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?
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
References :
What is the best initial treatment?
Correct Answer: B
A 79-year-old female is admitted to the ICU after repair of a pathologic femur fracture with an estimated blood loss of 1.2 L. She is oxygenating well on room air, is hemodynamically stable, and is appropriately alert and oriented. Physical examination is remarkable for incision site tenderness and signs of malnutrition. Laboratory studies reveal normal electrolytes, normal liver function tests, normal TSH and T4, and decreased levels of T3.
What would be the most appropriate management of her deranged thyroid function test?
Correct Answer: A
Euthyroid sick syndrome (ESS), also known as nonthyroidal illness syndrome, is often seen in patients with severe critical illness, deprivation of calories, and following major surgeries. Common causes include infection, trauma, cardiopulmonary bypass, and malignancy. Although the exact mechanism is not known, one possible hypothesis is that the presence of thyroid binding hormone inhibitor in serum and body tissues inhibits the binding of thyroid hormone to thyroid-binding protein. Cytokines such as interleukin 1, interleukin 6, tumor necrosis factor alpha, and interferon-beta may affect the hypothalamus and pituitary, thus inhibiting TSH, thyroid-releasing hormone, thyroglobulin, T3, and thyroidbinding globulins production have also been implicated. ESS has been classified as:
Low serum total T3 is the most common abnormality in ESS, and it is seen in about 70% of hospitalized patients. Both low T3 and the T4 syndromes are observed in critically ill patients admitted to intensive care units. Low-serum total T4 correlates with a bad prognosis; the probability of death correlates with the level of serum total T4. When total T4 levels drop below 4 µg/dL, the probability of death is approximately 50%, and when serum T4 levels are below 2 µg/dL, the probability of death reaches 80%.
Thyroid hormone replacement is not needed in patients with ESS (Choices B and C), and there is no role of steroids in the management of ESS (Choice D). Treatment and management of underlying medical illness is sufficient (Choice A).
References:
A 78 year-old female is admitted to the ICU with a 6 month history of generalized fatigue and muscle cramps, which are worsened with exercise. Her symptoms have been progressively worsening and now she is unable to ambulate. On physical examination, pressure stimulus on the muscles of the arm leads to formation of a palpable, painless ridge around the site of the stimulus, which subsides gradually returning the muscle contour to normal in a few seconds. She is also noted to have delayed deep tendon reflexes and anasarca. Her laboratory studies are within normal limits, except for an elevated TSH level.
Which of the following is most likely the cause of her symptoms?
Correct Answer: E
Hypothyroid myopathy is a complication of untreated or uncontrolled hypothyroidism. Although most cases are not clinically significant, severe cases can lead to muscle disease and functional limitations. The exact mechanism is not understood; however, it is believed to be related to intracellular changes secondary to decreased T4 levels. T4 deficiency leads to reduced mitochondrial oxidative capacity, abnormal glycogenolysis, and an insulin-resistant state of the cell causing selective atrophy of type 2 muscle fibers (fast-twitching type), which leads to slowing of muscle contraction seen clinically in patients with hypothyroidism.
“Myoedema” is characteristic of hypothyroid myopathy. It is demonstrated by percussion or a pressure stimulus on the muscles of the arm, which causes the muscle to form a palpable, painless ridge around the site of the stimulus. The swelling subsides gradually returning the muscle contour to normal in a few seconds. This is believed to be caused by prolonged muscle contraction due to delay in calcium reuptake by the sarcoplasmic reticulum after the stimulus causes local calcium release. This sign if elicited can help differentiate hypothyroid myopathy from other types of myopathies.
Four main types of myopathies are associated with hypothyroidism: Myasthenic syndrome, Atrophic form, Kocher-Debre-Semelaigne, and Hoffman syndrome. Hoffmann syndrome is usually seen in adults and characterized by pseudohypertrophy, painful spasms, proximal muscle weakness, and stiffness. Management of hypothyroidism is the mainstay of treating hypothyroid myopathy. It is reversible with timely diagnosis and prompt treatment.
An 81-year-old female is admitted to the ICU with altered mental status. She is lethargic and does not provide a good history. On physical examination, her skin is dry and pale, and her temperature is 35°C. She is noted to have decreased deep tendon reflexes.
Which of the following clinical/physiologic derangements is most likely to be present in the patient?
Based on the presentation, this patient likely has severe hypothyroidism causing myxedema coma. Myxedema coma is a severe manifestation of hypothyroidism that can carry up to 50% mortality. Patients experience decreased metabolic rate and decreased oxygen consumption. Systemic vascular resistance is increased (choice A) secondary to decreased beta adrenergic activity. Myocardial depression (choice B) results in profound hypotension. Hypothermia is common, occurring in up to 88% of patients. Central respiratory depression occurs, resulting in respiratory acidosis (choice C). Decreases in gastrointestinal motility typically manifests with constipation (choice D).
Click to expand