What causes headaches in bacterial meningitis?

In bacterial meningitis, headaches are typically caused by increased intracranial pressure. This pressure arises from the inflammation of the meninges, the protective membranes covering the brain and spinal cord, due to the infection. When bacteria invade the meninges, they elicit an immune response that causes swelling and an influx of inflammatory cells, which in turn leads to edema. This swelling increases the volume of fluid in the cranial cavity, resulting in increased intracranial pressure.

The symptoms associated with this increased pressure, such as severe headaches, are a direct consequence of the brain being encased within the rigid confines of the skull. As the pressure builds, it can lead to pain and discomfort, often described as a constant, throbbing headache. This mechanism helps explain why headache is a common presenting symptom in patients with bacterial meningitis.

Dehydration, infection of the nerves, and sinus pressure may contribute to headache in different contexts but are not the primary causes of headache specifically in the setting of bacterial meningitis. Sinus pressure could cause headache but is usually related to sinus infections, not meningitis.