title: Multiple electrolyte disorders in a neurosurgical patient: solving the rebus.
abstract: BACKGROUND
  It is important to ensure an adequate sodium and volume balance in neurosurgical patients in order to avoid the worsening of brain injury.Indeed, hyponatremia and polyuria, that are frequent in this patient population, are potentially harmful, especially if not promptly recognized.Differential diagnosis is often challenging, including disorders, which, in view of similar clinical pictures, present very different pathophysiological bases, such as syndrome of inappropriate antidiuresis, cerebral/renal salt wasting syndrome and diabetes insipidus.
  
  
  METHODS
  Here we present the clinical report of a 67-year-old man with a recent episode of acute subarachnoid haemorrhage, admitted to our ward because of severe hyponatremia, hypokalemia and huge polyuria.We performed a complete workup to identify the underlying causes of these alterations and found a complex picture of salt wasting syndrome associated to primary polydipsia. The appropriate diagnosis allowed us to correct the patient hydro-electrolyte balance.
  
  
  CONCLUSIONS
  The comprehension of the pathophysiological mechanisms is essential to adequately recognize and treat hydro-electrolyte disorders, also solving the most complex clinical problems.
authors.affiliation: Unit of Nephrology, Dialysis and Transplantation, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Piazzale Golgi 19, 27100 Pavia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Corradetti
authors.forename: Pasquale
authors.initials: P
authors.lastname: Esposito
authors.forename: Teresa
authors.initials: T
authors.lastname: Rampino
authors.forename: Marilena
authors.initials: M
authors.lastname: Gregorini
authors.forename: Carmelo
authors.initials: C
authors.lastname: Libetta
authors.forename: Francesca
authors.initials: F
authors.lastname: Bosio
authors.forename: Teresa
authors.initials: T
authors.lastname: Valsania
authors.forename: Eleonora Francesca
authors.initials: EF
authors.lastname: Pattonieri
authors.forename: Chiara
authors.initials: C
authors.lastname: Rocca
authors.forename: Stefania
authors.initials: S
authors.lastname: Bianzina
authors.forename: Antonio
authors.initials: A
authors.lastname: Dal Canton
mesh_terms: D000368:Aged; D006801:Humans; D007008:Hypokalemia / Q000150:complications / Q000175:diagnosis; D007010:Hyponatremia / Q000150:complications / Q000175:diagnosis; D008297:Male; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D059606:Polydipsia / Q000150:complications / Q000175:diagnosis; D011141:Polyuria / Q000150:complications / Q000175:diagnosis*; D014883:Water-Electrolyte Imbalance / Q000150:complications / Q000175:diagnosis*