(RCVS, sometimes called Call-Fleming syndrome) a disease characterized by a weeks-long course of thunderclap headaches, sometimes focal neurologic signs, and occasionally seizures.

Hypoxic pulmonary vasoconstriction, also known as the Euler-Liljestrand mechanism, is a physiological phenomenon in which small pulmonary arteries constrict in the presence of alveolar hypoxia (low oxygen levels).