Hypothyroidism does not cause nephritis, but hypothyroidism may cause kidney damage. Thyroid hormones promote the body’s metabolism and affect the thermogenesis process. Severe thyroid hormone deficiency affects the body’s substance metabolism and energy metabolism, affecting the function of multiple organs, and may also cause kidney damage. Hypothyroidism causes kidney damage through the following mechanisms: i. Decreased cardiac output, leading to kidney damage due to ischemia and hypoxia in the kidneys. Second, mucinous edema, a typical symptom of hypothyroidism is mucinous edema, mucinous edema can also involve the kidneys and kidney damage occurs. Third, hypercholesterolemia, hypothyroidism can cause hypercholesterolemia, which aggravates the occurrence and development of atherosclerosis. In addition, it can also lead to renal atherosclerosis, which reduces renal blood flow and glomerular filtration rate and affects kidney function. The combination of the above factors will lead to kidney injury, and even an increase in blood creatinine and urea nitrogen levels, while hematuria and proteinuria are not obvious. The kidney damage caused by hypothyroidism will gradually improve after the nail function is normalized.