Acquired Hypothyroidism - Causes, Symptoms, Diagnosis, and Treatment

What Is Hypothyroidism?

A small butterfly-shaped endocrine gland on the anterior part of the neck is called the thyroid gland, which produces thyroid hormone. When the secretion of the thyroid hormone is less than usual and cannot meet the body's requirements, that results in hypothyroidism. Although the symptoms of hypothyroidism are not evident in the early stages, it produces several chronic medical conditions like cardiac problems, fertility issues, obesity, and joint aches.

What Is Acquired Hypothyroidism?

Acquired hypothyroidism is similar to hypothyroidism in most cases, except that it is acquired after birth. It is sometimes known by the name Hashimoto's thyroiditis.

Acquired hypothyroidism equally affects children of both genders and is a permanent condition that requires lifelong treatment; it is one of the most common conditions in children.

What Are the Causes of Acquired Hypothyroidism?

1. Autoimmune Diseases:

A significant cause of acquired hypothyroidism is an autoimmune disorder called Hashimoto's thyroiditis. Like any autoimmune condition, the body's immune system attacks the thyroid tissues resulting in an underactive thyroid. Although the exact cause of this autoimmune condition is not really in own genetic factors and environmental factors are considered a trigger factor.

2. Surgery to the Thyroid Gland:

When a part or whole of the thyroid gland is removed during a surgical procedure, it can result in acquired hypothyroidism requiring lifelong synthetic thyroid hormone administration.

3. Hyperthyroidism Treatment:

Antithyroid medications or radioactive Iodine are used to treat hyperthyroidism to reduce thyroid hormone production, thereby bringing back normal thyroid function. However, sometimes it can lead to underactive thyroid by decreasing the ability of thyroid production.

4. Medicines:

Certain hypothyroidism prescription such as Lithium used in the treatment of psychiatric disorders has an essential role in reducing thyroid hormone levels.

5. Radiation Therapy:

Radiotherapy used in treating head and neck cancers also results in hypothyroidism.

6. Pituitary Tumor:

A benign tumor of the pituitary gland results in reduced production of the thyroid-stimulating hormone, leading to hypothyroidism.

7. Iodine Deficiency:

Iodine is very much needed for thyroid hormone production. When the amount of Iodine intake is less, hypothyroidism occurs. On the contrary, increased consumption of Iodine also causes hypothyroidism, but only in individuals who already have hypothyroidism.

8. Pregnancy:

During pregnancy, risk factors associated with hypothyroidism include preeclampsia, preterm labor, and miscarriage. In addition, it also brings about complications in the developing fetus. In some cases, hypothyroidism can also develop during or after the gestation period.

Who Is at an Increased Risk of Developing Acquired Hypothyroidism?

Women share an increased risk compared to men, and the risk is even higher in older women above the age of 60 years. The following conditions increase the risk of hypothyroidism:

• Trauma to the thyroid gland.

• Premature infants.

• Increased or reduced intake of Iodine.

• Thyroid removal surgery.

• Type 1 diabetes mellitus.

• Celiac diseases.

• Individuals who have received radiation therapy to the head and neck regions.

• Syndromes occurring due to chromosomal abnormalities like Turner syndrome, Williams syndrome, and Down syndrome.

• Pregnant women or those in their postpartum period.

How Is Acquired Hypothyroidism Manifested?

Initially, hypothyroidism does not exhibit any severe symptoms, but as age advances, the signs and symptoms become more prominent with a reduction in the rate of metabolism.

The following are the common signs and symptoms manifested in hypothyroidism:

• Skin dryness.

• Weakness.

• Muscle pain and stiffness.

• Increased cold sensitivity.

• Weight gain.

• Hoarseness of voice.

• Constipation.

• Puffiness of the face.

• Thinning down hair.

• High blood cholesterol level.

• Depression.

• Goiter or enlargement of the thyroid gland.

• Joint pain, swelling, and stiffness.

• Irregular menstrual cycle along with heavy bleeding.

• Reduced heart rate.

• Memory impairment.

In addition to the above, some unique manifestations are seen in children and adolescents.

