Impaired estimated glomerular filtration rate associated with hypothyroidism. Does it really mean an acute renal failure?

A case of a young man with myopathy, elevated serum aminotransferase and serum creatinine levels is presented. He had a polymyositis-like-syndrome caused by hashimoto thyroiditis with hypothyroidism. Thyroid hormone replacement therapy led to improvement in both the clinical and laboratory abnormalities. With the established tests for estimating the glomerular filtration rate we cannot determine if there was really a reversible acute renal failure or not.