Headaches which are due to non-vascular causes such as secondary intracranial hypertension, intracranial hypotension, headaches caused by disorders of homeostasis, infectious disease, neoplasm, cervicogenic headache, and the neuralgias.
https://pubmed.ncbi.nlm.nih.gov/20816456/#:~:text=Headache%20attributed%20to%20intracranial%20neoplasm,or%20hyposecretion%20and%20intrathecal%20injection.