Perioperative management of patients with hypothyroidism

Hypothyroidism Impacts Clinical and Healthcare Utilization Outcomes After Primary Total Hip Arthroplasty

BACKGROUND

Our objective was to assess the association of hypothyroidism with outcomes of primary total hip arthroplasty (THA) overall and stratified by underlying diagnosis.

METHODS

We identified patients undergoing primary THA in a national database from 2016 to 2020. We stratified them based on primary diagnoses into hip osteoarthritis (OA; N = 1,761,960), osteonecrosis (ON; N = 78,275), traumatic fracture (N = 532,910), inflammatory arthritis (IA; N = 3,520), and "other" (N = 90,550). We identified hypothyroidism and complications using secondary diagnoses. Among 2,467,215 patients undergoing primary THA, mean age was 68 years (range, 18 to 90), and 58.3% were women. Complications codes only included initial encounters. We performed time-trends analyses and multivariable-adjusted regression analyses adjusted for demographics, expected primary payer, a comorbidity score, elective versus non-elective admission, and hospital characteristic information, with clinical and healthcare utilization outcome as endpoints.

RESULTS

Overall, hypothyroidism was significantly associated with increased LOS, total charges, non-routine discharges, blood transfusions, and prosthetic fractures. In the OA cohort, hypothyroidism was associated with increased LOS, total charges, and non-routine discharges (P < .001 for each), and blood transfusions (P = .02). Hypothyroidism was associated with increased total charges (P = .001) in the ON cohort and with increased LOS, non-routine discharge, and blood transfusion (P < .05 each) in the traumatic fracture cohort.

CONCLUSIONS

Hypothyroidism was associated with blood transfusions, prosthetic fractures, and utilization outcomes in THA patients. Tailored intervention strategies for hypothyroidism should be tested for their efficacy to improve THA peri-operative outcomes.

Advancing Preoperative Strategies for Thyroidectomy in Graves' Disease: A Narrative Review

Graves' disease is an autoimmune disorder characterized by thyroid-stimulating antibodies that can potentially lead to thyrotoxicosis, goiter, skin disease, and eye disease. Available treatment options for Graves' disease include management with antithyroid drugs (ATDs), thyroid ablation with radioactive iodine (RAI), and surgical thyroid gland removal. For individuals unable to reach a normal thyroid hormone level, promptly considering a thyroidectomy is essential. Preoperative strategies to achieve a euthyroid state prevent thyroid storms and minimize postoperative complications and are therefore crucial. While variations in professional guidance exist, this review focuses on standard medical interventions as well as compares respective guidelines set forth by the American Thyroid Association, the European Thyroid Association, the American Association of Clinical Endocrinology, and the American Association of Endocrine Surgeons. There is consensus among these organizations underscoring the importance of rendering patients euthyroid prior to surgery and the use of ATDs. Most guidelines recommend screening for vitamin D deficiency as well as endorse thyroidectomy as the preferred treatment option for hyperthyroidism with skilled surgeons. Nevertheless, discrepancies do become apparent in aspects such as potassium iodide (SSKI) course duration and preoperative dexamethasone administration. By understanding these differing approaches, healthcare professionals can more effectively manage Graves' disease prior to surgery, resulting in improved patient outcomes and enhanced surgical success.

Severe hypothyroidism after orthognathic surgery: a case report

Hypothyroidism is a common endocrine disease with reduced systemic metabolism, but the initial diagnosis is rare in oral and maxillofacial surgery. Due to the nonspecific symptoms, it is easy to be misdiagnosed and missed diagnosis which results in serious consequences. This paper presents a case of severe hypothyroidism which was characterized by airway obstruction, facial swelling, unexplained anaemia and bipedal edema after orthognathic surgery. With review of relevant literatures, this article discusses the risk factors, symptoms, diagnosis and therapy of hypothyroidism.

Impact of subclinical hypothyroidism on outcomes of coronary bypass surgery

BACKGROUND

Subclinical hypothyroidism (SCH) is characterized by an elevated thyroid-stimulating hormone and normal free thyroxine. This study aimed to evaluate the influence of SCH on the recovery of patients after coronary artery bypass grafting (CABG).

