A wide variety and dozens of symptoms can indicate a hormonal imbalance in the body. However, a specific group of symptoms give an initial indication of a problem in the endocrine system. For example, excessive thirst, frequent urination, and unexplained weight loss are classic signs of diabetes mellitus, the most common endocrine disorder. Many primary-care physicians still treat endocrine problems, especially diabetes, themselves. However, the primary care doctor often makes a preliminary diagnosis and then refers the patient to an endocrine-system specialist, called an endocrinologist.
Disorders of the endocrine system often, but not always, result from an over-or underproduction of a particular hormone. Too much or too little of a hormone can be harmful. The endocrine organs use a feedback mechanism to regulate hormone levels. It acts much like a household thermostat, increasing production of a specific hormone when it detects too little in the blood, or decreasing production when it detects too much or the right amount. Tight control of hormone levels is needed for the body to function properly. The endocrine organs secrete hormones directly into the bloodstream, where special proteins usually bind to them, helping to maintain them as they travel through the body.
Common diseases and disorders
There are two basic classes of endocrine disorders: problems associated with hormone-production levels, and problems caused by tissues that are unable to respond to hormones. Hormone-production disorders are broken into two groups: insufficient hormone production, called hypofunction; and too much hormone production, called hyperproduction. Endocrine-system disorders include the following:
Diabetes mellitus is a disease that includes type 1 and type 2 diabetes. Type 1 is an autoimmune disease caused when the immune system destroys certain insulin-producing cells in the pancreas. This causes the pancreas to produce little or no insulin. Type 1 diabetes usually develops in children and young adults, but it can appear at any age. Symptoms include increased thirst and urination, unexplained weight loss, blurred vision, and extreme fatigue. There is no cure; insulin, first used in 1921, remains the only treatment. Type 2 diabetes accounts for 90% to 95% of diabetes cases. It usually develops in adults over age 40 and is usually associated with obesity. In type 2, the pancreas produces insulin, but the hormone is not used effectively by the body, a condition called insulin resistance. Several years after onset, insulin production decreases below the level needed to maintain glucose homeostasis. The result is the same as for type 1 diabetes: glucose builds up in the blood because the body cannot use it efficiently. Symptoms develop gradually and include increased thirst and urination, weight loss, fatigue, nausea, blurred vision, frequent infections, and wounds or sores that heal slowly. Insulin resistance is treated with drugs such as thiazolidinedions (rosiglitazone and pioglitazone) and biguanides (metformen). When insufficient insulin is produced, type 2 diabetes appears. However, research indicates progression of insulin resistance to type 2 diabetes can usually be halted or slowed with the insulin-resistance medications, or by lifestyle changes that result in weight loss.
Hypothyroidism is caused by the thyroid gland producing too little thyroid hormone. It can lead to severe hypothyroidism, a disorder that usually develops after age 40. Symptoms include intolerance to cold, lethargy, fatigue, weight gain, and mental sluggishness. Congenital hypothyroidism is present at birth and has the same symptoms. If left untreated, it can lead to mental retardation. The standard treatment for both hypothyroid disorders is thyroid hormone-replacement medications such as levothyroxine (Synthroid, Unithroid, Levoxyl, and Levothroid) and triiodothyrine.
Addison's disease is caused by underactivity or immune-system destruction of the adrenal gland. It can be life-threatening if left untreated. Symptoms include weakness, fatigue, nausea, dehydration, fever, and hyperpigmentation (darkening of the skin without sun exposure.) The standard treatment is with corticosteroid hormones and adequate dietary salt.