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Merck Manual

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Some Causes and Features of Dizziness

Some Causes and Features of Dizziness


Common Features*


Common causes


Sometimes nausea and vomiting

Normal hearing and neurologic function

A doctor's examination, typically including the Dix-Hallpike maneuver



Gadolinium-enhanced MRI

Vestibular neuronitis (probably caused by a virus)

Sudden, severe vertigo with no hearing loss or other findings


A doctor's examination

Sometimes gadolinium-enhanced MRI

Labyrinthitis (viral or bacterial cause)

Sudden hearing loss with severe dizziness, often with tinnitus

A doctor's examination


Temporal bone CT scan if doctors suspect a bacterial infection

Gadolinium-enhanced MRI for people with hearing loss and ringing in ear to exclude a tumor


Usually hearing loss in both ears

Possible causative drug recently started

A doctor's examination


Measuring blood levels of certain causative drugs

Sometimes electronystagmography and rotary chair tests to look for abnormal eye movements suggesting inner ear injury


Symptoms unrelated to movement or position

No hearing loss or other symptoms

Possible causative drug recently started

Measuring blood levels of certain causative drugs

Stopping the drug to see whether symptoms stop



Often history or family history of migraine

A doctor's examination

Sometimes MRI to rule out other causes

Trial of drugs to treat and prevent migraine


Middle ear infection (acute or chronic)

Ear pain, sometimes discharge from the ear

Abnormal appearance of the eardrum during examination

A doctor's examination


Sometimes CT scan (for people with chronic infection)


Obvious recent trauma

Other findings depending on location and extent of damage

A doctor's examination


Sometimes CT

Slowly progressive hearing loss and ringing in one ear

Rarely, numbness and/or weakness of the face


Gadolinium-enhanced MRI if hearing loss or tinnitus

Defect of the bone around a semicircular canal

Dizziness triggered by sound, low tone hearing loss

Audiometry with tympanometry

Usually a CT scan

Usually vestibular testing

Less common causes, typically without ear symptoms

Brain stem stroke

Sudden onset, continuous symptoms

Immediate gadolinium-enhanced MRI

Bleeding in the cerebellum

Sudden onset, with continuous symptoms

Difficulty walking and with tests of coordination

Often headache

Symptoms worsen rapidly

Immediate gadolinium-enhanced MRI


Gadolinium-enhanced MRI of brain and spine

Low blood sugar (usually caused by drugs for diabetes)

Recent dose increase

Sometimes sweating

Finger-stick glucose test (during symptoms if possible)




Testing directed at suspected cause

Pregnancy (often not known by the person)

Sometimes late menstrual period and/or morning sickness

No ear symptoms

Pregnancy test



Syphilis blood test

Weight change

Heat or cold intolerance

Thyroid function blood tests


† Although a doctor's examination is always done, it is only mentioned in this column if the diagnosis can sometimes be made only by the doctor's examination, without any testing. In other words, additional tests may not be needed.

CT = computed tomography; MRI = magnetic resonance imaging.