Definition of Meningitis
Three protective membranes - meninges - cover the brain and the spinal cord. Between the middle membrane(Arachnoid) and the soft inner membrane (Pia) is the cerebrospinal fluid (light blue). In meningitis the infection will typically spread from the cerebrospinal fluid to the membranes and therefore this fluid is examined by lumbar punture when meningitis is suspected.
Meningitis is inflamation of the protective membranes, the meninges, that cover the brain and the spinal cord. It is a dangerous disease not least as it develops very fast within hours.
The brain is surrounded by three membranes. The outer ultra hard membrane called dura, the mid membrane called araknoidea and the inner, soft membrane called pia. These membranes and the brain fluid located between the middle and inner membranes form a protection around the brain.
Meningitis occurs when bacteria or virus penetrates the brain and cause an inflammation. The bacterial meningitis is the most serious kind. It can be caused by a wide range of bacteria depending on age. In adults it is mostly meningococcal or pneumococcal. Virus gives a milder form of meningitis mostly in the form of enterovirus.
Meningitis is a serious condition, particularly the bacterial form. There are about 100 new cases of bacterial meningitis a year for every 25.000 citizens in the western world. The disease occurs both as individual cases and in small epidemics. The disease is seen in all age groups but is most dangerous in the elderly and small children with reduced resistance.
Bacteria and viruses can reach the brain in three ways:
- Via the bloodstream from an inflammation somewhere else in the body, for example a pneumonia or a urinary bladder infection.
- From the outside. Skull fracture might allow bacteria to penetrate into the brain.
- From nearby areas such as inflammation of the middle ear or sinusitis.
Source of infection and meningitis prevention
The most common, and most serious, cause of meningitis is the meningococcal bacteria. It is a bacterium found in the nose in a large proportion of the population and in this location the bacteria causes no harm. Infection can occur for example when healthy carriers of meningococcal bacteria or meningitis patients sneeze or blow the nose.
Compared to how many carries the bacterium it is very few who develop meningitis, and nobody knows why. The risk of meningitis is much greater if you are near someone with the disease, and therefore everyone in the household is treated with preventive antibiotics or vaccinations, when a case of meningitis is discovered.
Meningitis symptoms vary according to whether they are caused by virus or bacteria, and whether children or adults are involved. For information about cause, symptoms and treatment of meningitis in children, see: Meningitis in infants and children.
Symptoms of bacterial meningitis
- Fever up to 39-40 degrees Celcius.
- Symptoms of angina pectoris (throat inflammation), sore throat, cough, cold and hoarseness.
- Stiffness of neck and back (for example bending the chin down to the chest).
- Nausea and vomiting.
Later (after hours or a day) signs are:
- Sensitivity to sound and light.
- Reduced general condition (pallid, tired, flaccid).
- Blurred consciousness (drowsy, confused).
- Slight bleeding from the skin called petechiae from pin sized red spots resembling skin rash.
- Finally, convulsions and unconsciousness with untreated cases leading to death.
Symptoms of viral meningitis
- Symptoms of angina pectoris - sore throat.
- Fever, headache, nausea and vomiting.
- Stiffness of neck and back.
- Symptoms milder than the bacterial meningitis and with spontaneous recovery.
Precautions and diagnosis
Suspected meningitis cases require immediate medical attention. Call an ambulance for patients with the symptoms: high fever, headache, light sensitivity and stiffness of neck and back, or bring the patient to the nearest hospital. Bacterial meningitis can develop over a single day and it is not enough to await the arrival of a doctor on call unless the doctor can arrive right away.
The diagnosis is made on the basis of the typical symptoms described above. The examination includes drawing a sample of the spinal cord fluid (lumbar puncture), to examine the bacteria. Spinal cord fluid is the same as brain fluid located between the brain membranes and meningitis related bacteria or viruses and inflammatory cells can be identified from this fluid. Additionally, blood test are made to check for bacteria.
Treatment of meningitis
Treatment of bacterial meningitis:
The normal treatment is antibiotics administered directly into the bloodstream. Time is critical and it is important that treatment be started as soon as possible, hence a wide range of antibiotics are given up front to affect all kinds of meningitis bacteria, before it is determined which type of bacteria is involved. The treatment with antibiotics is continued for one to two weeks. As previously mentioned also preventive treatment of next of kin and other close relations takes place.
Treatment of viral meningitis:
Viral meningitis is not treated and recovery is spontaneous. The usual treatment consists of painkillers and fever-lowering medicine. Improvement or recovery usually takes a couple of weeks.
Outlook and complications
In some cases, bacterial meningitis is developing so fast that the bacteria has entered the blood before treatment is started. This is called blood poisoning or septic shock and is a very dangerous condition that can lead to a drop in blood pressure and risk of coma and death. However, it is less than 5% of bacterial meningitis cases where the outcome is fatal. The first day is crucial and if well managed there are usually very good chances of recovery without impairment. In some rarer cases meningitis can lead to cardiomyopathy (malfuntioning of the heart muscle) and myocarditis (inflammation of the heart muscle).
Viral meningitis can in some cases result in paralysis, which usually disappears after some time.
Before antibiotics death from meningitis was almost 100%. This is different today but it is still a disease that should be taken very seriously and with very fast response. Treatment takes up to two weeks.
There are no active agents against viral infections and the condition has to run its course. The symptoms can be alleviated with fever reduction, headache treatment and other assistance for the body immune system’s ability to fight the infection. Recovery normally takes two to three weeks.
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