Heparin-induced anaphylactoid reaction associated with heparin-induced thrombocytopenia in the ED.

: Although rare, heparin-induced anaphylactic and anaphylactoid reactions have been previously described in the literature. We present a case of a patient who presented to the emergency department with dyspnea and was subsequently diagnosed with an acute pulmonary venous thromboembolism. Shortly after being started on intravenous unfractionated heparin, she developed sudden cardiovascular collapse leading to a cardiopulmonary arrest. She was successfully resuscitated and, after further diagnostic evaluation, was found to have developed a heparin-induced anaphylactoid reaction.