The adrenal and thyroid glands are important parts of the endocrine system. The hormones produced by these glands are released into the bloodstream and travel around the body. They control a variety of functions that are fundamental to sustaining life. Symptoms result when a diseased gland either makes too much or too little of the hormone. A hyperfunctioning gland overproduces hormones, while hypoproduction produces too little hormones.
The two adrenal glands produce five major hormones: cortisol, corticosterone, androgens, aldosterone and adrenaline. Adrenal insufficiency, also known as Addison’s disease, causes all of these hormones to be produced in lesser amounts than normal. The Mayo Clinic Online Health Library lists the symptoms of adrenal insufficiency as muscle weakness, fatigue, weight loss, decreased appetite, darkening of the skin, low blood pressure and fainting, salt cravings, low blood sugar, nausea, diarrhea or vomiting, irritability and depression.
Cushing’s disease and syndrome occurs when an excessive amount of cortisol is produced. The Columbia University Adrenal Center notes that the overproduction of cortisol can occur from a tumor in the area of the pituitary gland that signals cortisol release or a tumor in the adrenal gland itself. The Mayo Clinic lists common symptoms of Cushing’s syndrome as abdominal obesity with fat pad along the upper back, rounding of the face, deep and thick pink or purple stretch marks, slow healing of cuts and infections, high blood pressure, acne, facial hair growth, decreased libido, irregular menstrual periods, glucose intolerance, erectile dysfunction in males, headaches and bone loss.
In addition to producing cortisol, corticosterone and androgens, the outermost region or cortex of the adrenal gland produces the hormone aldosterone. Aldosterone regulates blood volume and blood pressure by interacting with sodium; it keeps blood pressure levels from going too low. The Adrenal Center states that overproduction of this hormone leads to hypertension, low potassium and high sodium levels in the blood. Other symptoms may include excessive urination at night, fatigue and muscle weakness.
The innermost portion of the adrenal gland, the medulla, produces the hormone adrenaline. Adrenaline, also known as epinephrine, initiates the survival mechanism known as "fight or flight." Adrenaline has an effect on blood pressure. It strongly constricts the blood vessels, causing the blood pressure increases common to stressful situations. When a tumor causes adrenaline to be overproduced, the Adrenal Center notes that symptoms such as intermittent sweating, headaches, palpitations and anxiety can occur. They also note that in addition to poorly controlled hypertension, a person may experience symptoms of nausea, heat intolerance and weight loss.
According to the American Thyroid Association (ATA), the thyroid gland is a two-lobed, butterfly-shaped endocrine gland located in the front of the neck, just below the voice box. The function of the gland is to produce thyroid hormone. Thyroid hormone helps the body use energy, stay warm and regulate metabolism, or the amount of calories burned by the body at rest. Balint Kacsoh, author of “Endocrine Physiology,” notes that symptoms of low thyroid hormone production includes a slowed heart rate, decreased energy production, pale, dry skin, cold intolerance, moderate weight gain, muscle weakness, constipation, anemia, high cholesterol, hair loss, brittle hair and nails and dry skin.
Kacsoh notes that overproduction of thyroid hormone leads to hyperthyroidism. Many of the symptoms are exactly opposite to those of hypothyroidism and include fast heart rate, arrhythmias, hand tremors and lid lag. Flushed, warm and moist skin can result, in addition to heat intolerance, weight loss despite increased appetite, loose stools, low cholesterol, fine textured hair and irritability, restlessness and a reduced ability to concentrate.
- Mayo Clinic Online Health Library: Addison’s disease – symptoms
- Mayo Clinic Online Health Library: Cushing’s syndrome – symptoms
- The Columbia University Adrenal Center: Adrenal Disorders – Cushing’s Disease and Cushing’s Syndrome
- The Columbia University Adrenal Center: Adrenal Disorders – Hyperaldosteronism (Conn’s Disease)
- The Columbia University Adrenal Center: Adrenal Disorders – Pheochromocytoma