Diagnostic challenges in a young patient with antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune disorder that can affect several systems, characterized by arte-rial, venous, or small vessel thromboembolic events caused by antiphospholipid antibodies. It often occurs as a primary event and may be secondary to systemic lupus erythematosus or another autoimmune disease. Occasionally, it may pres-ent with an acute and severe condition with multiple thromboses, which is called catastrophic APS. The authors present the case of a 24-year-old man, who went to an emergency department of complaining of pain in the right flank, fever, nausea, and vomiting. During the first night he developed a sudden onset of dysarthria and left upper limb paresis (with complete recover in about 6 hours). The initial workup revealed leukocytosis (18,000x109/L) and C-reactive protein of 190 mg/L, creatinine 1.3 mg/dL, urinary sediment with 1-5 white blood cells per high-power field. An abdominal com-puted tomography (CT) scan revealed two foci of hypodensity in the right kidney suggestive of renal infarction with pos-sible focus of pyelonephritis. Brain CT that excluded ischemic or hemorrhagic lesions. Thoracoabdominal CT excluded pulmonary embolism and showed airspace condensation, cotton wool micronodular pattern in the lower lobes (especially the right) with ground glass densification. Prothrombotic study revealed a positive lupus anticoagulant (LA). He was transferred to the pulmonology department of our hospital and started ceftriaxone and pulses of methylprednisolone. Bronchoscopy showed no macroscopic abnormalities and the cultures of bronchial lavage and bronchoalveolar lavage were negative. He was transferred to the Department OF Internal Medicine to further study. Due to high suspicion of APS, therapeutic dose of enoxaparin was started and subsequently switched to warfarin. An autoimmune study (ANA, DsDNA, ENA, ANCA and anti-MBG), extended prothrombotic study were negative. A transthoracic and transesophageal echocardiogram and brain MRI were normal. There was clinical, analytical, and radiological resolution of the alterations presented. At 12 weeks LA was positive, establishing the diagnosis of APS. He is medicated with warfarin with controlled INR, without thrombotic or hemorrhagic events, after 3 years of follow-up.