Introduction to Dizziness Unsteadiness & Vertigo

Dizziness: Vertigo Unsteadiness Lightheadedness

Dizziness is a common problem. The experience of dizziness can be difficult to describe. Patients use many different words such as dizziness, giddiness, unsteadiness, imbalance, spinning, light-headedness etc. Broadly dizziness can be split into a number of types:

  • Vertigo: a sensation of spinning or movement. Often the word dizziness is used to describe this type of sensation. There is no loss of consciousness. This is often due to a problem in the vestibular system (in the inner ear, nerve to the inner ear and/or part of the brain involved in balance).
  • Unsteadiness/imbalance: a sensation of rocking from side to side or veering off to the side often when walking.The causes of this are more varied but can include inner ear problems.
  • Light-headedness or fainting: sensation one experiences if the blood pressure drops. This can progress to loss of consciousness. Generally this is not due to inner ear problems.

Other types of descriptions may include: “spaced out feeling” or “out of body experience”.

In many the problem is short lasting and the patient does not seek any medical attention. In some cases, however, the problem can be longer lasting and disabling. Dizziness/imbalance, particularly those due to inner ear problems, usually do eventually resolve spontaneously. Some types of dizziness/light headiness can be due to more serious problems such as an irregular heartbeat or low blood pressure. In order to determine if the problem is serious, doctors will assess patients using a combination of history taking (the story of the dizziness), examination and if required special investigations. The appropriate management/treatment can then be instituted. In some cases, particularly if the problem is improving nothing but reassurance is required. In other cases, specific treatments may be required. In a number of cases the exact cause of dizziness cannot be determined with certainty.

Control of balance and eye movements

To allow a person to maintain their balance a number of sensory structures must be intact and working correctly. The sensations involved in balance include the inner ear, vision and proprioception (signals from joints and skin). The brain integrates the signals from these 3 senses and sends signals to the muscles to control body movement. In addition signals from the inner ear and vision help control eye movements allowing a person to keep their vision on a target while their head is moving. Signals from these senses also provide a person with a sense of orientation in space.

Causes of dizziness

Inner ear

The inner ear is involved in detection of movement and gravity. This information is sent from each inner ear to the brain and integrated with information from the eyes and proprioception (sensation from joints and skin) to provide the sensory information for the brain. Using this information the brain can control movements of the eyes and body. This allows a person to keep their balance and to allow them to keep their eyes on a target whilst moving ahead. In addition the information allows patients to maintain a sense of orientation in space. Even at rest the inner ear on each side provides a steady signal to the brain. If the inner ear is working abnormally either sending too few signals or too many signals, a disturbance can occur causing it to be perceived as dizziness. The mismatch between the information coming from one ear that is malfunctioning and the remaining normal senses can cause disturbance in balance, eye movement and nausea/vomiting. Often the dizziness in this scenario is described as spinning (medical term: vertigo) or movement. If the inner ear malfunction is permanent/long-term, the brain eventually adjusts for the problem through a process called compensation. To allow compensation a patient will need to use their inner ear i.e. remain active and move their head. Certain types of exercise can help this compensation.

Common causes of dizziness due to inner ear problems include:
Brain, Spine and Nerve Disorders causing dizziness.

There are potentially dozens of different types of brain related disorders which could cause dizziness. In some cases there will be evidence that the problem is not an isolated ear problem. For example there may be headaches, blurred vision, numbness or tingling in the hands or feet. Some of the conditions affecting the brain which may be accompanied by ear symptoms are described below.

Migraine

Migraine (e.g. migraine associated vertigo or vestibular migraine). This is considered a brain related problem. During migraine the senses can become heightened including sense of balance making patients vulnerable to dizziness especially when they move. Some patient also develop headaches. This is a common condition. Although I have only dedicated a part of this page to migraine my experience of patient with troublesome recurrent dizziness which has been difficult to treat is that most are probably suffering from an atypical type of migraine. Unfortunately Migraine is not a condition which has been clearly worked out. The cause and mechanisms involved are not clear. There is no proven test. The diagnosis of migraine therefore relies on a checklist of symptoms. If you meet the criteria for another condition such as Meniere’s disease then things become confused. My own opinion is that Migraine, Menieres’s and a number of other condition (e.g. TMJ dysfunction and even IBS) are all manifestations of a condition which has not yet been defined. I use terms such as Migraine Spectrum Disorder.

Although most people think of Migraine as a cause of headache (and this is often the case) some patient with Migraine have no headaches. This is officially recognised. Most patient with Migraine headaches and dizziness do not have their dizziness at the same time as the headaches. I suspect this is due to a different mechanism in the migraine process causing the pain and the dizziness. Many patient with Migraine are also more sensitive to various stimuli even between their attacks of headaches. The pain of a migraine can be mild and may be in more varied places e.g. in the ear, neck, face.

My belief is that some people are genetically predisposed to this. Often some of the patient’s relatives will have a history of Migraine, Headaches, “Sinus” pain, neck pain, IBS, TMJ dysfunction, dizziness, Meniere’s disease etc. There is also a higher rate of asthma/allergy. This is, I suspect due to the inflammatory system (which can become active in migraine) having a lower threshold to activation and more severe response making the person more likely to have problems. Sometime a viral infection or trauma (physical or psychological) can activate a chronic activation of the sensory system. If this involves the nerves to the ear then patient can develop dizziness.

