The term sterile is often applied in medicine when talking about surgery equipment and fields free of germs, but the brain and other structures of the body are sterile as well. Different from the skin, the gastrointestinal tract, and the outer section of the urinary tract, internal organs are meant to be free from microbes, viruses, and germs, and severe diseases may arise when they are infected. For example, peritonitis is a life-threatening condition that results from infection and inflammation in the abdominal cavity, and meningitis is a severe ailment caused by bacteria or viruses that are relocated to the outer linings of the brain, called meninges. When these outer coverings get infected, an inflammatory process starts, and it is called meningitis.
Infection to the meninges often comes from other parts of the body. The bacteria are relocated to the central nervous system through the blood, and it quickly becomes a severe and dangerous problems. Certain populations are more susceptible to meningitis, as in HIV and immunocompromised patients, patients with chronic disease, infants, and older adults. The symptoms range from mild to severe according to each case, and the most common are as follows:
Not every case of headache is fully understood, and most of them remain undiagnosed because they are calmed down by using over-the-counter painkillers. However, it is known that most cases involve the dilatation of blood vessels in the meninges. Meningitis is an inflammation of this area of the body, and inflammation leads to vasodilation. Thus, it is probably the most common symptom in case of meningitis, and it is an important part of the triad of symptoms to diagnose meningitis.
The intensity of headache in meningitis depends on the severity of the disease. As the inflammation becomes worse, and the infection slowly spreads, the headache gets progressively worse. Thus, this is not a case of sudden and severe headache, as it happens in cerebrovascular disease. It is slowly evolving, and in late stages of the disease it might turn into an unbearable and very severe headache because the source of the infection is right there in the meninges, where pain perception is located.