Sunday, June 24, 2007

Hyperthyroidism and Pregnancy

Hyperthyroidism and Pregnancy

- Hyperthyroidism refers to the signs and symptoms which are due to the production of too much thyroid hormone. An overactive thyroid gland (hyperthyroidism) often has its onset in younger women. Because a woman may think that feeling warm, having a hard or fast heartbeats, nervousness, trouble sleeping, or nausea with weight loss are just parts of being pregnant, the symptoms and signs of this condition may be overlooked during pregnancy.

- In women who are not pregnant, hyperthyroidism can affect menstrual periods, making them irregular, lighter, or disappear altogether. It may be harder for hyperthyroid women to become pregnant, and they are more likely to have miscarriages. If a woman with infertility or repeated miscarriages has symptoms of hyperthyroidism, it is important to rule out this condition with thyroid blood tests. It is very important that hyperthyroidism be controlled in pregnant women since the risks of miscarriage or birth defects are much higher without therapy. Fortunately, there are effective treatments available. Antithyroid medications cut down the thyroid gland's overproduction of hormones and are reviewed on another page on this site. When taken faithfully, they control hyperthyroidism within a few weeks. In pregnant women thyroid experts consider propylthiouracil (PTU) the safest drug. Because PTU can also affect the baby's thyroid gland, it is very important that pregnant women be monitored closely with examinations and blood tests so that the PTU dose can be adjusted. In rare cases when a pregnant woman cannot take PTU for some reason (allergy or other side effects), surgery to remove the thyroid gland is the only alternative and should be undertaken prior to or even during the pregnancy if necessary. Although radioactive iodine is a very effective treatment for other patients with hyperthyroidism, it should never be given during pregnancy because the baby's thyroid gland could be damaged.

- Because treating hyperthyroidism during pregnancy can be a bit tricky, it is usually best for women who plan to have children in the near future to have their thyroid condition permanently cured. Antithyroid medications alone may not be the best approach in these cases because hyperthyroidism often returns when medications is stopped. Radioactive iodine is the most widely recommended permanent treatment with surgical removal being the second (but widely used) choice. It is concentrated by thyroid cells and damages them with little radiation to the rest of the body. This is why it cannot be given to a pregnant woman, since the radioactive iodine could cross the placenta and destroy normal thyroid cells in the baby. The only common side effect of radioactive iodine treatment is underactivity of the thyroid gland, which occurs because too many thyroid cells were destroyed. This can be easily and safely treated with levothyroxine. There is no evidence that radioactive iodine treatment of hyperthyroidism interferes with a woman's future chances of becoming pregnant and delivering a healthy baby.

Wednesday, June 20, 2007

Hypothyroidism: Prognosis and Future Perspectives

Hypothyroidism - Prognosis and Future Perspectives

Differential Diagnosis.

The differential diagnosis of hypothyroidism includes nonthyroidal illness (i.e., decreased T3 or T4 , or both, without clinical hypothyroidism), euthyroid hypothyroxinemia (decreased T4 caused by decreased thyroid-binding globulin), and drugs that inhibit T4 binding (salicylates, phenytoin, and phenobarbital). Once hypothyroidism has been diagnosed, the most important clinical distinction is between primary and secondary hypothyroidism. The clinical and laboratory similarities between myxedema coma and other life-threatening causes of the comatose state may make its diagnosis extremely difficult. Regarding hypothyroid myopathy, the muscular appearance, stiffness, and exacerbation by cold may suggest a mild form of myotonia congenita, which can present in adulthood. Although the stiffness noted in patients with pyramidal and extrapyramidal diseases may appear similar to that of hypothyroid myopathy, the characteristic history, appearance, and laboratory studies usually permit the diagnosis of hypothyroidism.

The combination of a low T4 level and an elevated thyroid-stimulating hormone (TSH) level is virtually diagnostic of primary hypothyroidism, because TSH elevation does not occur in central hypothyroidism. Further delineation between primary and secondary hypothyroidism is dependent on history, examination, and other laboratory studies. In addition to TFTs, other laboratory abnormalities have been described, including anemia (normocytic-normochromic, microcytic-hypochromic, or macrocytic) and hyponatremia (factitious due to hyperlipidemia or secondary to impaired free water excretion), as well as elevated serum creatine kinase, myoglobin, and prolactin. Because of the possibility of concomitant adrenal insufficiency, a serum cortisol level should also be obtained. The EEG may show slowing of the posterior dominant rhythm and a generalized voltage decrease, as well as triphasic waves that disappear with replacement therapy. CSF analysis may reveal an elevated protein content which may exceed 100 mg/dl.

