The thyroid gland is located on the front of the neck below the laryngeal prominence, and makes hormones that control metabolism.

Common hypothyroid symptoms manifest when thyroid cell damage is slow and chronic, and may include fatigue, weight gain, feeling "fuzzy headed", depression, dry skin, and constipation.

Other, rarer symptoms include swelling of the legs, vague aches and pains, decreased concentration and so on.

These symptoms include weight loss, irritability, anxiety, insomnia, fast heart rate, and fatigue.

[3] Some drugs, such as interferon, lithium, amiodarone (AIT type-2) and immune check point inhibitors can also cause thyroiditis.

Inflammatory markers such as white blood cell count, erythrocyte sedimentation rate and c-reactive protein may be elevated in some forms of thyroiditis.

For the most common type, which is known as Hashimoto's thyroiditis, the treatment is to immediately start hormone replacement.

Also, doctors may prescribe beta blockers to lower the heart rate and reduce tremors, until the initial hyperthyroid period has resolved.