title: Disordered calcium homeostasis of sepsis: association with calcitonin precursors.
abstract: BACKGROUND
  Hypocalcemia and increased serum levels of calcitonin precursors are common in critically ill patients, especially in those with sepsis. We investigated calcium homeostasis in such patients.
  
  
  METHODS
  Serum concentrations of total and ionized calcium and known factors influencing or reflecting calcium homeostasis were measured in 101 consecutive patients of a medical intensive care unit. Calcitonin precursor levels were determined using a highly sensitive radioimmunoassay.
  
  
  RESULTS
  Critical illness per se was associated with decreased serum total and ionized calcium levels, which correlated with the severity of the underlying disease as measured by the APACHE II score. In addition, total and ionized hypocalcemia was more pronounced with increasing severity of infection (P < 0.02), and occurred in parallel with a marked increase of calcitonin precursors (P < 0.001). Mature calcitonin levels, however, remained normal. Changes of serum ionized calcium concentrations from admission to discharge correlated significantly with changes in the serum calcitonin precursor concentration (r2 = - 0.14, P < 0.001). Circulating vitamin D levels, parathyroid hormone levels and other markers reflecting calcium homeostasis did not correlate with the severity of infection.
  
  
  CONCLUSIONS
  In critically ill patients with sepsis, markedly elevated circulating calcitonin precursors might play a role in the development of the pronounced hypocalcemia. The specific calcitonin precursor(s) responsible for this effect and the pathophysiological mechanism remain to be elucidated.
authors.affiliation: University Hospitals, CH-4031 Basel, Switzerland. happymiller@bigfoot.com
authors.forename: B
authors.initials: B
authors.lastname: Müller
authors.forename: K L
authors.initials: KL
authors.lastname: Becker
authors.forename: M
authors.initials: M
authors.lastname: Kränzlin
authors.forename: H
authors.initials: H
authors.lastname: Schächinger
authors.forename: P R
authors.initials: PR
authors.lastname: Huber
authors.forename: E S
authors.initials: ES
authors.lastname: Nylèn
authors.forename: R H
authors.initials: RH
authors.lastname: Snider
authors.forename: J C
authors.initials: JC
authors.lastname: White
authors.forename: H
authors.initials: H
authors.lastname: Schmidt-Gayk
authors.forename: W
authors.initials: W
authors.lastname: Zimmerli
authors.forename: R
authors.initials: R
authors.lastname: Ritz
mesh_terms: D000328:Adult; D000368:Aged; D002116:Calcitonin / Q000097:blood*; D002118:Calcium / Q000097:blood*; D005260:Female; D006706:Homeostasis; D006801:Humans; D006996:Hypocalcemia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011498:Protein Precursors / Q000097:blood*; D018805:Sepsis / Q000097:blood* / Q000503:physiopathology; D014807:Vitamin D / Q000097:blood
chemical_list: D011498:Protein Precursors; D014807:Vitamin D; D002116:Calcitonin; D002118:Calcium