Dizziness, Giddiness and Feeling Faint

Dizziness is a common complaint and has a very broad list of possible underlying causes. Dizziness is a nonspecific term which can mean different things to different people, including true vertigo, light-headedness, weakness (neurological impairment), unsteadiness, feeling faint (presyncope), funny turns, visual disturbance, or a psychological problem.

People with dizziness can experience significant social and occupational morbidity, and establishing the diagnosis is essential in view of the wide variety of possible causes and also to enable effective management. It is essential that patients who present with dizziness should be given the correct diagnosis, both to avoid missing serious neurological causes and to ensure that the right treatment is given^[1] .

The cause of the dizziness can be diagnosed in most cases on the basis of a thorough clinical history and examination and often does not require hospital referral.

Causes of dizziness

Aetiology of dizziness is diverse. Causes include:

• Cardiovascular:
  • Postural hypotension.
  • Cerebrovascular disease (stroke and TIA).
  • Carotid sinus syndrome.
  • Vertebrobasilar insufficiency.
  • Aortic stenosis.
  • Subclavian steal syndrome.
  • Cardiac arrhythmias.
• Neurological:
  • Following head injury.
  • Epilepsy.
  • Multiple sclerosis.
  • Parkinsonism.
  • Dementia.
  • Brain tumours, especially brainstem and cerebellar tumours.
  • Benign intracranial hypertension.
  • Normal pressure hydrocephalus.
  • Peripheral neuropathy (imbalance or unsteadiness may occur as a result of peripheral neuropathy, spinal posterior column lesions or cerebellar disease).
• Otological:
  • Ménière's disease.
  • Benign paroxysmal positional vertigo (BPPV).
  • Vestibular neuritis and labyrinthitis.
  • Vestibular migraine (generally presents with attacks of spontaneous or positional vertigo lasting seconds to days, with associated migraine symptoms).
  • Otosclerosis and Paget's disease of bone.
  • Middle ear trauma.
  • Following surgery - eg, stapedectomy, cochlear implant.
  • Tumours, cholesteatoma.
• Metabolic:
  • Hypoglycaemia.
  • Adrenal insufficiency.
  • Hypothyroidism.
• Haematological:
  • Anaemia.
  • Hyperviscosity.
• Psychogenic: eg, generalised anxiety, agoraphobia, panic attacks, hyperventilation.
• Miscellaneous:
  • Viral illness.
  • Migraine headaches.
  • Other infections - eg, acute bacterial infections, Lyme disease, HIV infection.
  • Ocular: visual impairment.
  • Cervical - eg, cervical spondylosis.
  • Multisensory dizziness syndrome: occurs when there are reduced inputs from more than one sensory system - eg, reduced vision, vestibular dysfunction, peripheral neuropathy, autonomic neuropathy.
  • Autoimmune/connective tissue disorders - eg, rheumatoid arthritis, systemic lupus erythematosus.
  • Drug intoxication - eg, acute intoxication with alcohol or drugs; carbon monoxide poisoning; chronic alcohol misuse.
  • Iatrogenic: side-effect of medication - eg, antihypertensives, antidepressants, aminoglycoside antibiotics, anti-arrhythmics. Medication is an extremely common cause of dizziness, particularly in older people.

Red flag signs associated with acute dizziness that indicate a possible central neurological cause (such as posterior circulation stroke) include:

• Abnormal neurological symptoms or signs.
• New headache.
• A normal vestibulo-ocular reflex as assessed by the head impulse test (which would imply that the vertigo does not originate in the peripheral vestibular system).

The most common causes of true vertigo encountered in primary care are labyrinthitis or vestibular neuronitis, BPPV, vestibular migraine and Ménière's disease. Even in the elderly, an underlying cause for dizziness can usually be established^[2] .

Assessment^{[3, 4, 5]}

See also the separate Neurological History and Examination article. A thorough history and examination usually provide a clear guide to initial investigations, treatment and the need for referral. When the patient first presents, it is really important to determine exactly what the patient is experiencing, because patients mean different things by the term 'dizziness'. Usually by history and examination alone it is possible to distinguish between a peripheral vestibular problem and a central one such as stroke, and being able to do so prevents unnecessary referral and investigation. Where a central cause is established then referral for urgent treatment can be instigated.