The treatment of hypothyroidism, regardless of cause, consists of thyroid hormone replacement. Even in the setting of hypothyroid-induced seizures, achievement of the euthyroid state facilitates control. Precipitants of myxedema coma (e.g., infection, cold exposure, certain drugs phenothiazines, narcotics, and sedative-hypnotics, phenytoin, rifampin , and other stressors surgery, trauma ) require correction.

Prognosis and Future Perspectives.
With early recognition and treatment, as well as improved intensive supportive care, the mortality rate of myxedema coma has decreased from roughly 50 to 70 percent to around 15 to 20 percent.
Without early recognition and prompt institution of replacement therapy, the prognosis is grave.

Data from Mitehell JM: Thyroid disease in the emergeney department: Thyroid fune~tion tests and hypothyroidism and myxedema eoma Emerg Med Clin North Am 1989;7:885-902; Mazzafern EL: Adult hypothyroidism: 1. Manifestations and elinical presentation. Postgrad Med 1986;79:64 72; Myers L, Hays J: Myxedema eoma. Cnt Care Clinie 1991;7:43 56.

Monday, June 18, 2007

Clinical Features of Hypothyroidism

Hypothyroidism: Clinical Features and Associated Disorders

Clinically, the onset of hypothyroidism may range from subtle and insidious findings to florid psychosis. The general examination features of hypothyroidism are numerous:
1) Subjective: Fatigue, somnolenee, eold intoleranee, syneope, exertional dyspnea, weight gain, arthralgias, nausea, anorexia, indigestion, eonstipation, menstrual abnormalities;
2) Objective: Bradyeardia, hair changes (sparse, eoarse, dry, brittle), puffy face, loss of lateral aspeets of the eyebrows, penorbital edema, maeroglossia, voiee deepening and hoarsening, skin ehanges (sealy, thiek, doughy, eoarse, dry, earotenemia), bnttle nails, nonpitting edema, galaetorrhea, effusions

CNS features include forgetfulness, inattention, apathy, and slowing of speech, movement and mentation. These features may mimic depression. Seizures, personality changes, psychotic states, coma, and dementia may also be clinically apparent. Cerebellar ataxia is seen in 5 to 10 percent of patients, and may be the presenting sign (so-called myxedema staggers). A psychotic presentation (myxedema madness) characterized by agitation, disorientation, delusions, hallucinations, paranoia, and restlessness is observed in approximately 3 to 5 percent of patients. Myxedema coma is extremely rare, and its characteristic features include extreme hypothermia, seizures (the presenting manifestation in nearly 20 percent of patients ), respiratory depression, and areflexia. Death can occur when early recognition and prompt treatment are lacking. Dementia may develop when hypothyroidism is severe. Except for the marked increase in the number of hours these patients remain asleep or resting, the clinical features of the dementia are similar to those secondary to other causes.
Peripheral neuromuscular features include cranial and peripheral neuropathies, prolonged reflex relaxation time (up to 85 percent of hypothyroid patients), and myopathy. Visual field defects can occur when pituitary enlargement causes hypothyroidism with concomitant chiasmal compression. A facial mononeuropathy, due to nerve entrapment in the fallopian canal of the temporal bone, may rarely occur. Although sensorineural hearing loss has been reported to correlate with the degree of hypothyroidism and has a high incidence among patients with congenital
Hypothyroidism, its reported incidence among adult hypothyroid patients varies. Minor evidence of polyneuropathy, such as distal lower extremity sensory dysfunction and absent ankle jerks, is observed in approximately 10 percent of patients, and rarely, a moderately severe sensorimotor polyneuropathy has been described. Carpal tunnel syndrome (i.e., median mononeuropathy at the wrist) occurs in 15 to 30 percent of hypothyroid patients, is usually bilateral, and is the most common mononeuropathy encountered.
Myopathy can be a feature of hypothyroidism and manifests with proximal muscle weakness. Regardless of the cause of the hypothyroidism, weakness is observed in about one third of these patients. Increased muscle size and firmness, which is most obvious in the limb musculature, as well as slowed muscle contraction are important features to identify. Exertional pain, stiffness, and cramps may be noted, and myoedema may be observed. Myoedema, a mounding of the muscle in response to direct percussion, is painless and electrically silent, and occurs in one third of hypothyroid patients. Difficulty relaxing the hand grip and exacerbation by cold weather may suggest myotonia. However, unlike myotonia, hypothyroid myopathy involves a slowness of muscle relaxation and contraction, and resolves with correction of the hypothyroid state. Although sleep apnea is usually of the obstructive type, other possibilities include a central abnormality, chest muscle weakness, and blunted responses to hypoxia and hypercapnia. Reports have associated hypothyroidism with SIADH, idiopathic intracranial hypertension, and myasthenia gravis.

