Unmasking early-morning hypoglycaemia with CGM in multifactorial vertigo: the interplay of recurrent BPPV, orthostatic dysregulation and hypnotic polypharmacy

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Dizziness and falls in older adults have multifactorial origins, including vestibular, autonomic, metabolic and pharmacological factors. Hypoglycaemia, particularly when occurring at home, is frequently under-recognised. A man in his 60s with chronic insomnia on multiple hypnotics experienced vertigo, unsteadiness and repeated falls over 5 years, resulting in vertebral compression fractures. Vestibular evaluation confirmed left posterior canal benign paroxysmal positional vertigo (BPPV) with BPPV fatigue, alongside orthostatic dysregulation, but no central neurological signs. Standard labs showed near-normal glucose and HbA1c, but continuous glucose monitoring (CGM) detected early-morning hypoglycaemia (<50 mg/dL), including an episode (<20 mg/dL) requiring emergency glucose. Insulinoma was excluded. Management included dietary regulation, controlled awakening, vestibular manoeuvres, Ryokeijutsukanto and voglibose for glucose intolerance. Despite partial improvement, dizziness and falls persisted. This case underscores the diagnostic value of CGM in non-diabetic patients and highlights the necessity of a multidisciplinary approach addressing vestibular, autonomic, metabolic and pharmacological contributors in complex dizziness syndromes.