What is meningitis?
Meningitis, also called misleading cerebrospinal meningitis, is an inflammation of the protective membranes surrounding the brains and spinal cord, the so-called meninges. The inflammation may be caused by infection with viruses, bacteria or other microorganisms, or also by certain medication, even though the latter occurs less often. Meningitis can be life-threatening, because the inflammation is located close to the brains and spinal cord. Therefore, the condition is considered a medical emergency. Sometimes occurs damage to surrounding structures so quickly (within 12 hours) that the life of the patient to save all is no longer at the moment that the diagnosis is made.
The most common symptoms of meningitis are headache and neck stiffness associated with fever, confusion or altered consciousness, vomiting and sensitivity to light (photophobia) or loud noises (phonophobia). Children often show only nonspecific symptoms, such as irritability and drowsiness. If there is a rash, it may indicate a particular cause of meningitis; as a consequence of the meningococcal meningitis, for example, may be accompanied by a characteristic skin rash.
A lumbar puncture (spinal) meningitis can be diagnosed or excluded. Thereby, a needle inserted into the spinal cord channel to a bit of cerebrospinal fluid (CSF, cerebral spinal fluid) to take off that the brains and spinal cord surrounds. This fluid is examined in a medical laboratory. The first treatment of acute meningitis consists of directly administered antibiotics, and at times anti-viral agents. Corticosteroids can also be used to prevent complications due to excessive inflammation. Meningitis can have serious long-term consequences such as deafness, epilepsy, hydrocephalus and cognitive deficits, especially if the meningitis is not treated quickly. Some forms of meningitis (such as meningitis caused by infection with Neisseria meningitidis (meningococcal), Haemophilus influenzae type B, Streptococcus pneumoniae (pneumococcus), or mumps virus) can be prevented by vaccination.
Signs and symptoms of meningitis
Clinical features
Infants, children and young adults are most at risk of getting meningitis. People with cochlear implants have an increased risk of meningitis.
In adults, the most common symptom of meningitis, severe headache, which occurs in almost 90% of cases of bacterial meningitis, followed by nuchal rigidity (inability to flex the neck forward passively by increased tension and muscle stiffness in the neck). The classic combination of three diagnostic clues include stiff neck, high fever and sudden behavioral changes; in bacterial meningitis, however, is only in 44-46% of cases involve all three characteristics. If none of the three symptoms occurs, meningitis is extremely unlikely. Other symptoms that are commonly associated with meningitis include photophobia (sensitivity to bright light) and phonophobia (sensitivity to loud noises).
- In children, the first symptoms, according to a major study, mostly of blood poisoning: a high fever, but cold hands and feet, leg pain (nuisance standing and walking!) And an unusual paleness of the skin .
- Small children often exhibit the above symptoms, and sometimes only irritable and look sick. In babies meningitis can proceed even more insidious: no longer want to drink, listless, moan, pale in diapers pain huidbloedinkjes (a late symptom). Sometimes fever is not present. Infants with such symptoms or who ingest less than one half of the normal daily diet or keeping need to be seen by a physician. In infants up to 6 months, the fontanelle (the soft spot on top of the head of a baby) protrude. Other features that distinguish meningitis from less severe illnesses in young children are leg pain, cold extremities, and abnormal skin color.
- Griepaal picture (fever, headache and muscle aches, mild to moderate neck stiffness, light meningism)
- Convulsions and / or consciousness disorders (if meningoencephalitis)
- Other signs of viral infection: eg measles, gastroenteritis or herpes lesions
- Possibly. convulsions (disturbance of internal environment of cells in brains)
- Loss of balance, slightly shy, mild to moderate respiratory distress,
- If necessary. psychological erectile dysfunction, mild constipation
Early complications
In an early stage of the disease can occur more problems. These may require specific treatment, and sometimes indicate severe illness or worse prognosis. The infection can lead to blood poisoning (sepsis), where the infection causes a reaction in the whole body, increased heart rate, high or abnormally low temperature and rapid breathing. Sometimes, there is decrease in blood pressure, and there is then spoken of shock. In the early stages can occur very low blood pressure, especially (but not exclusively) in meningococcal meningitis; this may have an insufficient blood supply to other organs as a result. Disseminated intravascular coagulation (excessive activation of coagulation) can impede blood flow to organs and paradoxically increase the risk of bleeding. With meningococcal disease may occur gangrene of the extremities. Severe meningococcal and pneumococcal infections may lead to bleeding in the adrenal glands and eventually syndrome Waterhouse Friderichsen, which is often fatal.