Thursday, June 14, 2007

Hypothyroidism: Causes and Risk factors

Causes of Hypothyroidism

Your thyroid gland produces two main hormones, thyroxine (T-4) and triiodothyronine (T-3), that influence every cell in your body. They maintain the rate at which your body uses fats and carbohydrates, help control your body temperature, influence your heart rate and help regulate the production of protein. Your thyroid gland also produces calcitonin, a hormone that regulates the amount of calcium in your blood.

The rate at which thyroxine and triiodothyronine are released is controlled by your pituitary gland and your hypothalamus — an area at the base of your brain that acts as a thermostat for your whole system. The hypothalamus signals your pituitary gland to make a hormone called thyroid-stimulating hormone (TSH). Your pituitary gland then releases TSH — the amount depends on how much thyroxine and triiodothyronine are in your blood. Finally, your thyroid gland regulates its production of hormones based on the amount of TSH it receives.

Although this process usually works well, the thyroid sometimes fails to produce enough hormones. This may be due to a number of different factors, including:
  • Autoimmune disease (Hashimoto's thyroiditis). Autoimmune disorders occur when your immune system produces antibodies that attack your own tissues. Sometimes this process occurs within the thyroid gland. Scientists aren't sure why the body produces antibodies against itself. Some think a virus or bacteria might trigger the response, while others believe a genetic flaw may be involved. Most likely, autoimmune diseases result from more than one factor. But however it happens, these antibodies affect the thyroid's ability to produce hormones.
  • Treatment for hyperthyroidism. People who produce too much thyroid hormone (hyperthyroidism) are often treated with radioactive iodine or anti-thyroid medications to reduce their thyroid function. However, function can be reduced too much, resulting in hypothyroidism.
  • Radiation therapy. Radiation used to treat cancers of the head and neck can affect your thyroid gland and may lead to hypothyroidism.
  • Thyroid surgery. Removing all or a large portion of your thyroid can diminish or halt hormone production. In that case, you'll need to take thyroid hormones for life.
  • Medications. A number of medications can contribute to hypothyroidism. One such medication is lithium, which is used to treat certain psychiatric disorders. If you're taking medication, ask your doctor about its effect on your thyroid gland.
Less often, hypothyroidism may result from one of the following:
  • Congenital disease. Approximately one in 3,000 babies in the United States is born with a defective thyroid gland or no thyroid gland at all. In most cases, the thyroid gland didn't develop normally for unknown reasons, but some children have an inherited form of the disorder. Often, infants with congenital hypothyroidism appear normal at birth. That's one reason why most states now require newborn thyroid screening.
  • Pituitary disorder. A relatively rare cause of hypothyroidism is the failure of the pituitary gland to produce enough TSH — usually due to a benign tumor of the pituitary gland.
  • Pregnancy. Some women develop hypothyroidism during or after pregnancy (postpartum hypothyroidism), often because they produce antibodies to their own thyroid gland. Left untreated, hypothyroidism increases the risk of miscarriage, premature delivery and preeclampsia — a condition that causes a significant rise in a woman's blood pressure during the last three months of pregnancy. It can also seriously affect the developing fetus.
  • Iodine deficiency. The trace mineral iodine — found primarily in seafood, seaweed, plants grown in iodine-rich soil and iodized salt — is essential for the production of thyroid hormones. In some parts of the world, iodine deficiency is common, but the addition of iodine to table salt has virtually eliminated this problem in the United States.

