Function

The thyroid is a small gland in the throat that regulates the body's metabolism. If the thyroid produces too little hormone, it leads to hypothyroidism, or low thyroid.

Causes

There are many potential causes of low thyroid. In many cases, the thyroid becomes inflamed and stops producing enough hormone, leading to symptoms of low thyroid. Alternatively, medical treatment with drugs or surgery can cause low thyroid function.

Infant Symptoms

An infant with low thyroid function likely will suffer from constipation and poor growth, will not eat well, and may be jaundiced. Low thyroid can cause failure to thrive in a baby.

Adult Symptoms

Adults suffering from low thyroid likely will become tired or even exhausted easily. In addition, someone with low thyroid function probably will gain weight, even though poor appetite is another sign of the disorder.

More Symptoms

Dry skin and hair loss also are common in low thyroid cases, as is carpal tunnel syndrome. Women who have low thyroid function are likely to have irregular menstrual periods, or even to stop menstruating entirely.

Mental Symptoms

Irritability and memory loss also can occur in a person with low thyroid function, as can depression. Patients can have all these symptoms, or just a few, and if the condition is not treated, symptoms generally will continue to get worse.

Source:

Endocrine Web: Hypothyroidism

Stop the Thyroid Madness: List of Symptoms

More Information:

eMedicineHealth: Thyroid Conditions