disease severity measurement hydronephrosis severity measurement 2012-11-15T17:49:33Z Any measurement of the degree to which the presentation of the hydronephrosis disease state, i.e. dilation of the pelvis and calices of one or both kidneys because of the accumulation of urine resulting from obstruction to urine outflow, causes pain or damage. CMO:0001207 JSmith clinical_measurement_ontology