The brain tissue may swell causing pressure inside the skull rises; the swollen brains can go protrude through the foramen in the skull base. This can be noticed by unconsciousness, the disappearance of the reflex and pupil an abnormal posture. The inflammation of the brain tissue may also obstruct the normal flow of cerebrospinal fluid surrounding the brains (hydrocephalus). For various reasons could seizures (seizures) occur. In children such attacks usually in the early stages of meningitis for (in 30% of the cases), but this does not necessarily indicate an underlying cause. The seizures can be the result of increased pressure and of inflamed areas of the brain tissue. Partial seizures (seizures in just one limb or body part), persistent seizures, seizures that occur later and seizures that are difficult with drugs to be put under control, are indications that the patient's long-term sequelae of the disease on hold.
Inflammation of the meninges may lead to abnormalities in the cranial nerves, a group of nerves that originate in the brain stem and the head and neck control, and which include eye movements, controlling the facial muscles and hearing. After experiencing meningitis may impair eyesight and hearing loss are permanent. Inflammation of the brains (encephalitis), inflammation of the blood vessels in the brains (vasculitis) and the formation of blood clots in the veins of the brains (cerebral venous sinus thrombosis) may result in each of which to weakness, loss of sensation, or an abnormal movement or functioning of the body part that is controlled by the affected part of the brains.
Causes of meningitis
Meningitis is usually caused by an infection with micro-organisms. The majority of infections are due to viruses, followed by bacteria, fungi and protozoa. There are also several non-infectious causes of the disease as possible. The term "aseptic meningitis" is used for cases of meningitis in which no bacterial infection can be demonstrated. This type of meningitis is usually caused by viruses, but may also be the result of a bacterial infection which already has been treated in part, when bacteria disappear from the meninges or pathogens infect a space near the meninges (e.g. sinusitis). Also endocarditis (an infection of the heart valves with small groups of bacteria spread through the bloodstream) may cause aseptic meningitis. Aseptic meningitis may further be the result of an infection with spirochetes, a type of bacteria which also includes Treponema pallidum (the causative agent of syphilis) and Borrelia burgdorferi (known as the causative agent of Lyme disease) belong. Meningitis can be sustained at cerebral malaria (malaria wherein the brains become infected) or amoebic meningitis (meningitis caused by infection with free-living amoebae, such as Naegleria fowleri, which is found in fresh water).
Bacterial meningitis
The types of bacteria that cause bacterial meningitis, vary with the age of the infected individual.
- In premature babies and newborns up to three months old meningitis is often caused by group B streptococci (subtype III which is normally present in the vagina, and is primarily a cause during the first week of life) and bacteria that normally occur in the digestive tract such as Escherichia coli (carrier of the K1 antigen). Listeria monocytogenes (serotype IVb) can infect newborns and occurs in epidemics.
- Older children are usually affected by Neisseria meningitidis (meningococcus) and Streptococcus pneumoniae (pneumococcus, serotypes 6, 9, 14, 18 and 23) and children under five by Haemophilus influenzae type B (in countries where there is vaccinating).
- In adults, Neisseria meningitidis and Streptococcus pneumoniae together accounted for 80% of the cases of bacterial meningitis. The risk of infection with Listeria monocytogenes is greater for people over 50 years. The development of the pneumococcal vaccine has led to a decrease in the incidence of pneumococcal meningitis in both children and adults.
Tuberculous meningitis, a form of meningitis caused by Mycobacterium tuberculosis, is more common among people in countries where tuberculosis is endemic, but is also found in people with immune problems like AIDS.
Recurrent bacterial meningitis can be caused by permanent anatomical defects, either congenital or acquired, or by disorders of the immune system. Because of anatomical defects, there may exist an open connection between the outside environment and the nervous system. The most common cause of recurrent meningitis is skull fracture, particularly a fracture involving the cranial base is involved or that stretches to the sinuses. About 59% of the cases of recurrent meningitis is due to such anatomical abnormalities; 36% is caused by immunodeficiencies (such as to be defective, the complement system, which make someone especially susceptible to recurrent meningococcal meningitis), and 5% is the result of ongoing infections in areas close to the meninges.