Assessment involves identification of the precise underlying cause, if possible:

• An assessment for any serious underlying disorder requiring urgent treatment - eg, coronary heart disease, cerebrovascular disease.
• Identifying the nature of the presenting symptom. Traditionally, dizziness has usually been categorised into one of four main groups:
  • Vertigo:
    • Vertigo is defined as an abnormal sensation of movement, either of the surroundings or the person (see also the separate Vertigo article). Descriptions of vertigo include spinning, tilting, and moving sideways.
    • Most cases seen in primary care are due to peripheral vestibular disorders such as BPPV, acute vestibular neuronitis and Ménière's disease, but causes also include central nervous system disorders such as vascular incidents or multiple sclerosis.
  • Presyncope:
    • A feeling of light-headedness, muscular weakness and feeling faint. Features may suggest a specific diagnosis.
    • See the separate Syncope article.
  • Disequilibrium:
    • A sensation of unsteadiness, not localised to the head, that occurs when walking and is relieved with rest.
    • The most common cause of disequilibrium is 'multiple sensory deficits' in elderly patients, who may have deficits with all three balance-preserving senses, ie vestibular, visual and proprioceptive.
  • Nonspecific dizziness:
    • Many patients with dizziness do not have specific features of vertigo, disequilibrium or presyncope.
    • The history is vague beyond a complaint of dizziness and there are no features that would point to causes in one of the other categories.

• However, it has been suggested that many people are unable to describe exactly what they mean in these terms and that it may be more helpful to ask about the timing and triggers involved. For example, asking whether it is:
• Constant or episodic.
• Triggered or spontaneous (eg, triggered by movement, specific events, medication, etc).
• Associated with other symptoms (eg, hearing loss, headache, panic attacks, nausea, vomiting).

• Using this line of questioning helps to guide examination, and narrows down likely diagnoses - for example:
• Where dizziness is episodic and triggered, causes include postural hypotension and BPPV.
• Where dizziness is episodic and not triggered, causes include Ménière's disease, vestibular migraine and anxiety attacks.
• Where dizziness is persistent and not triggered, consider acute vestibular syndrome (AVS). This is defined as the acute onset of persistent dizziness associated with nausea or vomiting, gait instability, nystagmus, and head-motion intolerance lasting days to weeks. The most common cause is vestibular neuritis (dizziness only) or labyrinthitis (dizziness plus hearing loss or tinnitus) The most frequent central cause is posterior circulation ischaemic stroke, generally in the cerebellum or brainstem.

Symptoms

• Actions that provoke symptoms may include:
  • Change in posture (suggests postural hypotension).
  • Movement of the head or neck (suggests vertigo from any cause, cervical spondylosis or vertebral artery syndrome).
  • Feeling anxious (may indicate hyperventilation).
• Associated symptoms may include:
  • Syncope.
  • Features suggestive of epilepsy, which need to be considered.
  • Falls: consider referring to a falls assessment service.
  • Tinnitus or hearing impairment: suggests a vestibular cause.
  • Olfactory hallucinations and amnesia, which may suggest a temporal lobe lesion.
• Consider medication.
• Determine the level of anxiety. It may be present without being the only cause, particularly in older people.
• Consider a possible cardiovascular cause; ask about smoking and any other risk factor for cardiovascular disease.
• Review past medical history.

Examination

The primary aim of the evaluation of a dizzy patient is the detection of any vestibular deficits^[6] . Careful examination is required in order to assess a possible underlying cause - for example:

• Cardiovascular (see also the separate Cardiovascular History and Examination article):
  • Blood pressure: sitting position, and also supine and standing, to assess any significant postural drop suggesting postural hypotension.
  • Aortic murmur (may suggest aortic stenosis and therefore prompt cardiology referral), carotid bruit.
• Eyes (see also the separate Examination of the Eye and Nystagmus articles):
• Visual impairment.
• Nystagmus.
• Ears - looking for infection, herpetic lesions, signs of cholesteatoma.
• Dix-Hallpike test (see the separate Benign Paroxysmal Positional Vertigo article for description of test).
• Neurological (see also the separate Abnormal Gait and Cerebellar Disorders articles):
  • Features of cerebrovascular disease, peripheral neuropathy or Parkinsonism.
  • Examine gait and ask the patient to do heel to toe walking - if these are abnormal, test reflexes and tone in the lower extremities, and test plantar responses. If gait is unsteady, check for peripheral neuropathy.
  • Perform a Romberg's test. (Ask the person to shut their eyes whilst standing - be ready to support if need be.) A positive test suggests a problem with proprioception or vestibular function. It does not help to distinguish between central and peripheral causes.
  • Test co-ordination by asking the patient to put the opposite heel on the knee and to run the foot down and up the shin (assuming the patient is physically able to do this).
  • A three-component bedside oculomotor examination - HINTS (horizontal head impulse test, nystagmus and test of skew) - has been shown to identify stroke with high sensitivity and specificity in patients with AVS and rules out stroke more effectively than early diffusion-weighted MRI^[7] . It differentiates between a central cause such as stroke, and a peripheral cause of AVS, and is described further below.

