What Causes Brain Infections?

All infections are in varying degrees dangerous, and even more so – neuroinfections. The most dangerous of neuroinfections are those that affect the brain. There can be no unserious diseases. Each pathogen that can overcome the blood-brain barrier poses a huge danger to the person’s health and life. Read our overview of brain encephalitis below. 

Types of brain infections

The whole variety of neuroinfections affecting the brain can be divided into several groups:

• bacterial (mycoplasma, meningococcus, pneumococcus, listeria);
• parasitic (plasmodium, which causes malaria, toxoplasma);
• viral (different viruses).

Actually, they are the causative agents of encephalitis. Encephalitis is an inflammation of the brain tissue. It is caused by a viral infection or autoimmune disease. The disease progresses rapidly and requires urgent medical attention. There are:

Fungal encephalitis is caused by a fungal infection that enters the bloodstream and attacks the spinal cord. This type of encephalitis is especially dangerous for people with weakened immune systems, such as those infected with HIV.

Toxoplasmic encephalitis is caused by a protozoan parasite that mainly lives on cats. You can not get infected from them, but by eating unwashed vegetables or raw meat. It is also dangerous for HIV-infected people or people with weakened immunity.

Autoimmune encephalitis can be caused by the immune system attack on the brain or develop as a result of an infection – such encephalitis is called “post-infectious”. Other types of encephalitis are associated with the activity of specific antibodies in the blood.

Encephalitis can also be caused by:

• Herpes simplex: first and second types
• Chickenpox: mumps, measles, rubella
• Influenza, enteroviruses
• Intestinal viruses
• Insect-borne viruses: Japanese encephalitis, West Nile virus, tick-borne encephalitis.

Bacterial infections influence on the brain

A huge number of pathogens related to bacterial infections can affect the brain.

Diseases such as meningitis, encephalitis, or brain abscess may well cause such “ordinary” pathogens as pneumococcus, staphylococcus, enterobacteria. But this can happen only when:

• You have skull bones damaged, with broken integrity of the membranes of the brain;
• entry of pathogens during a neurosurgical operation;
• the presence of a purulent focus in the body and a weakened immune system.

However, the situation is different from other pathogens.

Meningococcal disease is a traditional neuroinfection that affects the brain. The peak incidence is observed in the autumn-winter period when the immune system is reduced due to frequent hypothermia and lack of vitamins.

If the immune system is normal, then you will limit yourself to the usual nasopharyngitis. Otherwise, the likelihood of getting meningitis or meningoencephalitis increases.

Meningococcal infection symptoms:

• fever,
• an increase in body temperature to 39-40 ° C.
• chills,
• headache
• weakness
• neck muscle tension
• nausea,
• vomiting.

Specific symptoms

• A reddish-purple rash protruding above the surface of the skin, the elements of which resemble a star
• The disease begins very acutely (you can often define a specific time (hour) when the person became ill)
• You should start treatment within 24 hours while the person is conscious. Otherwise, he may get into a coma.

Mycobacterium tuberculosis, among other things, can affect the brain. Children, the elderly, and people suffering from immunodeficiency are more likely to get sick.

The symptomatology of the onset of the disease is not pronounced. More often, it is general weakness, malaise, lack of appetite, headache and irritability, body temperature is subfebrile (the temperature rises for a long time in the range of 37.1 – 38 ° C.). Subsequently, “usual” meningeal symptoms join.

After that, you may see neurological disorders – paresis and paralysis of the facial nerve, oculomotor muscles, dizziness. Against the background of neurological disorders, mental disorders occur.

Viral and prion infections

There is a huge variety of viruses that cause acute encephalitis (mosquito, tick-borne, epidemic). In general, they differ in vectors and geography of distribution.

Focal symptomatology occurs against the background of “general infectious manifestations”, these are:

• paresis
• respiratory muscle paralysis
• paralysis of the limbs,
• paralysis of the facial muscles, etc.

Rabies and slow viral brain infections can be a huge danger, and therefore, they are given special attention.

Rabies

Almost all mammals can suffer from rabies. The source of brain infection is usually dogs, wolves, foxes, and this dangerous infection is transmitted through the bite of infected animals to humans.

Symptoms:

• hydro and aerophobia
• convulsions
• attacks of aggressive behavior.

Emergency vaccine prophylaxis after a bite is the only way to recover; therefore, it is forbidden to wait for the first symptoms of the disease to develop since this can only mean that the person can no longer be saved.

Slow infections 

Slow infections are viral neuroinfections that have the ability to stay asymptomatic for a long time in the human nervous tissue, with the subsequent development of the disease.

Scientists have deduced four main signs that distinguish slow infections:

• an unusually long (months and years) incubation period;
• slowly progressive nature of the course;
• unusual damage to organs and tissues;
• the inevitability of a fatal outcome.

The causative agents of the virus are rubella and measles. For reasons not completely clear, these viruses, after suffering a disease, can remain in the cells of the brain and, after 4 or more years, cause the disease. 

Both viruses cause panencephalitis with similar symptoms:

• Personality change with the development of dementia
• Gradual paralysis of all striated muscles.

Unfortunately, even with treatment, the consequences of these neuroinfections are always the same – a lethal outcome.

Parasitic infections and the encephalitis

Let’s take an example with toxoplasmosis, which is a parasitic disease characterized by the possibility of intrauterine infection, damage to the nervous system, eyes, skeletal muscles, and heart muscles, and enlargement of lymph nodes, liver, and spleen.

For the causative agent of this disease, man is an intermediate host, and the main one is cats. In a normal state of immunity, the disease does not manifest itself in any way, but if a person suffers from immunodeficiency, then there may be such variants of the disease:

• encephalopathy, with the development of delirium, confusion up to coma;
• meningoencephalitis, with all its classic manifestations;
• toxoplasma brain abscess, which is manifested by general infectious symptoms, focal disorders, depending on the location, convulsions, impaired consciousness.

The most severe consequences of toxoplasmosis are in pregnant women, as it causes underdevelopment of the fetal brain.

Diagnostics

In order to diagnose neuroinfection, including the brain, a set of measures is used:

• general analysis of blood and urine;
• blood chemistry test;
• a blood test for antibodies to viral, bacterial, and other agents;
• imaging methods – MRI.

Encephalitis treatment

During the treatment of encephalitis, it is important:

• stop the process of infection with antiviral drugs;
• control any immediate complications, including fever, dehydration, epilepsy;
• prevent the development of long-term complications.

Most patients are hospitalized and admitted to intensive care units. Oxygen masks are worn to aid breathing. The body is fed through the feeding tubes.

With an infectious type of encephalitis, antiviral agents are used. The sooner drug therapy is prescribed, the lower the risk of death.

The post-infectious type of the disease is treated with drugs of the corticosteroid group. High dosages are prescribed. The number of days of admission is determined depending on the severity of the disease and the patient’s general condition. Corticosteroids calm the immune system and reduce inflammation.

Autoimmune encephalitis is treated with:

• corticosteroids;
• plasmapheresis;
• immunoglobulin therapy.
• additionally, immunosuppressants may be prescribed.

Chronic encephalitis of the subacute type can only be covered up. In this case, death occurs within 1-2 years after diagnosis. In such situations, antiviral treatment is prescribed.

If you have the first symptoms or suspect that you have a brain infection after our overview of brain encephalitis, do not postpone a visit to the doctor. An experienced neurologist will prescribe the best treatment and help you stay healthy.