title: A Study of Hyponatremia in Acute Encephalitis Syndrome: A Prospective Study From a Tertiary Care Center in India.
abstract: To evaluate the frequency and causes of hyponatremia in acute encephalitis syndrome (AES) and its effect on outcome.
  Consecutive patients with AES were subjected to neurological evaluation including Glasgow Coma Scale, focal weakness, movement disorder, and reflex changes. The etiology of AES was based on blood and cerebrospinal fluid enzyme-linked immunosorbent assay and polymerase chain reaction. We have categorized patients into neurological or systemic AES. Hyponatremia was diagnosed if 2 consecutive serum sodium levels were below 135 mEq/L, 24 hours apart. Serum and urinary osmolality and electrolytes were measured on alternate days. Fluid intake, output, and body weight were measured daily. The hyponatremia was categorized into syndrome of inappropriate secretion of antidiuretic hormone (SIADH), cerebral salt wasting (CSW), or miscellaneous group. Outcome at 1 month was assessed by modified Rankin scale.
  Of 79 patients, 34 had neurologic AES and 45 had systemic AES; 22 (27.8%) patients had hyponatremia. The neurologic AES as compared to systemic AES was more commonly associated with hyponatremia (38.2% vs 20%, P = .07), need longer hospitalization (25.0 vs 12.5 days, P = .003), and longer time for sodium correction (13.3 vs 8.2 days, P = .05). The hyponatremia was due to CSW in 12 patients, SIADH in 2 patients, and indeterminate in 8 patients. Thirty-six patients had poor outcome (15 died) and 43 had good outcome which was not related to hyponatremia.
  Hyponatremia occurs in one-third of patients with AES, being commoner in neurologic AES, and CSW is the commonest cause.
authors.affiliation: 1 Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Usha Kant
authors.initials: UK
authors.lastname: Misra
authors.affiliation: 1 Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Jayantee
authors.initials: J
authors.lastname: Kalita
authors.affiliation: 1 Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Rajesh Kumar
authors.initials: RK
authors.lastname: Singh
authors.affiliation: 1 Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Sanjeev Kumar
authors.initials: SK
authors.lastname: Bhoi
mesh_terms: D000071072:Acute Febrile Encephalopathy / Q000097:blood / Q000134:cerebrospinal fluid / Q000150:complications*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004573:Electrolytes / Q000032:analysis; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000209:etiology*; D007177:Inappropriate ADH Syndrome / Q000453:epidemiology / Q000209:etiology; D007194:India / Q000453:epidemiology; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012964:Sodium / Q000097:blood; D062606:Tertiary Care Centers; D019282:Wasting Syndrome / Q000453:epidemiology / Q000209:etiology; D055815:Young Adult
chemical_list: D004573:Electrolytes; D012964:Sodium
keywords: SIADH; cerebral salt wasting; encephalitis; encephalopathy; hyponatremia; mortality; outcome