To the editor We report a new case of glomerular disease associated to thyroid disease, after the one recently published in this same journal.1



A 60-year-old  female patient with an unremarkable  history  consulted  her  general  practitioner  complaining  of  fatigue,  depressive  symptoms,  and  mild ankle edema in the previous month. Laboratory  test  results  included  serum  albumin levels of 1.9 g/dL, cholesterol levels of 338 mg/dL,  creatinine  levels of 0.9  mg/dL,  proteinuria  of  5.8  g/24  h, TSH 9.9 μIU/mL (normal 0.4-4), antiperoxidase antibodies 714 IU/mL ( normal <  60).  Treatment was  started  with  levothyroxin 50 mcg/24 h and atorvastatin 20 mg/24 h, and patient was finally referred to hospital six months later for completing  work-up.  The  only  significant findings in physical examination were signs of venous  insufficiency  in  the lower  limbs with no noticeable ankle edema. At the time, the patient had normal renal function with the following laboratory test results: albumin 2.6 mg/dL, cholesterol  239 mg/dL,  proteinuria  3.4 g/24 h, TSH 10.9 μIU/mL, free T4 0.98 ng/dL (normal 0.6-1.8), antiperoxidase Ab > 1300 IU/mL, antithyroglobulin Ab > 500 IU/mL (normal<60). Autoimmune study was normal, and tumor markers and viral serologic tests (HBV, HCV) were  negative. Colonoscopy  and mammography were normal. A percutaneous renal  biopsy showed  lesions  consistent with a stage II membranous kidney disease. Based on diagnosis of autoimmune  phyroiditis,  subclinical  hypothyroidism, and nephrotic syndrome due to membranous nephropathy, levothyroxin was discontinued because  of  normal T4  levels and treatment was started with lisinopril 20 mg,  candesartan  16 mg,  and  sustained  release  fluvastatin  80  mg.  Six months  later,  the  patient  remained  in  a good clinical condition, with no edema, and laboratory tests showed a partial remission of nephrotic syndrome with proteinuria of 1.6 g/24 h, serum albumin 4.1 g/dL, cholesterol 177 mg/dL, as well as a virtually normal thyroid function (TSH 4.5 μIU/mL, T4 1 ng/dL).



Association of thyroid disease and glomerular diseases is known, though few cases have been reported. Particular mention should be made of association of Graves disease and membranous nephropathy.2 Autoimmune thyroiditis has also been reported to be associated to  this same nephropathy,3,4 and also  to IgA nephropathy,5,6 minimal change disease,1,7,8 and  membranoproliferative glomerulonephritis.9,10



As reported by some authors,1,10,11 simultaneous occurrence of thyroid and glomerular disease could be explained by the existence of an autoimmune pathogenesis common to both conditions, and incidence could be higher than suspected, with proteinuria being found in a high proportion of patients with autoimmune thyroiditis and Graves disease. In our case, thyroiditis was diagnosed  based  on positive antithyroid antibodies, and its clinical manifestation was a subclinical hypothyroidism. The parallelism seen between remission of nephrotic syndrome and TSH normalization should be noted. Use of levothyroxin, corticosteroids, or other immunosuppressants, that  were  administered  in  some  previously  reported cases,3,6-10 was  not  required.  The  need for  investigating  thyroid  function  in cases of apparently idiopathic nephrotic syndrome should be stressed.