METHODS

From January 2015 to December 2018, 548 SCH patients and 6718 euthyroid patients who underwent CABG were identified. Propensity score matching was used to create two cohorts with similar baseline characteristics (n = 545 in each group). The early postoperative outcomes were compared.

RESULTS

After CABG, there was no difference in the incidence of postoperative atrial fibrillation between the two groups (20.4% in the SCH group and 20.6% in the euthyroidism group; odds ratio: 0.99; 95% confidence interval: 0.74-1.33; p = 0.94). Subgroup analyses did not indicate an effect in any category of patients. The proportions of the use of dopamine and noradrenaline in the SCH group were higher than those in the euthyroid patients (76.7% vs. 68.6%, p = 0.003; 56.5% vs. 49.0%, p = 0.01, respectively). The total duration of inotropic support in the SCH group was longer than that in the euthyroid patients (median duration: 4 vs. 3 days, p = 0.002). The incidence of impaired wound healing was higher in the SCH group than in the euthyroid group (3.7% vs. 1.1%, p = 0.005).

CONCLUSIONS

Compared with euthyroidism, SCH is not associated with an increased risk of atrial fibrillation in patients undergoing CABG. It is associated with an increased risk of several minor perioperative problems, which should be anticipated and preemptively managed.

Perioperative Evaluation and Management of Endocrine Disorders

Evaluation of endocrine issues is a sometimes overlooked yet important component of the preoperative medical evaluation. Patients with diabetes, thyroid disease, and hypothalamic-pituitary-adrenal axis suppression are commonly encountered in the surgical setting and require unique consideration to optimize perioperative risk. For patients with diabetes, perioperative glycemic control has the strongest association with postsurgical outcomes. The preoperative evaluation should include recommendations for adjustment of insulin and noninsulin diabetic medications before surgery. Recommendations differ based on the type of diabetes, the type of insulin, and the patient's predisposition to hyperglycemia or hypoglycemia. Generally, patients with thyroid dysfunction can safely undergo operations unless they have untreated hyperthyroidism or severe hypothyroidism. Patients with known primary or secondary adrenal insufficiency require supplemental glucocorticoids to prevent adrenal crisis in the perioperative setting. Evidence supporting the use of high-dose supplemental corticosteroids for patients undergoing long-term glucocorticoid therapy is sparse. We discuss an approach to these patients based on the dose and duration of ongoing or recent corticosteroid therapy. As with other components of the preoperative medical evaluation, the primary objective is identification and assessment of the severity of endocrine issues before surgery so that the surgeons, anesthesiologists, and internal medicine professionals can optimize management accordingly.

Spirometry in adult hypothyroid patients: a comparative study

OBJECTIVES

Hypothyroidism adversely affects pulmonary function, which may improve by thyroxine therapy. Limited studies about the effect of hypothyroidism on spirometric parameters in adult patients were conducted in Basra, south of Iraq. Moreover, the effect of thyroxine therapy on spirometric parameters was not covered by these studies. In this study, pulmonary function in adult's hypothyroid patients was evaluated by spirometry to detect any impairment, type of impairment, and to evaluate the effect of thyroxine therapy.

METHODS

A comparative study was conducted in Al-Faiha Specialized Diabetes, Endocrine, and Metabolism Center (FDEMC) in Al-Faiha teaching hospital, Basrah, Iraq. Subjects are divided into four groups: uncontrolled hypothyroid group (n=72), controlled hypothyroid group (n=60), newly diagnosed hypothyroid group (n=52), and control group (n=110). Spirometry was done to all subjects in sitting position, it's repeated at least three times and the best result was recorded.

RESULTS

A significantly (p<0.05) less spirometric parameters and more abnormal pulmonary function test (PFT) were noticed in hypothyroid groups, the reduction were more pronounced in the uncontrolled hypothyroid group. The abnormality in PFT was mostly of restrictive type. A significantly (p<0.05) negative correlation has been found between thyroid-stimulating hormone (TSH) and spirometric parameters, while the correlation of fT4 is significantly (p<0.05) positive with FVC% and FEV%.

CONCLUSION

In hypothyroidism, high TSH and low fT4 are recognized causes of a reduction in spirometric parameters. Therefore, spirometry can be used to detect pulmonary function changes in hypothyroidism.

