Clinical and biochemical footprints of inherited metabolic diseases. IX. Metabolic ear disease

Abstract

Damages to the ear are very diverse and can depend on the type of inherited metabolic diseases (IMD). Indeed, IMDs can affect all parts of the auditory system, from the outer ear to the central auditory process. We have identified 219 IMDs associated with various types of ear involvement which we classified into five groups according to the lesion site of the auditory system: congenital external ear abnormalities, acquired external ear abnormalities, middle ear involvement, inner ear or retrocochlear involvement, and unspecified hearing loss. This represents the ninth issue in a series of educational summaries providing a comprehensive and updated list of metabolic differential diagnoses according to system involvement.

Keywords: Conductive hearing loss; Ear; External ear; Hearing loss; Inborn errors of metabolism; Inherited metabolic diseases; Sensorineural hearing loss; Tinnitus.

Figure 1.

Schematic of auditory system organization with external, middle ear and inner ear views and cross-section of the cochlear canal with the view of the organ of Corti. Legends: SV: scala vestibuli, ST: scala tympani, SM: scala media

Figure 2.

Occurrence (in percent) of ear symptoms associated with the 5 categories of IMDs. The percentages for ear involvement were calculated using the denominator of the total number of IMDs in each category presenting with any ear phenotype. The heat scale ranges from red (0%; diseases with no particular symptom reported) to violet (100%; diseases with particular symptoms reported) within the disorders group. For further information about the 9 categories of disorders affecting auditory system, see Supplemental Table 1. For interpretation of references to color in this figure legend, the reader is referred to the web version of this article.

Figure 3.

Otoscopies. A: Normal right otoscopy with visualization of the ossicular chain. B: Otitis media. C: Otitis media with effusion