Common Brain Infections – Types & Symptoms

Infections of the brain are typically caused by transmissible micro-organisms such as bacteria, virus, fungi, parasite, or protozoa. It is challenging to identify such infections with common or mild symptoms such as headache, neck stiffness, or fever. The severity of these symptoms changes when any of these infections attack membranes surrounding the brain and spinal cord (meninges).

Brain infections are entirely different from brain disorders. The mechanism of the central nervous system (CNS) protects it from certain infections, but is always prone to inflammation. However, some similar signs may complicate the process of identifying the difference.

Here’s some more on common brain infections, their types, symptoms, and causes, so that you can consult a doctor for timely treatment.

Types of Brain Infections

  1. Meningitis

Meningitis is a clinical syndrome characterized by inflammation of the meninges due to both bacterial and viral infections. Bacterial meningitis can cause life-threatening conditions and result in permanent disability or damage to the brain or nerves. Anyone at any age can get meningitis but most commonly it is found in babies and young children. Today, vaccination is available as effective treatment against the infection.


In adults, the first symptoms are usually fever, vomiting, headache and fatigue. Other signs associated with meningitis are cold hands and feet, pale skin, limb pain that appear before rashes in skin, confusion, sleeplessness, neck stiffness, sensitivity to bright light and seizures.

However in infants, the symptoms are more significant with decreased appetite, irritability, unusual crying, lethargy, sleepiness, fever and chills and pale & blotchy skin.

  1. Encephalitis 

Encephalitis attacks the active tissues of the brain due to severe viral infection or autoimmune responses. It’s an uncommon condition where the affected part of the brain can increase the risk of lasting complications or death if not treated timely. Despite the extensive testing, the cause of encephalitis remains unknown in 30% to 40% cases.

Without the intervention of treatment, some viral infections such as herpes simplex, chickenpox, rabies or mosquito borne viruses can often lead to the rapid spread and worsen the condition. Also, sometimes the body’s attempt to fight viruses goes wrong as an autoimmune response causes inflammation to the brain tissues.


Initially, people with encephalitis develop mild flu-like symptoms including headache, fever, body-ache or fatigue. In severe cases, the symptoms change into seizures, confusion or hallucinations, loss of sensation, or partial paralysis, muscle weakness, problems with speech and unconsciousness.

In children the signs include nausea or vomiting, body stiffness, irritability, poor feeding and bulging in the soft spots of the infant’s skull.

  1. Abscess

Brain abscess is an accumulation of pus, immune cells, infectious material and offending microorganisms in the brain causing swelling (resembles boils) in the affected parts.  It usually occurs when the brain is exposed to bacterial or fungal infections due to severe injury, trauma or surgery. The risk of developing a brain abscess is rare, although people with weakened immune systems including HIV patients or the ones who have received an organ transplant are prone to such infections.

Brain abscess could be life-threatening and should be diagnosed to prevent major complications or death.


‘Around 75% of people with a brain abscess develop an achy and dull headache’, says a Neurologist at AMRI Hospitals, Kolkata. However the symptoms vary depending on the size and location of the abscess. Headache is the prominent sign and is usually limited to the side of the brain where the abscess resides. Some people develop low grade fever with nausea and vomiting, stiffness in neck, muscular weakness on one side of the body. Such pain and discomfort cannot be relieved through aspirin or pain medications, a patient requires immediate treatment.


Brain infections are complex and cause mild to severe symptoms. In infants, it is difficult to recognize the condition without the help of a specialist. Several viral and bacterial infections can be completely treated with medications without any complications. However, one can lower the risk by monitoring the early signs & symptoms, and by seeking immediate medical attention.

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