[Safety and effectiveness of total hip arthroplasty in patients with hypothyroidism]

Objective

To evaluate the safety and effectiveness of total hip arthroplasty (THA) in patients with hypothyroidism.

Methods

Sixty-three patients with hypothyroidism (hypothyroidism group) and 63 euthyroid patients without history of thyroid disease (control group) who underwent primary unilateral THA between November 2009 and November 2018 were enrolled in this retrospective case control study. There was no significant difference between the two groups in gender, age, body mass index, hip side, reason for THA, American Society of Anesthesiology (ASA) classification, preoperative hemoglobin (Hb) level, and preoperative Harris score ( P>0.05). The perioperative thyroid stimulating hormone (TSH) and thyroxine (T ₄) levels, the hypothyroidism-related and other complications during hospitalization, the decrease in Hb, perioperative total blood loss, blood transfusion rate, length of hospital stays, and 90 days readmissions rate in the two groups were recorded and evaluated. The periprosthetic joint infection, aseptic loosening of the prosthesis, and hip Harris score during follow-up were recorded.

Results

The differences in the TSH and T ₄ of hypothyroidism group between pre- and 3 days post-operation were significant ( P>0.05) and no hypothyroidism-related complications occurred after THA. The decrease in Hb and perioperative total blood loss in the hypothyroidism group were significantly higher than those in the control group ( P<0.05), but there was no significant difference between the two groups in terms of transfusion rate, length of hospital stays, and 90 days readmission rates ( P>0.05). No significant difference in the rate of complications (liver dysfunction, heart failure, pulmonary infection, urinary infection, and wound complication) between the two groups was found ( P>0.05) except for the rate of intramuscular vein thrombosis which was significantly lower in the hypothyroidism group, and the rate of postoperative anemia which was significantly higher in the hypothyroidism group ( P<0.05). The two groups were followed up 1.0-9.9 years (mean, 6.5 years). At last follow-up, Harris score in both groups were significantly higher than those before operation ( P<0.05). An increase of 39.5±12.3 in hypothyroidism group and 41.3±9.3 in control group were recorded, but no significant difference was found between the two groups ( t=0.958, P=0.340). During the follow-up, 1 case of periprosthetic joint infection occurred in the hypothyroidism group, no loosening or revision was found in the control group.

Conclusion

With the serum TSH controlled within 0.5-3.0 mU/L and T ₄ at normal level preoperatively, as well as the application of multiple blood management, hypothyroid patients can safely go through THA perioperative period and effectively improve joint function, quality of life, and obtain good mid-term effectiveness.

Emergency Surgery in a Child with Cretinism with Anticipated Difficult Airway Under Low-Dose Subarachnoid Block

A child with cretinism poses multiple anaesthetic challenges due to the associated mental and physical disability, deranged metabolic and physiologic functions, difficult airway and propensity to perioperative cardiorespiratory complications. Spinal anaesthesia in children is associated with remarkable cardiorespiratory stability and provides complete surgical anaesthesia. Here, we report a case that describes the first successful anaesthetic management of a child who was an unevaluated case of cretinism under subarachnoid block.

Does well-controlled overt hypothyroidism increase the risk of total knee arthroplasty?

BACKGROUND

Overt hypothyroidism is widely accepted as a risk factor for adverse events following total knee arthroplasty (TKA). However, no prior study has preoperatively reversed hypothyroidism and reevaluated its risk. This retrospective study aimed at investigating whether well-controlled overt hypothyroidism would still increase the risk of TKA.

METHODS

Between November 2009 and November 2016, patients diagnosed with overt hypothyroidism but well controlled and underwent TKA were compared with euthyroid TKA patients. Data were extracted from our departmental database. Chi-squared test and t-tests were used for comparisons.

RESULTS

Hypothyroid patients had more blood loss and lower postoperative haemoglobin (Hb) and haematocrit level than the control group (all P < 0.05). Although the postoperative anaemia rate was lower in the control group (P = 0.01), there was no significant difference in the transfusion rate between the two groups (2.99% versus 7.46%, P = 0.10) or in the rates of other complications (P > 0.05). Interestingly, intramuscular venous thrombosis rate in hypothyroid patients was significantly lower than that in the control group (1.49% versus 9.70%, P = 0.00). Clinical outcome scores were comparable between the two groups throughout the course. And only one case of infection occurred in the hypothyroid patients.