Risk factors

Although anyone can develop hypothyroidism, it occurs mainly in women older than 50, and the risk of developing the disorder increases with age.
You also have an increased risk if you:

  • Have a close relative, such as a parent or grandparent, with an autoimmune disease
  • Have been treated with radioactive iodine or anti-thyroid medications
  • Received radiation to your neck or upper chest
  • Have had thyroid surgery (partial thyroidectomy)

Wednesday, June 13, 2007

Hypothyroidism: Complications

Complications of Hypothyroidism

Untreated hypothyroidism can lead to a number of health problems:
  • Goiter. Constant stimulation of your thyroid to release more hormones may cause the gland to become larger — a condition known as goiter. Hashimoto's thyroiditis is one of the most common causes of a goiter. Although generally not uncomfortable, a large goiter can affect your appearance and may interfere with swallowing or breathing.
  • Heart problems. Hypothyroidism may also be associated with an increased risk of heart disease, primarily because high levels of low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol — can occur in people with an underactive thyroid. Even subclinical hypothyroidism, a more benign condition than true hypothyroidism, can cause an increase in total cholesterol levels and impair the pumping ability of your heart. Hypothyroidism can also lead to an enlarged heart and heart failure.
  • Mental health issues. Depression may occur early in hypothyroidism and may become more severe over time. Hypothyroidism can also cause slowed mental functioning.
  • Myxedema. This rare, life-threatening condition is the result of long-term, undiagnosed hypothyroidism. Its symptoms include intense cold intolerance and drowsiness followed by profound lethargy and unconsciousness. A myxedema coma may be triggered by sedatives, infection or other stress on your body. If you have symptoms of myxedema, you need immediate emergency medical treatment.
  • Birth defects. Babies born to women with untreated thyroid disease may have a higher risk of birth defects than do babies born to healthy mothers. These children are more prone to serious intellectual and developmental problems.

Infants with untreated hypothyroidism present at birth are also at risk of serious problems with both physical and mental development. But if the condition is diagnosed within the first few months of life, the chances of normal development are excellent.

Tuesday, June 12, 2007

Hypothyroidism in children

Hypothyroidism in children and teens

Although hypothyroidism most often affects middle-aged and older women, anyone can develop the condition, including infants and teenagers. Initially, babies born without a thyroid gland or with a gland that doesn't work properly may have few signs and symptoms. When newborns do have problems with hypothyroidism, they may include:
  • Yellowing of the skin and whites of the eyes (jaundice). In most cases, this occurs when a baby's liver can't metabolize a molecule called bilirubin, which normally forms when the body recycles old or damaged red blood cells.
  • Frequent choking.
  • A large, protruding tongue.
As the disease progresses, infants are likely to have trouble feeding and may fail to grow and develop normally. They may also have:
  • Constipation
  • Poor muscle tone
  • Excessive sleepiness
When hypothyroidism in infants isn't treated, even mild cases can lead to severe physical and mental retardation.

In general, children and teens who develop hypothyroidism have the same signs and symptoms as adults do, but they may also experience:
  • Poor growth, resulting in short stature
  • Delayed development of permanent teeth
  • Delayed puberty
  • Poor mental development

Monday, June 11, 2007

Thyroid disorder during pregnancy

Thyroid disorder during pregnancy

Thyroid Problems During Pregnancy Shows Up with Headaches, Anxiety, Nervousness, and High Blood Pressure.These are the signs of Thyroid disease of Pregnancy.

  • The most common thyroid disorder occurring around or during pregnancy is thyroid hormone deficiency, or hypothyroidism.

Hypothyroidism can cause a variety of changes in a woman's menstrual periods: irregularity, heavy periods, or loss of periods. When hypothyroidism is severe, it can reduce a woman's chances of becoming pregnant. Checking thyroid gland function with a simple blood test is an important part of evaluating a woman who has trouble becoming pregnant. If detected, an underactive thyroid gland can be easily treated with thyroid hormone replacement therapy. If thyroid blood tests are normal, however, treating an infertile woman with thyroid hormones will not help at all, and may cause other problems.

