterized by fever, headache, stiff neck, and altered mental status.
• Superior sagittal sinus thrombosis may present with seizures, focal neurological deficits, or signs of increased intracranial pressure.
• Epidural abscess typically presents with localized pain, swelling, and tenderness over the affected area.
• Cerebral abscess can cause a range of symptoms, including fever, headache, confusion, and focal neurological deficits.

Key Points to Consider

• A lumbar puncture should not be performed in patients with clinical signs of raised intracranial pressure or focal neurological deficits (Source: [3])
• Imaging studies, such as CT or MRI scans, are essential for diagnosing subdural empyema and differentiating it from other conditions.
• Prompt surgical evacuation of the collection and administration of appropriate antibiotics are crucial for successful treatment.

References

[1] Subdural Empyema (Source: [10]) [2] Intracranial subdural empyema is a loculated pus collection in the intracranial subdural space (Source: [10]) [3] The condition was referred to as "subdural abscess," "cortical abscess," "purulent pachymeningitis," "phlegmonic meningitis," or "subdural suppuration" before 1943. (Source: [10]) [4] Successful treatment is predicated on prompt diagnosis, followed by surgical evacuation of the collection and administration of appropriate antibiotics. (Source: [12])