Renal Manifestation of Mixed Connective Tissue Disease

A young female presented with facial puffiness and swelling in both lower limbs for 3 months, distension of the abdomen, and breathlessness on exertion for 1 month with a history of hypertension and hypothyroid on regular treatment. On general physical examination, there were pallor, bilateral pitting edema, tachycardia, and blood pressure of 190/100 mmHg. Abdominal examination revealed shifting dullness. Respiratory and cardiovascular systems were normal. Fundoscopy revealed Grade 1 papilledema, and the rest of the neurological examination was unremarkable. Investigations showed normocytic normochromic anemia, serum creatinine of 1.6 mg/dl, and hypoalbuminemia; urine R/E showed significant proteinuria; and anti-U1 ribonucleoprotein particle antibodies were positive. Two-dimensional echocardiography showed mild concentric left ventricular hypertrophy and mild pericardial effusion. Ultrasonography abdomen showed bilateral renal parenchymal disease and moderate ascites. Renal biopsy revealed diffuse proliferative glomerulonephritis and lupus nephritis Class IV. Renal manifestation is very rare in mixed connective tissue disease as an initial presentation