The pathophysiology of<unk>  is poorly understood. Research points to an immune-mediated, inflammatory process. Cervical joint hypermobility and defective internal jugular venous drainage have also been suggested as causes. In 1987, Vanast first suggested autoimmune disorder with a<unk>  viral trigger for CDH (now referred to as<unk> . Post-infectious origins have been approximated to make up anywhere between 30–80% of<unk>  patients in different studies. Viruses that have been implicated include Epstein-Barr virus, herpes simplex virus and cytomegalovirus. Non-specific upper respiratory infections including rhinitis and pharyngitis are most often cited by patients. In one study, 46.5% patients recalled a specific trigger with a respiratory tract illness being the most common. In children, almost half report headache onset during an infection. A study by Rozen and Swindan in 2007 found elevated levels of tumor necrosis factor alpha, a proinflammatory cytokine, in the cerebrospinal fluid but not the blood of patients with<unk> , chronic migraine, and post-traumatic headaches suggesting inflammation as the cause of the headaches.<unk>  as an inflammatory, post-infectious manifestation indicates a potential meningoencephalitis event in<unk>  patients. Tissue specificity is a general feature of post-infectious, immune-mediated conditions, and the meninges are a type of connective tissue membrane. Inflammation of the meninges was first proposed as a possible pathophysiology for migraine in the 1960s and has recently been explored again. This hypothesis is based on meningeal mast cell activation. Reactive arthritis (ReA) is a post-infectious disease entity of synovium/joints with connective tissue membrane (synovial membrane of the joints) which provides a corollary.<unk>  has been reported in Hashimoto's encephalopathy, an immune-mediated type of encephalitis. A mean 5-year retrospective analysis of 53 patients with a history of viral meningitis and 17 patients with a history of bacterial meningitis showed an increased onset of subsequent<unk>  onset headache and increased severity of those with prior primary headaches.
New daily persistent headache
Chronic subjective dizziness
symptoms of Migraine
symptom of Migraine
Long-term depression
Headache attributed to a substance or its withdrawal
Acute visual loss
symptom of Cluster headache