According to the number and extent of the lesions, the reflux oesophagitis can be classified into different severities:

Savary and Miller

I   single or multiple non-confluent ulcers or erythemas with fibrincovers                                                   II  confluent changes (mainly dorsal)
III confluent, circular, peptic lesions without stenosis
IV metaplasia, ulcer

MUSE

M=Metaplasia M0 = no, M1 = 1 streak, M2 = > 2 streaks, M3 = circular                                             U=Ulcer           U0 = no, U1 = Transitionulcer, U2 = Barrett´s ulcer, U3 = both                             S=Constriction S0 = no, S1 = Lumen > 9mm, S2 = Lumen < 9mm, S3 = Constriction + brachyesophagus      E = Ulcer/Abrasion E0 = no, E1 = on 1 fold, E2 = >2 folds, E3 = circular