Thyrotoxicosis and Thyroid Storm

Thyrotoxicosis and the more severe form-thyroid storm-are uncommon but important causes of palpitations. Symptoms and signs of mild thyrotoxicosis are those expected from catecholamine excess. Patients with mild symptoms require no immediate treatment or only symptomatic therapy in the ED. Undiagnosed or undertreated Graves' disease is the most common cause of thyrotoxicosis.

Thyroid storm is a medical emergency that may mimic or complicate other conditions such as sepsis, sympathomimetic intoxication, or drug withdrawal. Findings defining thyroid storm include the following:

• Elevated temperature +++++ (T >38.7° C, but may be as high as 41° C)
• CNS dysfunction ++++ (anxiety, emotional lability, delirium)
• Cardiovascular dysfunction
• Gastrointestinal dysfunction (nausea, vomiting, hyperdefecation or diarrhea, crampy abdominal pain)

Causes

The precise cause is unknown, but doctors suspect that the immune system is involved. The condition sometimes surfaces after an infection or pregnancy. The problem is more common among women and in people with a family history of hyperthyroidism.

Symptoms

• Anxiety
• Tremor
• Weakness
• Heat intolerance
• Weight loss
• Hyperdefecation
• Sweating
• Angina and CHF may be present in the absence of prior known heart disease and indicate either the unmasking of a previously existing condition or severe hyperthyroidism overtaxing a healthy heart.

Signs

• Sinus tachycardia is almost always present in thyrotoxicosis and serves as a marker of the severity of catecholamine excess.
• PACs and PVCs may be present.
• Atrial fibrillation ++
• Enlarged thyroid gland may be palpable or have bruit on physical examination.
• Proptosis and other eye findings indicative of Graves' disease
• Brisk reflexes

Treatment

Your doctor is likely to prescribe medication known as a thiourea drug (carbimazole, methimazole or propylthiouracil) that will reduce the output of hormone from the thyroid.

This starts off at quite a high dose, and the dose comes down slowly once the blood test returns to normal. Usually most people are able to come off the tablets after a year or two, but sometimes the tablets need to be continued for longer, or restarted.

Sometimes your doctor may prescribe another type of medication, a beta blocker, to overcome some of the worst symptoms of an over-active thyroid gland, while waiting for the specific treatment for the thyroid to take its effect.

Sometimes, in certain cases, a surgical procedure is recommended, to remove part of the thyroid gland. This is known as a partial thyroidectomy. Removing part of the overactive gland results in a drop in the amount of hormone that it produces.