8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 1/12

Thyroid Problems Overview

The thyroid gland is located on the front part of the neck below the thyroid cartilage (Adam's

apple). The gland produces thyroid hormones, which regulate body metabolism. Thyroid

hormones are important in regulating body energy, the body's use of other hormones andvitamins, and the growth and maturation of body tissues.

Diseases of the thyroid gland can result in either production of too much (overactive thyroiddisease or hyperthyroidism), too little (underactive thyroid disease or hypothyroidism) thyroid

hormone, thyroid nodules, and/or goiter. All types of thyroid problems in women are much morecommon than thyroid problems in men.

y  Production of thyroid hormones: The process of hormone synthesis begins in a part of the brain

called the hypothalamus. The hypothalamus releases thyrotropin-releasing hormone (TRH). The

TRH travels through the venous plexus located in the pituitary stalk to the pituitary gland, also in

the brain. In response, the pituitary gland then releases thyroid-stimulating hormone (TSH) intothe blood. The TSH travels to the thyroid gland and stimulates the thyroid to produce the two

thyroid hormones, L-thyroxine (T4) and triiodothyronine (T3). The thyroid gland also needs

adequate amounts of dietary iodine to be able to produce T4 and T3.

y  Regulation of thyroid hormone production: To prevent the overproduction or underproduction

of thyroid hormones, the pituitary gland can sense how much hormone is in the blood and

adjust the production of hormones accordingly. For example, when there is too much thyroid

hormone in the blood, TRH and TSH production are both decreased. The sum effect of this is to

decrease the amount of TSH released from the pituitary gland and to reduce production of 

thyroid hormones from the thyroid gland to restore the amount of thyroid hormone in the

blood to normal. Defects in these regulatory pathways may result in hypothyroidism

(underactive thyroid problem) or hyperthyroidism (overactive thyroid problem).

y  Thyroid goiter: Thyroid goiter is any enlargement of the thyroid that can occur with

hyperthyroidism or hypothyroidism but also with benign and malignant (cancerous) nodules.

Worldwide, the most common cause of goiter is iodine deficiency. Although it used to be very

common in the U.S., it is now less common with the use of iodized salt. Multiple nodules in the

thyroid are very common, but only about 5% of the nodules are a thyroid cancer. Thyroid cancer

is diagnosed after a thyroid ultrasound exam and a needle aspiration biopsy of the nodule.

Thyroid Problems Symptoms

What Are the Symptoms of Thyroid Problems?

Symptoms of thyroid problems depends on the age of the person and the exact problem with the

thyroid. For example, some symptoms of hypothyroidism in children include:

y  Symptoms similar to adult symptoms

y  Excessive fatigue

y  Poor growth

y  Poor school performance

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 2/12

Symptoms of hypothyroidism in adults include:

y  Easy fatigue, exhaustion

y  Poor tolerance to cold temperatures

y  Constipation

y  Carpal tunnel syndrome (pain at the wrists and numbness of the hands)

Symptoms of hyperthyroidism in adults include:

y  Insomnia

y  Hand tremors

y  Nervousness...

Hypothyroidism in Pregnancy 

 Newly diagnosed hypothyroidism in pregnancy is rare because most women with untreated

hypothyroidism do not ovulate or produce mature eggs in a regular manner, which makes itdifficult for them to conceive.

It is a difficult new diagnosis to make based on clinical observation. The signs and symptoms of hypothyroidism (fatigue, poor attention span, weight gain, numbness, and tingling of the hands

or feet) are also prominent symptoms of a normal pregnancy.

Undiagnosed hypothyroidism during pregnancy increases the chance of stillbirth or growthretardation of the fetus. It also increases the chance that the mother may experience

complications of pregnancy such as anemia, eclampsia, and placental abruption.

Probably the largest group of women who will have hypothyroidism during pregnancy are thosewho are currently on thyroid hormone replacement. The ideal thyroxine replacement dose (for 

example, levothyroxine [Synthroid, Levoxyl, Levothroid, Unithroid]) during pregnancy may rise by 25% to 50% during pregnancy. It is important to have regular checks of T4 and TSH blood

levels as soon as pregnancy is confirmed; and frequently through the first 20 weeks of pregnancyto make sure the woman is taking the correct medication dose.

