Sep 26, 2017 · Secondary hyperthyroidism is a condition of the thyroid gland that can affect to a great extent. It is necessary to know the causes and symptoms of secondary hyperthyroidism to seek timely medical advice. Apr 29, 2019 · Hypothyroidism is diagnosed in your thyroid test when TSH is high. Sometimes, TSH can be high, but the thyroid is still producing enough hormones. This condition is referred to as subclinical (or mild) hypothyroidism. Congenital secondary hypothyroidism (associated with clinical signs of disproportionate dwarfism, lethargy, gait abnormalities, and constipation) has been reported in Giant Schnauzers, Toy Fox Terriers, and Scottish Deerhounds. Congenital secondary hypothyroidism also has been reported in German Shepherds,... It can be secondary hypothyroidism (pituitary) or tertiary hypothyroidism (hypothalamus) in origin. In children, it is usually caused by craniopharyngiomas or previous cranial irradiation for brain tumors or hematological malignancies. In adults, it is usually due to pituitary macroadenomas, pituitary surgeries or post-irradiation. pituitary hypothyroidism secondary hypothyroidism caused by a defect or lesion of the pituitary gland that interferes with production of thyrotropin; the majority of cases are caused by tumors. primary hypothyroidism hypothyroidism due to disease of the thyroid gland itself, usually accompanied by increased levels of thyrotropin.