Ruchi Mathur, MD, FRCP(C) is an Attending Physician with the Division of Endocrinology, Diabetes and Metabolism and Associate Director of Clinical Research, Recruitment and Phenotyping with the Center for Androgen Related Disorders, Department of Obstetrics and Gynecology at Cedars-Sinai Medical Center.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
The
signs and symptoms of hypothyroidism vary widely and some of the complaints experienced by
individuals with
hypothyroidism include:
fatigue,
mental fogginess and forgetfulness,
feeling excessively cold,
constipation,
dry skin,
fluid retention,
non specific aches and stiffness in muscles and joints,
excessive or prolonged menstrual bleeding (menorrhagia), and
depression.
Hyperthyroidism is suggested by a number of signs and symptoms. People with
mild hyperthyroidism or those older than 70 years of age usually experience no symptoms. In general, the symptoms
become more obvious as the condition worsens. Common symptoms of hyperthyroidism
include:
excessive sweating,
heat intolerance,
increased bowel movements,
tremor (usually a fine shake),
nervousness; agitation,
rapid heart rate,
weight loss,
fatigue,
decreased concentration, and
irregular and scant menstrual flow.
Introduction to thyroid disease
When I was asked to write an article on "thyroid disease", I took a very deep
breath. The task seemed daunting. As any Endocrinologist (hormone specialist)
knows, there are many subtopics within this giant topic, and an article like
this could go on for a hundred pages! So, once I caught my breath, I decided to
simply design this article to present a "rough guide" to the thyroid. This
article will be an outline or introduction to many conditions that involve the
thyroid gland. As you read through this, you will find a number of links that
will take you to more in-depth articles dealing with the specific topic in
question.
Thyroid 101: What is the thyroid and what does it do?
The thyroid is a butterfly-shaped gland located in the
front of the neck just
below the Adams apple. The gland wraps around the windpipe (trachea) and has a
shape that is similar to a butterfly formed by two wings (lobes) and attached by
a middle part (isthmus). The thyroid gland works like a tiny factory that uses
iodine (mostly from the diet in foods such as seafood and salt) to produce
thyroid hormones. These hormones help to regulate the body's metabolism and
effects processes, such as growth and other important functions of the body.
The
two most important thyroid hormones are thyroxine (T4) and triiodothyronine
(T3), representing 99.9% and 0.1% of thyroid hormones respectively. The hormone
with the most biological power is actually T3. Once released from the thyroid
gland into the blood, a large amount of T4 is converted to T3 - the active
hormone that affects the metabolism of cells throughout our body.
Thyroid hormone regulation - the chain of command
The thyroid itself is regulated by another gland located
in the brain, called the pituitary. In turn, the pituitary is regulated in part by the thyroid (via a
"feedback" effect of thyroid hormone on the pituitary gland) and by another
gland called the hypothalamus.
The hypothalamus releases a hormone called thyrotropin
releasing hormone
(TRH), which sends a signal to the pituitary to release thyroid stimulating
hormone (TSH). In turn, TSH
sends a signal to the thyroid to release thyroid hormones. If overactivity of
any of these three glands occurs, an excessive amount of thyroid hormones can be
produced, thereby resulting in hyperthyroidism. Similarly, if underactivity of
any of these glands occurs, a deficiency of thyroid hormones can result, causing
hypothyroidism.
Hypothalamus - TRH
Pituitary- TSH
Thyroid - T4 and T3
The rate of thyroid hormone production is controlled by
the pituitary gland. If there is an insufficient amount of thyroid hormone
circulating in the body to allow for normal functioning, the release of TSH is
increased by the pituitary in an attempt to stimulate more thyroid hormone
production. In contrast, when
there is an excessive amount of circulating thyroid hormone, TSH levels fall as
the pituitary attempts to decrease the production of thyroid hormone.
There is another hormone that is produced by the thyroid called calcitonin.
