Treatment of Subdural Empyema

About the disease

An empyema is an abscess, which is the accumulation of pus in an anatomical cavity. A subdural empyema is a subtype of empyema, and forms in the subdural area outside the brain.

Subdural space can form as a result of a separation of the membranes that connect the brain and spinal cord. Such separation usually occurs after trauma or if there is not enough cerebrospinal fluid in the patient’s brain. Membrane separation can also be a pathological process.

95% of subdural empyema cases develop in the cranium and sometimes in the frontal lobe or spinal neuraxis. According to American website Medscape, subdural empyema accounts for 15-22% of all intracranial infections. Before the introduction of penicillin, this disease was terminal. These days, survival rates are a lot better. In developed countries, the mortality rate reaches 6-35% depending on the time of diagnosis and when the treatment began.   

Subdural empyema is most often caused by infectious diseases such as meningitis, otitis and mastoiditis. Infection usually spreads throughout the whole subdural space. If not treated, it can also affect the middle ear and sphenoid sinus.

For reasons as yet unclear, 80% of subdural empyema cases occur in males, predominantly in children and middle-aged men.

Symptoms

• Fever
• Headaches
• Blurred vision
• Nausea
• Torpor
• Drowsiness
• Difficulty speaking and forming thoughts

Diagnosis

• A blood test is conducted to determine the number of white and red blood cells.
• MRI and other imaging tests provide precise images of the intracranial area and show if there are hypodense holes or formations, which could indicate empyema.
• A cranial CT scan is also widely used, as it generates contrast-enhanced images of the hemispheres, where the brain margins are distinctly delineated.

Treatment

In most cases, patients are recommended to undergo the surgical removal of the subdural empyema once it has been found. Before the surgery, a patient needs to submit a liver function test and get prepared. The following are surgical procedures to treat subdural empyema:

• A craniotomy is used to assess and remove the empyema. A section of skull is removed to gain access to the brain.
• Neurosurgical drainage is used if the patient’s condition is critical and immediate treatment is required. During this procedure, the empyema is drained completely.
• Debridement, which is the removal of infected tissue, is also used to eliminate empyema.

If there are contraindications to surgery, the patient may be prescribed only antibiotics. 

Authors: Dr. Nadezhda Ivanisova, Dr. Farrukh Ahmed