CONCLUSION

Well-controlled overt hypothyroidism did not increase the risk of TKA, except for perioperative blood loss. Surgeons should be aware that even if hypothyroidism is reversed, the risk of more perioperative blood loss still exists and that, consequently, perioperative blood management is still essential in this population.

Myxedema Coma: a Review

Myxedema coma, represents the extreme degree of severity of hypothyroidism, whose mortality can reach very high percentages, therefore, it is a true medical emergency. In general, its development is associated with the presence of a triggering factor in a controlled hypothyroid patient and manifests with multisystem alteration. Currently, tools have been developed for clinical diagnosis that use the profile and clinical models, and have good sensitivity-specificity. They allow an early diagnosis which favored the early start of treatment and therefore improves the prognosis. The patient with myxedema coma needs an integral approach, with intensive treatment and close monitoring of hemodynamic parameters. However, the basis of treatment remains hormone replacement, which should be initiated with a combination of levothyroxine and triiodothyronine.

Incidences of Hypothyroidism Associated With Surgical Procedures for Thyroid Disorders: A Nationwide Population-Based Study

Background and Aim: Limited information available about different types of thyroid surgeries with risk for postoperative hypothyroidism. This study aimed to investigate the risk of developing early and late-onset postoperative hypothyroidism in patients with thyroid disorders. Methods: We used a large cohort data from the Taiwan National Health Insurance Research Data Base (NHIRDB) and identified 9,693 (9, 348) patients from January 1998 to December 2010, admitted for thyroid disorder surgeries. We used the surgical procedures time as the index date. Our observational retrospective cohort study excluded the subjects diagnosed with hypoparathyroidism and hypothyroidism before any surgeries. We analyzed the data using the Cox regression model to calculate the hazard ratio. Result: Postoperative hypothyroidism associated with bilateral-total (HR, 4.27; 95% CI, 3.32-5.50), one-side total and another subtotal (HR, 3.16; 95% CI, 2.59-3.86), bilateral-subtotal (HR, 1.65; 95% CI, 1.37-1.98), and unilateral-total (HR, 1.17; 95% CI, 0.95-1.44) surgical procedures. The time intervals for thyroid disorders were 320 cases developed postoperative hypoparathyroidism in eight weeks, 480 cases the second month, and 1000 cases in the first year after surgery. Conclusion: Findings suggest that thyroidectomy was associated with transient postoperative hypothyroidism in thyroid disorder patients. The bilateral-total surgical procedure was strongly associated with temporary postoperative hypothyroidism.

Hypothyroidism as a Predictor of Surgical Outcomes in the Elderly

There is a high prevalence of hypothyroidism in the elderly population, mainly among women. The most important cause is autoimmune thyroiditis, but also iodine deficiency, radioiodine ablation, and surgery may be responsible for hypothyroidism in elderly hospitalized patients. Thyroid-related symptoms are sometimes comparable to physiological manifestations of the aging process, and hypothyroidism may be related with many symptoms which can be present in critical patients, such as cognitive impairment, cardiovascular, gastrointestinal, and hematological alterations, and eventually myxedema coma which is a severe and life-threatening condition in older adults. Adequate thyroid hormone levels are required to achieve optimal outcomes from any kind of surgical intervention. However, only few randomized clinical trials investigated the association between non-thyroidal illness (or low-T3 syndrome), and adverse surgical outcomes, so far. The goal of this review is to discuss the role of thyroid function as a predictor of surgical outcomes in the elderly.

Postoperative myxedema coma in patients undergoing major surgery: Case series

OBJECTIVE

Myxedema coma is a serious complication of hypothyroidism that can be precipitated by major surgery. It is extremely rare, with only a few reports in the literature. This study aims to present a relatively large case series of post-surgical myxedema coma and to analyze medical and surgical risk factors.

METHODS

Analysis of the patients' surgical records and medical charts.

RESULTS

Four patients developed postoperative myxedema coma and were evaluated for risk factors. Three had known hypothyroidism. Two had undergone large head and neck composite resections necessitating a free flap repair for malignant disease. One had undergone coronary artery bypass graft for ischemic heart disease, and another had undergone endoscopic cholecystectomy for complicated cholecystitis. All four patients required prolonged hospitalization, including treatment in the intensive care unit. One patient had undergone full cardiopulmonary resuscitation directly related to the myxedema coma state.

