ODP500 Nephrotic syndrome as a cause of worsening hypothyroidism due to Hashimoto's thyroiditis

BACKGROUND: Thyroid function has been reported to worsen when urinary protein levels increase from the loss of protein-bound thyroid hormones, such as thyroxine-binding globulin, transthyretin, and albumin, into the urine. In patients with previously undiagnosed Hashimoto's thyroiditis, subclinical hypothyroidism and overt hypothyroidism might develop at the onset of nephrotic syndrome. Here, we present an interesting case of Hashimoto's thyroiditis aggravated by newly developed nephrotic syndrome. Clinical case: A 43-year-old woman with no known underlying disease presented with generalized edema and weight gain of 5 kgs over 2 months. Physical examination revealed slightly enlarged thyroid goiter and pitting pedal edema. Thyroid function tests revealed hypothyroidism (FT4 0.71 ng/dL; reference range 0.93-1.70 ng/dL, TSH 8.32 uIU/mL; reference range 0.27-4.20 uIU/mL). Anti-thyroid peroxidase was negative but anti-thyroglobulin was positive. Thyroid ultrasound showed diffused heterogeneous parenchymal echotexture at both thyroid lobes, compatible with Hashimoto's thyroiditis. Subsequent investigations showed nephrotic range proteinuria (urine protein/creatinine ratio 7.5 grams), low serum albumin 2. 0 g/dL, and hypercholesterolemia 421 mg/dL. Viral infections including HIV, hepatitis B and C were negative. Kidney biopsy showed the presence of subepithelial immunoglobulin-containing deposits along the glomerular basement membrane, confirming membranous glomerulonephritis as a cause of nephrotic syndrome. Further investigations did not show potential secondary causes of membranous glomerulonephritis. Oral prednisolone and cyclosporin was given to treat nephrotic syndrome and levothyroxine 350 µg/week was initiated to treat hypothyroidism. Over the next 6 months, nephrotic syndrome went into remission and thyroid function tests showed stabilization. During a 3-year follow-up period, patient is still in stable condition with levothyroxine 450 µg/week. CONCLUSION: Nephrotic syndrome may trigger the onset of hypothyroidism or aggravate preexisting hypothyroidism, with subsequent increase in thyroid hormone requirements. Careful history taking and physical examination are necessary when evaluating the patients with new-onset hypothyroidism or patients with worsening hypothyroidism. The diagnostic workup of patients with increasing requirements of thyroid replacement therapy should not be concentrated on the digestive system alone. Presentation: No date and time listed