A 27-year-old man with primary sclerosing cholangitis and ulcerative colitis presents with high ileostomy output and abdominal pain for last few weeks associated with a 9-kg weight loss. He has no other medical history. Despite fluid resuscitation and pharmacologic therapy, his symptoms persist. He develops fever to 39.7°C and is transferred to the ICU with concerns for sepsis. On admission to the ICU:
His sepsis workup is negative, but his laboratory work is remarkable for a low TSH level.
What is the diagnosis?A. Serotonin syndrome
Correct Answer: C
Thyroid storm is a rare, life-threatening condition characterized by severe clinical manifestations of thyrotoxicosis. The incidence ranges between 0.02% and 1.3% and is associated with significant mortality. It may be precipitated by an acute event such as thyroid or nonthyroidal surgery, trauma, and infection. In addition to specific therapy directed against the thyroid, supportive therapy in an intensive care unit (ICU) and recognition and treatment of any precipitating factors is essential to prevent morbidity and mortality.
The diagnosis of thyroid storm is based on the presence of severe and life-threatening symptoms such as hyperpyrexia, cardiovascular dysfunction, and/or altered mentation along with biochemical evidence of hyperthyroidism (elevation of free T4 and/or T3 and suppression of TSH). A scoring system was devised in 1993 by Burch and Wartofsky using clinical criteria for the identification of thyroid storm (Table below). A score of 45 or more is highly suggestive of thyroid storm, whereas a score below 25 makes thyroid storm unlikely. A score of 25 to 44 is suggestive of impending storm. Although this scoring system is likely sensitive, it is not very specific.
The patient was not exposed to any drugs that could trigger malignant hyperthermia (anesthetic agents or succinylcholine), malignant neurolept syndrome (neuroleptic medications), or serotonin syndrome (serotonergic medications).
Treatment includes controlling the symptoms and signs induced by increased adrenergic tone, blocking the peripheral conversion of T4 to T3, decreasing the production of thyroid hormones, and decreasing enterohepatic recycling of thyroid hormones. Decreased production and secretion of thyroid hormones can be achieved with thionamide medications, such as propylthiouracil and methimazole. High-dose iodine can also reduce production; however, it is only effective after initial blockade with other agents. Glucocorticoids, such as hydrocortisone, are useful to block the peripheral conversion of T4 to T3, but take time. Medications such as propanolol block the sympathetic surge present during thyroid storm and avoid life-threatening complications.
Calcium channel blockers, such as diltiazem, can be used to decrease sympathetic surge if beta blockers are contraindicated. Cholestyramine and hydrocortisone are not the initial agents as they take time to act.
The Burch-Wartofsky Point Scale for diagnosis of thyroid storm