Middle and inner ear changes in congenital rubella.

Temporal bone changes in a 14-month-old female infant with congenital rubella are described. The inner ears showed cochleo-saccular degeneration, with more severe involvement of the right side. Perivascular round cell infiltration was demonstrated in the base of the cochlea, stria vascularis, and superior ampullary cribriform region, consistent with viral infection. Whether the latter was related to the rubella or the the patient's terminal viral infection is undetermined. Predominant involvement of the cochlea saccule may have been related o their blood supply from the vestibulo-cochlear artery, which is a more direct continuation of the labyrinthine artery than are the other branches. Middle ear changes consisted of a fetal type of stapes, a small area of malleus head fixation on one side, and absence of the medial component of the posterior incudal ligament, with a joint-like attachment between the short process of the incus and the medial wall of the fossa incudis. This may be an abnormality, or it might represent a variation of normal development.