Viral meningitis
Viruses that cause meningitis include enteroviruses (enterovirus in the narrower sense, ECHO Parecho, Coxsackie), herpes simplex virus type 2 (and often less type 1), measles, varicella-zoster virus (known as the cause of chickenpox and shingles) the mumps virus, HIV, and LCMV.
Fungal Meningitis
There are a number of risk factors for fungal meningitis, including the use of immunosuppressive drugs (such as after organ transplants), AIDS, and reduced immunity in older age. This form is rare in people with a normal immune system, but has occurred in contaminated drugs. Symptoms usually develop gradually, with at least a couple of weeks headache and fever before the diagnosis. The most common fungal meningitis, cryptococcal meningitis, which is caused by Cryptococcus neoformans. In Africa, cryptococcal meningitis probably the most common cause of meningitis, responsible for 20-25% of AIDS-related deaths in Africa. Other common fungi that cause meningitis are Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis and Candida.
Meningitis diagnosis
Blood and imaging tests
If there is a suspicion of meningitis, blood tests are performed to inflammatory markers in a patient (eg. C-reactive protein, blood count with differential) and blood cultures deployed.
The major study to establish or rule out meningitis is analysis of the cerebrospinal fluid (CSF), a lumbar puncture (spinal tap). A lumbar puncture, however, is contraindicated as a mass in the brains (tumor or abscess), or as is the intracranial pressure (pressure within the skull) is increased, because this may lead to clamping of the brainstem. If someone is at risk of a tumor or increased pressure in the skull (recent head injury, a known problem with the immune system, local neurological symptoms or signs of increased pressure within the skull after research), a CT scan or an MRI recommended scan before lumbar puncture is done. This is true for 45% of all adult patients. If before the lumbar puncture needed a CT or MRI scan or lumbar puncture is difficult to implement, according to professional guidelines should first be given antibiotics to avoid treatment delays, particularly if it takes more than 30 minutes. Often a CT or MRI scan then carried out at a later stage to investigate complications of meningitis.
In severe forms of meningitis can check the important electrolytes in the blood regularly. In bacterial meningitis, for example, is common for hyponatremia by a combination of factors, including dehydration, the inappropriate secretion of antidiuretic hormone (SIADH) and to aggressive intravenous administration of fluids.
Lumbar puncture
In a lumbar puncture, the patient is typically placed on the side, after which a local anesthetic is given, and a needle is inserted in the dura mater to brain and cerebrospinal fluid (CSF) to take off. When the insertion of the needle has succeeded, from the liquor, the opening pressure can be measured with a manometer. This pressure is normally between 6 and 18 cm water (cmH2O) in bacterial meningitis; but the pressure is usually increased. In cryptococcal meningitis the pressure in the skull is often particularly high. The sight of the liquid may be an indication of the nature of the infection: turbid liquor points to increased amounts of protein, white and red blood cells and / or bacteria, and therefore can be an indication for bacterial meningitis.
The liquor sample is examined for the presence and types of white blood cells, red blood cells, proteins, and glucose. In bacterial meningitis can be seen give Gram stain of the sample bacteria, but the absence of bacteria does not exclude bacterial meningitis out because they are too in only 60% of cases seen; This amount is 20% lower if antibiotics were administered before the sample was taken. Gram staining is also less reliable in particular infections such as listeriosis. Microbiological culture of the sample is more sensitive (this is demonstrated in 70-85% of cases which bacteria it is), but it may take up to 48 hours before results are available. The type of white blood cells which is the most present (see table), indicates whether the bacterial meningitis is (usually predominantly neutrophils) or viral (usually predominantly lymphocytes), although this is not always in the beginning of the disease is a reliable indicator. It is rare that eosinophils have the upper hand, which amongst others indicates that the meningitis is caused by parasites or fungi.
Examination after death
Meningitis can be established after the death. At autopsy is usually extensive inflammation of the pia mater and found the arachnoid mater. Neutrophils are often migrated to the brain and spinal fluid, brain, and the base, the cranial nerves, the spinal cord and the blood vessels may be surrounded by the meninges by pus.
