Bilateral Renal Infarction Revealing Primary Antiphospholipid Syndrome: A Case Report and General Review of Literature

Introduction: Renal infarction is a rare, nonspecific condition that is difficult to diagnose. We report a case of bilateral renal infarction presenting with acute low back pain that revealed primary antiphospholipid syndrome. Case Presentation: A 41-year-old female patient presented to the emergency department with sudden-onset bilateral low back pain radiating to the flanks, without fever, accompanied by chills and vomiting. Her medical history included cryoablation for Bouveret’s disease and current smoking. Laboratory results showed serum creatinine at 93 μmol/l, hemoglobin at 11.5 g/dl, leukocytosis at 22 G/l, platelets at 450 G/l, C-reactive protein at 180 mg/l, LDH at 682 IU/l, and a negative HIV serology test. The CT scan revealed hypodense parenchymal foci in the kidneys (nephritis) and foci of necrosis (absence of enhancement after contrast injection). A diagnosis of acute pyelonephritis was suspected, and the patient was treated with ceftriaxone. Given the negative blood culture and urine culture on day 6, the diagnosis was reoriented toward a bilateral renal infarction in the process of developing. Transthoracic echocardiography and Holter electrocardiogram were normal. The antiprothrombinase-type lupus anticoagulant was positive. The remainder of the immunological workup was normal. Management consisted of administering tinzaparin sodium for 3 months, followed by warfarin, for primary antiphospholipid syndrome. The course of the disease was favorable, marked by resolution of the pain and inflammation. Conclusion: Renal infarction is a rare condition with a polymorphic clinical presentation. It should be considered in any case of acute low back pain that is more or less associated with elevated LDH levels. Even in the absence of a suggestive clinical picture, antiphospholipid syndrome should be investigated.