  • Because some of the symptoms of hypothyroidism such as tiredness and weight gain are already quite common in pregnant women, it is often overlooked and not considered as a possible cause of these symptoms. Blood tests, particularly measuring the TSN level, can determine whether a pregnant woman's problems are due to hypothyroidism or not.

Since thyroid medications (particularly Levothyroxine) are essentially identical to the thyroid hormone made by the normal thyroid gland, a woman with an underactive thyroid gland can feel confident that it is perfectly safe to take thyroid hormone medication during pregnancy. There are no side effects for the mother or the baby as long as the proper dose is used. In the case where hypothyroidism in the mother is NOT detected, the thyroid will still develop normally in the baby.

  • Women with previously treated hypothyroidism should be aware that their dose of medication may have to be increased during pregnancy. They should contact their doctor, who should check their blood level of TSH periodically throughout pregnancy to see if their medication dose needs adjustment. Thyroid function tests should continue to be reviewed every 2-3 months throughout the pregnancy. After delivery, the thyroxine dose should be returned to the pre-pregnancy dose and thyroid function tests reviewed two months later.

Wednesday, June 06, 2007

Treatment of Hypothyroidism

Treatment of Hypothyroidism

Hypothyroidism is usually quite easy to treat (for most people)! The easiest and most effective treatment is simply taking a thyroid hormone pill (Levothyroxine) once a day, preferably in the morning. This medication is a pure synthetic form of T4 which is made in a laboratory to be an exact replacement for the T4 that the human thyroid gland normally secretes. It comes in multiple strengths, which means that an appropriate dosage can almost always be found for each patient. The dosage should be re-evaluated and possibly adjusted monthly until the proper level is established. The dose should then be re-evaluated at least annually. If you are on this medication, make sure your physician knows it so he/she can check the levels at least yearly.
Note: Just like we discussed above, however, this simple approach does not hold true for everybody. Occasionally the correct dosage is a bit difficult to pin-point and therefore you may need an exam and blood tests more frequently. Also, some patients just don't do well on some thyroid medications and will be quite happy on another. For these reasons you should not be shy in discussing with your doctor your blood hormone tests, symptoms, how you feel, and the type of medicine you are taking. The goal is to make you feel better, make your body last longer, slow the risk of heart disease and addition to making your blood levels normal! Sometimes that's easy, when its not, you need a physician who is willing to spend the time with you that you deserve while you explore different dosages other types of medications (or alternative diagnoses).
Some patients will notice a slight reduction in symptoms within 1 to 2 weeks, but the full metabolic response to thyroid hormone therapy is often delayed for a month or two before the patient feels completely normal. It is important that the correct amount of thyroid hormone is used. Not enough and the patient may have continued fatigue or some of the other symptoms of hypothyroidism. Too high a dose could cause symptoms of nervousness, palpitations or insomnia typical of hyperthyroidism. Some recent studies have suggested that too much thyroid hormone may cause increased calcium loss from bone increasing the patient's risk for osteoporosis. For patients with heart conditions or diseases, an optimal thyroid dose is particularly important. Even a slight excess may increase the patient's risk for heart attack or worsen angina. Some physicians feel that more frequent dose checks and blood hormone levels are appropriate in these patients.
After about one month of treatment, hormone levels are measured in the blood to establish whether the dose of thyroid hormone which the patient is taking is appropriate. We don't want too much given or subtle symptoms of hypert5hyroidism could ensue, and too little would not alleviate the symptoms completely. Often blood samples are also checked to see if there are antibodies against the thyroid, a sign of autoimmune thyroiditis. Remember, this is the most common cause of hypothyroidism. Once treatment for hypothyroidism has been started, it typically will continue for the patient's life. Therefore, it is of great importance that the diagnosis be firmly established and you have a good relationship with a physician you like and trust.
Synthetic T4 can be safely taken with most other medications. Patients taking cholestyramine (a compound used to lower blood cholesterol) or certain medications for seizures should check with their physician about potential interactions. Women taking T4 who become pregnant should feel confident that the medication is exactly what their own thyroid gland would otherwise make. However, they should check with their physician since the T4 dose may have to be adjusted during pregnancy (usually more hormone is needed to meet the increased demands of the mother's new increased metabolism). There are other potential problems with other drugs including iron-containing vitamins. Once again, pregnant women (and all women and men for that matter) taking iron supplements should discuss this with your physician. There are three brand name Levothyroxine tablets now available. You may want to consult with your physician or pharmacist on the most cost effective brand since recent studies suggest that none is better than the other.

