Preliminary diagnostic algorithm

Why am I dizzy?

By Marcello Cherchi, MD PhD

“Dizziness” is a non-specific term that means different things to different people. Related terms include “vertigo” and “unsteadiness.” We prefer the term disequilibrium, which is more inclusive.

Arriving at a correct diagnosis is a skill that physicians develop over many years of training and practice. We do not recommend that anyone rely on self-diagnosis; rather, we strongly recommend that a person consult with a qualified medical professional whose training is appropriate for the symptoms in question. The reader must understand that the information presented here is not intended to substitute for the role of a licensed and qualified medical professional in examination, diagnosis and provision of health care.

We also understand that many people are naturally curious about their symptoms and will turn to the internet for information regarding possible diagnoses. While the internet is an amazing resource, its information is largely unfiltered. Consequently, we provide a preliminary diagnostic algorithm for the symptom of disequilibrium that relies on the three major branch points:

• Chronicity. Is the symptom of disequilibrium continuous/constant/chronic (there all the time) or episodic/intermittent (starts and stops)?
• Onset. Was the onset of symptoms abrupt (over seconds to minutes), intermediate (over hours to days), or gradual (over weeks to months)?
• Ear symptoms. Are ear symptoms (such as hearing loss, ear fullness, ringing in the ears) absent, sometimes present, or always present? If ear symptoms are present, and are they unilateral or bilateral?

These are presented in the format of a Table, below.

You can click on an individual diagnosis to go to the web page on that topic.

	Abrupt onset (seconds to minutes)	Intermediate onset (hours to days)	Gradual onset (weeks to months)
Episodic/intermittent	Abrupt onset and episodic Ear symptoms absent: Benign paroxysmal positional vertigo Otolithic catastrophe of Tumarkin Orthostatic intolerance Cardiac arrhythmia Drop attacks, including vestibular paroxysmia Episodic ataxia Visual vertigo Cervicogenic vertigo Psychological disequilibrium Motion sickness Cybsersickness Epileptic vertigo Ear symptoms present and (usually) unilateral: Semicircular canal dehiscence Perilymphatic fistula Ear symptoms present and (usually) bilateral: Intracranial pressure fluctuations	Intermediate onset and episodic Ear symptoms absent: Migraine Mal de debarquement syndrome Adverse effect of medication Acute alcohol intoxication, recreational drugs Episodic ataxias Ear symptoms present and (usually) unilateral: Ménière’s disease Ear symptoms present and (usually) bilateral:	Gradual onset and episodic Ear symptoms absent: Ear symptoms present and (usually) unilateral: Ear symptoms present and (usually) bilateral:

Continuous/constant/chronic

Abrupt onset and continuous Ear symptoms absent: Vestibular neuritis Stroke Concussion Ear symptoms variably present: Labyrinthine concussion Otic barotrauma Ear symptoms present and (usually) unilateral: Labyrinthitis Temporal bone fracture Ear symptoms present and (usually) bilateral:

Intermediate onset and continuous Ear symptoms absent: Persistent postural perceptual dizziness Demyelination Wernicke’s encephalopathy (acute B1 deficiency) Other encephalitides Ear symptoms variably present: Infection, e.g., COVID‑19 Oculopalatal tremor Ear symptoms present and (usually) unilateral: Otitis media Ramsay Hunt syndrome Ear symptoms present and (usually) bilateral:

Gradual onset and continuous Ear symptoms absent: Idiopathic bilateral vestibular weakness Nutritional deficiencies (vitamin B1 deficiency, vitamin B12 deficiency) Spinocerebellar ataxia Other ataxias (e.g., Friedriech’s ataxia, gluten ataxia) Normal pressure hydrocephalus Myelopathy CANVAS Basal ganglionic disorders, such as Parkinson’s disease, progressive supranuclear palsy, multiple system atrophy Presbyvestibulopathy Space-occupying lesions Chronic alcoholism Paraneoplastic syndromes Chiari malformation Peripheral neuropathy Visual deficits (cataracts, macular degeneration, anisometropia) Ear symptoms variably present: Ototoxicity Fibromyalgia Ear symptoms present and (usually) unilateral: Vestibular schwannoma Cerebellopointine angle meningioma Ear symptoms present and (usually) bilateral: Autoimmune inner ear disease Superficial siderosis Usher syndrome

For people who prefer the logic of a flow chart format, we offer a diagram in the Figure below.