Cerebrovascularaccident (CVA) also referred as stroke is defined as sudden onset of aneurological deficit that is dogmatic to a focal vascular cause. It can causepermanent neurological damage or death and it is oneof the leading causes of chronic disability and death. The incidence of strokein India is much higher than Western countries. The estimated adjustedprevalence rate of stroke range, 84-262/100,000 in rural and 334-424/100,000 inurban areas. Both sodium and potassiumdisturbances have influences on the outcome of stroke. In neurologicaldisorders like stroke, hyponatremia is commonly faced electrolyte disturbance andcustomarily linked with syndrome of inappropriate secretion of antidiuretichormone (SIADH) and Cerebral salt wasting syndrome (CSWS).
In SIADH,hyponatremia is caused by water retention due to inappropriate secretion ofantidiuretic hormone. Antidiuretic hormone (ADH) is posterior pituitary hormonewhich regulates body water and responds to physiological change like drop inplasma volume or an increase in serum osmolality. In SIADH, there is constant productionof ADH despite the hypotonicity of body fluid. Since because of the expandedeffective circulatory volume, the negative feedback mechanism that supposed tocontrol ADH level fails and ADH continue to be released. CSWS is definedby the development of excessive natriuresis and subsequent hyponatremia,dehydration in patients with intracranial disease.
In CSWS, hyponatremiais characterized by increased urine output, high urinary sodium excretion and bloodvolume depletion. Subarachnoid hemorrhage (SAH) is one the most common cause ofCSWS and other acute CNS disorders such as septic, viral, and herpeticmeningitis have been reported as causes of CSWS. The symptoms owing tohyponatremia manifest with acute and marked reductions in the plasma sodiumconcentration and reflect neurologic dysfunction which is induced by cerebraledema and possibly adaptive responses of brain cells to osmotic swelling. The earlier findingof an altered sodium level might require investigations to find the underlying etiologybefore treatment is initiated.
The onset of hyponatremia and the development ofsymptoms are considered to be important because patients with the most rapidonset are more likely to become symptomatic. A differentiation mustbe made between hypervolemia with normal total body sodium (suggesting SIADH)and hypovolemia with disproportionately low total body sodium (suggestingCSWS). This differentiation is essential because the therapeutics of these two disordersare dissimilar. There is ascarcity of data and only limited studies had been done regarding the electrolytedisturbances in acute stroke, especially from rural population. The objectiveof this study was to estimate the serum sodium levels and to determine the incidenceand etiology of electrolyte disturbances in patients with newly diagnosedcerebro-vascular accidents.