Acquired central diabetes insipidus secondary to severe, chronic otitis media and interna in an 8‐year‐old Spanish Mastiff dog (canine)

Abstract

An 8‐year‐old spayed female Spanish Mastiff dog presented with a five‐month history of polyuria, polydipsia, persistent isosthenuria to hyposthenuria, urinary incontinence, and bilateral otitis externa, progressing to acute vestibular dysfunction. Endocrine testing excluded hypo‐ and hyperadrenocorticism, and the clinical signs were inconsistent with primary psychogenic polydipsia. Magnetic resonance imaging revealed severe left‐sided otitis media and interna and mild pituitary enlargement with signal characteristics suggestive of depleted arginine vasopressin stores. Transient central diabetes insipidus (CDI) was diagnosed secondary to chronic otitis media/interna based on imaging findings and a rapid response to desmopressin acetate. Treatment consisted of targeted otitis therapy, desmopressin acetate (DDAVP), and anti‐inflammatory glucocorticoids. Although glucocorticoids transiently reduced DDAVP responsiveness, this resolved after the course of glucocorticoids was completed. Following resolution of the otitis, DDAVP was discontinued and the dog’s water balance normalized without recurrence, confirming a reversible CDI secondary to localized inflammatory disease.