A brain infection refers to an infection caused by viruses, bacteria, fungi, or parasites that affects the brain , spinal cord , or the surrounding area. Brain infections are serious and can be life-threatening.
Infections and conditions affecting the brain and spinal cord can activate the immune system, leading to inflammation . These diseases and the resulting inflammation can produce a wide range of symptoms, including fever, headache, seizures, and changes in behavior or confusion. In extreme cases, they can result in brain damage, stroke , or even death.
There are different types of brain infections, and each type has its own unique cause and treatment. Encephalitis refers to inflammation in the brain, and meningitis is inflammation of the meninges, the membranes that surround the spinal cord. Myelitis refers to inflammation of the spinal cord, and a brain abscess describes a collection of pus in the brain. Infections of the brain require emergency treatment.
Verywell / Sydney Saporito
The different types of brain infections vary by cause and location. Some like encephalitis affect the entire brain, while others are localized to one area of the brain, such as an abscess. However, each type of brain infection requires treatment right away.
Meningitis can be caused by a virus or bacteria. Bacterial meningitis is a serious condition and needs to be treated immediately. Rarely, meningitis can also be caused by a fungus or parasite.
Several types of bacteria can first cause an upper respiratory tract infection and then travel through the bloodstream to the brain. Bacterial meningitis can also occur when certain bacteria invade the meninges directly.
The classic signs of meningitis include a sudden fever , severe headache , stiff neck, photophobia , and nausea and vomiting. Being unable to bend your chin down to your chest is a sign of meningitis. While the symptoms may start out resembling those of a cold or upper respiratory infection, they can quickly become more severe.
Encephalitis is usually caused by a virus, such as the herpes simplex virus types 1 and 2, or arboviruses, in the United States. Arboviruses are spread from animals to humans and causes mosquito-borne disease. An example is the West Nile virus.
Symptoms may start out as mild flu-like symptoms and headaches, quickly followed by behavioral changes, hallucinations, and confusion.
Some forms of bacterial meningitis and encephalitis are contagious and can be spread through contact. For example, meningococcal meningitis is easily spread among people who live together such as college students in a dormitory. If you have recently been in contact with someone who has been diagnosed with bacterial meningitis or encephalitis, talk with your doctor to find out if you need prophylactic antibiotics, which can help prevent a bacterial infection.
The spinal cord is responsible for carrying sensory information back to the brain and motor messages from the brain to the body. When it is inflamed like in the case of myelitis , symptoms can include pain, weakness in the limbs, bowel and bladder problems, and sensory problems. Many people with myelitis also experience muscle spasms , headache, fever, and loss of appetite.
Myelitis may be related to an immune disorder or infection from a virus, bacterium, fungus, or parasite. Most people who experience myelitis make a full recovery, but the process can take months to years. There is no cure for myelitis, but the symptoms can be treated.
A brain abscess occurs when a collection of pus becomes enclosed in brain tissue. This rare condition can be caused by a bacterial or fungal infection, and is also a possible complication of surgery or trauma. People with compromised immune systems are more at risk of having a brain abscess.
Symptoms include a high fever, severe headache, behavior changes, and nausea and vomiting. Over time, an abscess can cause changes in speech, motor weakness, spasticity, and seizures . Once it is discovered, an abscess must be located and surgically drained, followed by four to eight weeks of antibiotic therapy.
There are several types of causes of brain infections, and each one has its own transmission route. Viruses may be spread through close contact or respiratory secretions, such as sharing drinking glasses or kissing. Bacterial infections can also be spread through close contact or contaminated food preparation.
Here's a breakdown of all possible causes of brain infections:
The symptoms of a brain infection will depend on the area of the brain that has been infected, as well as the severity of the infection.
The symptoms for each type of brain infection is as follows:
The diagnostic tool used to diagnose your brain infection will depend on your symptoms and physical exam findings. Any symptoms of a brain infection should be evaluated by a physician right away. If you are concerned about a brain infection, your doctor will perform a neurological exam to evaluate your motor and sensory function.
After taking a thorough history and performing a physical exam, your physician may recommend the following tests:
A lumbar puncture may be used for diagnosis but cannot be performed if there is too much brain swelling because it could worsen the pressure in the brain and cause complications like brain herniation. Symptoms of increased intracranial pressure to watch out for include a headache, blurred vision, vomiting, behavioral changes, muscle weakness, and extreme drowsiness.
Treatment for a brain infection depends on which type of infection you have. However, early treatment is essential for minimizing complications and dangerous symptoms, so never hesitate to see your doctor if you are concerned.
Therapies used to treat a brain infection can include the following:
The prognosis for a brain infection depends on the severity of your condition, what caused the infection, and how fast treatment was initiated. Most people who experience a brain infection make a full recovery.
The following treatments may be needed for long-term recovery:
Recovery from an infection of the brain will vary depending on the degree of brain inflammation. Inflammation of the brain can lead to coma and death. Earlier symptoms include severe fatigue, muscle weakness, behavioral changes, memory problems, changes in speech, hearing loss, vision loss, and paralysis. Seek treatment right away if you believe you have a brain infection.
A brain infection cannot always be prevented, but one effective step to take is to get vaccinated. Many causes of bacterial brain infections are now preventable with the following vaccines:
To prevent viral and bacterial infections that can spread to the brain, take regular safety precautions like washing your hands and avoiding contact with individuals who are ill. To protect yourself against mosquito- or tick-borne illnesses that could lead to a brain infection, use insect repellent when spending time outdoors and opt for long sleeves and pants. Aim to limit your outdoor activities at night when mosquitoes are more active and address any standing water around your home.
If you have symptoms of a brain infection, talk to your doctor or get emergency medical help immediately. Left untreated, a brain infection can cause serious complications.
A brain infection is a serious condition that can quickly become life-threatening if left untreated. Learning what signs to look out for can help you prepare and get help right away if you do become infected. Be on the lookout, especially if you have a condition that places you at higher risk of a brain infection. If you or a loved one believe you are experiencing the symptoms of a brain infection, see your doctor or seek emergency medical help right away. Early treatment is crucial, and remember that most people who are treated right away make a full recovery.