DIZZI­NESS

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

The Gulf Today - Time Out - - TRAVEL - Dr Asheesh Me­hta In­ter­nal Medicine Spe­cial­ist

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.

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