Brain abscess is linked to chronic ear, sinus or lung infections as well as contaminated penetrating wounds or post operative surgery. The source of infection can also come from skin infections, bone, teeth or heart. Most brain abscesses occur when infection spreads to the brain from elsewhere in the body, mostly from nearby areas such as the ears. Improved microbiological techniques to support the growth of fastidious aerobes and anaerobes have allowed a greater understanding of the bacteriology of intracranial sepsis. However, survivors may suffer complications; 1 in 3 will experience seizures (fits).
Abscess can occur anywhere in the brain. Sometimes fungi and parasites can also cause abscesses. Sometimes they are caused by head injuries or surgery. A brain abscess causes the surrounding brain tissue to swell and causes pressure to increase within the skull. The larger the abscess, the greater the swelling and the pressure.
Local inflammatory necrosis, edema and septic thrombosis of vessels represent early bacterial invasion of the brain. This is followed by encapsulation of the liquified brain and accumulated pus. Brain coma associated with the abscess and products of bacterial metabolism result in raised intracranial pressures.
A brain abscess is a mass of immune cells, pus, and other material that can occur when the brain is infected by bacteria or fungus. The bacteria or fungi, along with infected brain cells and pus, mass together in one area of the brain . The infection may also be introduced through a skull fracture following a head trauma or surgical procedures. They can result from the spread of an infection somewhere else in the head (such as in a tooth, in the nose, or in an ear), from a head wound that penetrates the brain, or from an infection in another part of the body that spreads through the bloodstream. If prolonged, this can cause brain damage, because the oxygen supply to these tissues has been disrupted. It is therefore important to treat abscesses as early as possible. Brain abscess is usually associated with congenital heart disease in young children. It may occur at any age but is most frequent in the third decade of life. The recommendations for the management of intracranial mass lesions in human immunodeficiency virus-infected individuals has changed as the incidence of toxoplasmic encephalitis has decreased with the use of trimethoprim-sulfamethoxazole prophylaxis. They can also be carried in the blood from further away areas of the body.
Intracranial abscesses are uncommon, serious, life-threatening infections. Dental abscess, sinusitis, and middle ear infection were the most common causes of this disease; treatments for these predisposing illnesses are more efficacious, and this has reduced the incidence of intracranial abscess. The infection may also be introduced through a skull fracture following a head trauma or surgical procedures. A brain abscess is an infection in the brain that is encapsulated (confined within its own area) and localized to one or more areas inside of the brain. Clinical manifestations include local and radicular pain, weakness, sensory loss, URINARY INCONTINENCE, and FECAL INCONTINENCE. The swelling inside the brain can put pressure on delicate brain tissue and the mass of pus itself can block blood vessels that are supplying essential blood to parts of the brain .
Causes of Brain Absecess
The common Causes of Brain Absecess :
- Most brain abscesses originally stemmed from nasopharyngeal infections such as otitis media, mastoiditis, and sinusitis. Because of improved antibiotic therapy, these sources now account for approximately 40% of cases.
- Aerobic and anaerobic streptococci (especially Streptococcus intermedius )
- Traction - a medical device that uses pins/screws that are placed around the head to hold the head and neck areas still; used in patients with broken necks or for specific surgeries that require the head and neck to be immobilized.
- The bacteria or fungi can reach the brain through the blood, by traveling from a neighboring infected area, or by direct contamination from an injury or surgery
- Bacteroides , Prevotella, and Fusobacterium species
- Chronic middle ear and sinus infections
- Infection is spread through the blood stream from the lung or chest area.
- Viral or bacterial germs enter directly into the brain through an open wound in the head.
- This risk of infection is higher if fragments and dead tissue are left behind, and if antibiotic therapy is not started immediately surgery, especially when the air sinuses were opened or a foreign body was left in the brain (intracranial pressure monitor, stimulating electrode), can result in an infection.
Symptoms of Brain Absecess
Some common Symptoms of Brain Absecess :
- Severe headache
- Stiff neck, shoulders, or back
- Aching of neck, shoulders, or back
- Vague early symptoms
- Decreased movement
- Fever and chills
Treatment of Brain Absecess
Here is the list of the methods for treating Brain Absecess :
- The treatment includes lowering the increased intracranial pressure and starting intravenous antibiotics (and meanwhile identifying the causative organism mainly by blood culture studies).
- Surgical aspiration or removal of brain abscess are performed for patients that are resistant to medical treatments.
- In cases of multiple abscesses or in abscesses in essential brain areas, repeated aspirations are preferred to complete excision. High-dose antibiotics for an extended period may be an alternative approach in this group of patients.
- Patients who present with seizure, in whom a high index of suspicion exists for brain abscess, also require intubation and hyperventilation. Seizures should be treated aggressively as well in order to decrease the risk of sustained increases in intracranial pressure
- The presence of a compressive lesion (which is injuring brain tissue by pressing on it) or a large abscess with a high degree of swelling around it can raise intracranial pressure to the point where immediate treatment is needed.
- It is not uncommon for multiple antibiotic medications to be used to ensure effective treatment.
- Patients who have symptoms for less than a week have a more favorable response to medical therapy than patients with symptoms persisting longer than 1 week.
- Surgery is required if there is persistent or progressive increase in intracranial pressure, if the mass does not reduce after use of antimicrobial medications, or if the mass contains gas (produced by some types of bacteria).