How is thyroid storm diagnosed?

Thyroid storm is a clinical diagnosis that relies on careful assessment of historical information, physical examination findings, and laboratory test results. The greatest hurdle that must be overcome in establishing a diagnosis of thyroid storm may involve suspecting it in the first place, as there are a range of life-threatening disorders that may present with fevers, accelerated heart rates, gastrointestinal disturbances, and mental status changes. Some attempts have been made to outline scoring systems that use specific criteria to estimate the likelihood and severity of thyroid storm.

In many cases of suspected thyroid storm historical information must be gathered from friends and family members, as patients may be too agitated or confused to provide accurate details. Questions may focus on searching for clues relating to reported symptoms or changes in behavior that may be consistent with unrecognized Graves’ disease. In cases that develop in the setting of previously diagnosed Graves’ disease, friends and family members may be able to provide information about prior treatment or compliance with therapy. Physical examination may focus on tracking the profile of fevers along with changes in heart rates and abnormal heart rhythms. Thyroid storm may be associated with accelerated heart rates that do not slow down when fevers are brought under control. The thyroid gland may be carefully inspected to search for any evidence of enlargement or increased blood flow. The eyes may be inspected to check for signs of thyroid eye disease, and the skin may be inspected to check for signs of pretibial myxedema or changes in texture. Review of laboratory tests may focus on determining whether measurements of TSH and thyroid hormone levels reveal any evidence of underlying thyrotoxicosis. It is interesting to note that while levels of thyroid hormone measured in patients with confirmed thyroid storm may be increased, they are often not much higher than levels measured in patients with uncomplicated Graves’ disease. Patients with thyroid storm may be noted to have increased glucose levels, increased calcium levels, increased white blood cell counts, and characteristic patterns of changes in blood tests that measure the function of the liver.

An important consideration in the evaluation of a patient with suspected thyroid storm is the question of what may have triggered its onset. A thorough evaluation will usually focus on searching for any evidence of an underlying infection or unsuspected illness that may require treatment.