Hyperthyroidism in Pregnancy 

 Newly diagnosed hyperthyroidism occurs in about 1 in 2,000 pregnancies. Grave's disease

accounts for 95% of cases of hyperthyroidism newly diagnosed during pregnancy.

As with hypothyroidism, many symptoms of mild hyperthyroidism mimic those of normal pregnancy. However, anyone experiencing symptoms such as significant weight loss, vomiting,

increased blood pressure, or persistently fast heart rate should have blood tests to evaluatewhether hyperthyroidism is present.

Untreated hyperthyroidism does cause fetal and maternal complications including poor weight

gain and tachycardia (an abnormally fast heart rate).

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 3/12

Treatment of hyperthyroidism during pregnancy is primarily medical. Propylthiouracil or methimazole (Tapazole) are the usual first-line agents to block the synthesis of thyroid hormone.

They appear to be equally effective and have the same rate of side effects. The rate of sideeffects of each medication is not increased in pregnancy.

Iodine will cross the placenta, so its use in either a thyroid scan or in treatment with radioactiveiodine is prohibited in pregnancy.

One positive note for women with hyperthyroidism is that those with Grave's disease or 

Hashimoto's thyroiditis may have improvement in their symptoms during pregnancy.

G oiter in Pregnancy 

It is common for a goiter to enlarge slightly during pregnancy. It is more common when the

mother lives in an area of iodine deficiency. In the United States, the average intake of iodine is

adequate but can be low if someone avoids consumption of milk, eggs, and iodized salt.  Not all

 prenatal vitamins contain iodine, but it is recommended that only prenatal vitamins that containiodine should be used during pregnancy.

Postpartum Thyroid Disease

Some women may have thyroiditis that usually occurs within 3 to 6 months after giving birth. It

also may occur after miscarriage. The classic clinical picture is a woman who will first havesymptoms of hyperthyroidism, followed by hypothyroidism, culminating in normal thyroid

function.

Women with type I diabetes have a 25% risk of developing postpartum thyroid dysfunction.

Consult your doctor if you have symptoms of hypothyroidism or hyperthyroidism after 

 pregnancy or miscarriage.

TThhyyrrooiidd PPrroobblleemmss CCaauusseess 

Hypothyroidism Causes 

y  Loss of thyroid tissue: Treatment of hyperthyroidism by radioactive destruction of thyroid

tissue or surgical removal of thyroid tissue can result in hypothyroidism.

y  Antithyroid antibodies: These may be present in people who have diabetes, lupus,

rheumatoid arthritis, chronic hepatitis, or Sjogren's syndrome. These antibodies may cause

decreased production of thyroid hormones.

y  Congenital: Hypothyroidism can be present from birth. This is commonly discovered early

with nationwide newborn screening for this disease.

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 4/12

y  Defects in the production of thyroid hormone: Hashimoto's thyroiditis occurs

when there are defects in the production of thyroid hormone, resulting in an increased amount

of TSH. The increased TSH results in a goiter (enlargement of the thyroid gland itself that can be

seen as an obvious swelling in the front of the neck).

y  Medications: Some medications, particularly lithium (Eskalith, Lithobid), may cause a drug-induced hypothyroidism.

Hyperthyroidism Causes 

y  Grave's disease: This thyroid condition results from abnormal stimulation of the thyroid

gland by a material in the blood termed the thyroid stimulating immunoglobulin (TSI). TSI

overstimulates the thyroid causing a goiter. It also causes Grave's eye disease, including a "bug-

eyed" look and "frightened stare." This can progress to severe eye pain or eye muscle weakness

causing tearing and double vision. It also causes raised, thickened skin over the shins or tops of 

the feet.

y  Toxic multinodular goiter: This occurs when part of the thyroid gland produces thyroid

hormones all by itself, without regard to TSH stimulation. It usually occurs in people with a long-

standing goiter, usually in the elderly. Toxic multinodular goiter is different from Grave's disease

because of the general lack of eye complications and less severe signs of hyperthyroidism.

y  Thyroiditis: This inflammatory disorder of the thyroid gland includes such conditions as de

Quervain's thyroiditis or Hashimoto's thyroiditis. In these conditions, you may have periods of 

increased thyroid hormone release due to the inflammation, causing a hyperthyroid state. As

thyroid failure occurs due to the inflammatory response, hypothyroidism may occur.

y  Pituitary adenoma: This tumor of the pituitary gland causes independent TSH production

leading to overstimulation of the thyroid gland.

y  Drug-induced hyperthyroidism: This is most commonly caused the heart medication

amiodarone (Cordarone). It may be prevented by monitoring this possible side effect and

weighing them against the benefits of using this heart medication.