HINTS test for people with acute vestibular syndrome

• Head Impulse - the person sits upright and is asked to keep their gaze fixed on the examiner. Turn their head about 20-40° to one side and watch their eyes. Normal response (normal peripheral vestibular system, may suggest central pathology) = eyes remain fixed on the examiner. Abnormal response = if eyes are dragged off target by the turning action, and there is a correcting movement (saccade) as the eyes move back to the examiner. (Confusingly, the abnormal response is therefore reassuring as it suggests a peripheral cause not a central one.)
• Nystagmus - the person follows the examiner's finger moved across horizontally:
• Unidirectional horizontal nystagmus which worsens when gazing in the direction of the nystagmus suggests a peripheral cause such as vestibular neuritis.
• Vertical nystagmus, torsional nystagmus or nystagmus which changes direction with gaze is suggestive of a central cause. Centrally caused nystagmus can usually be suppressed by fixing the gaze.
• Test of Skew - ask the person to look straight ahead then cover each eye in turn then uncover it. Vertical deviation/correction after uncovering is suggestive of central pathology such as brainstem stroke.

There are demonstrations available to view on line^[8] .

Investigations

The most useful diagnostic approach in distinguishing different types of dizziness is a thorough history and physical examination and additional tests are rarely necessary^[9] .

However, if the diagnosis is still not obvious, then consider referral to secondary care. Initial investigations may include:

• Urinalysis: to exclude urinary tract infection.
• FBC: anaemia; mean cell volume (MCV) can be elevated with alcohol abuse.
• Renal function, blood glucose, electrolytes, LFTs.
• ECG and ambulatory 24-hour ECG for possible arrhythmia.

Further investigations may include electroencephalography (EEG), CT or MRI brain scan, pure tone audiometry, vestibular function tests (eg, electronystagmography), further cardiology investigations (eg, echocardiogram) or other investigations suggested by the presentation of each individual patient.

However, CT has poor sensitivity in acute stroke, and an MRI scan can miss up to one in five strokes in the posterior fossa in the first 24-48 hours^[7] . Diffusion weighted imaging (DWI) is a commonly performed MRI sequence for evaluation of acute ischaemic stroke, and is more sensitive for small, early and posterior infarcts^[10] . All those with abnormal neurological signs on examination need MRI scan. MRI scanning is also indicated for persisting vertigo, where less common causes such as neoplasms may be picked up.

Management

Management depends on the underlying cause but, in general terms, management includes:

• Thorough discussion with the patient and explanation of the problem and any underlying cause.
• Immediate urgent referral to secondary care if a central cause for acute vestibular syndrome is suspected.
• Evaluation and correction or amelioration of any associated medical problem.
• Medication for symptoms of vertigo and any associated nausea or vomiting. Great care should be given in prescribing, especially to the elderly, in view of potential sedative effects and possible increase in risk of falls. Medication should not be prescribed without a thorough assessment of the underlying cause of the dizziness. Options which may be used include anti-emetics, some of which have vestibulosuppressant effects, such as cinnarizine, cyclizine, prochlorperazine, hyoscine and promethazine. In some cases buccal or rectal administration may be needed if there is significant vomiting.
• Vestibular rehabilitation, including correction of remedial problems, a general fitness programme, specific exercises to make the balance system less sensitive, psychological assessment and realistic family, social and occupational goals.
• Psychological intervention - eg, cognitive behavioural therapy.
• Surgery is rarely indicated but might be required for:
  • Life-threatening complications of chronic middle ear disease - eg, intracranial abscess.
  • Neoplasia involving otological structures - eg, acoustic neuroma.
  • Trauma to the middle or inner ear - eg, a perilymph fistula.