Association Between Thyroid Dysfunction and Intensive Care Unit Acquired Weaknesss

Study Overview
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Brief Summary
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Intensive care unit-acquired weakness (ICU-AW) is the most common neuromuscular impairment in critically ill patients. It affects more than 50 % of patients in the intensive care and is related to many problems as difficult weaning from mechanical ventilation, prolonged hospital stay and increased mortality.Thyroid disorders are also associated with neuromuscular abnormalities and may decrease the threshold for the development of any type of myopathy. However, no previous study investigated the direct relationship between thyroid dysfunction and ICUAW.This study aims at evaluation of the association between thyroid dysfunction and intensive care unit acquired weakness.

Detailed Description
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Intensive care unit acquired weakness refers to muscle weakness encountered in the intensive care unit as a consequence of critical illness. It affects more than 50 % of patients in the intensive care and is related to many problems as difficult weaning from mechanical ventilation, prolonged hospital stay and increased mortality. There are three distinct entities for ICUAW that can only be differentiated by neurophysiological studies. These are critical illness myopathy (CIM), critical illness polyneuropathy (CIP) and critical illness neuromyopathy (CINM). Identification of risk factors responsible for the development of ICUAW is the first step in the prevention and management of this disorder. Till time septic shock, hyperglycemia, high dose steroid therapy, prolonged mechanical ventilation and the use of neuromuscular blocking agents are the main accused. Thyroid disorders are also associated with neuromuscular abnormalities. Unfortunately, the prevalence of thyroid dysfunction in the intensive care is high reaching 90%. Moreover, patients with severe critical illness, who are typically prone to the development of ICUAW, show changes in their thyroid biochemistry namely low T3 levels (with or without low T4 levels) in the presence of normal TSH levels. These changes are collectively known as Non-Thyroidal illness syndrome (previously low T3 syndrome and Euthyroid sick syndrome) which is the most common form of thyroid dysfunction in the intensive care unit.

Official Title
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Association Between Thyroid Dysfunction and Intensive Care Unit Acquired Weakness: A Case Control Study

Conditions
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Thyroid Abnormalities, ICU Acquired Weakness

Intervention / Treatment
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* Other: withdrawl of blood samples for thyroid function testing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients of both sexes admitted to the general ICU of Ain Shams University Hospitals with critical illness for more than 7 days * Diagnosis of ICU acquired weakness will be made based on clinical criteria for ICUAW and confirmed by nerve conduction studies. Exclusion Criteria: Patients with cerebrovascular accidents, neuromuscular disorders, spine abnormalities, spinal cord or head injuries, CNS tumors, secondary thyroid disorders and electrolyte disturbances were excluded from the study. Patients receiving thyroid replacement or anti-thyroid drugs for the treatment of any throid disorder will be also excluded from the study as these drugs may alter their thyroid biochemistry

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cases (ICUAW)<br>57 critically ill patients developing ICUAW during their stay in the intensive care unit will be included in the study as cases. | Other: withdrawl of blood samples for thyroid function testing<br>* Blood samples will be withdrawn from patients admitted to the intensive care for more than 7 days to measure Thyroid hormones (Free T3: Tri-iodothyronine and Free T4:thyroxine) and TSH ( Thyroid Stimulating Hormone) using ELISA kits. Reference ranges will be as follows: TSH 0.4-4mU/L, Free T3 2-4.4 mU/L, Free T4 0.8-1.9 mU/L. Patients will be then categorized into one of the following categories Euthyroid ( Normal TSH, FT3 and FT4) Hyperthyroid (Low TSH) either overt (increased FT3 and /or FT4) or subclinical (normal FT4 and FT3). Hypothyroid (Elevated TSH) either overt (Low FT3 and FT4) or subclinical (Normal FT3 and FT4) Non-thyroidal illness syndrome : normal or low TSH in addition to low FT3 ± Low FT4 levels.<br>|
| Controls<br>A total of 57 Critically ill patients in the same period who did not develop ICU acquired weakness during their ICU stay will be included as controls. | Other: withdrawl of blood samples for thyroid function testing<br>* Blood samples will be withdrawn from patients admitted to the intensive care for more than 7 days to measure Thyroid hormones (Free T3: Tri-iodothyronine and Free T4:thyroxine) and TSH ( Thyroid Stimulating Hormone) using ELISA kits. Reference ranges will be as follows: TSH 0.4-4mU/L, Free T3 2-4.4 mU/L, Free T4 0.8-1.9 mU/L. Patients will be then categorized into one of the following categories Euthyroid ( Normal TSH, FT3 and FT4) Hyperthyroid (Low TSH) either overt (increased FT3 and /or FT4) or subclinical (normal FT4 and FT3). Hypothyroid (Elevated TSH) either overt (Low FT3 and FT4) or subclinical (Normal FT3 and FT4) Non-thyroidal illness syndrome : normal or low TSH in addition to low FT3 ± Low FT4 levels.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association between thyroid dysfunction and ICUAW | Comparison between both groups as regards thyroid functions and the incidence of each of the four categories of thyroid function.Logistic regression will be done to assess each of the four categories of thyroid function as a risk factor in the development of ICUAW in the presence of other risk factors. | Patients admitted to the intensive care for more than 7 days |