Goiter or Nodules Causes 

y  Most of the time thyroid nodules and thyroid goiters do not cause any symptoms. Some goiters

are found because of the thyroid hormone overproduction or underproduction from the thyroidgland. Some nodules are found because a patient or doctor sees or feels a lump in the neck

y  Nodular or multinodular goiter: This is a condition in which multiple nodules form in

the thyroid. There are only two conditions that cause thyroid enlargement and nodules: 1)

external radiation exposure, or 2) iodine deficiency. Often several members of a family will have

an enlarged goiter as the condition can be inherited

y  Thyroid cancer: There are several types of thyroid cancer. The most common type, papillary

thyroid carcinoma, occurs in more than 85% of cases. This type of cancer can be caused by

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 5/12

radiation exposure as a child or adolescent, including therapeutic radiation used in the

treatment of cancers or in accidents such as the Chernobyl nuclear disaster.

When to Seek Medical Care

The signs and symptoms of hypothyroidism and hyperthyroidism typically develop slowly over a

 period of weeks to months. If an individual has prolonged symptoms or signs of either condition,

call a doctor to be evaluated.

Untreated hypothyroidism may have severe effects on the brain as well as cause

intestinal obstruction and inability of the heart to beat effectively. An infection, exposure to cold,trauma, and certain medications may often cause a worsening of hypothyroidism.

Seek immediate attention at a hospital's emergency department if you have these signs andsymptoms associated with thyroid problems.

y  Shortness of breath

y  Abdominal pain

y  Vomiting

y  Confusion

y  Coma

Severe hyperthyroidism, called thyrotoxic crisis (thyroid storm), may be life-

threatening because of the effects it has on the heart and brain. It often occurs in people who areuntreated or are receiving inadequate treatment for thyroid problems. A severe infection can alsocause a thyrotoxic crisis.

Seek immediate attention at a hospital's emergency department if you have these signs and

symptoms associated with thyroid problems.

Chest pain , Rapid and/or irregular heartbeat, Shortness of breath, Abdominal pain, Vomiting,

Extreme agitation or irritability, Dizziness, Disorientation (person has no knowledge of the date or

location), Coma

Severe goiter or nodule problem: Seek immediate attention at a hospital's emergencydepartment if you have these signs and symptoms associated with thyroid problems.

y  Shortness of breath especially with stridor (a whistling sound in your neck when you breathe)

y  Extreme pain in your thyroid gland that prevents you from swallowing

y  Sudden enlargement of your thyroid gland, especially if associated with problems breathing or

swallowing

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 6/12

y  Pain and high fever with the thyroid enlargement

Thyroid Problems Diagnosis

The medical history and physical exam are important parts of the evaluation for thyroid

 problems. The health care practitioner will focus on eye, skin, cardiac (heart), and neurologicfindings.

Blood tests 

y  Thyroid-stimulating hormone (TSH): In most cases, this is the single most useful lab test in

diagnosing thyroid disease. When there is an excess of thyroid hormone in the blood, as in

hyperthyroidism, the TSH is low. When there is too little thyroid hormone, as in hypothyroidism,

the TSH is high.

y  Free (T4): T4 is one of the thyroid hormones. High T4 may indicate hyperthyroidism. Low T4 may

indicate hypothyroidism.

y  Triiodothyronine (T3): T3 is another one of the thyroid hormones. High T3 may indicate

hyperthyroidism. Low T3 may indicate hypothyroidism.

y  TSH receptor antibody (TSI): This antibody is present in Grave's disease.

y  Antithyroid antibody: This antibody is present in Hashimoto's and Grave's disease.

Nuclear thyroid scan: During this scan a small amount of radioactive iodine is swallowedor a similar material 99m-technetium, is injected into the blood, and then an imaging study of the

thyroid is taken that reveals localization of the radioactivity. Increased uptake of the radioactivematerial in the thyroid gland indicates hyperthyroidism, while decreased uptake is present in

hypothyroidism. This test should not be performed on women who are pregnant.

