Timothy C. Hain, MD DizzinessTumor index Page last modified: July 14, 2012
|MRI showing normal pituitary||MRI showing pituitary macroadenoma secreting growth hormone.|
Pituitary adenomas are common "brain tumors", but only on rare occasions are they sources of dizziness or imbalance. The reason for this is because the pituitary is far away from the inner ear as well as structures that process motion information from the ear. There are nevertheless a few situation where the pituitary could cause or contribute to dizziness.
The pituitary is the "master gland" of the body, and controls secretion of many hormones. For example, TSH (thyroid stimulating hormone) as well as many sexual hormones are controlled by the pituitary, and disturbances of these can occasionally trigger dizziness. Low pituitary function can cause dizziness due to low adrenal output. Pituitary surgery can precipitate hyponatremia (Wei et al, 2003).
The pituitary is adjacent to the optic nerve, and can compress the optic nerve. The "classic" pituitary type visual deficit is the "bitemporal hemianopia", where the pituitary compresses fibers in the optic chiasm.
The pituitary is close to several of the oculomotor nerves, and can potentially cause double vision when the tumor is very large.
The pituitary is close to the brain-sinus interface, and tumors can occasionally cause CSF leak (Makin et al, 2011)
Some medications intended to affect the pituitary have dizziness as a side effect. For example, Quinagolid and cabergoline -- dopamine agonists for the treatment of prolactinoma, may have dizziness as a side effect (Deluis et al, 2000).
Radiation treatment of the pituitary often traverses the cavernous sinus, and can damage oculomotor nerves causing diplopia. (Fricke et al, 2002).