Severe hypothyroidism presenting as reversible proteinuria: two case reports

BACKGROUND: Hypothyroidism is a common medical disorder which results in many metabolic effects, such as dyslipidemia, hypertension, accelerated atherosclerosis, and coronary artery disease. Hypothyroidism affects the renal physiology by affecting the renal blood flow, vascular resistance, and sodium handling. Recent studies have shown hypothyroidism is associated with decreased estimated renal function and proteinuria. Rhabdomyolysis and acute renal insufficiency have also been described in association with hypothyroidism. The severity of the proteinuria was directly proportional to thyroid-stimulating hormone levels. Currently, there is a lack of evidence on the reversibility of proteinuria in hypothyroidism. This is the first report in the literature, to the best of our knowledge, demonstrating the reversibility of proteinuria associated with hypothyroidism, with treatment. CASE PRESENTATION: Here we describe two cases, a 72-year-old Sinhalese man and a 47-year-old Tamil woman, from Sri Lanka, presenting with overt hypothyroidism; they were found to have elevated creatinine, proteinuria, and elevated creatinine kinase levels. Due to lack of active sediment in urine analysis, these patients were observed after the initiation of thyroxine therapy. They were investigated in the adult-onset proteinuria pathway, excluding common reasons for proteinuria. Both patients responded to treatment: their serum creatinine, creatinine kinase, and urine protein levels reverted to physiological levels within 6 months of treatment with thyroxine, and with normalization of thyroid-stimulating hormone. CONCLUSION: Hypothyroidism can present as renal insufficiency, proteinuria, and can mimic rhabdomyolysis. Prompt initiation of thyroxine treatment and control of thyroid-stimulating hormone levels could reverse these changes.