Subdural empyema is collection of pus between the two layers that cover the brain. To be more precise it is pus collected between the dura matter and the arachnoid matter. The brain is covered by three meningeal layer namely the outer dura matter, middle arachnoid matter and inner pia matter. These three layers lie between the skull and the brain.
Subdural empyema is a life threatening condition caused as a complication of sinusitis, middle ear infection and infection of the mastoid bone behind the ear. The classical clinical symptoms of subdural empyema resemble those of meningitis.High fever, neck rigidity, vomiting, progressive neurological deterioration, if left untreated can result in coma and death.
With modern day diagnostic tools such as MRI and CT scan, subdural empyema is easily diagnosed. This serious condition needs aggressive management which includes antibiotic therapy for few weeks and surgical drainage of pus.
Most Common Cause Of Subdural Empyema
Subdural empyema is pus accumulated between dura mater and arachnoid mater of brain. Infection can spread rapidly through the subdural space. However, the infection is unilateral and limited only in one sphere because of the specific boundary made by the falx cerebri, foramen magnum and tentorium cerebelli.At least 20 percent of intracranial abscess are subdural empyema.
Men are more affected than women. The disease can occur in children as well as adults though the cause may differ. In children it may develop as a complication of purulent meningitis or sinusitis. In adults it can be caused due to a distant source probably from the lung or heart valve.
Subdural empyema is mainly caused due to bacterial infection. Rarely fungi and protozoa are involved. The pathogenic organisms can reach the area through various channels that include.
- Penetrating injury in head and skull.
- Spread of infection from sinuses and mastoid bone infection.
- Bacterial infection in middle ear.
- Infection caused after head surgery.
- Infection in lungs and bacterial infection of heart valves can reach the area and cause subdural empyema. The infection from distant foci is rare.
Most common pathogens involved are staphylococcus bacteria.
Symptoms Of Subdural Empyema
The symptoms of subdural empyema usually are those of raised intracranial pressure and meningitis. The clinical triad of fever, sinusitis and neurological deficit is classical presentation of subdural empyema. The other symptoms include high grade fever since few days. Headache which is initially is focal and it is a prominent symptom in almost all cases. Headache later on becomes diffuse as the infection worsens.
After a period of time when the condition remains untreated, neurological symptoms start developing in its severity. This may consist of neck rigidity, vomiting, confused state of mind, drowsiness, and seizures. Patient may also complain of weakness in one side of the body.
Difficulty in speaking words, blurring of vision are some of the symptoms that may indicate worsening of the disease. Patient may progress to coma if the condition is left unchecked.
Diagnosis And Treatment Of Subdural Empyema
With advancement in medical technology diagnosis of subdural empyema has become far easier. The doctor after taking detailed medical history and physical examination of patient may recommend certain tests which will help in diagnosing the disease.
They are certain blood tests, cerebrospinal fluid examination after lumbar puncture, and imaging studies such as MRI or CT scan. Blood tests include complete blood count; blood culture will help the doctor in determining appropriate antibiotic to be administered.
Subdural empyema is a serious disease which requires prompt treatment for a better prognosis. It is considered to be a neurological emergency. Early diagnosis, surgery and administration of antibiotics are the three important criteria for a favorable outcome.
Once the patient is diagnosed with subdural empyema, the pus inside the space needs to be drained surgically. Due to modern imaging techniques it is possible to locate the area of pus accurately. The infected pus is removed through burr hole surgery. At the same time the source of infection should is also treated.
Antibiotics are administered intravenously to eliminate the microorganisms. Antibiotic therapy is given for few weeks. During the recovery the patient is closely monitored for his clinical condition.