Non-thyroidal illness syndrome predicts outcome in adult critically ill patients: a systematic review and meta-analysis

[Abnormal thyroid markers in critically ill patients-harmless irritation or a real problem?]

BACKGROUND

Abnormal thyroid markers are a frequent occurrence in emergency and intensive care medicine. Correct interpretation of their clinical relevance and distinction from a primary thyroid disease, particularly prior to potential administration of iodine-containing antiarrhythmic drugs such as amiodaron or radiocontrast agents, are both essential and challenging.

OBJECTIVE

This article aims to present the pathophysiology of abnormal thyroid markers in acute or protracted critical disease. Their relevance for administration of amiodaron or iodine-containing radiocontrast agents is discussed, and concrete practical recommendations are presented.

MATERIALS AND METHODS

The current work comprises a discussion of expert recommendations, guidelines, and basic research.

RESULTS AND CONCLUSION

Approximately one third of intensive care patients develop non-thyroidal illness syndrome (NTIS) during the course of their critical disease. NTIS is characterized by a reduction in the serum concentration of fT3 and, during the course, also in those of thyroid-stimulating hormone (TSH) and fT4, despite an organically intact thyroid gland. A greater extent of the deviations correlates with a worse overall prognosis. The mechanisms involved are manifold and influence different levels of hormonal signaling axes. They are mediated by interaction with acute stress signals such as inflammatory factors and elevated cortisol levels and are influenced by medication. The components vary depending on disease severity and the protracted course. NTIS does not require any specific treatment; the focus is on treating the underlying disease. Latent hyperthyroidism in particular must be distinguished from NTIS. In unclear situations and high-risk constellations, perchlorate is indicated before (and after) iodine exposure.

Impact of thyroid hormone replacement therapy on the course and functional outcome of aneurysmal subarachnoid hemorrhage

BACKGROUND

Thyroid hormones were reported to exert neuroprotective effects after ischemic stroke by reducing the burden of brain injury and promoting post-ischemic brain remodeling.

OBJECTIVE

We aimed to analyze the value of thyroid hormone replacement therapy (THRT) due to pre-existing hypothyroidism on the clinical course and outcome of aneurysmal subarachnoid hemorrhage (SAH).

METHODS

SAH individuals treated between January 2003 and June 2016 were included. Data on baseline characteristics of patients and SAH, adverse events and functional outcome of SAH were recorded. Study endpoints were cerebral infarction, in-hospital mortality and unfavorable outcome at 6 months. Associations were adjusted for outcome-relevant confounders.

RESULTS

109 (11%) of 995 individuals had THRT before SAH. Risk of intracranial pressure- or vasospasm-related cerebrovascular events was inversely associated with presence of THRT (p = 0.047). In multivariate analysis, THRT was independently associated with lower risk of cerebral infarction (adjusted odds ratio [aOR] = 0.64, 95% confidence interval [CI] = 0.41-0.99, p = 0.045) and unfavorable outcome (aOR = 0.50, 95% CI = 0.28-0.89, p = 0.018), but not with in-hospital mortality (aOR = 0.69, 95% CI = 0.38-1.26, p = 0.227).

CONCLUSION

SAH patients with THRT show lower burden of ischemia-relevant cerebrovascular events and more favorable outcome. Further experimental and clinical studies are required to confirm our results and elaborate the mechanistic background of the effect of THRT on course and outcome of SAH.

Triiodothyronine hormone supplementation therapy in septic shock patients with euthyroid sick syndrome: two pilot, placebo-controlled, randomized trials

BACKGROUND

To assess 28-day survival in two pilot groups of septic shock patients with euthyroid sick syndrome (ESS) supplemented with triiodothyronine (T3).

METHODS

A total of 95 septic shock patients with ESS were divided according to values of the thyroid hormones into low T3 and low T3T4 groups. Among 48 patients with low T3, 24 (50%) were randomized to T3 for 4 days and 24 (50%) to placebo. Among 47 patients with low T3T4, 24 (51%) were randomized to T3 for 4 days and 23 (49%) to placebo. The analysis included 28-day survival as the primary outcome and laboratory with hemodynamics as the secondary outcomes. Laboratory data were analyzed on the day of admission (T0), on the first (T1), third (T2) and seventh day (T3) with hemodynamics analyzed for the first four days.

RESULTS

In the low T3 population, 18 (75%) patients receiving T3 died at day 28 compared with 8 (33.3%) patients receiving placebo (p = 0.004). In the low T3T4 population, 6 (25%) patients receiving T3 died in ICU compared with 12 (52.1%) patients receiving placebo (p = 0.039). Oral T3 treatment increased mean arterial pressure values at day 1, day 3 and day 7 in the low T3T4 population, (p = 0.015, =0.005 and =0.042 respectively), and had no significant effect on these values in the low T3 population.

CONCLUSION

T3 supplementation was associated with a low 28-day mortality rate in patients with low T3T4 but with increased mortality in patients with low T3 ESS. These results suggest caution before initiating thyroid supplementation in septic patients.

