Vertigo is a symptom of an underlying condition. Diagnosis of that condition is based on history and investigations.
Vertigo alone may be diagnosed by patient’s accounts of his or her experiences. Three quarters of patients with vertigo complain of dizziness.
True vertigo usually means a feeling of the “world spinning around” rather than just feeling dizzy or light headed. (1-4)
Causes of vertigo
Vertigo may be caused by diseases of the central nervous system or those of the inner ear.
Diagnosis attempts to distinguish between causes in the inner ear or in the brain.
From history the trigger of the vertigo may be assessed. This helps to determine the cause of the condition.
For example, a change in position of the head brings about vertigo in Benign paroxysmal positional vertigo (BPPV), in labyrinthitis or in some brain tumors.
Those episodes that precipitate without an apparent cause include Ménière’s disease, migraine, multiple sclerosis and stroke.
Usually a middle ear infection or respiratory tract infection precedes vestibular neuronitis.
Stress precipitates vertigo due to a psychological cause or vertigo due to migraine.
Duration of vertigo is also indicative of the underlying cause. It may last a few seconds to a few minutes in Ménière’s disease, vestibular neuronitis, BPPV etc.
It may last for hours in early stages of Ménière’s disease, migraine or due to injury or surgery.
In stroke, migraine, multiple sclerosis or psychological causes of vertigo, a single episode may last for days or weeks.
Initial stages of the acute vestibular neuronitis manifests with severe vertigo while in Ménière’s disease the attacks of vertigo initially increase in severity, then lessen in severity as the disease progresses.
Clinical examination may reveal nystagmus or uncontrolled movement of the eyes.
In vertigo due to causes in the inner ear the nystagmus is usually side to side and reduces when the patient focuses the gaze.
Nystagmus caused by diseases of the central nervous system is usually side to side or up and down and does not stop when the patient focuses the gaze and lasts longer.
Physicians usually perform a detailed neurological examination to detect the underlying cause.
The Dix-Hallpike maneuver is commonly performed. It is a test that triggers an episode of vertigo. It is often used to confirm cases of BPPV.
The test involves moving quickly from a sitting to a lying position with the head placed lower than the surface of the bed the patient is lying on.
On lying the patient is asked to rotate the head towards the physician with eyes open. In cases of BPPV, the symptoms of vertigo may appear for several seconds before disappearing spontaneously.
Ears would be thoroughly examined to rule out external ear or middle ear infections.
Hearing is tested using a tuning fork. The tests are called Rinne’s and Weber’s tests and detect hearing defects that may be present along with vertigo.
Blood pressure and pulse rate is examined to determine if the vertigo is caused due to sudden fall in blood pressure.
Laboratory tests for vertigo
Laboratory investigations for diagnosis include (1-4) –
- Routine blood tests – Tests for blood sugar, blood counts, electrolytes and thyroid function help identify cases of dizziness. For example anemia and low blood sugar are known to cause dizziness. This should be differentiated from vertigo.
- Audiometry tests are performed to detect Ménière’s disease. An audiometer produces sounds of different volume and pitch. The patient listens to the sounds through headphones and signal when they hear sounds by pressing a button.
- Radiological imaging studies – Neuroimaging studies are useful in patients suspected with brain tumors, stroke etc. In general, magnetic resonance imaging (MRI) is more appropriate than computed tomography (CT scan) as it shows more details of the brain structures. These tests are not of much use in patients with BPPV, vestibular neuronitis or Ménière’s disease.