CONCLUSION

We present a series of four patients who developed myxedema coma following major surgery. We recommend that patients with known hypothyroidism who are scheduled for major surgery should be tested for thyroid function status and assessed for postoperative risk of hypothyroidism. Those who develop complications following major surgery, should be immediately tested for thyroid function to rule out myxedema coma.

Comparison of Hospital Outcomes of Transcatheter AorticValve Implantation With Versus Without Hypothyroidism

Comparative outcomes of transcatheter aortic valve implantation (TAVI) in patients with and without hypothyroidism were not previously reported. This study aimed to appraise the clinical outcomes and impact of hypothyroidism on patients who underwent TAVI. Patients with hypothyroidism who underwent TAVI from 2011 to 2014 were identified in the National Inpatient Sample database using the International Classification of Diseases, ninth Revision, Clinical Modification. The primary outcome was the effect of hypothyroidism on inpatient mortality. Secondary outcomes were the impact of hypothyroidism on post-TAVI complications. We also evaluated the length of hospital stay and the cost of hospitalization. Propensity score-matched analysis was performed to address potential confounding. The hypothyroid patients who underwent TAVI had no significant increase in the risk of in-hospital mortality (odds ratio 0.78; 95% confidence interval 0.51 to 1.21, p = 0.282), or most postprocedural complications. However, hypothyroid patients were more likely to develop hemorrhage requiring transfusion (odds ratio 1.36, 95% confidence interval 1.05 to 1.76, p = 0.043). In conclusion, TAVI is a feasible and relatively safe alternative with reasonable in-hospital outcomes in patients with hypothyroidism and severe symptomatic aortic stenosis. However, hypothyroid patients are more likely to require a blood transfusion after TAVI. Additional randomized trials are needed to evaluate TAVR outcomes in hypothyroid patients.

Comorbidities and Consequences in Hospitalized Heart Failure Patients with Depression

Objective

To evaluate the demographic predictors of major depressive disorder (MDD) in hospitalized congestive heart failure (CHF) patients and measure the differences in hospital stay and cost per comorbidities and the associated risk of in-hospital mortality.

Methods

This retrospective cross-sectional study used nationwide inpatient data from the healthcare cost and utilization project (HCUP). We identified patients with CHF as the primary diagnosis and MDD as the secondary diagnosis using ICD-9-CM codes and compared with the CHF patient without MDD. The differences in comorbidities were quantified using chi-square tests and the logistic regression model was used to evaluate mortality risk among comorbidities using odds ratio (OR).

Results

Elder CHF patients, 36–50-year-old (OR: 1.324) and whites (OR: 1.673), have a higher likelihood of a co-diagnosis of MDD. Females with heart failure have two-fold higher odds of MDD (OR: 2.332). Majority of the medical comorbidities were seen in a higher proportion of CHF patients without MDD. Hypothyroidism (10.2%) and drug abuse (15.2%) were seen more in depressed patients comparatively. Among substance use disorder, patients with drug abuse stayed longer and had a higher hospitalization total cost ($51,828). And, hypothyroidism was associated with longer inpatient stay (5.6 days) and cost ($64,726), and four-fold higher odds of in-hospital mortality (OR: 4.405). Though alcohol abuse was seen only in 7.4% of CHF patients with MDD, it was associated with the three-fold higher likelihood of deaths during hospitalization (OR: 3.195).

Conclusion

A middle-aged, white female with comorbid depression has a higher risk of hospitalization for heart failure. Depressed CHF patients with comorbid hypothyroidism were hospitalized for a longer duration with higher inpatient cost and four times higher risk of mortality during hospitalization stay. Further studies are required to evaluate the underlying cause of worse hospital outcomes in depressed CHF patients with alcohol abuse and hypothyroidism. An integrated healthcare model is required for early diagnosis and treatment of depression and associated comorbidities in CHF patients to reduce mortality and improve post-CHF outcomes.