Calcitonin is produced by specific cells in the thyroid gland, and unlike T3 and
T4, it is not involved in this regulation of metabolism. Calcitonin is a hormone
that contributes to the regulation of
calcium and helps to lower calcium levels
in the blood. Excess calcium in the blood is referred to as
hypercalcemia.
Hypothyroidism is any state in which thyroid hormone production is below normal. Normally, the
rate of thyroid hormone production is controlled by the brain at the pituitary.
Hypothyroidism is a very common condition and the symptoms of hypothyroidism are
often subtle.
Hyperthyroidism is an excess of thyroid hormone resulting from an overactive thyroid gland. Symptoms can include increased heart rate, weight
loss, depression, and cognitive slowing. Treatment is by medication, the use of
radioactive iodine, thyroid surgery, or reducing the dose of thyroid hormone.
Hashimoto's thyroiditis is the most common cause of hypothyroidism in the US. This conditions is caused by inflammation of the thyroid gland. Symptoms may include: fatigue, weight gain, cold intolerance, excessive sleepiness, dry or coarse hair, difficulty swallowing, a lump in the front of the throat, and many more. Treatment is usually hypothyroid medication.
Thyroid nodules are the most common endocrine problem in the United States. The term "thyroid nodule" refers to any abnormal growth that forms a lump in the thyroid gland. The vast majority of thyroid nodules are benign.
There are four major types of thyroid cancer: papillary, follicular, medullary, and anaplastic thyroid cancer. Tumors on the thyroid are referred to as thyroid nodules. Symptoms of thyroid cancer include swollen lymph nodes, pain in the throat, difficulty swallowing, hoarseness, and a lump near the Adam's apple. Treatment usually involves chemotherapy, surgery, radioactive iodine, hormone treatment or external radiation and depends upon the type of thyroid cancer, the patient's age, the tumor size, and whether the cancer has metastasized.
Celiac disease is a result of an immune reaction to gluten, a protein found in wheat or related grains and present in many foods that we eat. Celiac disease causes impaired absorption and digestion of nutrients through the small intestine. Signs and symptoms of celiac disease include malabsorbption (diarrhea, foul smelling gas, bloating, and increased amounts of fat in the stool) and malnutrition (weight loss, edema, anemia, bruising easily, neuropathy, and infertility). Treatment for celiac disease is a gluten free diet, and at times if necessary, medications
There are many causes of scalp hair loss. This featured article covers the common ones such as patchy hair loss (alopecia areata, trichotillomania, and tinea capitis), telogen effluvium, and androgenetic alopecia (male-pattern baldness, female-pattern baldness).
A miscarriage is any pregnancy that ends spontaneously before the fetus can survive. Miscarriage usually occurs before the 13th week of pregnancy. The cause of a miscarriage cannot always be determined. The most common causes of a miscarriage in the first trimester are collagen vascular disease (lupus), hormonal problems, diabetes, chromosomal abnormalities, and congenital abnormalities of the uterus.
Hypothyroidism during pregnancy can be treated with synthetic thyroid hormones to maintain the proper thyroid hormone balance. Hypothyroidism symptoms include fatigue, weight gain, lethargy, and constipation. Treatment of hypothyroidism in pregnant women is important, because inadequate levels of thyroid hormones may affect the fetus, and child during growth and development.
Fatigue can be described in various ways. Sometimes fatigue is described as feeling a lack of energy and motivation (both mental and physical). The causes of fatigue are generally related to a variety of conditions or diseases for example, anemia, mono, medications, sleep problems, cancer, anxiety, heart disease, drug abuse, and more. Treatment of fatigue is generally directed toward the condition or disease that is causing the fatigue.
