The endocrine system controls just about every function of the body, from growth and reproduction to energy storage and sleep. Endocrine disorders can cause anything from subtle changes in mood to life-threatening problems like Diabetic Ketoacidosis.
The endocrine system also maintains homeostasis of essential functions such as blood pressure, electrolytes, body temperature, and fluid balance. Understanding the structure and function of the endocrine system is essential for caregivers seeking to better understand their patients and provide them with appropriate care.
Related CE for nurses: The Endocrine System: Conditions, Diseases, and Disorders
Anatomy and physiology of the endocrine system
The endocrine system includes many different glands and organs. When learning about the most common disorders of the endocrine system, providers must understand the function of the following glands and organs:
- Thyroid gland: Located at the front of the neck, just at the “Adam’s apple,” it releases thyroxine and triiodothyroxine. These hormones regulate energy production, body temperature, and growth.
- Parathyroid: These four glands are located just behind the thyroid and release parathyroid hormone, which is essential for the storage and regulation of calcium ions in the blood.
- Pituitary gland: Located at the base of the brain, below the hypothalamus. This gland releases 8 hormones, including growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, lutenizing hormone, oxytocin, and antidiuretic hormone.
- Adrenal glands: Located on top of the kidneys, these glands release hormones such as adrenaline. They are responsible for stress responses, metabolism, and blood pressure.
- Pancreas: Located in the posterior portion of the abdominal cavity, this organ is essential in the regulation of insulin and blood glucose. The pancreas releases insulin, glucagon, somatostatin, gastrin, and digestive enzymes.
Disorders of the adrenal gland
Addison’s Disease. Addison’s Disease is typically caused by an autoimmune reaction. In this disorder, not enough cortisol or aldosterone is produced by the adrenal gland. This results in fatigue, muscle and weight loss, low blood pressure, and possible depression.
Cushing’s Syndrome. Cushing’s Syndrome, originating from the adrenal gland, is nearly the opposite of Addison’s disease. In this disorder, an excess of cortisol leads to weight gain, hypertension, and thinning skin. Severe Cushing’s disease can be treated with surgical removal of the adrenal glands.
Pheochromocytoma. A pheochromocytoma is a tumor that produces epinephrine and norepinephrine. Both of these hormones can cause high blood pressure, elevated heart rate, and headaches. These tumors are usually surgically removed.
Disorders of the pituitary gland
Cushing’s Syndrome. Cushing’s Syndrome can be caused by problems in the adrenal gland or the pituitary gland. When the pituitary gland releases too much ACTH, cortisol levels rise, resulting in Cushing’s Syndrome. Symptoms of Cushing’s Syndrome include weight gain, easy bruising, osteoporosis, slow wound healing, difficulty concentrating, and high blood pressure.
Acromegaly. An overproduction of growth hormone causes the relatively rare problem known as acromegaly . A benign tumor on the pituitary gland typically cause this condition. Symptoms of acromegaly include: large hands, feet, and tongue, joint pain, carpal tunnel, and heart enlargement.
Diabetes Insipidus. Diabetes Insipidus causes extreme water loss through excessive urination. It’s the result of too little antidiuretic hormone. In addition to dehydration, untreated DI can cause severe electrolyte imbalances. DI is most commonly found in patients with traumatic brain injuries or after brain surgery.
Hypopituitarism. In hypopituitarism, the pituitary gland is underactive. This impacts the secretion of many hormones and can cause problems in the adrenal glands, thyroid, and sexual organs. Tumors, infections, autoimmune disorders, and congenital disorders can all lead to hypopituitarism.
Prolactinomas. Prolactinomas are the most common type of hormone-secreting tumor of the pituitary gland. These tumors produce excessive prolactin and can cause irregularity or loss of a period, infertility, or secretion of breast milk without pregnancy or birth of a baby. In men, prolactinomas can cause a decreased libido or erectile dysfunction.
Disorders of the thyroid gland
Hypothyroid. In hypothyroidism, the thyroid secretes too little T3, T4, or both. Hypothyroidism can cause fatigue, feeling cold, weight gain, dry skin, and bradycardia. Hormone replacement therapy is the treatment of choice for hypothyroidism.
Hyperthyroid. In hyperthyroidism, patients may feel hot, tachycardic, be unable to gain weight, and suffer from anxiety. Antithyroid drugs, beta-blockers, or surgery can treat hyperthyroidism.
Disorders of the pancreas
The most well-known and common disorder in the pancreas is diabetes mellitus.
Type 1 Diabetes Mellitus. This is an autoimmune disorder where the islet cells of the pancreas cannot create insulin. Without insulin, cells cannot use glucose for energy, and they die.
Type 2 Diabetes Mellitus. Type 2 diabetes occurs when cells fail to respond well to insulin. Medication such as metformin can treat this, but patients may require insulin injections in more severe cases.
Disorders of the parathyroid
Similar to the thyroid, the parathyroid can either be overactive or underactive.
Hypoparathyroidism. If the parathyroid is underactive, it doesn’t release enough parathyroid hormone (PTH). If the parathyroid doesn’t secrete enough PTH, the blood takes too much calcium to store in the bones. Without enough calcium in the blood, essential cellular functions are disrupted, particularly in the heart and skeletal muscle. Symptoms of hypoparathyroidism include muscle spasms, tingling or numbness in the extremities, nausea and vomiting, and irregular heart rhythms.
Hyperparathyroidism. Hyperparathyroidism is the opposite of hypoparathyroidism. When the thyroid releases too much parathyroid hormone is secreted, the bones release too much calcium into the blood. High blood calcium can lead to low phosphorus levels and can cause fatigue, depression, muscle weakness, and bone pain.
Interconnectivity of the system
Many endocrine system functions rely on each other to function normally. For example, the pituitary gland releases thyroid-stimulating hormone, which tells the thyroid to release its essential hormones. Clinicians must be careful not to assume that they know where a hormonal problem originates.