If my theory that Migraine and Meniere’s Disease (and possibly some other causes of dizziness) are all part of one condition is true then it needs to explain why some patient with Meniere’s Disease develop permanent inner damage and hearing loss. Migraine typically is not supposed to cause permanent damage. This is not, I believe, true. It is well know that patient with migraine do have more “white matter lesion” in the brain. This is picked up on MRI scans. These white matter lesion represent some damage possibly related to vascular or inflammatory effects of migraine. This process, I believe can also effect the inner ear causing damage which may be reversible or permanent. Although my theory is only a theory I have noted that other specialist have also consider the possibility that Migraine and Meniere’s Disease are related (see here, here and here). I also believe that many cases of Vestibular Neurontis and even BPPV can be precipitated by an episode of migraine (with some contribution from viral infections as a co-stressor).

Brain tumours

Although patients are often worried about the possibility of this, brain tumours causing dizziness without other problems are rare. Any tumour sufficiently large may press on part of the brain involved in balance and cause dizziness. Generally this type of problem would cause constant dizziness and unsteadiness. There may be disturbance of vision (double vision) and headaches which are worse in the morning. One particular type of brain tumour called a vestibular schwannoma also known as an acoustic neuroma develops on the balance nerve to the inner ear. It is a benign type of tumour. This means it does not spread to other areas of the body. It is generally very slow growing. It usually causes hearing loss and tinnitus with only mild or no dizziness.

Idiopathic intracranial hypertension

This condition generally affects young women who are overweight. The symptoms typically include dizziness, pulsatile tinnitus (a pulse-like noise in the ears), headaches and possibly visual disturbance. The cause of the condition is not known with certainty. There is increased pressure in the fluids around the brain causing the problems. If left untreated in some cases this may cause pressure on the nerve to the eye causing visual problems.

Multiple sclerosis (MS)

This is a condition causing damage to the nervous tissue within the brain. MS can cause dizziness. The problem can fluctuate. It often causes other problems such as visual problems, numbness or tingling or problems passing urine.
Stroke. Stroke occurs when blood flow to the brain is insufficient. This can lead to damage to nervous tissue. A stroke can cause many different types of symptoms: weakness in the arm, legs or face, numbness, slurred speech or visual loss. Some types of stroke can affect the bottom part of the brain where the balance function occurs. This can lead to dizziness/unsteadiness. Usually there are other clues that the problem is due to a stroke rather than an inner ear problem.

Epilepsy

Dizziness is not a common feature of epilepsy. Most cases of epilepsy are fairly clear if associated with seizures which cause shaking (tonic clonic seizures). Occasionally epilepsy can be associated with a period of altered consciousness which does not result in the patient falling or collapsing. Generally however the patient is not aware of what has happened. This is unusual in dizziness due to the inner ear.

Spinal cord problems

If the spinal-cord is working incorrectly nerve signals going to or from the brain to the muscles and joints respectively do not reach their destination. This can lead to unsteadiness/imbalance (Generally not described by patients as dizziness). Examples of problems include a slipped disc in the back or neck pressing onto the spinal cord or Vitamin B12 deficiency (for example due to pernicious anaemia).

Neuropathy

Sometimes the nerves supplying sensation to the legs, ankle and feet are not working correctly. This can for example happen in patients with diabetes or due to side effect of certain drugs. This causes reduced sensation and information for the brain to work out where your legs are. This can contribute to imbalance/unsteadiness.

Cardiovascular system

If the blood pressure drops this causes disturbance of brain function and can result in dizziness or even loss of consciousness (this usually called faint or by the medical term syncope or pre-syncope). Blood pressure can drop if for example there is an irregular heartbeat (arrhythmia). If the heart is beating irregularly its function can be impaired resulting in a drop in blood pressure. If the irregular heartbeat is such that blood pressure drops significantly there may be a period of loss of consciousness/fall. Other causes of drop in blood pressure may include orthostatic hypotension In this condition the blood pressure drops often as the patient stands up. It can occur in patients on blood pressure tablets. Generally the problem only occurs on standing. This can be assessed with blood pressure measurement while lying and standing. In some patients particularly young women there appears to be a tendency to have low blood pressure which can cause dizziness.

There is evidence that on rare occasions some types of migraine can be associated with periods of loss of consciousness/syncope/faint.

Other causes

Metabolic conditions including anaemia, disturbance in salts in the blood and abnormal hormone levels (e.g. abnormal thyroid function) can cause dizziness. These conditions tend to cause fairly persistent dizziness or tiredness.

Vision contributes a large proportion of information required for balance, movement and sense of orientation. Any conditions where the vision is affected can potentially contribute to dizziness/imbalance.

Arthritis/joint problems and muscle problems can contribute to a state of imbalance/unsteadiness.

Psychological problems such as anxiety, hyperventilation and panic disorder can also cause dizziness.