title: Comparison of hyponatremia and SIADH frequency in patients with tick borne encephalitis and meningitis of other origin.
abstract: OBJECTIVE
  The aim of the study was the evaluation of frequency and origin of hyponatremia in tick borne encephalitis (TBE) in comparison to non-TBE viral meningitis and bacterial meningitis.
  
  
  METHODS
  A total of 124 patients aged 18-80 years, with TBE were included to the study. The mild form of TBE was diagnosed in 59 patients, while the severe form was diagnosed in 65 patients. The first control group (VMG) consisted of 72 patients with viral meningitis, but excluded TBE. The second control group (BMG) consisted of 16 patients diagnosed with bacterial meningitis.
  
  
  RESULTS
  Hyponatremia was diagnosed in 55 (44.4%) patients with TBE. In 12 (9.7%) patients (mean age 56.6 ± 19.9 years; 9 men, 3 women) syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was diagnosed. In VMG hyponatremia was diagnosed in 7 (9.7%) patients. In the age group <35 years and in the age group of 50-64 years the frequency of hyponatremia and SIADH was higher in TBE than in VMG (p < 0.05). In BMG hyponatremia was diagnosed in 6 (37.5%) patients. No statistically significant differences in frequency of hyponatremia between BMG and TBE groups were observed.
  
  
  CONCLUSIONS
  (1) Hyponatremia is a common disorder in TBE and is more frequent than in other viral types of meningitis, especially in young patients (< 35 years). (2) The most common cause of hyponatremia in TBE patients is dehydration and fluid supplementation should be a treatment of choice. (3) Overall, 16.9% of the patients with the severe form of TBE develop SIADH syndrome and they required treatment based on fluid restriction and hypertonic saline infusion.
authors.affiliation: a Department of Infectious Diseases and Neuroinfections , Medical University in Białystok , Białystok , Poland ;
authors.forename: Piotr
authors.initials: P
authors.lastname: Czupryna
authors.affiliation: a Department of Infectious Diseases and Neuroinfections , Medical University in Białystok , Białystok , Poland ;
authors.forename: Anna
authors.initials: A
authors.lastname: Moniuszko
authors.affiliation: b Department of Radiology , Medical University in Bialystok , Białystok , Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Garkowski
authors.affiliation: a Department of Infectious Diseases and Neuroinfections , Medical University in Białystok , Białystok , Poland ;
authors.forename: Sławomir
authors.initials: S
authors.lastname: Pancewicz
authors.affiliation: a Department of Infectious Diseases and Neuroinfections , Medical University in Białystok , Białystok , Poland ;
authors.forename: Joanna
authors.initials: J
authors.lastname: Zajkowska
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D004675:Encephalitis, Tick-Borne / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000453:epidemiology / Q000821:virology*; D007177:Inappropriate ADH Syndrome / Q000097:blood / Q000453:epidemiology / Q000821:virology*; D008297:Male; D016920:Meningitis, Bacterial / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D008587:Meningitis, Viral / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D008875:Middle Aged; D055815:Young Adult
keywords: Tick borne encephalitis; bacterial meningitis; hyponatremia; syndrome of inappropriate secretion of antidiuretic hormone; viral meningitis