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986 PART 8: Renal and Metabolic Disorders

receive physiologic replacement doses of corticosteroids due to primary CHAPTER Thyroid Disease
dysfunction of the HPA axis, for example, patients with primary adre-
nal failure due to Addison disease, congenital adrenal hyperplasia or
patients with secondary adrenal insufficiency due to hypopituitarism. 103 Roy E. Weiss
It is likely that these latter patients are unable to increase endogenous Samuel Refetoff
cortisol production in the face of stress. These patients require adjust-
ment of their glucocorticoid dose during surgical stress under all
circumstances. KEY POINTS
■ CONCLUSION • Virtually all patients admitted to an ICU have low levels of serum

Critical illness–related corticosteroid insufficiency (CIRCI) is a complex triiodothyronine (T ), and 30% to 50% have low levels of thyroxine
3
disease; our understanding of which continues to develop. In critically (T ) with normal or low levels of serum thyrotropin (TSH).
4
ill patients with septic shock poorly responsive to fluids and vasopres- • Patients who have a T level of less than 3.0 µg/dL despite normal
4
sor agents and patients with persistent severe ARDS treatment with levels of T -binding proteins have a 68% to 84% mortality rate.
4
stress-dose corticosteroids (200-350 mg hydrocortisone/day or 60 mg • T is the logical choice for critically ill patients requiring thyroid
3
methylprednisolone/day) should be considered. Treatment for at least hormone replacement.
7 days (and up to 14 days) is suggested, followed by a slow taper. These • Early intubation and mechanical ventilation are crucial for suc-
recommendations are based on limited data and are likely to evolve as cessful treatment of myxedema coma.
additional studies are published.
• Management of myxedema coma should include administration of
glucocorticoids while the adrenal status is being assessed.
• Alterations in thyroid function change the metabolism of almost
KEY REFERENCES all drugs, and the doses need careful adjustment to prevent drug
• Annane D, Cariou A, Maxime V, et al. Corticosteroid treatment toxicity or decreased efficacy.
and intensive insulin therapy for septic shock in adults: a random- • Autonomous hypersecretion and exogenous overdose of thyroid
ized controlled trial. JAMA. 2010;303:341-348. hormone are the most common causes of severe thyrotoxicosis.
• Annane D, Maxime V, Ibrahim F, et al. Diagnosis of adrenal insuf- • Hyperpyrexia and altered mental status are the hallmarks of
ficiency in severe sepsis and septic shock. Am J Respir Crit Care thyroid storm.
Med. 2006;174:1319-1326. • Medical treatment of severe hyperthyroidism usually normalizes
• Annane D, Sebille V, Charpentier C, et al. Effect of treatment with circulating thyroid hormone levels in 2 to 3 weeks, except under
low doses of hydrocortisone and fludrocortisone on mortality in circumstances of iodine overload, in which case hyperthyroxinemia
patients with septic shock. JAMA. 2002;288:862-871. may persist for months.
• Boonen E, Vervenne H, Meersseman P, et al. Reduced cortisol metab- • Blockade of hormonal secretion is best accomplished by the addi-
olism during critical illness. N Engl J Med. 2013;368(16):1477-1488. tion of stable iodine to an antithyroid drug regimen.
• Egi M, Bellomo R, Stachowski E, et al. Variability of blood glucose • In severe thyrotoxicosis, treatment with iopanoic acid can be lifesaving.
concentration and short-term mortality in critically ill patients. • β-Blockers prevent thyroid storm in the thyrotoxic patient undergo-
Anesthesiol. 2006;105:244-252. ing surgery, and they may ameliorate cardiovascular dysfunction in
• Fernandez J, Escorsell A, Zabalza M, et al. Adrenal insufficiency in thyroid storm, but their side effects often interfere with therapy in the
patients with cirrhosis and septic shock: effect of treatment with elderly, in patients with asthma, and in patients with cardiomyopathy.
hydrocortisone on survival. Hepatology. 2006;44:1288-1295. • Amiodarone-induced thyrotoxicosis in a critically ill patient
• Hafezi-Moghadam A, Simoncini T, Yang Z, et al. Acute cardio- should be managed with methimazole (30-50 mg/d), potassium
vascular protective effects of corticosteroids are mediated by non- perchlorate (500 mg twice a day), and prednisone (30-40 mg/d).
transcriptional activation of endothelial nitric oxide synthase. Nat • After gastric aspiration and lavage, only symptomatic and support-
Med. 2002;8:473-479. ive treatment is needed in cases of levothyroxine overdose.
• Loisa P, Parviainen I, Tenhunen J, et al. Effect of mode of hydro- • Neonatal thyrotoxicosis can be life threatening; it is usually caused
cortisone administration on glycemic control in patients with by transplacental transfer of thyroid-stimulating antibodies. It is
septic shock: a prospective randomized trial. Crit Care. 2007; transient and requires only short-term treatment.
11:R21. doi:10.1186/cc5696.
• Marik PE, Pastores SM, Annane D, et al. Recommendations for the
diagnosis and management of corticosteroid insufficiency in criti-
cally ill adult patients: consensus statements from an international HYPOTHYROIDISM, NONTHYROIDAL ILLNESS,
task force by the American College of Critical Care Medicine. Crit
Care Med. 2008;36:1937-1949. AND MYXEDEMA COMA
• Marik PE, Varon J. Requirement of perioperative stress doses of Hypothyroidism is a state of tissue deprivation of thyroid hormone. It
corticosteroids: a systematic review of the literature. Arch Surg. is manifested by general reduction of the metabolic rate accompanied
2008;143:1222-1226. by specific symptoms and signs. Usually, hypothyroidism is caused by
• Sprung CL, Annane D, Keh D, et al. Hydrocortisone therapy for a decreased supply of thyroid hormone due to one of the following:
patients with septic shock. N Engl J Med. 2008;358:111-124. (1) failure of the gland to synthesize and secrete thyroid hormone,
(2) failure of the pituitary to secrete thyrotropin (thyroid-stimulating
hormone [TSH]), or (3) hypothalamic disease resulting in a deficiency
of thyrotropin-releasing hormone (TRH).
Perhaps the most controversial, if not the most challenging, aspects
REFERENCES of thyroidology for the intensivist are how to interpret thyroid func-
tion tests in critically ill patients and what to do when the test results
Complete references available online at www.mhprofessional.com/hall are abnormal. Clinically important hypothyroidism in its most severe

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