Labyrinthitis involves acute inflammation of the membranous labyrinth, affecting both vestibular and cochlear structures. Viral pathogens (influenza, HSV, VZV, adenovirus, mumps) cause direct cytopathic damage to labyrinthine epithelium and vestibular ganglion neurons. The resulting asymmetry in vestibular afferent firing rates between the two ears — reduced from the affected side and normal from the intact side — generates a false rotational signal interpreted as spinning vertigo. Nystagmus beats away from the lesion side due to unopposed tonic vestibular output from the intact ear. Cochlear inflammation damages outer and inner hair cells, producing sensorineural hearing loss and tinnitus. Bacterial labyrinthitis occurs via tympanogenic spread (through the round or oval window from middle ear infection) or meningogenic spread (through the internal auditory canal from meningitis), and constitutes a medical emergency. The nurse differentiates viral from bacterial etiologies, performs comprehensive neurological screening to exclude central causes, manages acute symptoms, and coordinates vestibular rehabilitation.