Nonsyncope Nonvertigo: Understanding the Symptoms and Causes

Nonsyncope Nonvertigo: A Vestibular Syndrome

Nonsyncope nonvertigo describes paroxysmal episodes of intense autonomic and visceral symptoms without true vertigo (spinning) or syncope (loss of consciousness). It is considered a functional vestibular disorder, often overlapping with panic disorder.

Typical Episode

• Sudden intense fear/doom
• Pallor, diaphoresis (profuse sweating)
• Nausea, retching, abdominal discomfort
• Vomiting, diarrhea
• Near-syncope (pre-syncope) or actual syncope
• Trembling, palpitations, dyspnea
• Duration: minutes to hours
• No nystagmus, no true rotational vertigo

Pathophysiology

• Autonomic nervous system dysregulation (sympathetic surge + parasympathetic withdrawal)
• Vestibular-autonomic network hypersensitivity
• Overlap with panic attacks: similar symptoms, but nonsyncope nonvertigo may lack cognitive fear component initially.
• May be triggered by motion, visual stimuli, stress, or occur spontaneously.

Differential Diagnosis

• Panic disorder (DSM-5 criteria)
• Vasovagal syncope (prodrome similar but progresses to LOC)
• Vestibular migraine (may have headache, photophobia, phonophobia)
• Pheochromocytoma (paroxysmal hypertension)
• Carcinoid syndrome (flushing, diarrhea, wheezing)
• Seizure (autonomic seizure)

Evaluation

• Detailed history (triggers, duration, associated symptoms)
• Orthostatic vitals, ECG, Holter if syncope
• Vestibular testing (VNG, VEMP)
• Lab: catecholamines, 5-HIAA, metabolic panel
• Neuroimaging if focal signs

Management

• Cognitive-behavioral therapy (CBT) for panic/vestibular anxiety
• Vestibular rehabilitation therapy (VRT)
• SSRIs/SNRIs for comorbid anxiety/depression
• Beta-blockers or fludrocortisone if orthostatic component
• Antiemetics prn
• Education: reassurance that episodes are not life-threatening

Multidisciplinary approach (neurology, otology, psychiatry) often needed.