Spontaneous HIT syndrome clinically/serologically resembles HIT but without proximate heparin. Rarely, spontaneous HIT syndrome complicates total knee arthroplasty surgery. Mesenteric vein thrombosis is a rare presentation of spontaneous HIT syndrome. IVIg rapidly corrects thrombocytopenia by inhibiting heparin‐independent platelet activation. Summary Spontaneous heparin‐induced thrombocytopenia (HIT) syndrome is an autoimmune HIT (aHIT) disorder characterized by thrombocytopenia, thrombosis, and HIT antibodies despite no proximate heparin exposure. For unknown reasons, many cases occur after total knee arthroplasty. A 52‐year‐old woman presented 12 days posttotal knee replacement (aspirin thromboprophylaxis) with gastrointestinal bleeding (superior mesenteric vein thrombosis); the platelet count was 63 × 109 L−1. After bowel resection and a brief course of heparin, treatment was changed to argatroban followed by fondaparinux. In addition, high‐dose intravenous immunoglobulin (IVIg), 1 g kg−1 on 2 consecutive days, resulted in abrupt platelet count rise from 21 (nadir) pre‐IVIg to 137 (post‐IVIg), and 2 days later to 200 × 109 L−1. Heparin‐independent serum‐induced serotonin‐release abruptly decreased from 91% (pre‐IVIg) to 14% (post‐IVIg); although serotonin‐release later rebounded to 49%, the patient's platelet counts remained normal. Our observations support the emerging concept that high‐dose IVIg is effective for treating aHIT disorders, including spontaneous HIT syndrome.

Statin-associated necrotizing myopathy is a symmetric proximal muscle weakness associated with extreme elevations of CK. It is common in males and can occur after months of statin use. It is associated with necrosis on muscle biopsy and the presence of anti-HMG-CoA reductase antibodies. It usually requires discontinuation and immune suppression for resolution. Rechallenge with statin is unsuccessful in most cases.

Hypercalcemia from cosmetic injections can be severe and life threatening and can present years after the initial procedure. Cosmetic injection-associated granuloma should be considered a cause of hypercalcemia, especially in middle-aged females presenting with non-PTH-mediated, non-malignant hypercalcemia, which is often associated with elevated calcitriol; however, it should be noted that calcitriol level may be normal as well.

APS should be considered in young patients with AMI, especially if previous unprovoked thromboses, lower platelet counts, high partial thromboplastin times, and normal coronary arteries or coronary thromboses are identified.

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