In the case of children, the following signs and symptoms are seen:

• Reduced energy.

• Short limbs or slow growth.

• Delayed development of teeth.

• Feeling inactive.

• Less energetic.

• Poor performance in school.

The following signs and symptoms are seen in adolescents with hypothyroidism:

• Delayed puberty.

• Slurred speech.

• Drooping eyelids.

How Is Acquired Hypothyroidism Diagnosed?

The first and foremost step in diagnosing hypothyroidism is by doing a complete physical examination and collecting a proper medical history of the patient.

After this, the following diagnostic tests are recommended to help in the diagnosis of hypothyroidism:

1. Blood Examination: Hypothyroidism is diagnosed by measuring Thyroxine or T4 and Thyroid-stimulating hormone (TSH) levels in the blood. When the level of Thyroxine (thyroid hormone T4) is reduced, or the level of TSH is increased in the bloodstream, it denotes hypothyroidism. In general, when the thyroid hormone levels are reduced, the pituitary gland synthesizes TSH to stimulate the thyroid gland to produce more thyroid hormone. Therefore, the increased level of TSH is attributed to the effort made by the pituitary gland in stimulating the thyroid gland to increase its production of thyroid hormone.

2. Computed Tomography Scan: The computed tomography scan produces a more detailed image of the thyroid gland to look for abnormalities.

3. Ultrasound: The ultrasound scan helps diagnose any structural abnormalities in the thyroid gland with the help of sound waves.

What Is the Treatment for Acquired Hypothyroidism?

The treatment for acquired hypothyroidism involves the administration of the synthetic hormone, Levothyroxine to bring the thyroid hormone levels back to normal. With the hormone intake, the cholesterol levels and other associated signs of hypothyroidism return around. However, treatment is intended throughout life. This does not mean periodic check-up is needed. It is advisable to check with the doctor at least once a year or at the intervals of checkups suggested by the doctor. It is done to make sure the dosage of Levothyroxine corresponds with the level of your TSH. In children with acquired hypothyroidism, treatment may be needed until puberty or growth. However, few may require lifelong treatment.

How Is the Dosage of Levothyroxine Determined?

Initially, a particular dose of the drug is prescribed, and the level of TSH is checked after six to eight weeks. If it turns out to be expected, then the period is increased to six months. While in patients with a severe condition or those with coronary artery diseases, the dosage is only gradually increased to ensure adjustment of the heart for the change in metabolism. Stopping the drug abruptly without the doctor's recommendation can cause thyroid hormone levels to drop.

How Should the Synthetic Hormone Levothyroxine Be Taken?

It is very effective when taken at the same time daily. When taking the drug, make sure it is taken on an empty stomach, preferably an hour before taking any food or medication in the morning or four hours after taking a meal, if taken at bedtime.

If a dose of Levothyroxine is missed, two tablets can be taken on the following day, but with the doctor's advice.

The following symptoms indicate that an increased level of Levothyroxine is taken:

• Inability to sleep.

• Palpitations.

• Trembling.

• Increased appetite.

Absorption of Levothyroxine is significantly affected when taken together with the following medications and supplements:

• Antacids that contain Aluminium hydroxide.

• Iron supplements.

• Calcium supplements.

What Are the Complications of Acquired Hypothyroidism?

1. Cardiac problems and heart failure.

2. Myxedema (severe hypothyroidism characterized by cold insensitivity, lack of consciousness, lethargy, etc.).

3. Depression and delayed mental functioning.

4. Goiter (thyroid gland enlargement).

5. Interferes ovulation (release of the egg for fertilization in a female) and might cause fertility problems.

6. Peripheral neuropathy (weakness of the nerves of the arms and legs that causes tingling, pain, and burning sensation in the affected area).

7. Congenital disabilities in children born to women with hypothyroidism.

Conclusion:

Hypothyroidism is an endocrine disorder for which the administration of the synthetic hormone, Levothyroxine can be the best treatment. Therefore, it is advisable to consult with your doctor at the earliest if you have any hypothyroidism symptoms. Hypothyroidism due to Iodine deficiency can be easily prevented by including table salt in your diet.