Neurologic complications in immune-mediated heparin-induced thrombocytopenia

Objective: To evaluate neurologic complications in patients with immune-med iated heparin-induced thrombocytopenia (HIT) with respect to incidence, cli nical characteristics, outcome, and therapy. Methods: One hundred and twent y consecutive patients with immune-mediated HIT were recruited over a perio d 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 a nd immunologic tests. Results: Eleven of the 120 patients (9.2%) presented with neurologic complications; 7 suffered from ischemic cerebrovascular eve nts, 3 from cerebral venous thrombosis, and 1 had a transient confusional s tate during high-dose heparin administration. Primary intracerebral hemorrh age was not observed. The relative mortality was much higher (Chi-square te st, p < 0.01) in HIT patients with neurologic complications (55%) as compar ed to patients without neurologic complications (11%). The mean platelet co unt nadir in neurologic patients was 38 +/- 25 x 10(9)/l on average, and wa s 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 th ree patients neurologic complications preceded thrombocytopenia. There was a high coincidence of HIT-associated neurologic complications with other HI T-associated arterial or venous thrombotic manifestations. Conclusion: Neur ologic 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.