Classical phenotype (type 1 thyroid allostasis)
Causes
Causes of classical euthyroid sick syndrome include a number of acute and chronic conditions, including pneumonia, fasting, starvation, anorexia nervosa, sepsis, trauma, cardiopulmonary bypass, malignancy, stress, heart failure, hypothermia, myocardial infarction, kidney failure, cirrhosis, diabetic ketoacidosis, surgery, infection, brain injury, shock, cancer, and HIV.Outside the hospital setting, euthyroid sick syndrome (nonthyroidal illness syndrome - NTIS) has been assumed closely related with a series of chronic diseases, such as inflammatory bowel disease, chronic fatigue syndrome, and autoimmune diseases.Additionally, an NTIS-like phenotype can be present in major depressive disorder, as well as overexercise. Pathophysiology
In critical illness, the activity of different deiodinases is altered. Humoral and neuronal inputs at the level of the hypothalamus may adjust the set point of thyroid homeostasis. This may play an important role in the pathogenesis of the central component of thyroid allostasis in critical illness, tumors, uremia and starvation (TACITUS). In addition, both illness and medication (e.g. salicylates and heparin) may impair plasma protein binding of thyroid hormones, resulting in reduced levels of total hormones, while free hormone concentrations may be temporarily elevated.Euthyroid sick syndrome probably represents an overlap of an allostatic response with pathologic reactions and drug interferences. Allostatic overload may result in wasting syndrome and myxedema coma. Thyroid storm, though, represents allostatic failure, where the organism is unable to develop NTIS in the situation of thyrotoxicosis. Deiodinases
Three primary deiodinases are responsible for thyroid hormone conversion and breakdown.
Difluprednate is a corticosteroid, It is chemically a butyrate ester of 6(alpha),9(alpha)-difluoro prednisolone acetate. Accordingly, difluprednate is sometimes abbreviated DFBA, for difluoroprednisolone butyrate acetate. Approval
On June 24, 2008, the US Food and Drug Administration (FDA) approved difluprednate for the treatment of post-operative ocular inflammation and pain. It is marketed by Alcon under the tradename Durezol. Clinical trials
Difluprednate ophthalmic emulsion 0.05% is also being studied in other ocular inflammatory diseases, including a phase 3 study evaluating difluprednate for the treatment of anterior uveitis


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