Perioperative Management of Thyroid Dysfunction

Due to the manifold effects of thyroid hormone across virtually all organ systems, the complications associated with thyroid dysfunction are numerous and diverse. The stresses encountered during the perioperative period may exacerbate underlying thyroid disorders, potentially precipitating decompensation and even death. Thus, it is of the utmost importance for the clinician to comprehend the mechanisms by which thyroid disease may complicate surgery and postoperative recovery and to be cognizant of the most effective means of optimizing the status of thyrotoxic and hypothyroid patients perioperatively. This article describes the adverse effects of thyroid dysfunction as they relate to the patient undergoing both thyroid and nonthyroid surgery and recommends treatment approaches aimed at decreasing perioperative risk.

Pulmonary consequences of hypothyroidism

BACKGROUND

Although hypothyroidism has an insidious onset and relatively asymptomatic, exertional dyspnea and fatigue can be the presenting complaints.

OBJECTIVES

The aim is to assess functional lung impairment in hypothyroid patients both at rest and during exercise.

METHODS

A case-control study was carried out on 42 patients with newly diagnosed hypothyroidism and 12 control subjects. Hypothyroidism was diagnosed based on high value of thyroid stimulating hormone (TSH) ≥6 μIU/ml, and low value of free thyroxin (FT4) ≤0.8 ng/dl, both groups had chest X-ray, spirometry, diffusing capacity of the lungs for carbon monoxide (DLCO), arterial blood gases (ABGs) and symptom-limited exercise testing using treadmill.

RESULTS

Both groups were comparable as regard age, sex, and body mass index. Although ABG and spirometry were within normal in both groups, forced vital capacity %, and forced expiratory flow (FEF_25-75) % were significantly reduced in the hypothyroid group (P = 0.014, 0.000, respectively), DLCO significantly reduced in hypothyroidism (P = 0.005). As regard exercise testing parameters, maximum oxygen consumption %, minute ventilation, tidal volume, and oxygen pulse were significantly reduced in hypothyroidism (0.005, 0.000, 0.000, and 0.02 respectively). TSH significantly negatively correlated with forced expiratory volume in 1 s %, FEF_25-75%, and DLCO while they significantly positively correlated with FT4.

CONCLUSION

Even with the presence of normal chest X-ray, arterial blood gases, and spirometry in patients with hypothyroidism DLCO and exercise testing parameters can be significantly reduced.

Comparison of Therapeutic Efficacy and Clinical Parameters Between Recombinant Human Thyroid Stimulating Hormone and Thyroid Hormone Withdrawal in High-Dose Radioiodine Treatment with Differentiated Thyroid Cancer

PURPOSE

High-dose radioiodine treatment (HD-RIT) after injection of recombinant human thyroid stimulating hormone (rh-TSH) has become widely used. This study compared the therapeutic efficacy of HD-RIT and clinical parameters between rh-TSH supplement and thyroid hormone withdrawal (THW) after total thyroidectomy in patients with differentiated thyroid cancer.

METHODS

We retrospectively reviewed 266 patients (47 male and 219 female; age, 49.0 ± 10.9 years) with differentiated thyroid cancer detected from September 2011 to September 2012. Patients comprised THW (217, 81.6 %) and rh-TSH (49, 18.4 %). Inclusion criteria were: first HD-RIT; any TN stage; absence of distant metastasis. To evaluate the complete ablation of the remnant thyroid tissue or metastasis, we reviewed stimulated serum thyroglobulin (sTg), I-123 whole-body scan (RxWBS) on T4 off-state, and thyroid ultrasonography (US) or [F-18]-fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) 6-8 months after HD-RIT. We defined a complete ablation state when all three of the follow-up conditions were satisfied; <2.0 ng/ml of the sTg, I-123 RxWBS (-), and thyroid US or F-18 FDG PET/CT (-). If one of the three was positive, ablation was considered incomplete. We also compared various clinical biomarkers (body weight, body mass index, liver and kidney function) between THW and rh-TSH groups.

