Understanding Brain Abscess
A brain abscess, or
cerebral abscess, is a collection of pus that develops in the brain due to a
focal infection within the brain parenchyma. Initially, the infection is
localized to the cerebellum, but over time, it becomes a collection of pus
within a well-vascularized capsule. This condition can cause brain swelling,
impairing various brain functions.
Causes of Brain Abscess
A brain abscess is
usually caused by a bacterial or fungal infection. If the immune system is
unable to kill the infection, it will limit its spread by using healthy tissue
to prevent the pus from infecting other tissues. However, this can actually
lead to the formation of an abscess.
Brain infections are
rare because the body has developed defense systems to protect the brain. One
of these is the blood-brain barrier, a thick membrane that filters impurities
from the blood before allowing them to enter the brain.
Although the exact
location of the infection cannot always be identified, it is generally found in
the skull, bloodstream, or after a head injury.
1. Infection in the
skull
A brain abscess can
occur as a complication of an infection around the skull, such as:
- Persistent middle ear infection
(otitis media).
- Sinusitis, which is an
infection of the sinuses, air-filled cavities in the cheekbones and
forehead.
- Mastoiditis, an infection of the bone behind the ear.
This used to be the
leading cause of brain abscesses. But with improved treatments for infections,
brain abscesses have become a rare complication.
2. Infection through the
bloodstream
Infections can spread
through the bloodstream, causing brain abscesses. People with compromised
immune systems are at higher risk of developing brain abscesses due to blood-borne
infections. This is because the immune system may not be able to fight the
infection initially.
A person may have a weak
immune system if:
- Having a medical condition that
weakens the immune system, such as HIV/AIDS.
- Undergoing medical treatments that
can weaken the immune system, such as chemotherapy.
- Having an organ transplant and taking immunosuppressant drugs to prevent the body from rejecting the new organ.
Meanwhile, infections
and health conditions that can cause brain abscesses are:
- Cyanotic heart disease, a type
of congenital heart disease present from birth, occurs when the heart is
unable to carry enough oxygen throughout the body. When the body lacks
oxygen, it becomes more susceptible to infection.
- Pulmonary arteriovenous fistula,
a rare condition in which an abnormal connection develops between blood
vessels in the lungs, allows bacteria to enter the bloodstream and
eventually reach the brain.
- Tooth abscess or treatment for
tooth decay.
- Lung infections, such as
pneumonia or bronchiectasis.
- Having a heart infection, such
as endocarditis.
- Skin infection
- There is an infection in the
abdomen, such as peritonitis (infection of the lining of the intestine).
- Having a pelvic infection, such as an infection of the lining of the bladder (cystitis).
3. Infection after head
injury
Direct trauma to the
skull can also cause a brain abscess. The most common causes are:
- Skull fracture caused by
penetrating head injury.
- Gunshot or shrapnel wounds to
the brain.
- Complications after neurosurgery are possible, but they are rare.
Risk Factors for Brain
Abscess
Almost anyone can get
it, but some people are at greater risk than others.
Several conditions that
can increase the risk of brain abscess, namely:
- Having a weak immune system,
for example due to having HIV/AIDS, undergoing chemotherapy, or taking
immunosuppressant drugs.
- Having endocarditis, pneumonia,
bronchiectasis, and other lung infections or conditions, abdominal
infections, cystitis, and other pelvic infections.
- Suffering from a severe head injury
or a fractured skull.
- Suffering from sinus infections, chronic middle ear infections, meningitis, tooth abscesses.
Symptoms of Brain
Abscess
Symptoms usually appear
slowly over several weeks, but they can also appear suddenly. Symptoms that may
appear include:
- Changes in consciousness, such
as becoming unconscious, confused, and unresponsive to commands.
- Decreased speech function.
- Decreased sensation.
- Decreased muscle movement and
function.
- Sharp decrease in vision.
- Vomiting.
- Fever.
- Stiffness in the neck.
Diagnosis of Brain
Abscess
The diagnosis is made by
delving deeper into the patient's symptoms. The doctor then performs a complete
neurological examination. This examination determines whether there is pressure
on the brain caused by the abscess. Several additional tests may be performed
to help confirm the diagnosis, including:
- CT scan and MRI imaging are
used to see if there is an abscess forming in the brain.
- A lumbar puncture is used to obtain a sample of cerebrospinal fluid from the spinal cord. This cerebrospinal fluid is then examined microscopically to determine the cause of a brain abscess.
Brain Abscess Treatment
Antibiotics can be used
to treat this condition, particularly if the abscess is less than 2.5
centimeters from the head. Surgery is performed if antibiotic therapy fails.
This may also be necessary if there is a risk of the abscess sac in the brain
rupturing.
Brain Abscess Prevention
A brain abscess is a
serious condition. This health condition can be prevented by maintaining
personal and environmental hygiene to prevent the spread of the abscess. Some
ways to reduce the risk of a brain abscess include:
- Medical procedures, such as
tooth extraction or other dental procedures, need to be carried out
carefully to prevent infections that can trigger brain abscesses.
- Post-procedure or medical
treatment care, post-procedure care that is carried out carefully and
takes into account sterility aspects.
- Regular check-ups for chronic diseases, such as heart disease or diabetes.
Complications of Brain
Abscess
Complications that can
occur include:
- Recurrent abscesses. This is
more common in people with weakened immune systems or cyanotic heart
disease.
- Brain damage. Mild to moderate
brain damage may improve over time, but severe brain damage is likely to
be permanent. The risk of complications from a brain abscess is greater if
diagnosis and treatment are delayed.
- Epilepsy, which causes a person
to have repeated seizures.
- Meningitis, a life-threatening infection of the protective membranes surrounding the brain, requires immediate treatment. It is more common in children.