Enlarged vestibular aqueduct

Large vestibular aqueduct, is a structural deformity of the inner ear. Enlargement of this duct is one of the most common inner ear deformities and is commonly associated with hearing loss during childhood.. Some use the term enlarged vestibular aqueduct syndrome but this is felt by others to be erroneous as it is a clinical finding which can occur in several syndromes. Large vestibular aqueduct, is a structural deformity of the inner ear. Enlargement of this duct is one of the most common inner ear deformities and is commonly associated with hearing loss during childhood.. Some use the term enlarged vestibular aqueduct syndrome but this is felt by others to be erroneous as it is a clinical finding which can occur in several syndromes. Although large vestibular aqueducts are a congenital condition, hearing loss may not be present from birth. Age of diagnosis ranges from infancy to adulthood, and symptoms include fluctuating and sometimes progressive sensorineural hearing loss and disequilibrium. It is possible that a small portion of those with large vestibular aqueducts will not exhibit auditory symptoms such as hearing loss. While this is uncommon, hearing loss can progress later in life especially after head trauma. The vestibular aqueduct acts as a canal between the inner ear and the cranial cavity. Running through it is a tube called the endolymphatic duct, which normally carries a fluid called endolymph from the inner ear to the endolymphatic sac in the cranial cavity. When the endolymphatic duct and sac are larger than normal, as is the case in large vestibular aqueduct syndrome, endolymph is allowed to travel back from the endolymphatic sac into the inner ear. This often results fluctuations in hearing levels. Enlarged vestibular aqueducts often occur with other inner ear development problems, such as cochlear deformities. Enlarged vestibular aqueducts are part of the classic Mondini deformity. Enlarged vestibular aqueducts with enlarged endolymphatic sacs occur in Pendred syndrome which is caused by a defect on chromosome 7q31.. Enlarged vestibular aqueducts can also occur in Branchio-oto-renal syndrome, CHARGE syndrome and renal tubular acidosis.