Mimic of massive pulmonary embolism: heparin-induced thrombocytopaenia (HIT)-associated anaphylactoid reactions following subcutaneous low molecular weight heparin.

A female in her 60s was admitted via the emergency department following a respiratory collapse at home. She was profoundly hypoxic and hypertensive. For 1 week prior, she had been self-administering subcutaneous (SC) low molecular weight heparin (LMWH) for a small postoperative pulmonary embolism (PE) and reported worsening, self-resolving episodes of breathlessness 1 hour post-injection.