Symptoms of Hypothyroidism

When your thyroid gland is underactive (called hypothyroidism) and produces too little hormone, your metabolism slows down and your organs' ability to function normally is diminished. This may lead to a variety of symptoms, including weight gain, fatigue, depression, dry skin, brain fog, cold intolerance, muscle cramps, and constipation. Without treatment with thyroid hormone replacement, a goiter (an enlarged thyroid gland) may develop, as well as other complications like high cholesterol, nerve pain, anemia, and infertility.

It's also worth noting that the symptoms of hypothyroidism are often non-specific, easily missed, or attributed to stress, aging, or some other cause. It is only by looking at symptoms in their totality that people (and their doctors) begin to suspect an underactive thyroid gland. 

Frequent Symptoms

The symptoms of hypothyroidism tend to be mild or even unnoticeable when the disease develops gradually, but more dramatic when it develops rapidly. Moreover, the symptoms vary greatly from person to person; there is no single symptom that definitively clinches a diagnosis of hypothyroidism. 

For instance, while weight gain is common in people with hypothyroidism, many people with an underactive thyroid are of normal weight or even thin.

Slowing of Metabolic Processes

Some of the major symptoms and signs that may manifest in hypothyroidism (as a result of a slowed metabolism) include:

• Fatigue and sleepiness
• Slowed movement and speech
• Intolerance to cold 
• Weight gain
• Slow heart rate
• Sluggish reflexes
• Constipation 
• Shortness of breath when exercising 
• Muscle cramps and stiffness, in addition to weakness

Skin/Hair/Nail Changes

Due to decreased blood flow, water retention, and slow processes (for example, hair regrowth), the following skin, hair, and nail changes are seen in hypothyroidism:

• Pale, cool, and thick or "doughy" skin 
• Dry, brittle hair, and hair loss, especially near the outer edge of the eyebrows
• Brittle, dull, and thin nails
• Decreased sweating
• Swelling of the hands, face, and eyelids (called edema)

"Brain Fog" 

Another symptom commonly described in connection with hypothyroidism is "brain fog." While this is not a medical term, per se, it has become a well-recognized description of a group of cognitive symptoms that are often used by patients and doctors alike. Brain fog may involve:

• Difficulty concentrating
• Short-term and long-term memory problems
• Forgetfulness
• Lack of focus
• Feeling "spaced out"
• Confusion
• Difficulty thinking clearly

The reason brain fog may occur in hypothyroidism is because your brain requires sufficient levels of thyroid hormone in order to function properly. 

Psychiatric Problems

Hypothyroidism may mimic the symptoms of depression. Fatigue, sleepiness, slowing of speech, in addition to a lack of interest in personal relationships and general apathy, are signs of depression and hypothyroidism.

Sexual and Reproductive Problems 

For some women with hypothyroidism, their first and perhaps the biggest clue is a history of menstrual and reproduction problems, including missed or frequent periods, heavy bleeding, recurrent miscarriage, repeated failure to conceive, or failed assistive reproduction treatments.

Over half of men with hypothyroidism experience decreased libido, erectile dysfunction, and delayed ejaculation.

Rare Symptoms

In a person with severe hypothyroidism, myxedema may occur. This skin condition involves the deposition of connective tissue components (mostly hyaluronic acid) in the lower layer of the skin, causing symptoms and signs like:

• Coarse hair and skin
• Puffiness of the face or all over
• Tongue enlargement
• Hoarseness

In Children

The cause of hypothyroidism in children can either be congenital (meaning inherited from your parents) or acquired (caused by other conditions such as Hashimoto's disease, iodine deficiency, or radiation treatment).

Congenital Hypothyroidism

The most common cause of congenital hypothyroidism is thyroid dysgenesis wherein the thyroid gland is either missing, deformed, or severely underdeveloped.

Most newborns with congenital hypothyroidism will have no signs of the disease. 

Another telltale sign is prolonged jaundice. This is when the yellowish color of a newborn's skin, seen in around 50 percent of full-term babies, persists for longer than two weeks.

