title: Critical illness with hyponatraemia and impaired cell membrane integrity--the "sick cell syndrome" revisited.
abstract: OBJECTIVE
  To determine whether impaired cell membrane permeability exists in critically ill patients with "sick cell" type hyponatraemia.
  
  
  METHODS
  A 36 year old male patient was identified in an intensive care unit (ICU) with liver disease and multi-organ failure. His initial serum sodium (Na) was 101 mmol/L and osmolar gap + 35 mmol/L. A flow cytometric system was used to assess lymphocyte membrane integrity using fluorescein diacetate (FDA) and propidium iodide (PI). Following this, similar studies were carried out in 17 hyponatraemic (Na < 130 mmol/L) and 19 normonatraemic (Na > 136 mmol/L) ICU patients.
  
  
  RESULTS
  Flow cytometry in the index patient showed two clear populations of cells-one was normal (with identical characteristics to a healthy control) and the other had dysfunctional cell membrane integrity. The extended patient series, however, revealed only 2 other patients with similar flow cytometric patterns-one hyponatraemic and one normonatraemic.
  
  
  CONCLUSIONS
  Cell membrane studies in the index patient demonstrated supportive evidence for the "sick cell syndrome" in critically ill patients. The extended series revealed that 3/37 (8%) had this abnormality, which was however not consistently associated with hyponatraemia.
authors.affiliation: Department of Medicine, University Hospital Aintree, Liverpool L9 1AL, UK. g.gill@liv.ac.uk
authors.forename: Geoffrey V
authors.initials: GV
authors.lastname: Gill
authors.forename: Jacqueline C
authors.initials: JC
authors.lastname: Osypiw
authors.forename: Euan
authors.initials: E
authors.lastname: Shearer
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: English
authors.forename: Ian D
authors.initials: ID
authors.lastname: Watson
mesh_terms: D000328:Adult; D000368:Aged; D002463:Cell Membrane Permeability; D016638:Critical Illness; D017809:Fatal Outcome; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007010:Hyponatremia / Q000209:etiology*; D008107:Liver Diseases / Q000503:physiopathology; D008214:Lymphocytes / Q000166:cytology; D008297:Male; D009102:Multiple Organ Failure / Q000503:physiopathology; D014883:Water-Electrolyte Imbalance / Q000503:physiopathology