Krystal has Hashitmoto's Thyroditis Autoimmune Disease

From http://www.mayoclinic.org/

Hashimoto's disease is a condition in which your immune system attacks your thyroid, a small gland at the base of your neck below your Adam's apple. The thyroid gland is part of your endocrine system, which produces hormones that coordinate many of your body's activities.

The resulting inflammation from Hashimoto's disease, also known as chronic lymphocytic thyroiditis, often leads to an underactive thyroid gland (hypothyroidism). 

Signs and symptoms of hypothyroidism include:

Increased sensitivity to cold

Constipation

Pale, dry skin

A puffy face

Hoarse voice

Unexplained weight gain 

Muscle aches, tenderness and stiffness, especially in your shoulders and hips

Pain and stiffness in your joints and swelling in your knees or the small joints in your hands and feet

Muscle weakness, especially in your lower extremities

Excessive or prolonged menstrual bleeding (menorrhagia)

Depression

An underactive thyroid gland (hypothyroidism) caused by Hashimoto's disease can lead to a number of health problems:

Heart problems. 

Hashimoto's disease also may 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 gland (hypothyroidism). If left untreated, hypothyroidism can lead to an enlarged heart and, in rare cases, heart failure.

Mental health issues. 

Depression may occur early in Hashimoto's disease and may become more severe over time. Hashimoto's disease can also cause sexual desire (libido) to decrease in both men and women and can lead to slowed mental functioning.

Myxedema (miks-uh-DEE-muh). 

This rare, life-threatening condition can develop due to long-term hypothyroidism as a result of untreated Hashimoto's disease. Its signs and 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. Myxedema requires immediate emergency medical treatment.

Birth defects.

Babies born to women with untreated hypothyroidism due to Hashimoto's disease may have a higher risk of birth defects than do babies born to healthy mothers. Doctors have long known that these children are more prone to intellectual and developmental problems. There may be a link between hypothyroid pregnancies and birth defects, such as cleft palate. A connection also exists between hypothyroid pregnancies and heart, brain and kidney problems in infants. If you're planning to get pregnant or if you're in early pregnancy, be sure to have your thyroid level checked.

Goiter. 

Constant stimulation of your thyroid to release more hormones may cause the gland to become enlarged, a condition known as goiter. Hypothyroidism is one of the most common causes of goiter. Although generally not uncomfortable, a large goiter can affect your appearance and may interfere with swallowing or breathing.