Meningitis - Causes and Symptoms

Definition

Meningitis is an inflammation of the membranes that surround the brain and spinal cord (meninges). This inflammatory process can be caused by many factors; often, it is on an infectious basis, but it can also be caused by other diseases or irritative phenomena.

Meningitis produces a triad of characteristic signs and symptoms, such as: fever , headache and neck stiffness . If the inflammation is neglected, these manifestations may be associated with drowsiness, confusion, disorientation, tremors, automatic movements, vomiting and photophobia.

The symptoms of meningitis can occur over a few hours or days (acute form) or in a longer period of time (subacute or chronic form). The severity of the disease and the treatment vary depending on the cause.

Infectious meningitis

The meninges, normally sterile, represent a warm and nutrient-rich environment, therefore ideal for the growth of viruses, bacteria or fungi.

Particular circumstances can favor the spread of infectious agents in the blood up to the meninges, through the cerebral spinal fluid, the fluid that permeates and protects the brain and spinal cord.

In particular, bacteria, viruses and fungi can colonize the cerebro-spinal fluid by diffusion from adjacent foci of infection (such as sinusitis, pneumonia and mastoiditis) or through direct penetration from the outside following, for example, penetrating trauma or neurosurgical maneuvers .

The inflammation can have an exclusive localization in the meninges (ie the germ found in the membranes that cover the brain the ideal conditions for its reproduction), or it can occur in conjunction with other pathologies, such as tuberculosis, typhus, measles, rubella, and chickenpox, syphilis, Lyme disease and leptospirosis.

Other causes of meningeal inflammation include: brucellosis, listeriosis, cat scratch disease, cryptococcosis, malaria and toxoplasmosis.

Non-infectious causes

Meningeal inflammation can be caused by irritative factors, such as physical injuries, intrathecal chemotherapy, neoplastic infiltration (primary brain tumors or metastases, leukemias and lymphomas), the presence of cysts or intracranial masses, lead intoxication and reactions to radiopaque contrast agents.

Occasionally, meningitis is a consequence of some systemic diseases, such as: sarcoidosis, vasculitis, Behçet's syndrome, Wegener's granulomatosis and systemic lupus erythematosus.

Infrequently, inflammation is the result of systemic drug use. The agents most commonly responsible for this phenomenon are NSAIDs (especially ibuprofen in patients with collagen-vascular disease), antibiotics (especially sulfonamides), immunosuppressants (eg cyclosporine and immunoglobulins administered intravenously) and some vaccines ( any reactions occur mainly due to rabies and whooping cough).