REGISTRATION

ClinTrials.gov (NCT05270798).

An unusual evolution of thyroid function after therapeutic plasma exchange in Graves' disease with cholestatic jaundice: A case report

RATIONALE

Methimazole (MMI) is the first-line agent in the treatment of hyperthyroidism. However, rare but severe cholestatic jaundice may occur. Therapeutic plasma exchange (TPE) may provide an alternative treatment for such patients and they received thyroidectomy/radioactive iodine ablation or continued oral anti hyperthyroidism medication immediately after TPE session in the reported literatures. The case reported here is, to our knowledge, the first to describe the long interval between anti hyperthyroidism therapy and TPE in such patients.

PATIENT CONCERNS

A 49-year-old Chinese woman had developed worsening jaundice 3 weeks after receiving methimazole (20 mg/day) for the treatment of hyperthyroidism secondary to Graves' disease (GD). Additionally, she had a 2-year history of type 2 diabetes.

DIAGNOSIS

Hyperthyroidism secondary to GD, MMI-induced severe cholestatic jaundice and type 2 diabetes.

INTERVENTIONS

Methimazole was discontinued and the patient received 3 times of TPE, about 3-month glucocorticoid treatment, insulin administration accordingly and other conventional liver-protecting therapy.

OUTCOMES

Her thyroid function was stabilized with small dose of thyroxine substitution and euthyroid status persisted after thyroxine discontinuation until hyperthyroidism recurred 7 months later while her cholestatic jaundice was eventually recovered by about 3-month glucocorticoid therapy.

LESSONS

Due to the complex interplay between liver function and thyroid hormones, there may be unusual changes of thyroid function in GD patients with severe liver injury after TPE. By this case, we want to highlight the importance of a closely following up of thyroid function in order to deliver appropriate health suggestions for patients.

Low T3 syndrome upon admission and response to nutritional support in malnourished medical inpatients

INTRODUCTION

During illness, deiodination of thyroxine (T4) to triiodothyronine (T3) is down regulated. This is called "low T3 syndrome", an adaptive metabolic mechanism to reduce energy expenditure and prevent catabolism. We investigated the prognostic role of low T3 syndrome in patients at nutritional risk regarding mortality, clinical outcomes and response to nutritional support.

METHODS

This is a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized-controlled Swiss multicenter trial comparing effects of individualized nutritional support with usual care in adult medical inpatients at nutritional risk. The primary endpoint was all-cause mortality over 30-,180-days and 5-years.

RESULTS

We had complete data including fT3 concentration of 801/2028 (39.5%) patients from the initial trial. Of these 492 (61.4%) had low T3 syndrome (fT3 < 3.2 pmol/l). Low T3 syndrome was associated with higher mortality over 30 days (adjusted hazard ratio 1.97 [95%CI 1.17 to 3.31], p 0.011) and other adverse clinical outcomes. Nutritional support only lowered mortality in the group of patients with but not in those without low T3 syndrome (adjusted odds ratio of nutritional support of 0.82 [95%CI 0.47 to 1.41] vs. 1.47 [95%CI 0.55 to 3.94]). This finding, however, was not significant in interaction analysis (p for interaction = 0.401).

CONCLUSIONS

Our secondary analysis of a randomized trial suggests that medical inpatients at nutritional risk with low T3 syndrome have a substantial increase in mortality and may show a more pronounced beneficial response to nutritional support interventions.

Biochemical indicators of euthyroid sick syndrome in critically ill children

OBJECTIVES

This study aimed to determine the prevalence and predictors of euthyroid sick syndrome (ESS) in pediatric intensive care, and to establish a link between thyroid function tests and mortality.

METHODS

Between January 2015 and March 2020, children admitted to our pediatric intensive care unit (PICU) and tested for free triiodothyronine (fT3), free thyroxine (fT4), and thyrotropin (TSH) levels were included. Patients with decreased fT3, with normal or decreased fT4, and normal or decreased TSH levels were assigned to the ESS group. The association between biochemical indicators and ESS, as well as the relationship between fT3 and mortality, were examined.

RESULTS

A total of 141 (36%) of 386 children included to study were classified in the ESS group. The ESS group had a higher rate of 28-day mortality (12 [8.5%] vs. 9 [3.7%]). Blood urea nitrogen (BUN), albumin, platelet, lactate, and pediatric index of mortality 3 [PIM3 (%)] were significantly associated with ESS (odds ratios in order: 1.024, 0.422, 0.729, 1.208, 1.013). Multivariate regression analysis showed that BUN, albumin, platelet, and lactate were independently associated with ESS progression. The area under curve (AUC [95%CI]) for fT3 was 0.644 (0.555-0.789) to detect mortality. Children with a fT3 level lower than 2.31 pg/mL had significantly higher 28-day mortality (log rank test, p=0.001).

CONCLUSIONS

Our study identified BUN, albumin, lactate, and platelet count as independent risk factors for ESS progression in children. Furthermore, our findings indicated a correlation between fT3 and mortality, which makes fT3 an ideal candidate to be included in mortality indices.