Acquired Hypothyroidism

Hashimoto's disease (also known as Hashimoto's thyroiditis) is, by far, the most common cause of hypothyroidism in children. It is an autoimmune disorder in which the immune system malfunctions and launches an attack on healthy thyroid tissue.

One of the characteristic signs is the swelling of the neck caused by the enlargement of the thyroid gland (goiter).

Other symptoms of hypothyroidism include:

• Short stature or deceleration of growth
• Rough, dry skin
• Constipation
• Cold intolerance
• Headaches
• Fatigue
• Excessive sleeping
• Vision problems
• Easy bruising
• Milky nipple discharge (called galactorrhea)
• Early puberty (mostly seen in children with severe, longstanding disease)
• Delayed puberty (often the first obvious sign in the teen years)
• Menstrual irregularities

Complications

A number of medical conditions may occur as a result of hypothyroidism, especially when untreated or uncontrolled. 

Goiter

Some people with hypothyroidism experience thyroid enlargement known as a goiter. Your goiter can range from slight enlargement, which may have no other symptoms, to a substantial increase in size that is symptomatic.

If you have a large goiter, you may feel swelling or general discomfort in the neck area. Scarves or ties may feel uncomfortable due to neck enlargement. In some cases, your neck and/or throat may be sore or tender.

Less commonly, swallowing or even breathing can become difficult if a goiter is blocking your windpipe or esophagus.

Peripheral Neuropathy

Hypothyroidism is known to cause a condition known as peripheral neuropathy, which causes abnormal localized sensations and pain such as:

• Numbness
• Burning, tingling, or a "pins-and-needles" sensation
• Muscle weakness
• Hypersensitivity to touch or temperature

Although the association between thyroid function and peripheral neuropathy isn't fully understood, it is believed that hypothyroidism leads to fluid retention, resulting in swollen tissues.

One of the areas commonly affected by this fluid retention is the wrist, where nerves travel through a channel of soft tissue known as the carpal tunnel. When pressure is exerted in this area, it can result in carpal tunnel syndrome. 

Symptoms of carpal tunnel syndrome may begin with burning and tingling in the palm of the hand and fingers, especially the thumb, index finger, and middle finger.

This discomfort is often worse at night, causing a person to wake up in the morning feeling like they need to "wring their wrist out."

Anemia

A deficiency of thyroid hormone impairs the production of red blood cells in your bone marrow, the spongy tissue that lies in the center of certain bones. With this, anemia develops, causing symptoms like:

• Fatigue and weakness
• Paleness
• Fast or irregular heartbeats
• Feeling faintish
• Shortness of breath

High Cholesterol

When the thyroid gland produces too little hormone, your body's ability to process cholesterol becomes impaired. This can lead to elevated total cholesterol and LDL levels.

Besides high cholesterol, other heart-related complications associated with hypothyroidism include high blood pressure and fluid around the heart (pericardial effusion). 

Myopathy

Myopathy (or muscle disease) may result from an underactive thyroid gland. People with hypothyroidism-induced myopathy often complain of muscle pain and stiffness, along with proximal muscle weakness that can make simple activities like rising from a chair, climbing stairs, or washing hair difficult.

Infertility and Pregnancy Problems

Besides the fact that untreated hypothyroidism can lead to menstrual irregularities, which can lead to infertility, research suggests that hypothyroidism puts a pregnant woman at a higher risk for pregnancy loss, placental abruption, preterm delivery, and neonatal death. 

When to See a Doctor

If you are worried that you or a loved one is experiencing one or more symptoms of hypothyroidism, call your doctor for an appointment. In addition to a medical history and physical examination, your he or she can perform a blood test called the thyroid-stimulating hormone (TSH) test, which can rule in or out a thyroid problem.

Lastly, if you are considering pregnancy or are pregnant and taking thyroid hormone replacement medication, be sure to work with your doctor to ensure that your thyroid hormone level is optimized for the health of both you and your baby.