Any condition that affects the vestibular apparatus, the vestibule cochlear nerve or the areas of the brain processing these signals may lead to vertigo. Benign paroxysmal positional vertigo (BPPV) is one of the commoner causes
Dizziness is a fairly common and quite disturbing complaint. Dizziness is a relatively vague term covering a variety of sensations including feeling of weakness, unsteadiness or imbalance, fainting or a sensation of spinning around. When someone complains of dizziness what is really meant needs to be understood because the implications of these various types of dizziness are different. A sensation of spinning around is quite specific and is called vertigo. When by fainting the reference is to a momentary loss of consciousness two important possibilities need consideration. Syncope is the term used for momentary loss of consciousness due to blood supply to the brain being transiently disturbed or interrupted. Syncope may be due to minor problems such as the sight of blood or a severe emotional disturbance. This is usually due to a vasovagal attack which causes a transient circulatory collapse because of pooling of blood in the lower limbs. This type of attack almost always occurs when one is standing. As one sinks to the ground circulation to the brain is restored and unless one has hurt oneself during the fall there are no aftereffects. Syncope due to other causes such as a transiently abnormal heart rhythm preventing adequate blood supply from reaching the brain may be much more ominous. The other important cause of transient loss of consciousness is epilepsy which is also known as seizures or fits. Epilepsy is a neurological disorder due to abnormal electrical discharge in the brain and may cause symptoms such as transient loss of consciousness, twitching of part of the body, sensory symptoms, etc. Vaguer symptoms such as generalized fatigue, light headedness and even breathlessness may also be referred to as dizziness and may be due to a wide variety of causes. Thus, a clear understanding of what is being experienced by the patient is essential to be able to clarify the cause and provide relief.
Vertigo is a fairly specific term used for a spinning sensation. The complaint may be that the surrounding are spinning or that the head is spinning but both have the same significance. Our brain is able to know the position of our body with respect to surroundings by means of data received from three different sources. Visual information is received from the eyes. Proprioceptive receptors located in muscles, tendons and joints provide information about the position of the body with respect to the ground and other surroundings. Lastly, the vestibular apparatus located in the inner ears provides information about motion, equilibrium and spatial orientation. The utricle and saccule which are components of this apparatus perceive gravity and movement in a linear plane. There are three semicircular canals placed at right angles to each other which detect rotational movement. These canals contain a fluid called endolymph and with rotational movements there is a slight lag in the movement of the fluid which allows perception of this type of movement. Normally the brain receives identical information from the eyes, proprio-ceptor receptors and the vestibular system. Should there be a conflict in the information received from these sources vertigo is the result. Also, disturbance of the vestibular system, the vestibular nerve conveying information to the brain and the parts of the brain processing these signals results in vertigo. The vestibular apparatus is located in the inner ear in close proximity to the cochlea which senses sound. Nerve fibres conveying information from the cochlea and the vestibular apparatus to the brain travel together in the vestibule-cochlear nerve. This makes it very common for people suffering vertigo due to a vestibular problem to also have auditory symptoms such as tinnitus and deafness. Tinnitus is the perception of sounds, usually ringing or buzzing, which are actually not present. Vertigo also causes other unpleasant symptoms such as unsteadiness and fall, sweating, nausea and vomiting. Not all people are able to appreciate the spinning sensation that is vertigo and they may only complain that they are feeling a little unsteady or having problems in maintaining balance.
Any condition that affects the vestibular apparatus, the vestibule cochlear nerve or the areas of the brain processing these signals may lead to vertigo. Benign paroxysmal positional vertigo (BPPV) is one of the commoner causes. BPPV occurs due to development of calcium particles in the semicircular canals of the vestibular apparatus. Vertigo lasting a few seconds occurs shortly after moving the head in a particular direction depending on the location of the calcium particles in a specific semicircular canal. Symptoms often start suddenly and usually subside in a few days but may recur from time to time. In some affected individuals symptoms may be much more persistent. A wait and watch policy with medicines to suppress vertigo may be all that is required since symptoms resolve spontaneously in a few days in most patients. When persistent or recurrent symptoms are troublesome a manoeuvre to reposition the calcium particles may be tried out. This involves positioning the head to a particular position based on the projected position of the calcium particles within the semicircular canals. This manoeuvre can be carried out by a doctor trained in this procedure in a clinic setting. It achieves a fairly good success rate. In unresponsive cases with debilitating symptoms surgery may have to be resorted to.
Meniere’s disease is another important cause of vertigo. Accumulation of fluid within the semicircular canals causing increased hydrostatic pressure within them is believed to be the underlying mechanism. Symptoms include sudden onset of vertigo, tinnitus, hearing loss and a feeling of fullness in the ears. These symptoms occur in an unpredictable relapsing and remitting manner ranging from every few weeks to a gap of months. Individual episodes usually subside in a few hours. Some degree of deafness tends to persist after each episode and generally increases in subsequent episodes. In later stages acute episodes no longer occur but the patient may be left with substantial deafness and unsteadiness. In some people with Meniere’s symptoms a specific cause such as trauma, infection or hormonal disorder can be identified as causing the buildup of fluid in the semicircular canals. In the majority no underlying cause is identifiable. Supportive medicines to suppress vertigo and prevent or correct dehydration are required in acute attacks. Also, medicines such as diuretics to reduce hydrostatic pressure within semicircular canals and steroids to reduce inflammation may be indicated. Use of substances such as salt, caffeine, nicotine and chocolate which may trigger acute episodes may need to be controlled. More aggressive measures may need to be adopted in severe recurrent disease. If only one ear is involved the affected inner ear can be destroyed surgically or by injecting appropriate drugs into it. Surgical procedures to salvage the affected ear and prevent pressure buildup in the semicircular canals may also be attempted but results are somewhat erratic. Meniere’s disease is a difficult problem with largely unsatisfactory response in severe cases.
When symptoms are of light headedness rather than of a spinning sensation systemic causes need consideration. This is a fairly nonspecific symptom and could just denote anxiety, fear or fatigue or be from exposure to inclement atmospheric conditions like severe heat or severe cold. Systemic problems such as anaemia and hypoglycaemia could also be responsible. Hypoglycaemia is the medical term for low blood glucose. It may be due to inadequate intake of food as during a fast but in clinical practice the usual cause is diabetes medicines, either an overdose or activities such as missing a meal or undertaking unusual exercise which may both lower blood glucose levels, sometimes quite markedly. Mild to moderate hypoglycaemia may cause dizziness along with palpitations, sweating and tremors. Reduced alertness and confusion may cause problems in operation of machinery including vehicles. Severe hypoglycaemia causes altered level of consciousness including coma and is a medical emergency. Treatment of hypoglycaemia depends on its severity. Intravenous glucose is essential for severe cases while milder cases can be managed by glucagon injection, oral glucose or other sugar feeds. Also, patient education and rationalization of diabetes medicine dosage is vital to prevent recurrence. Anaemia may cause dizziness but usually only when it is severe. Symptoms are usually brought on by standing up suddenly or by exertion. Mild anaemia is more likely to cause fatigue and affect effort tolerance rather than cause dizziness. Rapidly evolving anaemia is more likely to cause dizziness because the circulatory system lags in implementing compensatory mechanisms. Any other signiicant systemic problem such as high fever and dehydration may also cause dizziness. Dizziness is thus a symptom which needs careful consideration with signiicance varying from the trivial to denoting a major catastrophe.