Endocrine interventions in the intensive care unit

Critically ill patients: Histopathological evidence of thyroid dysfunction

PURPOSE

Critical illness is characterized by severe biphasic physical and metabolic stress as result of systemic inflammatory response syndrome and/or multiple organ dysfunction syndrome, and is frequently associated with non-thyroidal illness. Purpose of this study is to better understand the cytomorphological basis of NTI by performing histopathological examinations of thyroid gland on autopsies of patients who died from critical illness.

METHODS

Histopathological examination of thyroid gland of 58 critically ill patients was performed in our hospital. The cases included 24 cases of burn injury, 24 cases of traumatic brain injury, and 10 cases of cerebral stroke. Thyroid samples obtained during autopsy were preserved in formol saline and stained with hematoxylin and eosin. The sections were visualized under light microscopy.

RESULTS

Out of 58 cases examined, 21 patients showed normal thyroid findings, and rest of the cases had unusual thyroid findings in the histopathological study. The principal finding was distortion of thyroid follicular architecture. Other findings include mononuclear cell infiltration, clumping of thyroglobulin, and exhaustion of thyroid follicles.

CONCLUSION

Critical illness produces metabolically damaging effects on thyroid gland, which functionally corresponds to a state of low T3 syndrome. These changes are more pronounced in BI and cerebral stroke than in TBI.

Novel insights in endocrine and metabolic pathways in sepsis and gaps for future research

Sepsis is defined as any life-threatening organ dysfunction caused by a dysregulated host response to infection. It remains an important cause of critical illness and has considerable short- and long-term morbidity and mortality. In the last decades, preclinical and clinical research has revealed a biphasic pattern in the (neuro-)endocrine responses to sepsis as to other forms of critical illness, contributing to development of severe metabolic alterations. Immediately after the critical illness-inducing insult, fasting- and stress-induced neuroendocrine and cellular responses evoke a catabolic state in order to provide energy substrates for vital tissues, and to concomitantly activate cellular repair pathways while energy-consuming anabolism is postponed. Large randomized controlled trials have shown that providing early full feeding in this acute phase induced harm and reversed some of the neuro-endocrine alterations, which suggested that the acute fasting- and stress-induced responses to critical illness are likely interlinked and benefical. However, it remains unclear whether, in the context of accepting virtual fasting in the acute phase of illness, metabolic alterations such as hyperglycemia are harmful or beneficial. When patients enter a prolonged phase of critical illness, a central suppression of most neuroendocrine axes follows. Prolonged fasting and central neuroendocrine suppression may no longer be beneficial. Although pilot studies have suggested benefit of fasting-mimicking diets and interventions that reactivate the central neuroendocrine suppression selectively in the prolonged phase of illness, further study is needed to investigate patient-oriented outcomes in larger randomized trials.