Which of the following is a potential cause of headache when accompanied by altered mental status?

Meningitis is a potential cause of headache accompanied by altered mental status due to the inflammation of the protective membranes (meninges) surrounding the brain and spinal cord. This condition can lead to increased intracranial pressure and can significantly affect neurological function, contributing to symptoms such as confusion, lethargy, or other alterations in mental status.

In cases of meningitis, the headache is typically severe and may present with additional symptoms such as fever, stiff neck, and photophobia. The combination of these symptoms signals a critical condition that requires prompt diagnosis and treatment. The presence of altered mental status alongside a headache is particularly concerning, as it can indicate an infection that is impacting the central nervous system.

Other conditions, like dehydration, sinusitis, and tension headaches, generally do not present with altered mental status. Dehydration can cause headaches but is less likely to lead to changes in mental status unless it is severe. Sinusitis generally causes localized pain and pressure but does not typically cause any significant changes in consciousness. Tension headaches are mostly associated with muscle tension and stress and usually do not result in altered mental status unless there are additional complicating factors.