RESULTS

The rates of complete ablation were 73.7 % (160/217) for the THW group and 73.5 % (36/49) for the rh-TSH group. There was no significant difference between the two groups (p = 0.970). The follow-up aspartate transaminase (p = 0.001) and alanine transaminase (p = 0.001) were significantly higher in the THW group. The renal function parameters of blood urea nitrogen (p = 0.001) and creatinine (p = 0.005) tended to increase in the THW group. The change of body weight was + Δ0.96 (±1.9) kg for the THW group and was decreased by -Δ1.39 (±1.5) kg for the rh-TSH group. The change of body mass index was 0.4 (±0.7) kg/m(2) in the THW group and was decreased by -0.6 (±0.6) kg/m(2) in the rh-TSH group.

CONCLUSIONS

Consistent with previous studies, the rates of complete ablation between the THW and rh-TSH groups were not significantly different. The clinical parameters, as we mentioned above, were elevated for THW group but were irrelevant for the rh-TSH group. The findings favor HD-RIT after rh-TSH, especially for patients with chronic liver and kidney disease.

Clinical significance of diffuse intrathoracic uptake on post-therapy I-131 scans in thyroid cancer patients

PURPOSE

The purpose of this study was to identify the frequency and possible cause of diffuse intrathoracic uptake on post-therapy I-131 scans in thyroid cancer patients.

METHODS

We retrospectively reviewed 781 post-therapy scans of 755 thyroid cancer patients who underwent total thyroidectomy and radioactive iodine therapy between January and December 2010. Diffuse intrathoracic uptake on post-therapy scans was examined, and clinical patient characteristics including sex, age, regimen for thyroid-stimulating hormone (TSH) stimulation (thyroid hormone withdrawal or recombinant human TSH injection), TSH, thyroglobulin (Tg) and anti-thyroglobulin antibody (anti-Tg Ab) levels, therapeutic dose of radioactive iodine therapy and prior history of radioactive iodine therapy were recorded.Scan findings were correlated with chest CT, chest radiographs, laboratory tests and/or clinical status. Diffuse intrathoracic uptake without evidence of pathologic condition was categorized as indeterminate. The association between clinical characteristics and intrathoracic uptake were analyzed for negative intrathoracic uptake and indeterminate uptake groups.

RESULTS

Diffuse intrathoracic uptake on post-therapy scans was demonstrated in 39 out of 755 (5.2 %) patients, among which 3 were confirmed as lung metastasis. The 14 patients that showed high Tg or anti-Tg Ab levels were considered to be at risk of having undetected micrometastasis on other imaging modalities. The remaining 22 were indeterminate (2.9 %).Upon comparison of negative intrathoracic uptake and indeterminate uptake groups, TSH stimulation by thyroid hormone withdrawal was shown to be significantly correlated with diffuse intrathoracic uptake (p < 0.05).

CONCLUSION

The frequency of diffuse intrathoracic uptake on post-therapy scans was 5.2 % and could be seen in thyroid cancer patients with underlying lung metastasis as well as those without definite pathologic condition. In the latter, there was a higher frequency for diffusely increased intrathoracic uptake in those who underwent thyroid hormone withdrawal rather than recombinant human TSH injection.

Treatment with thyroid hormone

Thyroid hormone deficiency can have important repercussions. Treatment with thyroid hormone in replacement doses is essential in patients with hypothyroidism. In this review, we critically discuss the thyroid hormone formulations that are available and approaches to correct replacement therapy with thyroid hormone in primary and central hypothyroidism in different periods of life such as pregnancy, birth, infancy, childhood, and adolescence as well as in adult patients, the elderly, and in patients with comorbidities. Despite the frequent and long term use of l-T4, several studies have documented frequent under- and overtreatment during replacement therapy in hypothyroid patients. We assess the factors determining l-T4 requirements (sex, age, gender, menstrual status, body weight, and lean body mass), the major causes of failure to achieve optimal serum TSH levels in undertreated patients (poor patient compliance, timing of l-T4 administration, interferences with absorption, gastrointestinal diseases, and drugs), and the adverse consequences of unintentional TSH suppression in overtreated patients. Opinions differ regarding the treatment of mild thyroid hormone deficiency, and we examine the recent evidence favoring treatment of this condition. New data suggesting that combined therapy with T3 and T4 could be indicated in some patients with hypothyroidism are assessed, and the indications for TSH suppression with l-T4 in patients with euthyroid multinodular goiter and in those with differentiated thyroid cancer are reviewed. Lastly, we address the potential use of thyroid hormones or their analogs in obese patients and in severe cardiac diseases, dyslipidemia, and nonthyroidal illnesses.

