Vertigo, the sensation of spinning or feeling off-balance, commonly stems from inner ear issues. A pituitary tumor, though a less common cause, can also trigger vertigo or general dizziness. These tumors are typically benign, but their location allows them to interfere with the body’s master control system. The link is usually indirect, resulting from physical growth or disruption of hormonal balance.
The Role and Types of Pituitary Tumors
The pituitary gland, often called the “master gland,” is a small, pea-sized organ situated at the base of the brain. It plays a central role in the endocrine system by producing hormones that regulate crucial functions like growth, metabolism, and reproduction. Abnormal growths in this gland are called pituitary tumors, or pituitary adenomas, and most are non-cancerous.
Pituitary tumors are categorized based on function. Functional tumors (secreting adenomas) produce an excess of pituitary hormones, causing systemic symptoms related to that hormone’s overproduction. Non-functional tumors (non-secreting adenomas) do not release excess hormones but cause problems purely through their size and location. Tumors smaller than one centimeter are microadenomas, while larger ones are macroadenomas.
The pituitary gland is nestled in a bony pocket called the sella turcica. This physical confinement means that even a benign growth can affect nearby delicate structures. This location is why macroadenomas, whether functional or non-functional, can cause symptoms extending beyond simple hormonal issues, potentially leading to vertigo.
How Pituitary Tumors Can Trigger Vertigo
Pituitary tumors can cause vertigo or dizziness through two primary mechanisms: physical pressure (mass effect) and systemic disruption from hormonal imbalances. The physical growth of a macroadenoma is concerning due to its proximity to cranial nerves and brain structures.
A large tumor can extend upward from the sella turcica, potentially pressing on the brainstem or cranial nerves responsible for coordinated movement and balance. The nerves carrying balance information from the inner ear to the brain are vulnerable to this pressure. Impingement on the oculomotor nerves can also cause double vision or trouble with eye movement, which manifests as dizziness or disequilibrium.
The second mechanism involves hormonal imbalance, which creates systemic effects mimicking inner ear problems. For example, a deficiency in hormones stimulating the adrenal glands can lead to secondary adrenal insufficiency. This condition causes symptoms like low blood pressure, low blood sugar, and severe fatigue, all contributing to lightheadedness or unsteadiness.
Excess hormone secretion by functional tumors, such as those causing Cushing’s disease or acromegaly, can disrupt fluid and electrolyte balance. These systemic changes can indirectly impact the vestibular system or cause general instability interpreted as vertigo. Additionally, medications used to treat these tumors, such as dopamine agonists, may list dizziness as a side effect.
Associated Symptoms That Should Raise Concern
When vertigo or dizziness results from a pituitary tumor, it is usually accompanied by other signs that differentiate it from common inner ear disorders. These additional symptoms suggest a central cause requiring medical investigation.
Visual disturbances are a hallmark symptom because the optic nerves cross directly above the gland at the optic chiasm. Tumor expansion often compresses these nerves, leading to peripheral vision loss known as bitemporal hemianopsia. Any new loss of side vision, double vision, or trouble with eye movement combined with vertigo is a significant red flag.
Severe and persistent headaches are also commonly reported due to the pressure the mass exerts within the skull. These headaches are often unrelieved by typical pain medication and may be accompanied by nausea and vomiting, especially in the morning.
Hormonal dysfunction presents with specific symptoms depending on the hormone affected.
Examples of Hormonal Symptoms
- Excess prolactin can cause irregular or absent menstrual periods in women.
- Excess prolactin can cause decreased sex drive or erectile dysfunction in men, sometimes with unexplained breast milk production.
- Deficiency in growth hormone can lead to fatigue and loss of muscle mass.
- Issues with thyroid-stimulating hormone can cause symptoms of an underactive or overactive thyroid.
Medical Evaluation and Treatment Options
A comprehensive medical evaluation is necessary when a pituitary tumor is suspected. Diagnosis begins with a physical examination, symptom review, and blood and urine tests. These laboratory studies measure hormone levels, such as prolactin, growth hormone, and cortisol, to identify any excess or deficiency.
If hormonal abnormalities or visual symptoms are present, a visual field examination checks for characteristic peripheral vision loss. The definitive diagnosis relies on high-resolution imaging, typically a magnetic resonance imaging (MRI) scan of the brain and pituitary gland. The MRI provides detailed images of the tumor’s size, location, and relationship to nearby structures like the optic chiasm.
Treatment Approaches
Treatment is determined by the tumor type, size, and whether it causes symptoms via mass effect or hormone secretion. For many prolactin-secreting tumors, the first-line treatment is medication, specifically dopamine agonists, which shrink the tumor and normalize hormone levels.
Non-functional tumors or those causing severe symptoms due to size generally require surgical removal. The most common procedure is transsphenoidal surgery, where the tumor is removed through the nose and sphenoid sinus. Radiation therapy, including stereotactic radiosurgery, may be used if tumors cannot be completely removed or to control residual growth. A multidisciplinary team manages the care plan to address both the tumor and resulting hormonal imbalances.