A Case of Takayasu Arteritis with Thrombotic Microangiopathy Secondary to Malignant Hypertension Due to Bilateral Renal Artery Stenosis

Abstract

A 20 year old woman presented with right arm pain. Pulses of right upper extremity were weak, acute phase reactants were elevated and MR angiography demonstrated total occlusion of subclavian artery and right axillary artery with collaterals. The diagnosis was Takayasu arteritis and she was treated with prednisolone, azathioprine and acetylsalicylic acid. During follow up, azathioprine was switched to methotrexate. Three years later, patient presented with elevated blood pressure. CT angiography demonstrated reduced calibration of the aorta and almost total occlusion of the lumen of proximal parts of left and right renal arteries. C-reactive protein was elevated. Steroid dose was increased, methotrexate was discontinued and IV tocilizumab and antihypertensive medications were initiated. One month later, she presented to emergency department with elevated blood pressure and blurred vision in the left eye. Fundoscopic examination revealed bilateral grade 3 hypertensive retinopathy and serous detachment of retina in the left eye. Laboratory results revealed normal CRP, elevated creatinine, elevated lactate dehydrogenase, thrombocytopenia, low hemoglobin and low haptoglobin. Peripheral blood smear revealed 2-3 schistocytes in every field. She was admitted to rheumatology department with the diagnosis of thrombotic microangiopathy secondary to malignant hypertension. IV tocilizumab was administered, and methylprednisolone was maintained at a dose of 20 mg/day. Despite treatment with maximum dose of six antihypertensive medications, her blood pressure was not controlled adequately and she became hypervolemic. After undergoing ultrafiltration, balloon dilation was performed in the left renal artery, and a stent was placed there. After stent placement, creatinine and platelet count normalized, hemoglobin increased and hypertension was controlled. In this case, malignant hypertension which was triggered by bilateral renal artery stenosis due to Takayasu arteritis had caused acute kidney injury and advanced stage hypertensive retinopathy. In addition, unlike other Takayasu arteritis cases with malignant hypertension, thrombotic microangiopathy was also detected.