Generality
Meningitis is an "inflammation of the meninges, the membranes that enclose and protect the brain and spinal cord. The fulminant form of this disease is rare, but extremely serious, and can be fatal.
Fulminant meningitis is generally of bacterial origin. CSF testing is often useful for etiological diagnosis.
What's this
Fulminant meningitis is an inflammatory process that affects the membranes surrounding the brain and spinal cord (meninges).
The function of these three membranes (pia mater, arachnoid and dura mater) is to protect the central nervous system from infection. When a pathogen threatens this area, the dura mater (the outermost menynx) becomes more permeable, so as to allow a greater influx of white blood cells (cells responsible for defending the body from the attack of bacteria, viruses and fungi from the "external). This immune reaction determines, however, the inflammation of the membranes themselves. The result is the formation of edema (ie an accumulation of fluids) and the increase in intracranial pressure, with poor oxygenation of the tissues and risk of brain damage.
The fulminant form occurs in a small percentage of all cases of bacterial meningitis, which can be contracted at any age.
The most feared infectious agent is meningococcus (Neisseria meningitidis), of which there are several serotypes (currently, 13 are known, but only 5 - A, B, C, Y, W135 and X - are clinically relevant, as they can cause epidemics and diseases that are dangerous for the " man).
In Italy, meningococcus C is the most aggressive serotype and is found most frequently together with the B strain.
Note
Usually, meningitis recognizes an infectious cause (viral, bacterial or fungal), but there are also forms caused by irritative phenomena (eg drugs, neoplastic infiltration from primary brain tumors or metastases, physical lesions, etc.) and some systemic diseases (e.g. such as sarcoidosis and vasculitis).
Causes
Many bacteria can cause fulminant meningitis.
In general, the microorganisms responsible for the disease are invasive (ie capable of multiplying quickly and spreading throughout the organism) and vary with the age of the patient:
- In the newborn, the main etiological agents are Escherichia Coli and group B streptococci;
- In adolescents and young adults, the bacterium is most commonly implicated Neisseria meningitidis (meningococcus), of which there are several serogroups (A, B, C, Y, W135 and X);
- In the elderly, the cases are mainly due to the Streptococcus pneumoniae (pneumococcus) and to the Listeria monocytogenes.
Among the agents that can cause fulminant meningitis it should also be remembered "haemophilus B or Hib (Haemophilus influenzae type b).