How to manage perioperative endocrine insufficiency

Patients with endocrinopathies frequently present to the operating room. Although many of these disorders are managed on a chronic basis, patients may have acute changes in the perioperative period that, if left unrecognized, can have a negative effect on perioperative morbidity and mortality. It is imperative that anesthesiologists understand the implications of the surgical stress response on hormonal flux. This article focuses on the 4 most commonly encountered endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Specific challenges pertaining to patients with pheochromocytoma are also discussed.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Myxedema coma

Myxedema coma is the term given to the most severe presentation of profound hypothyroidism and is often fatal in spite of therapy. Decompensation of the hypothyroid patient into a coma may be precipitated by a number of drugs, systemic illnesses (eg, pneumonia), and other causes. It typically presents in older women in the winter months and is associated with signs of hypothyroidism, hypothermia, hyponatremia, hypercarbia, and hypoxemia. Treatment must be initiated promptly in an intensive care unit setting. Although thyroid hormone therapy is critical to survival, it remains uncertain whether it should be administered as thyroxine, triiodothyronine, or both. Adjunctive measures, such as ventilation, warming, fluids, antibiotics, pressors, and corticosteroids, may be essential for survival.

Optimizing treatment of hypothyroidism

Several thyroid hormone preparations are currently available, including levothyroxine sodium (thyroxine), liothyronine (triiodothyronine), and desiccated thyroid extract, as well as a combination of levothyroxine sodium and liothyronine. Levothyroxine sodium monotherapy at an appropriate daily dose provides uniform levels of both thyroxine and triiodothyronine in the circulation without diurnal variation. Therefore, it is the preparation of choice in most patients with hypothyroidism of both the primary and central types. A normal thyrotropin (TSH) level of 1-2 mU/L is considered the determinant of optimal daily levothyroxine sodium dose in patients with primary hypothyroidism, whereas normal thyroxine and triiodothyronine levels in the mid or upper normal range may denote optimal replacement in patients with central hypothyroidism. Optimal daily levothyroxine sodium dose may be determined according to serum TSH level at the time of diagnosis of primary hypothyroidism. Initial administration of close to the full calculated dose of levothyroxine sodium is appropriate for younger patients, reducing the need for follow-up visits and repeated laboratory testing for dose titration. In the elderly and in patients with a history of coronary artery disease (CAD), the well established approach of starting with a low dose and gradually titrating to the full calculated dose is always the best option. Levothyroxine sodium can and should be continued in patients receiving treatment for CAD. Even minor over-replacement during initial titration of levothyroxine sodium should be avoided, because of the risk of cardiac events. Chronic over-replacement may induce osteoporosis, particularly in postmenopausal women, and should also be avoided.

Hypothyroidism as a risk factor for cardiovascular disease

The cardiovascular risk in patients with hypothyroidism is related to an increased risk of functional cardiovascular abnormalities and to an increased risk of atherosclerosis. The pattern of cardiovascular abnormalities is similar in subclinical and overt hypothyroidism, suggesting that a lesser degree of thyroid hormone deficiency may also affect the cardiovascular system. Hypothyroid patients, even those with subclinical hypothyroidism, have impaired endothelial function, normal/depressed systolic function, left ventricular diastolic dysfunction at rest, and systolic and diastolic dysfunction on effort, which may result in poor physical exercise capacity. There is also a tendency to increase diastolic blood pressure as a result of increased systemic vascular resistance. All these abnormalities regress with L-T4 replacement therapy. An increased risk for atherosclerosis is supported by autopsy and epidemiological studies in patients with thyroid hormone deficiency. The "traditional" risk factors are hypertension in conjunction with an atherogenic lipid profile; the latter is more often observed in patients with TSH >10 mU/L. More recently, C-reactive protein, homocysteine, increased arterial stiffness, endothelial dysfunction, and altered coagulation parameters have been recognized as risk factors for atherosclerosis in patients with thyroid hormone deficiency. This constellation of reversible cardiovascular abnormalities in patient with TSH levels <10 mU/L indicate that the benefits of treatment of mild thyroid failure with appropriate doses of L-thyroxine outweigh the risk.