Brain infection


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What is brain infection?

Our brain, the spinal cord, and its surrounding structures can become infected by a large spectrum of germs. Parasites, fungi, and other organisms can infect the central nervous system (CNS), although more rarely.

The infecting germ causes an inflammation of the affected area. Depending on the location of the infection, different names are given to the diseases.

  • Meningitis is the inflammation of the meninges, the surrounding three-layered membranes of the brain and spinal cord, and the fluid it is bathed in, called cerebrospinal fluid (CSF).
  • Encephalitis is an inflammation of the brain itself.
  • Myelitis actually means a spinal cord inflammation.
  • Abscess is an accumulation of infectious material and offending microorganisms, and this can occur anywhere within the CNS.

The following are other common brain infections:

  • Toxoplasmosis (also known as toxo) is caused by the parasite Toxoplasma gondii.
  • Cerebral cysticercosis is caused by the pork tapeworm.
  • Trichinosis is caused by the roundworm Trichinella spiralis.
  • One of the most common infections transmitted by insects in the U.S. is Lyme disease.
  • Coccidioidal meningitis is a severe complication of coccidiomycosis (valley fever), a common fungal infection in the southwestern U.S.
  • An uncommon causative agent of meningitis, affecting almost exclusively immunocompromised people, is a fungus from the Cryptococcus family.
  • Tuberculosis, caused by Mycobacterium tuberculosis, can spread through the lymphatic system to the CNS.

How common is brain infection?

Please discuss with your doctor for further information.


What are the symptoms of brain infection?

Various types of brain infections lead to many different symptoms, which can depend on the age of the person, the type of bacteria, the type of infection, and the acuteness of the disease.

In general, people older than 2 years of age with acute bacterial infection develop high fever, severe headache, stiff neck, nausea, vomiting, discomfort when looking into a bright light, sleepiness, and confusion.

Newborns and infants can be unusually fussy, irritable, and sleepy. They may feed poorly and not be comforted by holding. Seizures can be a late development of the disease.

Severe forms of bacterial meningitis, particularly meningococcal, can cause shock with complete loss of consciousness and coma and bring about a spreading purplish rash. An infant can have bulging fontanelles (soft spots) on the head and have a decreased muscle tone in arms and legs.

Someone with viral brain infections tends to appear somewhat less ill. Flu-like symptoms in addition to mild signs and symptoms outlined for each condition may be seen.

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

Early diagnosis and treatment are very important with brain infections. However, most of the symptoms of meningitis and other central nervous system infections can be caused by other medical conditions, too. Do not panic. In young infants, meningitis might look like general symptoms such as crying too much, sleeping too much, eating too little, irritability, and listlessness. Whenever one suspects meningitis or any other brain infection, or are in doubt, call a doctor.

Seek emergency care if an ill person has an altered level of consciousness with high fever, respiratory distress, severe headache with vomiting, a new seizure or if a baby appears to be lethargic, with poor feeding, a high fever, and vomiting.


What causes brain infection?

Bacteria and viruses are the most common offenders. These include:

  • Streptococcus pneumonia (causing pneumococcal meningitis)
  • Neisseria meningitidis (causing meningococcal meningitis)
  • Haemophilus influenza type b (Hib)
  • The West Nile virus and other members of the encephalitis-causing virus family (St. Louis encephalitis, western equine and eastern equine encephalitis, and La Crosse encephalitis)
  • The members of herpes virus family (herpes simplex types 1 and 2, varicella zoster, Epstein-Barr, as well as cytomegalovirus)
  • A small poliovirus
  • The rubella virus
  • Rabies
  • Human immunodeficiency virus (HIV)
  • Zika virus

Risk factors

What increases my risk for brain infection?

Please consult with your doctor for further information.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is brain infection diagnosed?

Otherwise healthy people with classic signs of acute brain infection can usually be diagnosed promptly. The challenge is when someone has a less severe brain infection, such as chronic or partially treated meningitis, encephalitis, or other rare infections.

