The Two Systems That Cause Vertigo
Your sense of balance depends on a chain of structures working together. It begins in the inner ear — the semicircular canals and their balance nerve — which detects head movement and sends signals up towards the brain. Those signals are then received and processed by the brainstem and cerebellum, the parts of the brain that combine ear, eye and body information to keep you steady. Vertigo arises when something disrupts this chain, and where the disruption sits divides all vertigo into two great families.
Peripheral vertigo comes from a problem in the inner ear or balance nerve itself — conditions such as BPPV, vestibular neuritis, labyrinthitis and Ménière's disease. These are the commonest causes by far, and although they can be intensely unpleasant, the great majority are benign and treatable.
Central vertigo comes from a problem in the brain — most importantly a stroke in the brainstem or cerebellum, but also tumours, multiple sclerosis or migraine. Central causes are less common but far more consequential, because a missed brainstem stroke can be fatal. The entire art of assessing an acutely dizzy patient is deciding, quickly and reliably, which family they belong to.
How to Distinguish Peripheral from Central — Key Features
Although only a trained examination is definitive, the pattern of symptoms gives strong clues. Peripheral and central vertigo tend to feel and behave differently.
Peripheral vertigo typically produces:
- Severe, true spinning — the room clearly whirls
- Symptoms that worsen sharply with head movement or position change
- Prominent nausea and vomiting
- Sometimes hearing change, tinnitus or ear fullness (as in Ménière's)
- No other neurological symptoms — speech, vision and limb strength are normal
Central vertigo tends to produce:
- Spinning that may be milder but is often constant rather than fleeting
- Relatively little nausea compared with the degree of imbalance
- Accompanying neurological signs — double vision, slurred speech, facial droop, limb weakness or numbness
- Marked unsteadiness or an inability to walk or sit unsupported
- A new, severe headache or neck pain
A useful rule of thumb: if a patient with vertigo simply cannot walk at all, or has any symptom outside the ear, think central until proven otherwise. However, these features overlap enough that pattern alone is not safe — which is why neurologists rely on a focused examination rather than the history in isolation.
The HINTS Exam — What Neurologists Use in Emergency
The single most powerful tool at the bedside is the HINTS exam, a three-part eye examination that, in the hands of a trained clinician, distinguishes peripheral from central vertigo more accurately than an early MRI. Counter-intuitively, in the first day or two a HINTS exam pointing to stroke is more reliable than a normal scan, because small brainstem strokes are frequently invisible on MRI in the first 24–48 hours.
HINTS stands for three components:
- Head Impulse — the doctor turns your head quickly to one side while you fix your gaze on their nose. In peripheral vertigo the eyes lag and then catch up with a corrective flick, which is reassuring. A normal, smooth head-impulse response in an acutely vertiginous patient is paradoxically worrying, because it suggests the inner ear is intact and the problem is central.
- Nystagmus — the direction of the involuntary eye flicker is observed. Nystagmus that beats in one direction only and settles is typical of a peripheral cause; nystagmus that changes direction with gaze, or is purely vertical, points to a central cause.
- Test of Skew — the doctor covers and uncovers each eye. A vertical realignment of the eye (skew deviation) is a red flag for a central lesion.
Taken together, the pattern that reassures is a positive head impulse, single-direction nystagmus and no skew. Any deviation from that combination — the so-called "dangerous HINTS" — prompts urgent imaging and stroke evaluation, even if the patient looks otherwise well.
When Vertigo Is a Stroke
The most important reason to take vertigo seriously is that a stroke in the back of the brain — the brainstem or cerebellum, supplied by the vertebral and basilar arteries — can present with vertigo as its leading, and sometimes only, symptom. These posterior-circulation strokes are among the most commonly missed strokes precisely because they masquerade as an ordinary inner-ear upset.
Certain patients are at higher risk and deserve a lower threshold for concern: those over 60, and anyone with high blood pressure, diabetes, high cholesterol, smoking or atrial fibrillation. In our practice at Gini, where many patients have long-standing diabetes and vascular disease, this vigilance is routine. Sudden vertigo in a person with several vascular risk factors is treated as a possible stroke until the examination says otherwise.
Time matters enormously. If a posterior-circulation stroke is caught early, clot-dissolving or clot-removal treatment can prevent devastating disability. That is why the message is blunt: do not assume new, severe vertigo is "just the ears", especially in an older or high-risk person. Call the Gini emergency line on +91 82888 43800 or go straight to an emergency department.
Red Flag Symptoms That Mean Go to Emergency Now
Seek emergency care immediately if vertigo comes with any of the following. Each one raises the possibility of a central, potentially life-threatening cause:
- Double vision, or loss of part of the field of vision
- Slurred, garbled or difficult speech
- Drooping of one side of the face
- Weakness, clumsiness or numbness of an arm or leg
- A sudden, severe headache unlike any before, or new neck pain
- Inability to walk, or a strong tendency to veer or fall to one side
- Difficulty swallowing, hiccups that will not stop, or hoarseness
- Vertigo that is severe and unremitting and does not fit the brief, position-triggered pattern of BPPV
The reassuring counterpoint is that vertigo which is clearly triggered by rolling over in bed, lasts only seconds, and comes with no symptom outside the ear is very likely benign BPPV. But when in doubt, get checked — a benign cause simply means reassurance, while a missed brainstem stroke is catastrophic.
The Investigations Used to Diagnose Each Type
The investigation of vertigo is guided by whether the picture looks peripheral or central. Reassuringly, most peripheral vertigo needs no scan at all — a positive Dix-Hallpike test diagnoses BPPV at the bedside, and vestibular neuritis is largely a clinical diagnosis supported by the HINTS exam.
When a central cause is suspected, the key investigation is an MRI of the brain with diffusion-weighted imaging, ideally including the blood vessels of the neck and brain (MR angiography) to look for narrowing or clot. It is worth repeating that a normal MRI in the first day or two does not fully exclude a small brainstem stroke, which is why the examination carries such weight and why imaging may be repeated. A CT scan is quicker and useful for excluding bleeding, but it is poor at showing small strokes at the back of the brain.
For suspected peripheral disease, other tests have their place: an audiogram (hearing test) if Ménière's or labyrinthitis is possible, and specialised vestibular testing such as videonystagmography or the video head-impulse test in difficult or recurrent cases. Blood tests for blood sugar, cholesterol and cardiac rhythm assessment help define stroke risk. Dr. Iqbal Singh chooses the smallest set of tests needed to answer the question safely — most patients need far less than they expect. To arrange an assessment, call 0172 4120100.