symptoms and treatment for brain Fungal and Bacterial abscess

Dr. Moradi, a neurologist

An abscess in the brain of an otherwise healthy person is usually caused by bacterial infection. Fungal brain abscesses tend to occur in people with weakened immune systems. The infection will cause your brain to swell (لینک به ورم یا ادم مغزی) from the collection of pus and dead cells that forms.

A brain abscess forms when fungi, viruses, or bacteria reach your brain through a wound in your head or an infection somewhere else in your body. infections from other parts of the body account for between 20 and 50 percent of all brain abscess cases. Heart and lung infections are among the most common causes of brain abscesses. However, brain abscesses can also begin from an ear or sinus infection, or even an abscessed tooth.

What are the symptoms of a brain abscess?

Symptoms usually develop slowly over several weeks, but they can also come on suddenly. Symptoms you should watch for are:

  • differences in mental processes, such as increased confusion, decreased responsiveness, and irritability
  • headaches
  • decreased speech
  • decreased sensation
  • decreased movement due to loss of muscle function
  • changes in vision
  • changes in personality or behavior
  • vomiting
  • fever
  • chills
  • neck stiffness, especially when it occurs with fevers and chills
  • sensitivity to light

In babies and young children, most of the symptoms are similar. However, your child may show other symptoms of a brain abscess. The soft spot on top of your baby’s head, called the fontanelle, may be swollen or bulging. Other symptoms in your child can include:

  • projectile vomiting
  • high-pitched crying
  • spasticity in the limbs

What causes a brain abscess?

A brain abscess usually occurs when bacteria or fungi enter the brain tissue. This can be caused by:

  • An infection in another part of the skull, such as a dental abscess, which can spread directly into the brain.
  • An infection in another part of the body - for example, the infection that causes pneumoniaspreading via blood into the brain . These types of infection are believed to account for around 1 in 4 cases of brain abscesses. People with a weakened immune system (the body’s defence system) have a higher risk of developing a brain abscess from infections carried by the blood because their immune system may not be capable of fighting off the initial infection. You may have a weakened immune system if you have HIV or AIDS, are receiving chemotherapy, or take immunosuppressant medication.
  • Trauma , such as a severe head injury, that cracks open the skull, allowing bacteria or fungi to enter the brain. Direct trauma to the skull is thought to be responsible for 1 in 10 cases of brain abscess.

Infections

The most commonly reported infections that may cause a brain abscess are:

  • Dental infections or treatment for tooth decay
  • Lung infections, such as pneumonia or bronchiectasis
  • Skin infections
  • Infections of the abdomen - such as peritonitis (an infection of the bowel lining)
  • Pelvic infections - such as infection of the bladder lining ( cystitis)
  • Infections of the heart - such as endocarditis

Infections in the skull, such as a persistent middle ear infection (otitis media),sinusitis (infection of the sinuses, the air-filled cavities inside the cheekbones and forehead), or mastoiditis (infection of the bone behind the ear) used to be a major cause of brain abscesses. However, because of improved treatments, a brain abscess is now a rare complication of these infections.

What are the risk factors? 

Nearly anyone can get a brain abscess, but certain groups of people are at a higher risk than others. Some diseases, disorders, and conditions that raise your risk include:

  • a compromised immune system due to HIV or AIDS
  • cancer and other chronic illnesses
  • congenital heart disease
  • major head injuryor skull fracture
  • meningitis
  • immunosuppressant drugs, such as those used in chemotherapy
  • chronic sinusor middle ear infections

Certain birth defects allow infections to reach the brain more easily through the teeth and intestines. One example of this is tetralogy of Fallot, which is a heart defect.

How is a brain abscess diagnosed? 

Many of these symptoms closely resemble other diseases or health problems. Talk to your doctor immediately if you develop any of the symptoms. You’ll likely need a neurological exam. This exam can reveal any increased pressure within the brain, which can occur from swelling. CT and MRI scans  can also be used to diagnose a brain abscess.

In some cases, your doctor may need to perform a lumbar puncture, or spinal tap. This involves the removal of a small amount of cerebral spinal fluid to test for any problems other than an infection. A lumbar puncture will not be performed if any significant brain swelling is suspected, as it can temporarily worsen the pressure inside the head. This is to avoid the risk of brain hematoma, or a ruptured blood vessel in the brain.

