<unk>  is a medical term referring to a presentation of disease symptoms that become worse over time<unk> , followed by periods of less severe symptoms that do not completely cease<unk> . The term is sometimes applied to groupings of presentations of particular diseases that display this pattern, such as: *<unk>  multiple sclerosis
Relapsing–remitting
Acute 
Pauci-immune
Endemic 
Epidemic
Biphasic disease
Modic changes
Depurative