Prevention
Against some causes of meningitis can be offered long-term protection by vaccination or short term with antibiotics. Some behavioral changes may also be effective. Preventive treatment of contacts of patients is generally little sense because the chances of another near it also gets is small (a few percent). Only demonstrated within the family is a clear increased risk. Family members and children with whom close contact exists, with proven bacterial meningitis can possibly get a preventive course of antibiotics. The large-scale campaigns are highlighted in the media are more a result of public pressure than a real risk of contamination. Increased alertness and discovered somewhere a case of meningitis is usually sufficient protection.
Meningitis vaccine
Since the 80s, many countries vaccination against Haemophilus influenzae type B in their regular vaccination programs for children. In the Netherlands this vaccination since 1987 included in the national vaccination program. This bacterium was hitherto responsible for about a quarter of the cases of bacterial meningitis. Therefore this pathogen in these countries practically wiped out as a cause of meningitis in young children. In countries where the disease burden is highest, the vaccine is still too expensive. Just as has vaccination against mumps led to a sharp decrease of meningitis due to mumps, which occurred prior to the vaccination at 15% of all cases of mumps.
Since 2002, means that vaccination encountered the rapidly emerging meningococcus, Neisseria meningitidis type C. The expected number of cases of bacterial meningitis will decrease by approximately 50%. It is still not possible to protect itself by vaccination against all forms of bacterial meningitis. To prevent one fatal case should be vaccinated tens of thousands; whether in the other ten thousand cases is completely harmless, is currently (2003) is plausible but not proven for sure.
Meningitis antibiotics
Another method of prevention, particularly for meningococcal meningitis, is a short course of antibiotics. With meningococcal meningitis can prophylactic administration of antibiotics (e.g. rifampicin, ciprofloxacin or ceftriaxone) to people who are in close contact with a patient to reduce the risk that they will contract the disease, but does not protect them against future infections. It was found that increases resistance to rifampicin with use, so that sometimes it is recommended to consider other means. Although antibiotics are often used to occur in patients with basilar skull fracture meningitis, there is insufficient evidence to determine whether this is beneficial or harmful. This applies both to patients with and without leakage of cerebro-spinal fluid.
Meningitis treatment
Meningitis can be life-threatening; if the disease is not treated, the risk of death is high; postponement of treatment is associated with a worse outcome. Therefore, treatment with broad-spectrum antibiotics should not be delayed while still under investigation to confirm the diagnosis. If meningococcal disease is suspected in primary care, according to the guidelines recommend that benzylpenicillin been administered before the patient is transferred to hospital. Intravenous fluid must be administered if there is any of hypotension (low blood pressure), or a shock. Since meningitis at an early stage can cause a number of serious complications, regular medical monitoring is recommended to identify these complications early and the patient, if necessary, to take intensive care.
At a very low consciousness or at a ventilator respiratory failure may be required. Are there indications of increased pressure within the skull can then be taken measures to monitor the pressure. This allows the cerebral perfusion pressure, and different treatments for reducing the pressure in the skull by means of medication (e.g. mannitol) may be optimized. Seizures are treated with anticonvulsants. In hydrocephalus (blocked flow of the brain and spinal fluid), it may be necessary to temporarily or long-term placing in a drainage aid, such as a cerebral shunt.
Bacterial meningitis
-Antibiotics
It should be started immediately with empiric antibiotic treatment (treatment without exact diagnosis), even before the results of the lumbar puncture and CSF testing are known. The choice of the initial treatment depends largely on the kind of bacterium that causes meningitis in a particular place and in a given population. In the UK and the Netherlands, the empirical treatment consists of a third-generation cephalosporin, such as cefotaxime or ceftriaxone. In the US, which is found in streptococcal increasingly resistant to cephalosporins, addition of vancomycin is recommended to start treatment. Chloramphenicol, either alone or in combination with ampicillin, however, appears to work just as well.
-Steroids
Corticosteroids (usually dexamethasone) appear to offer any benefit such as reduced hearing loss and better neurological outcomes in the short term in adolescents and adults in rich countries where HIV is rare. According to some studies, decreases the death rate, but according to other studies that is not the case. This treatment also seems to be conducive for patients with tuberculous meningitis, in any event, in patients who are HIV-negative.
