Definition and Scope of Endocrinology
Endocrinology is a branch of internal medicine that deals with the diagnosis and treatment of diseases of the endocrine system. The endocrine system comprises the major glands of the body including the pancreas, the adrenal glands, the pituitary gland, the thyroid gland, the parathyroid gland, the thymus gland, and some parts of the ovaries and testes which form the reproductive glands. These glands produce and secrete hormones which play key roles in vital functioning of the body such as growth, metabolism, the function of other glands, lactation, sleep, reproduction, temperature, sweat, excretion, psychological state, respiration, and perception.
An endocrinologist is a specialist trained to diagnose and treat pathologies affecting the endocrine system. Endocrinology is a subspecialty not only of internal medicine but also of pediatrics. Within obstetrics and gynecology, specialists in the field of reproductive endocrinology (a/k/a repo endos or REIs) address endocrine issues related to fertility.
Endocrinology-Related Medical Specialities
Internal Medicine: Endocrine diseases cause hormonal imbalances which affect other organ systems. For that reason, endocrinologists and internists typically work closely to manage endocrine disorders, particularly diabetes and thyroid dysfunction.
Endocrine Surgeons and Surgical Oncologists: Endocrine surgeons and surgical oncologists are sometimes needed to treat endocrine diseases, since benign and malignant tumors of the endocrine organs can require surgical intervention.
Retina-Vitreous Ophthalmology: As diabetes harms small vessels, it may manifest in those that supply the retina, causing tissue death and the separation of the retina as a result of diabetic retinopathy.
Vascular Surgery: Due to vascular disease secondary to diabetes, vascular surgeons frequently cotreat and operate on diabetic patients, performing peripheral bypasses and even amputations.
Wound Care: Diabetics are prone to vascular compromise, particularly of the small vessels. This can precipitate wound formation and hinder wound healing, which necessitates endocrinologists to collaborate with wound care physicians.
Infectious Disease: Again, due to perfusion issues, diabetics are much more susceptible to microbial infections.
Podiatry: Diabetics tend to manifest issues in the most distal regions such as the feet, particularly the toes. These problems are most commonly secondary to hypoperfusion, and to damage and destruction of blood vessels.
Neurology: Small vessels supply nerves. When perfusion to nerves is impaired by diabetes, temporary and permanent nerve damage can occur which can be central (in the brain) or peripheral.
Urology: An early sign of small vessel disease may be erectile dysfunction.
Orthopaedic Surgery: Orthopaedists are regularly treating patients with osteoporosis or osteopenia as these conditions predispose to fractures.
Gynecology: Hormonal imbalances can significantly affect reproductive health. At times, gynecologists work with endocrinologists to treat an endocrine disorder.
Pediatric Endocrinology: This is the pediatric subspeciality of endocrine medicine. Precocious puberty, delayed puberty, diabetes, and thyroid disorders are common endocrine conditions in pediatric patients.
Nephrology and Urology: Hyperparathyroidism can result in the formation of renal calculi (kidney stones). Urologists treat and remove renal calculi. Nephrologists focus more on the treatment of disorders that lead to stone formation in order to prevent recurrence.
Dieticians and Nutritionists: Hormonal imbalance can affect nutritional status. Hence, dietary consultation with a registered dietician is essential for management of an endocrine disorder.
Pathologists: Pathologists diagnose endocrine disorders via tissue samples and blood tests.
Common Endocrine Diseases and Medical Procedures
Type 1 Diabetes: An autoimmune condition in which the pancreas can no longer produce insulin which controls the blood sugar naturally.
Type 2 Diabetes: This form of diabetes is more common than type 1. In type 2, diabetes, there is normal production of insulin in the pancreatic cells, but the tissues can’t absorb the insulin and regulate glucose levels.
Hyperthyroidism: An overactive thyroid gland secretes an excess amount of thyroid hormone.
Hypothyroidism: The thyroid gland produces a less than normal amount of thyroid hormone.
