Meningitis and Encephalitis

Meningitis and encephalitis can be caused by viral or bacterial infections. When the brains or cerebral membranes have been infected, the consequences involved may be life-threatening. The differences between viral and bacterial infections will be dealt with below.

Viral infections of the brain

Meningitis and encephalitis are caused by a viral or bacterial infection. The differences between viral and bacterial infections are dealt with below.

Meningitis

Meningitis can be caused by viruses that travel through air or the gastrointestinal tract. The symptoms of viral meningitis are:

• General sick feeling

• Severe headache

• Fever and chills

• Nausea

• Vomiting (in about 35% of the patients)

• Neck stiffness.

Though neck stiffness is usually caused by a bacterial infection, it is also found in viral infections. However much the symptoms mentioned above are similar to those of a strong flu, neck stiffnes will rule out flu because they never occur at the same time. If somebody is troubled by neck stiffness, a sudden cramp will occur in the back of the neck, causing the head to adopt a neck-up position.

Though the viral disease polio or infantile paralysis used to be the main cause of meningitis, it has been virtually eradicated thanks to the introduction of the DTaP/IPV/Hib (5-in-1) vaccination. Nowadays, the vaccine is administered to all babies to protect them against five different diseases:

• Diphtheria (D)

• Tetanus (T)

• Pertussis (whooping cough, aP is the acellular pertussis vaccine)

• Polio (IPV is inactivated polio vaccine)

• Hib (Haemophilus influenzae type b).

Meningitis caused by polio

Up to 95 percent of people infected with poliovirus will have no symptoms. If, nevertheless, polio turns out to be the cause of meningitis in a patient, the consequences involved may be severe. When a person becomes infected with poliovirus, the virus begins to multiply within the cells that line the back of the throat, nose, and intestines.

The symptoms can be categorized into one of three groups, which include:

• Minor polio symptoms (also known as abortive poliomyelitis)

• Aseptic meningitis

• Paralytic poliomyelitis.

Minor polio symptoms

About 4 to 8 percent of people who have been infected with the poliovirus will develop minor symptoms. Minor symptoms of polio can include:

• Fever

• Sore throat

• Nausea

• Vomiting

• Abdominal pain

• Constipation

• Flu-like symptoms.

People who develop minor symptoms of polio develop no paralysis or other serious symptoms. These symptoms last for 2 to 3 days with complete recovery.

Aseptic meningitis

About 1 to 2 percent of infected people will develop aseptic meningitis from poliovirus. For these people, early symptoms can be similar to minor polio symptoms. Then aseptic meningitis symptoms can develop, including stiffness of the back or legs and increased or abnormal sensations. These symptoms improve rapidly, usually within a couple of days days with complete recovery.

Paralytic poliomyelitis

Less than 1 percent of polio cases will result in paralysis. In these severe cases, symptoms begin with fever, muscle aches, loss of reflexes and other minor illness symptoms. These early symptoms improve after several days. However, 5 to 10 days later, the fever returns and paralysis begins, progressing for two to three days. Once the temperature returns to normal, progression of paralysis has come to an end.

Along with paralysis, other polio symptoms with paralytic poliomyelitis can include painful muscle cramps and muscle twitching. Many people with paralytic poliomyelitis recover completely, and muscle function returns to some degree. However, paralysis is usually permanent after six months.

Treatment of meningitis

If meningitis is caused by other viruses, it is usually mild and the patient will make a full recovery. The symptoms should be gone within a couple of days without severe consequences for the patient (lingering symptoms). Generally, the medical approach of viral meningitis implies bed rest and treatment of the symptoms.

Encephalitis

In a few cases, encephalitis will be developed. Often, this can be easily recognised because the symptoms become more serious all of a sudden. Likewise, convulsions and loss of consciousness will occur, which, in a few cases, will lead to a coma. Encephalitis involves inflammation of several regions of the brain tissue or membranes of the brain, manifesting itself in neuropsychological dysfunction whose symptoms depend on the location of the infection. Typical symptoms are:

• Confusion or agitation

• Personality changes

• Seizures

• Loss of sensation or paralysis in certain areas of the body

• Muscle weakness

• Hallucinations

• Double vision

• Perception of foul smells

• Problems with speech or hearing

• Altered consciousness

The treatment of viral encephalitis is far more intensive than that of meningitis. Patients will be examined frequently for their vital functions. Sometimes, treatment of disorders as a result of encephalitis is required as well. It is not uncommon for a person to have lingering symptoms of neuropsychological dysfunction after medical treatment. A patient's period of recovery may take several years, and in many cases they will never recuperate their health completely.

Bacterial infections of the brain

Bacterial meningitis

Bacterial meningitis is also called cerebrospinal meningitis. This disorder is a syndrome that causes epidemics on a limited scale. This means that there are periods when meningitis is found more often than in other periods. Frequently, there is an outbreak of panic among their relatives and friends when very young children die of the consequences of cerebrospinal meningitis,. Because meningococcus is considered the main cause of bacterial meningitis, this form of meningitis is also called meningococcal meningitis.

Bacterial meningitis has a very short incubation period. Often, the average time between the moment of infection and the moment the first symptoms are known is no longer than 3 days. It is an acute disease and often has the same symptoms as viral meningitis, including convulsions and loss of consciousness.

In case of bacterial meningitis, bacteria attacking the protective lining between the brain and skull make the meninges or system of membranes there swell, thus putting great pressure on the central nervous system and causing symptoms of temporary or permanent neuropsychological dysfunction, which may occur as:

• paralysis of the extraocular muscles controlling the movements of the eye

• deafness

• facial paralysis

As soon as there is suspicion that the usually young patient suffers from bacterial meningitis, examination is required. A lumbar puncture may be used to diagnose or exclude bacterial meningitis. This involves inserting a needle into the spinal canal to extract a sample of cerebrospinal fluid (CSF), the fluid that envelops the brain and spinal cord. If the bacterium is found in the CSF, the patient suffers from bacterial meningitis.

Treatment is often based on administering penicillin, which makes the symptoms disappear soon. If treatment is started timely, the patient nearly always recovers without lingering symptoms.

Meningococcal sepsis

In very severe cases, fatal complications may occur. This is meningococcal sepsis, which means that the bacteria have invaded the bloodstream. Symptoms of meningococcal sepsis are:

• Fever

• Drowsiness

• Bleeding in adrenal glands, kidneys and lungs and underneath the skin

• Shock (not in every patient).

Both the infection and shock involved in meningococcal sepsis will have to be combatted during treatment. The patient is administered corticosteroids for treatment of the shock. Complications that may occur as a result of meningococcal sepsis are:

• Waterhead (hydrocephalus or abnormal accumulation of cerebrospinal fluid in the cavities of the brain)

• Deafness

• Mental disability

These complications predominantly occur in very young children whose immune system is still weak. Though there are vaccinations against various groups of meningococci, they are still not considered standard procedure in various countries to this very day.

Sources: www.todio.nl