title: Neurologic complications in immune-mediated heparin-induced thrombocytopenia.
abstract: OBJECTIVE
  To evaluate neurologic complications in patients with immune-mediated heparin-induced thrombocytopenia (HIT) with respect to incidence, clinical characteristics, outcome, and therapy.
  
  
  METHODS
  One hundred and twenty consecutive patients with immune-mediated HIT were recruited over a period of 11 years and studied retrospectively for the occurrence of neurologic complications. Diagnosis of HIT was based on established clinical criteria and confirmed by detection of heparin-induced antibodies using functional and immunologic tests.
  
  
  RESULTS
  Eleven of the 120 patients (9.2%) presented with neurologic complications; 7 suffered from ischemic cerebrovascular events, 3 from cerebral venous thrombosis, and 1 had a transient confusional state during high-dose heparin administration. Primary intracerebral hemorrhage was not observed. The relative mortality was much higher (Chi-square test, p < 0.01) in HIT patients with neurologic complications (55%) as compared to patients without neurologic complications (11%). The mean platelet count nadir in neurologic patients was 38 +/- 25 x 10(9)/l on average, and was lower in patients with fatal outcome compared to those who survived (21 +/- 13 x 10(9)/l versus 58 +/- 21 x 10(9)/l; p < 0.05, Wilcoxon test). In three patients neurologic complications preceded thrombocytopenia. There was a high coincidence of HIT-associated neurologic complications with other HIT-associated arterial or venous thrombotic manifestations.
  
  
  CONCLUSIONS
  Neurologic complications in HIT are relatively rare, but associated with a high comorbidity and mortality. HIT-associated neurologic complications include cerebrovascular ischemia and cerebral venous thrombosis. They may occur at a normal platelet count.
authors.affiliation: Department of Neurology, Rheinische Friedrich Wilhelms Universität, Bonn, Germany. c.pohl@uni-Bonn.de
authors.forename: C
authors.initials: C
authors.lastname: Pohl
authors.forename: U
authors.initials: U
authors.lastname: Harbrecht
authors.forename: A
authors.initials: A
authors.lastname: Greinacher
authors.forename: I
authors.initials: I
authors.lastname: Theuerkauf
authors.forename: R
authors.initials: R
authors.lastname: Biniek
authors.forename: P
authors.initials: P
authors.lastname: Hanfland
authors.forename: T
authors.initials: T
authors.lastname: Klockgether
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D009422:Nervous System Diseases / Q000150:complications*; D010976:Platelet Count; D011379:Prognosis; D013921:Thrombocytopenia / Q000097:blood / Q000150:complications* / Q000276:immunology*; D013997:Time Factors
chemical_list: D006493:Heparin