Immune thrombocytopenia a key piece of the puzzle for the diagnosis of atypical systemic lupus erythematosus in critically ill patients. Case report

Introduction: immune thrombocytopenia (ITP) is an autoimmune disorder characterized by autoantibody-mediated destruction of platelets, resulting in low platelet count and increased risk of bleeding, and may be an initial manifestation of systemic lupus erythematosus (SLE), especially in patients with findings suggestive of autoimmunity.Clinical Case: a 52-year-old male presented with fever, hematuria, generalized petechiae (including mucous membranes), myalgia, mucosal bleeding, oliguria progressive to anuria, and severe arterial hypertension. Initial studies revealed severe anemia, severe thrombocytopenia, and acute kidney injury, which led to his admission to the Intensive Care Unit (ICU). Complementary studies showed positive ANA, low complement (C3, C4), and positive anti-Ro, while anti-dsDNA antibodies, ANCA, and markers of antiphospholipid syndrome were negative. Imaging revealed pulmonary edema with mild alveolar hemorrhage and renal ultrasound findings consistent with active lupus nephritis. These findings raised the possibility that severe thrombocytopenia was a prelude to SLE. After initial treatment refractory, the patient was escalated to rituximab, with a favorable response without complications, which allowed discharge from the ICU.Conclusions: this case highlights the importance of considering SLE in patients with refractory thrombocytopenia without apparent cause, even in men, and underlines the need for a multidisciplinary approach for timely diagnosis and treatment, thus preventing serious complications.