Paroxysmal attacks or paroxysms (from Greek παροξυσμός) are a sudden recurrence or intensification of symptoms, such as a spasm or seizure. These short, frequent, and stereotyped symptoms can be observed in various clinical conditions. They are usually associated with multiple sclerosis or pertussis, but they may also be observed in other disorders such as encephalitis, head trauma, stroke, asthma, trigeminal neuralgia, breath-holding spells, epilepsy, malaria, tabes dorsalis, and Behçet's disease, paroxysmal nocturnal hemoglobinuria (PNH). It has also been noted as a symptom of gratification disorder in children.