Spontaneous post-orthopedic HIT-like syndrome: A case report and literature review with a diagnostic and therapeutic guidance

Spontaneous heparin-induced thrombocytopenia-like syndrome (spHIT) is a severe thromboembolic complication, most often occurring after total knee arthroplasty. We report an original case and review 25 published cases to propose diagnostic and therapeutic guidance for this challenging condition. A 57-year-old man developed thrombocytopenia and multiple thrombotic events, including pulmonary embolisms, hepatic and renal vein thromboses, as well as bilateral adrenal hemorrhages, starting on postoperative day 7. Despite limited heparin exposure, anti-PF4/heparin antibodies and positive functional assays confirmed spHIT. Clinical deterioration occurred under heparin therapy, with subsequent ischemic stroke. Treatment with intravenous immunoglobulins (IVIG) and non-heparin anticoagulation (argatroban) led to rapid platelet recovery and favorable outcome. Based on this case and literature review, spHIT probability can be assessed using the 4T score, considering surgery day as day 0. Adrenal infarction or hemorrhage after orthopedic surgery should prompt suspicion of spHIT. Early initiation of non-heparin anticoagulation and high-dose IVIG are mandatory.