Hyperparathyroidism is a disorder of the parathyroid glands. There are two types of hyperparathyroidism, primary and secondary. When the parathyroid glands produce too much hormone, hyperparathyroidism is the resulting condition. Most cases of hyperparathyroidism have no evident cause. Symptoms include fatigue, weakness, depression, loss of appetite, nausea, vomiting, constipation, or confusion. Increased calcium and phosphorous excretion may cause kidney stones. The main treatment of hyperparathyroidism is parathyroidectomy.
Dry skin (xeroderma) may be caused by external factors, like cold temperatures, low humidity, harsh soaps, and certain medications, or internal factors, such as thyroid disease, diabetes, psoriasis, or Sjogren's syndrome. Symptoms and signs of dry skin include itching and red, cracked or flaky skin. The main treatment for dry skin is frequent, daily lubrication of the skin.
Myxedema coma is the loss of brain function due to severe longstanding low levels of thyroid hormone in the blood. Myxedema coma is a life-threatening complication of hypothyroidism. Examples of triggers of myxedema coma include medications, infections stroke, trauma and more. Some of the ymptoms of myxedema coma include: hypothermia, seizures, coma, difficulty breathing and more. Treatment of myxedema coma depend on the severity of the condition.
Graves' disease is an autoimmune disease that affects the thyroid. Some of the symptoms of Graves' disease include hand tremors, rapid heartbeat, trouble sleeping, enlarged thyroid, thinning of the skin or fine brittle hair. Causes of Graves' disease are thought to be multifactorial such as genes, gender, stress, and infection. Treatment for Graves' disease is generally medication.
Fast food consumption and lack of exercise are just a couple of causes of childhood obesity. Health effects of childhood obesity include type 2 diabetes, heart attack, stroke, high cholesterol, asthma, sleep apnea, gallstones, fatty liver disease, GERD, depression, and eating disorders.
Thyroiditis is the inflammation of the thyroid gland. The inflamed thyroid gland can release an excess of thyroid hormones into the blood stream, resulting in a temporary hyperthyroid state. Some forms of thyroiditis can be diagnosed based on tenderness and enlargement of the thyroid gland. A thyroid scan sometimes is used in making the diagnosis. Thyroiditis can also be diagnosed with a biopsy of the thyroid gland.
In hypoparathyroidism, the parathyroid gland does not produce enough parathyroid hormone. Causes of hypoparathyroidism include injury to the parathyroid glands, autoimmune disorder association, or may be present ab birth. Symptoms of hypoparathyroidism include: tingling fingers, toes, and lips, brittle nails, dry, coarse skin, dry hair; memory loss, headaches, severe muscle cramps, cataracts, malformed teeth, and convulsions. Treatment of hypoparathyroidism is to restore the calcium and phosphorus to normal levels in the body.
Stiff-Person syndrome is a neurological disorder associated with features of an autoimmune disease. Signs and symptoms of Stiff-Person syndrome include a heightened sensitivity to stimuli (noise, touch, emotional distress) and fluctuating muscle rigidity of the trunk and limbs. Conditions associated with Stiff-Person syndrome include thyroiditis, vitiligo, pernicious anemia, and diabetes. Treatment for Stiff-Person syndrome is generally medication to control symptoms.
Hashimoto's thyroiditis is the most common cause of hypothyroidism in the
United States. It is named after the first doctor who described this condition,
Dr. Hakaru Hashimoto, in 1912.
What causes Hashimoto's thyroiditis?
Hashimoto's thyroiditis is a condition caused by inflammation of the
thyroid gland. It is an
autoimmune disease, which means that the body inappropriately attacks the thyroid
gland--as if it was foreign tissue. The underlying cause of the autoimmune
process still is unknown. Hashimoto's thyroiditis tends to occur in families, and is
associated with a clustering of other autoimmune conditions such as Type 1
diabetes, and celiac disease. Hashimoto's
thyroiditis is 5-10 times more common in women
than in men and most often starts in adulthood. Blood drawn from patients with
Hashimoto's throiditis reveals an increased number of antibodies to the enzyme, thyroid
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