title: Heparin-induced thrombocytopenia and thrombosis following subarachnoid hemorrhage. Case report.
abstract: The authors present a case of heparin-induced thrombocytopenia and thrombosis (HITT) that occurred after aneurysmal subarachnoid hemorrhage (SAH), and they review the relevant literature. An immune-mediated syndrome, HITT is characterized by moderate thrombocytopenia and paradoxical vascular thromboses. Although it has been estimated in prospective studies that HITT occurs in between 1 and 3% of patients receiving heparin, it is underrecognized in the neurosurgical literature. In the present case, a 49-year-old woman underwent clipping of a right posterior communicating artery aneurysm after suffering a Hunt and Hess Grade III SAH. She had an uncomplicated postoperative course with good clip positioning and no vasospasm observed on a cerebral angiogram obtained on Day 7. On Day 23, the patient developed a right hemiparesis and experienced a grand mal seizure. A head computerized tomography scan revealed a hemorrhagic infarct in the left middle cerebral artery distribution. Repeated cerebral angiograms did not show vasospasm. She was thrombocytopenic (platelet count as low as 46 x 10(9)/L on Day 28 compared with 213 x 10(9)/L on Day 1) and had been receiving heparin flushes to maintain intravenous catheter patency. An assay for HITT-associated antibodies was positive. The heparin flushes were discontinued and the platelet count recovered (121 x 10(9)/L). She improved neurologically, but was left with a significant right hemiparesis at discharge. This patient had assay-proven heparin-induced thrombocytopenia despite minimal exposure to heparin. Because there was no evidence of vasospasm or other factors to account for her delayed hemorrhagic infarction, an HITT-related disorder seemed most likely. Despite a large body of literature describing HITT in nonneurosurgical patients, only three previous neurosurgical cases have been published. This case report may serve to heighten awareness of this disorder.
authors.affiliation: Department of Surgery, University of Alberta, Edmonton, Canada.
authors.forename: I F
authors.initials: IF
authors.lastname: Parney
authors.forename: D E
authors.initials: DE
authors.lastname: Steinke
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000000981:diagnostic imaging; D005260:Female; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000601:surgery*; D020766:Intracranial Embolism / Q000139:chemically induced* / Q000000981:diagnostic imaging; D008875:Middle Aged; D011183:Postoperative Complications / Q000139:chemically induced* / Q000000981:diagnostic imaging; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000601:surgery*; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D000925:Anticoagulants; D006493:Heparin