primary progressive multiple sclerosis DOID:0050784 SNOMEDCT_US_2025_09_01:428700003 MESH:D020528 disease_ontology MESH:D020528 2013-11-07T11:26:58Z A multiple sclerosis that is characterized by steady worsening of neurologic functioning, without any distinct relapses or periods of remission. The rate of progression may vary over time, with occasional plateaus or temporary improvements, but the progression is continuous. PPMS Primary-progressive MS UMLS_CUI:C0751964 ICD10CM:G35.B multiple sclerosis