The first symptom is a sudden increase in intracranial pressure, mainly due to a sudden hemorrhage or infarction in the pituitary tumor, which can affect the surrounding normal brain tissue and lead to an increase in intracranial pressure. The second symptom is compression of adjacent organs, such as compression of the optic nerve or optic cross, which may result in decreased visual acuity, severe visual field loss, and changes in vital signs. If the hypothalamus is compressed, it can cause hypothalamic syndrome. If the cavernous sinus is compressed, it can cause paralysis of the extraocular muscles or venous reflux disorders. There may also be signs and symptoms of hypopituitarism.