title: [High digoxin serum levels in an elderly patient for the endogenous digoxin-like immunoreactive substances. A case report].
abstract: Digoxin is typically prescribed in the treatment of heart failure. Its limited therapeutic range requires systematic monitoring of plasmatic concentration through immunoreactive tests. Laboratory results, however, can be altered by the presence of digoxin-like immunoreactive factors (DLIF) which are released in all clinical conditions involving volemic expansion.
  
  
  METHODS
  An 86-year-old woman arrived in emergency with severe dyspnoea, atrial flutter and a medical history of ischemic cardiopathy. The patient was treated with ACE inhibitor, furosemide, spironolactone and digoxin. The first lab test for digoxin showed levels of digoxin of 7.05 ng/ml. Although the patient did not show any clinical evidence of digital intoxication nor was she treated with drugs which might interfere with digoxin kinetics and even if she had markers of renal function within clinical limits, digoxin was suspended and a treatment was initiated with 0.9% NaCl solution and furosemide. The second lab test showed levels of digoxin of 8.38 ng/ml. A possible interference of DLIF with immunoreactive tests was therefore assumed.
  
  
  METHODS
  The patient's serum was ultrafiltered and centrifugated to remove possible DLIF; subsequently, the measurement of digoxin levels was repeated. As a result, the digoxin level decreased to 0.25 ng/ml.
  
  
  CONCLUSIONS
  DLIF increase in several diseases, including heart failure, end-stage renal disease, pre-eclampsy and acromegaly. High digoxin levels in a patient who does not show any symptoms of digital intoxication should lead to suspect the presence of these factors and to preventively determine DLIF in serum so as not to incur the risk of suspending an important treatment like digoxin in heart failure.
authors: Dipartimento di Emergenza Accettazione, Azienda Policlinico Umberto I. Università "Sapienza" di Roma, Italia. marianna.suppa@uniroma1.it
authors: M
authors: M
authors: Suppa
authors: G
authors: G
authors: Giancaspro
authors: A
authors: A
authors: Coppola
authors: M
authors: M
authors: Colzi
authors: M E
authors: ME
authors: Marini
authors: E
authors: E
authors: Magnanelli
authors: E
authors: E
authors: Baldini
authors: F
authors: F
authors: Cavicchi
authors: C
authors: C
authors: Petroni
authors: E
authors: E
authors: Contu
authors: C
authors: C
authors: Boccardo
authors: M G
authors: MG
authors: Scarpellini
mesh_terms: D000369:Aged, 80 and over; D002298:Cardenolides / Q000097:blood*; D004077:Digoxin / Q000097:blood* / Q000627:therapeutic use; D016903:Drug Monitoring; D004791:Enzyme Inhibitors / Q000097:blood* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D012503:Saponins / Q000097:blood*
chemical_list: D002298:Cardenolides; D004791:Enzyme Inhibitors; D012503:Saponins; C034504:digoxin-like factors; D004077:Digoxin