In professional guidelines is recommended to start with dexamethasone or a similar corticosteroid just before the first dose of antibiotics administered, and thus to continue for four days. Because most of the benefits of this treatment are limited to patients with pneumococcal meningitis, it is suggested in some guidelines that dexamethasone should be stopped is determined as another cause of meningitis. The effect is probably due to suppression of overactive inflammation.
Viral meningitis
With viral meningitis is usually needed only supportive treatment, because most viruses that cause meningitis are not sensitive to a specific treatment. Viral meningitis often proceeds more benign than bacterial meningitis. The herpes simplex virus and varicella zoster virus sometimes respond to anti-viruses as acyclovir but has done no clinical scientific study that investigated whether the illness duration reduced. Mild cases of viral meningitis can be treated at home with measures such as fluids, bed rest and analgesics.
Fungal Meningitis
Fungal meningitis, such as cryptococcal meningitis, is treated with prolonged courses of high doses of antifungals such as amphotericin B and flucytosine. Fungal meningitis often occurs when increased pressure in the skull. Recommended that pressure regularly, preferably daily, reduce by epidurals or with a drain tube (drain) between the spinal cord.
Epidemiology
Although meningitis in many countries is a notifiable disease, the exact incidence is not known. Bacterial meningitis is in the western world annually at about 3 per 100,000 people. From screening has shown that viral meningitis is more common (in 10.9 per 100,000 people), and that this happens often in summer. In Brazil, bacterial meningitis is more common: 45.8 cases per 100,000 people annually. Sub-Saharan Africa has more than a century, suffered extensive epidemics of meningococcal meningitis, and is therefore called the "meningitis belt". Epidemics usually do in the dry season (December to June), an epidemic wave may last two to three years and dies out during the intervening rainy season. In this region are 100-800 cases per 100,000 inhabitants for, for whom little medical care available. These cases are mainly caused by meningococci. The largest epidemic ever recorded, engulfed the region in 1996 and 1997, 250,000 people became ill and 25,000 people died.
Meningococcal disease occurs epidemically in places where many people live together for the first time, such as army barracks during mobilization, on college campuses and during the annual hajj, the pilgrimage to Mecca. The pattern of cycles in Africa epidemic is not yet well understood, but there are several factors associated with the development of epidemics in the meningitis belt. These factors include: medical conditions (the system of the population is susceptible to meningitis), demographic conditions (travel and movement of large populations), socioeconomic conditions (overcrowding and poor living conditions), climatic conditions (drought and dust storms), and concurrent infections (acute respiratory infections).
There are considerable differences in the local distribution of causes of bacterial meningitis. The N. meningitidis groups A and B, for example, cause the most disease cases in Europe, while Group A is found in Asia and prevails in Africa, where this group with about 80 to 85% of registered cases of meningococcal meningitis largest caused epidemics in the meningitis belt.
History
It is said that Hippocrates, the existence of meningitis may have already realized, and it seems that meningism was already known to doctors before the Renaissance, such as Avicenna. The description of tuberculous meningitis, at that time "dropsy of the brains", is in a posthumously in 1768 published report often attributed to the Edinburgher physician Robert Whytt, although the link with tuberculosis and the pathogens of tuberculosis until the century was found thereon.
Epidemic meningitis is a more recent problem. The first major outbreak was recorded, took place in 1805 in Geneva. Shortly thereafter, several epidemics in Europe and the United States were documented, and the first report of an epidemic in Africa appeared in 1840. In the 20th century, African epidemics much more common, with the first great epidemic of 1905-1908 and Nigeria Ghana engulfed.
The first report of bacterial infection underlying meningitis, came from the Austrian bacteriologist Anton Weichselbaum, who described the meningococcus in 1887. In the first reports the mortality from meningitis was very high (more than 90%). In 1906, an anti-serum was produced in horses; This horse serum was developed by the American scientist Simon Flexner, causing the deaths of meningococcal disease decreased significantly. In 1944 was first reported that penicillin was effective in meningitis. Late in the 20th century haemophilusvaccin was introduced, increasing the number of cases of meningitis caused by this pathogen declined sharply. In 2002, evidence was found that treatment with steroids could improve the outcome of bacterial meningitis.