  • A doctor looks for particular clinical signs when examining a patient. An altered level of consciousness with behavioral and personality changes with a high fever always alerts the doctor to the possibility of a central nervous system infection. Particular signs of meningeal irritation in someone with a fever, including neck pain or stiffness with neck flexion or knee extension, or involuntary flexion of both hips with neck flexion, could signify brain infection.
  • The doctor will perform an eye exam, looking for swelling of the main nerve of the eye and any subtle changes in eye movement or pupil reactions. These could represent increased intracranial pressure (ICP), seen with an abscess, or advanced meningitis or encephalitis. Someone will also undergo a complete neurologic examination, which helps a doctor to discover any signs and problems with the nervous system.
  • Standard laboratory blood work and a urine specimen will be obtained. Also, a special set of cultures from blood, urine, nose, or respiratory secretions might be taken.
  • Imaging studies, such as a CT scan of the head with contrast (that is, a special injectable dye that enhances the view of the brain) or an MRI scan with contrast, may be performed. These diagnostic procedures help to rule out any process in the brain that increases pressure inside the brain, as well as to show any complications of meningitis.
  • The definitive diagnosis is usually derived from an analysis of a sample of spinal fluid. This fluid is obtained by performing a lumbar puncture, commonly known as a spinal tap. This procedure involves inserting a small needle into an area in the lower back between the vertebrae, where fluid in the spinal canal is readily accessible. The fluid sample then is sent to a lab where analysis will determine the existence of any CNS infection, determine the difference between bacterial and other types of infection, and identify the type of the organism responsible.
  • Lumbar puncture, when performed in appropriate sterile way, is a very safe procedure. The needle is inserted below the ending of the spinal cord, so no neurologic complications should occur. The sample of fluid taken is small. Strict sterile technique eliminates the possibility of infection. The most common side effects are headache and mild tenderness at the site of needle insertion. Lumbar puncture is not used if there is any clinical or X-ray evidence of increased pressure in the brain.

How is brain infection treated?

Based on your condition, your doctor will recommend the suitable treatment, including:

  • Antibiotics given through a vein, as well as medications for fever and headache, are used in the treatment of brain infections.
  • Anyone in respiratory distress will receive oxygen and be closely observed.
  • IV fluids and electrolyte replacement are given to those with continuing nausea and vomiting.
  • Anticonvulsants are used to prevent or treat seizures.
  • Irritable or restless people will receive mild sedation.
  • If there is evidence of brain swelling, steroids will be given. The role of steroids in managing adult bacterial meningitis remains controversial. In some cases of Hib meningitis in children, IV steroids are used to decrease the possibility of hearing loss.
  • Acutely ill people with suspected bacterial CNS infection are treated with antibiotics that target the most common organisms. The first dose usually is given within 30 minutes of being evaluated by a doctor in the emergency department, and if possible, before the lumbar puncture. Once the results of the lumbar puncture are available, and the organism is identified, more targeted therapy with the most effective antibiotics is begun.
  • Treatment of a brain abscess is complex. Depending on the size and location, the drainage could be performed by a neurosurgeon. Antibiotic therapy is similar to that of bacterial meningitis.
  • Viral infections: Most viral infections go away on their own with a complete recovery. They do not require any specific treatment. The only exception to this is the herpes viruses. Special antiviral drugs are used to treat brain infections caused by herpes.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage brain infection?

If a person suspects that someone has some kind of brain infection, first, call a doctor or an emergency service and follow their advice.

Provide cooling measures and give temperature-lowering medications to reduce fever.

If the person is vomiting, put him or her on their side to prevent them from inhaling and choking on the vomit.

Avoid any strenuous activities, and keep the person on strict bed rest. Always follow the advice of a doctor.

If you have any questions, please consult with your doctor to better understand the best solution for you.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: October 25, 2017 | Last Modified: October 26, 2017

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