What’s the treatment for a brain abscess?

A brain abscess is a serious medical situation. A stay in the hospital will be required. Pressure due to swelling in the brain can lead to permanent brain damage.

If your abscess is deep inside your brain or it’s 2.5 centimeters or less, it will probably be treated with antibiotics. Antibiotic medications will also be used to treat any underlying infections that may have been the cause of the brain abscess. Broad-spectrum antibiotics that kill a variety of different bacteria are the most commonly prescribed. You may need more than one type of antibiotic.

Surgery is often the next step if an abscess doesn’t get smaller with the use of antibiotics. It may also be the preferred treatment for abscesses greater than 2.5 centimeters wide. Surgically removing an abscess usually involves opening the skull and draining the abscess. The fluid that’s removed is normally sent to a lab to determine the cause of the infection. Knowing the cause of the infection will help your doctor find the most effective antibiotics. Surgery may also be necessary if antibiotics aren’t working, so that the organism causing the abscess can be determined to help guide the most effective treatment.

Surgery must be performed in the most severe cases when the abscess causes a dangerous buildup of pressure in the brain. Your doctor may recommend surgery as the best option in the following cases:

  • Your brain abscess is at risk of rupturing inside of your skull.
  • Your brain abscess contains gasses sometimes produced by bacteria.

Can a brain abscess be prevented?

A brain abscess is a serious medical condition. Prevention is important. You can lower your risk by monitoring any conditions that can cause a brain abscess. Call your doctor at the first sign of a brain abscess.

If you have any type of heart disorder, talk with your doctor before having any dental or urological procedures. Your doctor can prescribe antibiotics for you to take before these procedures. This will reduce your risk of an infection that could spread to your brain.

How does the infection enter the brain?

Brain infections are fairly uncommon for several reasons. One reason is the blood-brain barrier. This is a protective network of blood vessels and cells that blocks certain components from blood as it flows to the brain, and permits others.

Sometimes, an infection can get through the blood-brain barrier and infect the brain. This can happen when inflammation compromises the integrity of the blood brain barrier and causes gaps to open.

The infection enters the brain from three main routes. It may be carried in the blood from an infection in another part of the body, spread from a nearby site, such as an ear infection, or result from trauma.

Infection from another place in the body

The bloodstream carries infectious organisms. This route accounts for about 25 percent of abscesses.

If an infection occurs somewhere else in the body, it can travel through the bloodstream, bypass the blood-brain barrier, and enter and infect the brain.

Many bacterial brain abscesses stem from a lesion somewhere else in the body. It is crucial to find that primary lesion, or there may be a repeat infection in the future.

People with a weakened immune system have a higher risk of developing a brain abscess caused by a blood-borne infection.

Examples include people with HIV/AIDS, infants under the age of 6 months, patients receiving chemotherapy, individuals on long-term steroid use, and organ transplant recipients who take immunosuppressant drugs to prevent organ rejection.

The most common infections known to cause a brain abscess are:

  • Endocarditis, an infection of the heart valve
  • Pneumonia, bronchiectasis, and other lung infections and conditions
  • Abdominal infections, such as peritonitis, an inflammation of the inner wall of the abdomen and pelvis
  • Cystitis, or inflammation of the bladder, and other pelvic infections.

Direct contagion

Direct contagion accounts for between 50 percent of brain abscesses.

Infection starts inside the skull, for example in the nose or the ear, and it spreads into the brain.

Examples include otitis media or middle ear infections, sinusitis, or mastoiditis, an infection of the bone behind the ear.

The location of the abscess may depend on the site and type of the original infection.

Direct trauma

Trauma accounts for a small percentage of brain abscesses.

A blow to the head can cause a compound skull fracture, in which fragments of bone are pushed into the brain, causing a brain abscess. A foreign body, such as a bullet, which is left in place may also be a source of infection.

Rarely, a brain abscess may be a complication of surgery.

People with a weakened immune system are more prone to brain abscesses stemming from fungi and parasites.