Dizziness is a common but non-specific complaint. The first step is to find out which of four types of dizziness the patient means, because each type has different causes and a different level of urgency.

Types of dizziness

• Vertigo: a false sensation that the person or the surroundings are spinning or moving. It usually comes from the inner ear (vestibular system) and less often from the brainstem or cerebellum (see the article "Vertigo").

• Presyncope: light-headedness or a feeling of being about to faint, caused by reduced blood flow to the brain (for example low blood pressure, dehydration, bleeding or an abnormal heart rhythm).

• Disequilibrium: unsteadiness or loss of balance when standing or walking, without a spinning sensation (for example peripheral neuropathy, cerebellar disease, poor vision or Parkinson disease).

• Non-specific light-headedness: a vague feeling of dizziness that is often linked to anxiety, hyperventilation, depression or medicines.

Pathophysiology

Balance depends on the brain combining information from the inner ear (vestibular system), the eyes and the sensory nerves of the joints and muscles (proprioception). Dizziness occurs when one of these inputs is disturbed, when the brain cannot combine them correctly, or when blood flow to the brain falls.

History and Physical Examination

History

• Ask the patient to describe the feeling in their own words: spinning, about to faint, unsteady on the feet, or vague.

• Onset, duration and pattern: seconds, minutes to hours, or continuous for days; first episode or recurrent.

• Triggers: turning the head or lying down, standing up quickly, exertion, stress or a new medicine.

• Associated symptoms: hearing loss, tinnitus or fullness of the ear; chest pain, palpitations or shortness of breath; headache, double vision, difficulty speaking or swallowing, weakness or numbness; nausea and vomiting.

• Medicines and substances: antihypertensives, diuretics, sedatives, antiepileptics, insulin and oral antidiabetic medicines, aminoglycosides and alcohol.

• Background conditions: diabetes, hypertension, heart disease, anaemia, pregnancy, recent bleeding, diarrhoea or poor oral intake.

Physical Examination

• Vital signs, including blood pressure and pulse while lying down and after 3 minutes of standing. A fall in systolic blood pressure of 20 mmHg or more, or in diastolic blood pressure of 10 mmHg or more, suggests orthostatic hypotension.

• Heart rate, rhythm and murmurs; signs of anaemia, dehydration or bleeding.

• Eyes: nystagmus, its direction and whether it changes with the direction of gaze.

• Neurological examination: speech, cranial nerves, power and sensation of the limbs, coordination (finger–nose and heel–shin tests), gait and the Romberg test.

• Ears and hearing; perform the Dix–Hallpike manoeuvre when the vertigo is triggered by changes in head position.

Investigations

• Random blood glucose in every patient with dizziness.

• Haemoglobin or full blood count.

• ECG when there is presyncope, palpitations, chest pain or known heart disease.

• Pregnancy test in women of reproductive age when relevant.

• Serum electrolytes and renal function when there is dehydration, vomiting, diarrhoea or diuretic use.

• Brain imaging (CT or MRI) when there are neurological signs or red flags.

Red flags: manage as an emergency and refer

• Sudden severe dizziness with headache, double vision, difficulty speaking or swallowing, weakness or numbness of the face or limbs, or inability to stand or walk (possible stroke of the brainstem or cerebellum).

• Dizziness with chest pain, palpitations, shortness of breath or fainting (possible arrhythmia, myocardial infarction or pulmonary embolism).

• Signs of shock, severe bleeding (including gastrointestinal bleeding with black stools) or severe dehydration.

• Hypoglycaemia or very high blood glucose.

• New dizziness after a head injury.

• Dizziness in a pregnant woman, or a woman with a missed period, together with abdominal pain or vaginal bleeding (possible ectopic pregnancy).

Medical causes

• Peripheral vestibular causes: benign paroxysmal positional vertigo (BPPV), vestibular neuritis, labyrinthitis and Ménière's disease (see the article "Peripheral vertigo (Ménière's disease and benign paroxysmal positional vertigo)").

• Central causes: stroke or transient ischaemic attack (TIA) of the brainstem or cerebellum, migraine, multiple sclerosis and tumours of the posterior fossa.

• Cardiovascular causes: orthostatic hypotension, arrhythmias, aortic stenosis, heart failure and vasovagal syncope.

• Metabolic and blood causes: hypoglycaemia, anaemia, dehydration and electrolyte disturbances such as hyponatraemia.

• Infections and fever, for example malaria.

• Medicines, alcohol and other substances.

• Psychological causes: anxiety, panic attacks, hyperventilation and depression.

Management

Treat the underlying cause. Do not routinely give medicines that suppress the vestibular system for dizziness that is not vertigo.

• Red flags: stabilise airway, breathing and circulation, check blood glucose and correct hypoglycaemia, then refer urgently.

• Orthostatic hypotension and dehydration: give fluids, review and adjust blood pressure–lowering medicines, and advise the patient to get up slowly.

• Anaemia, hypoglycaemia, infections and other causes: treat according to the relevant STG article.

• Vertigo: manage according to the articles "Vertigo" and "Peripheral vertigo (Ménière's disease and benign paroxysmal positional vertigo)".

• Medicine-related dizziness: stop, reduce or change the medicine where possible.

Patient counseling

• Sit or lie down immediately when dizziness starts, to avoid falls.

• Get up slowly from lying or sitting.

• Avoid driving, working at heights or operating machines until the dizziness is controlled.

• Drink enough fluids and limit alcohol.

• Return immediately if any red flag symptom appears.

Pediatric pointers

• In children, consider middle ear infection, benign paroxysmal vertigo of childhood (often linked to migraine), head injury, dehydration, hypoglycaemia and anaemia.

• Young children may not be able to describe dizziness; instead they may become clumsy, fall often, refuse to walk or hold on to objects.