Thyroid ultrasound: Thyroid ultrasound helps to determine the size and number as well as

the different types of nodules in the thyroid gland. This exam can also detect if there are enlarged parathyroid glands or lymph nodes near the thyroid gland.

Fine-needle aspiration: During this procedure, a small needle is inserted into the thyroid

gland in order to get a sample of thyroid tissue, usually from a nodule. This test can be done in ahealth care practitioner's office without special preparations. The tissue is then observed under a

microscope by a pathologist to look for any signs of cancer.

Computerized axial tomography (CT) scan: A CT scan is occasionally used to look for 

the extent of a large goiter into the upper chest or to look for narrowing or displacement of thetrachea (breathing tube) from the goiter.

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 7/12

Thyroid Problems Treatment 

Thyroid Problems Medications

Medications for Hyperthyroidism 

y  Beta-blockers: This class of medication works by blocking many of the body's responses to

hyperthyroidism. It decreases tremor, nervousness, and agitation. It also reduces the fast heart

rate. Beta blocker tablets are prescribed to a patient with mild to moderate symptoms of 

hyperthyroidism, and as an IV preparation to the person with the severe form of 

hyperthyroidism (thyrotoxic crisis).

y  Propylthiouracil: This antithyroid drug works by blocking thyroid hormone synthesis. It

takes several months after starting the medication for the full therapeutic effect to be achieved.

Common mild side effects include an itchy rash. More rare, serious side effects include a

decrease in white blood cell count, which can decrease the ability to fight off infection.Therefore, a high fever should prompt a call to the doctor. This medication can rarely cause liver

dysfunction.

y  Methimazole (Tapazole): This antithyroid drug also works by blocking thyroid hormone

synthesis. It may take slightly longer than propylthiouracil to achieve its full effect. It has similar

side effects as propylthiouracil.

y  Iodide (Lugol's solution, Strong iodine): This medication works by inhibiting the

release of thyroid hormone from the overfunctioning thyroid gland. It must be used in

conjunction with an antithyroid drug because the iodine can be used to increase the amount of 

thyroid hormone produced and worsen the hyperthyroidism. Common side effects include

nausea and a metallic taste in the mouth.

y  Radioactive iodine therapy: An endocrinologist or nuclear medicine specialist can treat

overactive thyroid conditions with radioactive iodine swallow. This is generally a different type

of radioactive iodine than used for diagnostic scans. This treatment takes several months to

work by scarring down the thyroid gland, resulting in a smaller- sized gland, often accompanied

by hypothyroidism.

Medications for Hypothyroidism 

y  L-thyroxine (Synthroid, Levoxyl, Levothroid, Unithroid): This medication is the

mainstay of thyroid hormone replacement therapy in hypothyroidism. This is a synthetic form of 

thyroxine. This is exactly the same hormone that the thyroid makes. The body tissues convert it

to the active product L-triiodothyronine. Side effects are rare, and it has an excellent safety

record.

y  L-triiodothyronine: This is rarely used alone as thyroid hormone replacement, because it

has a much shorter persistence in the blood than L-thyroxine. Its use can cause rapid increases

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 8/12

in L-triiodothyronine concentration, which can be dangerous in the elderly and in people with

cardiac disease. It may be used in combination with L-thyroxine for people who have poor

symptomatic relief with L-thyroxine alone.

y  Thyroid extract or "natural" thyroid hormone: This is dried and powdered pig

thyroid gland. The hormone is not purified and the exact amount of T4 and T3 can be variable.This is not recommended as a thyroid hormone replacement. There is an excess of T3 in this

preparation.

Medications for Thyroid Nodules and Goiter 

y  If the thyroid function is abnormally high or low, then the treatments are as described above.

y  If the thyroid function is normal with thyroid nodules, there are no good medical treatments to

shrink the nodules. Many years ago it was standard of care to give levothyroxine to "shrink"

nodules, but it was found after careful research that administration of thyroid hormone rarely

shrinks large nodules.

y  An emerging treatment of nontoxic goiters/nodules is radioactive iodine therapy. This therapy is

used commonly in Europe and South America but is not yet commonly used in all patients in the

United States. This treatment is considered when a patient has a large goiter and there are

medical problems that prevent a surgical treatment.