Tuesday, June 05, 2007

Diagnosis of Hypothyroidism

Potential Dangers of Hypothyroidism

Because the body is expecting a certain amount of thyroid hormone the pituitary will make additional thyroid-stimulating-hormone (TSH) in an attempt to entice the thyroid to produce more hormone. This constant bombardment with high levels of TSH may cause the thyroid gland to become enlarged and form a goiter (termed a "compensatory goiter"). Our goiter page goes into this topic in detail, and outlines that a deficiency of thyroid hormone is a common cause of goiter formation. Left untreated, the symptoms of hypothyroidism will usually progress. Rarely, complications can result in severe life-threatening depression, heart failure or coma.
Hypothyroidism can often be diagnosed with a simple blood test. In some persons, however, its not so simple and more detailed tests are needed. Most importantly, a good relationship with a good endocrinologist will almost surely be needed.
Hypothyroidism is completely treatable in many patients simply by taking a small pill once a day! Once again, however, we have made a simplified statement and its not always so easy. There are several types of thyroid hormone preparations and one type of medicine will not be the best therapy for all patients. Many factors will go into the treatment of hypothyroidism and it is different for everybody.
Diagnosis of Hypothyroidism
Since hypothyroidism is caused by too little thyroid hormone secreted by the thyroid, the diagnosis of hypothyroidism is based almost exclusively upon measuring the amount of thyroid hormone in the blood. There are normal ranges for all thyroid hormones which have been calculated by computers which measured these hormones in tens of thousands of people. If your thyroid hormone levels fall below the normal range, that is consistent with hypothyroidism These tests are very accurate and reliable and are so routine that they are available to everybody.
hypo = too little
thyroidism = disease of the thyroid
Thus, hypo-thyroidism = a disease of too little thyroid activity
The idea is to measure blood levels of T4 and TSH.
In the typical person with an under-active thyroid gland, the blood level of T4 (the main thyroid hormone) will be low, while the TSH level will be high. This means that the thyroid is not making enough hormone and the pituitary recognizes it and is responding appropriately by making more Thyroid Stimulating Hormone (TSH) in an attempt to force more hormone production out of the thyroid. In the more rare case of hypothyroidism due to pituitary failure, the thyroid hormone T4 will be low, but the TSH level will also be low. The thyroid is behaving "appropriately" under these conditions because it can only make hormone in response to TSH signals from the pituitary. Since the pituitary is not making enough TSH, then the thyroid will never make enough T4. The real question in this situation is what is wrong with the pituitary? But in the typical and most common form of hypothyroidism, the main thyroid hormone T4 is low, and the TSH level is high.
The next question is: When is low too low, and when is high too high? Blood levels have "normal" ranges, but other factors need to be taken into account as well, such as the presence or absence of symptoms. You should discuss your levels with your doctor so you can interpret how they are helping (or not?) fix your problems.

Oh, if only it were this simple all the time!
Although the majority of individuals with hypothyroidism will be easy to diagnose with these simple blood tests, many millions will have this disease in mild to moderate forms which are more difficult to diagnose. The solution for these people is more complex and this is due to several factors. First we must realize that not all patients with hypothyroidism are the same. There are many degrees of this disease from very severe to very mild. Additionally, and very importantly, we cannot always predict just how bad (or good) an individual patient will feel just by examining his/her thyroid hormone levels. In other words, some patients with very "mild" deviations in their thyroid laboratory test results will feel just fine while others will be quite symptomatic. The degree of thyroid hormone abnormalities often, but NOT ALWAYS will correlate with the degree of symptoms. It is important for both you and your physician to keep this in mind since the goal is not necessarily to make the lab tests go into the normal range, but to make you feel better as well! We must also keep in mind that even the "normal" thyroid hormone levels in the blood have a fairly large range, so even if a patient is in the "normal" range, it may not be the normal level for them.
For the majority of patients with hypothyroidism, taking some form of thyroid hormone replacement (synthetic or natural, pill or liquid, etc) will make the "thyroid function tests" return to the normal range, AND, this is accompanied by a general improvement in symptoms making the patient feel better. This does not happen to all individuals, however, and for these patients it is very important to find an endocrinologist who will listen and be sympathetic. (We aim to help you find this type of doctor.) Because most patients will be improved (or made completely better) when sufficient thyroid hormone is provided on a daily basis to make the hormone levels in the blood come into the normal range, physicians will often will rely on test results to determine when a patient is on the appropriate dose and therefore doing well. Remember, these tests have a wide normal range.

