thyrotoxic crisis more commonly called thyroid storm is a severe acute complication of hyperthyroidism in hyperthyroidism there's an excess of thyroid hormone and in thyroid storm the symptoms and physiologic effects of having excessive thyroid hormones are suddenly magnified normally the hypothalamus which is located at the base of the brain detects low blood levels of thyroid hormones and releases thyrotropin-releasing hormone into the hypotheseal portal system which is a network of capillaries linking the hypothalamus to the anterior pituitary the anterior pituitary then releases thyroid stimulating hormone also called thyrotropin or simply tsh tsh stimulates the thyroid gland which is a gland located in the neck that looks like two thumbs hooked together in the shape of a v the thyroid gland is made up of thousands of follicles which are small spheres lined with follicular cells follicular cells convert thyroglobulin a protein found in follicles into two iodine-containing hormones triiodothyronine or t3 and thyroxine or t4 once released from the thyroid gland these hormones enter the blood and bind the circulating plasma proteins only a small amount of t3 and t4 will travel unbound in the blood and these two hormones get picked up by nearly every cell in the body once inside the cell t4 is mostly converted to t3 where it can exert its effect t3 speeds up the cell's basal metabolic rate so as an example the cell might produce more proteins and burn up more energy in the form of sugars and fats it's as if the cells are in a bit of a frenzy t3 increases cardiac output stimulates bone reabsorption thinning out the bones and then activates the sympathetic nervous system the part of the nervous system responsible for our fight or flight response thyroid hormone is important and the occasional increase can be really useful when you need a boost to get through the final rounds of a sporting competition or when you're trying to stay warm during a snow storm now hyperthyroidism can happen a few different ways all of them result in too much thyroid hormone in a hyper metabolic state where cellular reactions are happening faster than normal the most common primary cause is graves disease an autoimmune disorder where b cells produce antibodies against several thyroid proteins these auto antibodies include thyroid stimulating immunoglobulins which bind to the tsh receptor on the follicular cells and imitate tsh another primary cause is toxic nodular goiter where one or more follicles starts generating lots of thyroid hormone in some cases it's because of a mutated tsh receptor that inappropriately keeps these follicular cells active regardless of the cause of hyperthyroidism occasionally a person can develop thyroid storm which is when the effect of having excess thyroid hormones is suddenly magnified the exact reason that this happens is unclear but there are some proposed mechanisms the first is that there may be more unbound thyroid hormone in the blood which is the active form of the hormone the second is that the level of unbound thyroid hormone may be unchanged but the tissues might become more sensitive to thyroid hormone third the body might become more sensitive to catecholamines like epinephrine or dopamine which are part of the sympathetic nervous system triggers for thyroid storm include stressors like surgery trauma infection or childbirth other triggers are abruptly stopping treatment for hyperthyroidism or taking too much thyroid hormones which is relevant for individuals that have hypothyroidism the end result is the same a state of severe hyper metabolism so all the effects of the excess thyroid hormones on the body are magnified the symptoms of thyroid storm are mostly an exaggerated version of the symptoms of hyperthyroidism which include weight loss despite an increase in appetite because of the higher basal metabolic rate heat intolerance because the body is producing more heat and rapid heart rate sweating hyperactivity anxiety and insomnia because of the effects of thyroid hormones on the sympathetic nervous system in thyroid storm heat intolerance turns to fever hyperactivity and anxiety turn into agitation confusion and can go as far as seizures and coma cardiovascular symptoms like tachycardia can turn into cardiac arrhythmias and high output cardiac failure thyroid storm can be extremely severe and can cause death if it's not quickly recognized and managed the diagnosis of thyroid storm is usually based on the severity of symptoms and can be confirmed by tests like an ecg to detect a cardiac arrhythmia typically there isn't much of a difference in thyroid hormone levels between hyperthyroidism and thyroid storm the biggest difference is how the hormone levels affect the various body systems treatment for thyroid storm requires intensive supportive care with various medications like beta blockers to treat symptoms thionamides to block thyroid hormone production as well as iodine preparations glucocorticoids and bile acid sequestrants all of these medications are aimed at reducing the amount of thyroid hormone and its effects on the body if this approach doesn't work plasmophoresis can be tried that's where blood plasma is removed thyroid hormone can also be removed and the remaining plasma is returned to the person all right as a quick recap thyroid storm is an acute life-threatening complication of hyperthyroidism where the body becomes very sensitive to the effects of excess thyroid hormone it can cause symptoms like high fever and severe tachycardia and because of its high mortality rate medications like beta blockers and thionamides have to be given rapidly helping current and future clinicians focus learn retain and thrive learn more