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 9/12

T  T  h h  y  y  r  r  o o i id d P P  r  r  o ob b l l e e  m m s  s  

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 10/12

 

CardiovascularDisease

Heart disease or cardiovascular diseases is the class of diseases thatinvolve the heart or blood vessels (arteries and veins). While the term technically

refers to any disease that affects the cardiovascular system (as used in MeSHC14), it is usually used to refer to those related to atherosclerosis (arterial

disease). These conditions usually have similar causes, mechanisms, andtreatments.

In practice, cardiovascular disease is treated by cardiologists, thoracic surgeons,

vascular surgeons, neurologists, and interventional radiologists, depending on the

organ system that is being treated. There is considerable overlap in thespecialties, and it is common for certain procedures to be performed by different

types of specialists in the same hospital.

Most countries face high and increasing rates of cardiovascular disease. Each year,

heart disease kills more Americans than cancer. In recent years, cardiovascular

risk in women has been increasing and has killed more women than breast

cancer.[2] A large histological study (PDAY) showed vascular injury accumulates

from adolescence, making primary prevention efforts necessary from

childhood.[3][4] 

By the time that heart problems are detected, the underlying cause

(atherosclerosis) is usually quite advanced, having progressed for decades. There

is therefore increased emphasis on preventing atherosclerosis by modifying risk 

factors, such as healthy eating, exercise and avoidance of smoking.

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 11/12

Pathophysiology

Population based studies in the youth show that the precursors of heart disease

start in adolescence. The process of atherosclerosis evolves over decades, and

begins as early as childhood. The Pathobiological Determinants of Atherosclerosis

in Youth Study demonstrated that intimal lesions appear in all the aortas and

more than half of the right coronary arteries of youths aged 7²9 years. However,

most adolescents are more concerned about other risks such as HIV, accidents,

and cancer than cardiovascular disease.

This is extremely important considering that 1 in 3 people will die fromcomplications attributable to atherosclerosis. In order to stem the tide of 

cardiovascular disease, primary prevention is needed. Primary prevention starts

with education and awareness that cardiovascular disease poses the greatest

threat and measures to prevent or reverse this disease must be taken.

Obesity and diabetes mellitus are often linked to cardiovascular disease. In fact,

cardiovascular disease is the most life threatening of the diabetic complications

and diabetics are two- to four-fold more likely to die of cardiovascular-relatedcauses than nondiabetics.

Diagnosis

Associated diagnostic markers

y  Low-density lipoprotein

y  Lipoprotein(a)

y  Apolipoprotein A1

y  Apolipoprotein Bho

Screening

Some biomarkers are thought to offer a more detailed risk of cardiovascular

disease. However, the clinical value of these biomarkers is questionable.[10] 

Currently, biomarkers which may reflect a higher risk of cardiovascular diseaseinclude:

y  Higher fibrinogen and PAI-1 blood concentrations

y  Elevated homocysteine, or even upper half of normal

y  Elevated blood levels of asymmetric dimethylarginine

y  Inflammation as measured by C-reactive protein

8/6/2019 Cvd & Thyroid

http://slidepdf.com/reader/full/cvd-thyroid 12/12

y  Elevated blood levels of brain natriuretic peptide (also known as B-type)

(BNP) [11] 

y  Elevated levels of NT-proBNP

Prevention

Evidence shows that the Mediterranean diet improves cardiovascular

outcomes.[12] As of 2010 however vitamins have not been found to be effective at

preventing cardiovascular disease.[13] 

Modifiable risk factors to improve or prevent atherosclerosis include: diet high infibers from vegetables while low in saturated fat and cholesterol; tobacco

cessation and avoidance of second-hand smoke; decreased alcohol consumption;lower blood pressures if elevated through the use of antihypertensive

medications; strict diabetes management; decrease BMI if overweight or obese;increase daily activity to 30 minutes of moderate to vigorous exercise; anddecrease emotional stress in day to day life.

Management

Cardiovascular disease is treatable with initial treatment primarily focused on diet

and lifestyle interventions. Medication may also be useful for prevention.

Prepared by:

Sharon P. Estrella

BSN 2-C