Shake it off: A curious case of rigors

Heparin-induced Anaphylactoid reactions are rare systemic reactions to heparin exposure. Although the exact pathogenesis of the reaction is unclear, in vivo platelet activation from inflammation may play a role. The reaction involves anti-platelet factor 4, a common factor also noted to be involved in heparin-induced thrombocytopenia (HIT). Like HIT, prompt identification of the reaction, immediate discontinuation of heparin, and supportive care are the mainstays of treatment to avoid severe and potentially fatal outcomes. Previous cases have described heparin-induced anaphylactoid reactions in the setting of heparin-induced thrombocytopenia. However, we will present a case of an isolated heparin-induced anaphylactoid reaction without HIT.