Monday, June 04, 2007

Hypothyroidism: Too little thyroid hormone

Hypothyroidism: Introduction, Causes, and Symptoms of Hypothyroidism

  • Hypothyroidism is a condition in which the body lacks sufficient thyroid hormone.

Since the main purpose of thyroid hormone is to "run the body's metabolism", it is understandable that people with this condition will have symptoms associated with a slow metabolism. Over five million Americans have this common medical condition. In fact, as many as ten percent of women may have some degree of thyroid hormone deficiency. Hypothyroidism is more common than you would believe...and, millions of people are currently hypothyroid and don't know it!

  • There are two fairly common causes of hypothyroidism.

The first is a result of previous (or currently ongoing) inflammation of the thyroid gland which leaves a large percentage of the cells of the thyroid damaged (or dead) and incapable of producing sufficient hormone. The most common cause of thyroid gland failure is called autoimmune thyroiditis (also called Hashimoto's thyroiditis), a form of thyroid inflammation caused by the patient's own immune system. The second major cause is the broad category of "medical treatments". As noted on a number of our other pages, the treatment of many thyroid conditions warrants surgical removal of a portion or all of the thyroid gland. If the total mass of thyroid producing cells left within the body are not enough to meet the needs of the body, the patient will develop hypothyroidism. Remember, this is often the goal of the surgery as seen in surgery for thyroid cancer. But at other times, the surgery will be to remove a worrisome nodule, leaving half of the thyroid in the neck undisturbed. Sometimes (often), this remaining thyroid lobe and isthmus will produce enough hormone to meet the demands of the body. For other patients, however, it may become apparent years later that the remaining thyroid just can't quite keep up with demand. Similarly, goiters and some other thyroid conditions can be treated with radioactive iodine therapy. The aim of the radioactive iodine therapy (for benign conditions) is to kill a portion of the thyroid to prevent goiters from growing larger, or producing too much hormone (hyperthyroidism). Occasionally, (often?) the result of radioactive iodine treatment will be that too many cells are damaged so the patient often becomes hypothyroid a year or two later. This is O.K. and usually greatly preferred over the original problem. There are several other rare causes of hypothyroidism, one of them being a completely "normal" thyroid gland which is not making enough hormone because of a problem in the pituitary gland. If the pituitary does not produce enough Thyroid Stimulating Hormone (TSH) then the thyroid simply does not have the "signal" to make hormone, so it doesn't.

Symptoms of Hypothyroidism

  • Fatigue
  • Weakness
  • Weight gain or increased difficulty losing weight
  • Coarse, dry hair Dry, rough pale skin
  • Hair loss
  • Cold intolerance (can't tolerate the cold like those around you)
  • Muscle cramps and frequent muscle aches
  • Constipation
  • Depression
  • Irritability
  • Memory loss
  • Abnormal menstrual cycles
  • Decreased libido

Each individual patient will have any number of these symptoms which will vary with the severity of the thyroid hormone deficiency and the length of time the body has been deprived of the proper amount of hormone. Some patients will have one of these symptoms as their main complaint, while another will not have that problem at all and will be suffering from a different symptom. Most will have a combination of a number of these symptoms. Occasionally, some patients with hypothyroidism have no symptoms at all, or they are just so subtle that they go unnoticed.

Note: Although this may sound obvious, if you have these symptoms, you need to discuss them with your doctor and probably seek the skills of an endocrinologist. If you have already been diagnosed and treated for hypothyroidism and you continue to have any or all of these symptoms, you need to discuss it with your physician. Although treatment of hypothyroidism can be quite easy in some individuals, others will have a difficult time finding the right type and amount of replacement thyroid hormone.