Grave’s disease: An autoimmune condition in which the thyroid gland produces an excess amount of thyroid hormone causing hyperthyroidism.
Hashimoto’s thyroiditis: An autoimmune condition in which inflammation of the thyroid gland (thyroiditis) leads to hypothyroidism. It is the most common cause of hypothyroidism in the United States.
Thyroid cancer: Often asymptomatic initially, one of the most common symptoms of thyroid cancer is a lump in the neck.
Addison’s disease: Also known as primary adrenal insufficiency, this disorder of the adrenal glands causes them to produce lower than normal levels of the hormone cortisol.
Cushing’s syndrome: Excess cortisol is produced by the adrenal glands. Characteristic symptoms are central body obesity, glucose intolerance, hypertension, osteoporosis, kidney stones, excess hair growth, menstrual irregularity, and stress.
Osteoporosis/Osteopenia: In this condition, the calcium content of the bone decreases and results in weakened, less dense bones. Bones become brittle and can break easily. Osteoporosis is mainly caused by reduced calcium and phosphate levels. Levels of these minerals are affected by endocrine conditions including:
Hyperthyroidism
Hyperparathyroidism (parathyroid glands produce excess parathyroid hormones)
Menopause in women and a drop in testosterone levels in men can also affect calcium levels in the body leading to osteoporosis.
Common medical tests in endocrinology:
ACTH stimulation test: Adrenocorticotrophic hormone (ACTH) is produced by the pituitary gland. The main function of this hormone is to stimulate the adrenal glands to produce the hormone cortisol. For this test, two blood samples are required. After the first blood sample is collected, the patient is given an ACTH injection. Following the injection, another blood sample is drawn. In normal people, cortisol levels increase after ACTH injection. In Addison’s disease patients, cortisol levels do not increase even after an ACTH injection.
CRH-stimulation test: Corticotrophin-releasing hormone (CRH) causes the pituitary gland to release the ACTH hormone. Similar to an ACTH stimulation test, two blood samples are required. Following the first blood sample, the patient is given a CRH injection. After an interval of 30-120 minutes, the second blood sample is taken.
Five-day glucose sensor test for diabetes: A small sensor and an electronic recorder monitor blood sugar levels of a potentially diabetic patient. The test is conducted over a period of five days in order to detect patterns in the glucose levels.
TSH: Thyroid stimulating hormone is made by the pituitary gland. It stimulates the thyroid gland to produce its hormone. This blood test is useful in patients suspected of hypothyroidism. Because the thyroid gland is underactive, TSH hormone is not utilized by the thyroid, which resulting in high circulating levels of TSH in the blood stream.
Bone density test (bone densitometry test): Dual x-ray absorptiometry (DEXA) is the most accurate test for checking the density of bones. Important diagnostic medical procedure in endocrinology:
Fine-needle aspiration (FNA) biopsy: This diagnostic procedure employs a small needle to remove a cell sample from a thyroid nodule or a lump. The procedure is advised for patients who have a palpable thyroid mass and can help determine whether it is benign or malignant.
Medical-Legal Cases Involving Endocrinology
Endocrinology expert witnesses can testify and provide insight on legal issues related to the endocrine system of which thyroid disorders and diabetes are the two most common. If these conditions are misdiagnosed or mismanaged, there could be serious consequences.
Failing to diagnose or misdiagnosing diabetes can result in kidney disease, poor vision (e.g., through diabetic retinopathy), or gangrene. Medical negligence of monitoring of diabetes can also lead to complications. Undiagnosed or misdiagnosed thyroid disorders can lead to autoimmune disorders and psychiatric illnesses. Undiagnosed thyroid disorders in pregnant women can result in birth defects. Misdiagnosis of thyroid cancer or medical negligence in the management of thyroid cancer can cause life-threatening complications.
Other legal claims against endocrinologists include failing to undertake genetic surveillance for thyroid disorders in high-risk patients and misdiagnosis of genetic endocrine disorders.