Márcia Martins Ferreira

Lipid profile in different degrees of hypothyroidism and effects of levothyroxine replacement in mild thyroid failure

The aim of this study was to evaluate the lipid profile of patients with different degrees of hypothyroidism and the effect of levothyroxine replacement in subclinical hypothyroidism (SH). Initially, a cross-sectional study was performed with 226 participants [SH = 133 participants, manifest hypothyroidism (MH) = 23 participants, and euthyroidism (EU) = 70 participants]. The mean levels of atherogenic lipid variables were greater in MH than in SH and were greater in SH than in EU, although the differences between SH and EU did not reach statistical significance. The SH subgroup with greater serum thyrotropin (TSH) levels and that with positive antithyroperoxidase antibodies (TPO-Ab) had greater levels of triglycerides and of the atherogenic index Apo B/Apo A. A positive correlation exists between serum TSH and total cholesterol (rs = 0.167; P = 0.006), triglycerides (rs = 0.219; P < 0.001), and ApoB levels (rs = 0.205; P < 0.001). Eleven patients who received levothyroxine (L-T4) treatment and 15 patients who received placebo were reevaluated 1 year after TSH adjusted intervention. A fall in atherogenic variables was observed in the L-T4-treated group, with significance for total cholesterol (-20.0 vs +16.1 mg/dL in the placebo group) and LDL-c (-21.7 vs +17.2 mg/dL). We concluded that SH leads to an intermediary lipid profile between euthyroid individuals and that found in manifest hypothyroidism and that a significant lipid profile improvement occurred 1 year after L-T4 replacement therapy.

Functional Capacity and Muscular Abnormalities in Subclinical Hypothyroidism

Background:Neuromuscular abnormalities and low exercise tolerance are frequently observed in overt hypothyroidism, but it remains controversial if they can also occur in subclinical hypothyroidism (sHT). The aim of this study is to evaluate neuromuscular symptoms, muscle strength, and exercise capacity in sHT, compared with healthy euthyroid individuals. Methods:A cross-sectional study was performed with 44 sHT and 24 euthyroid outpatients from a university hospital. Neuromuscular symptoms were questioned. Muscle strength was tested for neck, shoulder, arm, and hip muscle groups, using manual muscle testing (MMT). Quadriceps muscle strength was tested with a chair dynamometer and inspiratory muscle strength (IS) by a manuvacuometer. Functional capacity was estimated based on the peak of oxygen uptake (mL/kg/min), using the Bruce treadmill protocol. Results:Cramps (54.8% versus 25.0%; P < 0.05), weakness (45.2% versus 12.6; P < 0.05), myalgia (47.6% versus 25.0%; P = 0.07), and altered MMT (30.8% versus 8.3%; P = 0.040) were more frequent in sHT. Quadriceps strength and IS were not impaired in sHT and the same was observed for functional capacity. IS was significantly lower in patients complaining of fatigue and weakness (P < 0.05) and tended to be lower in those with altered MMT (P = 0.090). Conclusion:Neuromuscular complaints and altered MMT were significantly more frequent in sHT than in controls, and IS was lower in patients with these abnormalities. Results suggest that altered muscle strength by MMT and the coexistence of neuromuscular complaints in patients with sHT may indicate neuromuscular dysfunction.

Avaliação clínica e de sintomas psiquiátricos no hipotireoidismo subclínico

BACKGROUND: This investigation evaluated and correlated clinical, laboratorial aspects and psychiatric symptoms in sub clinical hypothyroidism (SH). METHODS: Cross sectional study involving 103 patients with SH and 60 subjects without thyroid disease. Clinical and psychiatric evaluation was respectively based on the Zulewski score and Hamilton A, Hamilton D and Beck questionnaires. Serum thyreotropin (TSH), (thyroxine) FT4 and (antithyroperoxidase) ATPO were measured in all participants. Analysis of continuums data was assessed by the Student t- test, for normally distributed data, and by the Mann- Whitney and Kruskal Wallis tests for non-parametric data. The c2, Fishers and Kruskal Wallis tests were used to study qualitative variables. Multivariate analyses were used to study confounding variables. RESULTS: Mean serum TSH level was 7.76 ± 2.9 µUI/mL in SH and 1.66 ± 0.6 µUI/mL in the group without thyroid disease (p=0.001). Mean serum T4L was slightly lower among patients with HS, and showed a negative linear correlation with TSH. Higher frequencies of abnormal clinical score (48.3 vs. 67.0%; p=0.02), depression self reported symptoms (20.5 vs. 44.2%; p=0.011) and anxiety symptoms (86.0 vs. 63.4%; p=0.004) occurred more frequently in SH. Frequency of psychiatric symptoms had a positive correlation with the clinical score and serum TSH. There was no association between the clinical and psychiatric findings and the etiology of SH, presence of ATPO, age or menopause. CONCLUSIONS: The study showed that SH was associated with clinical findings and with psychiatric symptoms. Clinical trials are required to evaluate possible improvement with levotiroxine.

Impact of subclinical hypothyroidism treatment in systolic and diastolic cardiac function

OBJECTIVE To evaluate the effects of levothyroxine (L-T4) replacement in echocardiographic parameters of middle-aged women with subclinical hypothyroidism (SH). SUBJECTS AND METHODS This was a randomized, double-blind, placebo-controlled study. Echocardiographic evaluation was carried out at baseline and one year after restoration of euthyroidism. Thirty-three women with SH were assigned to one of two groups (L-T4 or placebo). RESULTS The two groups had similar basal characteristics. There was a significant deterioration of left ventricular Tei index after one year of placebo use, which differed from the effect of L-T4 replacement (+0.086 ± 0.092 vs. -0.014 ± 0.012; p = 0.047). There was also a slight reduction in cardiac output and cardiac index with placebo use, which was not different from L-T4 effect. CONCLUSION Results suggest a positive impact of L-T4 replacement in cardiac function of middle-aged women with SH.

Avaliação clínica e da função muscular em pacientes com hipotireoidismo subclínico

Some symptoms and signs of hypothyroidism, as well as some laboratory abnormalities, may be present in subclinical hypothyroidism (SH). This study evaluates the prevalence of signs and symptoms of hypothyroidism and skeletal muscle dysfunction in 57 patients with SH compared to 37 euthyroid controls. The participants received a clinical score based on signs and symptoms of hypothyroidism. The muscle strength was estimated by manual testing and chair dynamometer and inspiratory force by manuvacuometer. Thyroid hormones and muscle enzymes were measured. The SH group presented with higher score (p< 0.01), complained about mialgia and weakness more frequently (p< 0.05), and showed strength disability in scapular and pelvic girdles (p< 0.05). The median free T4 serum levels were lower in SH (p< 0.001). These findings suggest that signs and symptoms of thyroid dysfunction may be related to lower levels of FT4 in SH and should be taken into account in the decision of beginning LT4 therapy.

Monitorização ambulatorial da pressão arterial em pacientes normotensos com hipotireoidismo subclínico

BACKGROUND Overt hypothyroidism is associated with elevation of diastolic blood pressure; however the association of subclinical hypothyroidism (SH) with arterial blood pressure (ABP) alteration is unknown. OBJECTIVE The aim of the present study was to evaluate ambulatory blood pressure monitoring (ABPM), over 24 hours, in normotensive patients with SH in comparison to euthyroid (EU) normotensive individuals. METHODS A cross-sectional study was performed with 50 participants (SH = 30 and EU = 20) that did not differ regarding risk factors for hypertension. The ABPM was carried out with a DINAMAPA TM monitor, using the oscillometric method validated by AAMI (Association for the Advancement of Medical Instrumentation) and by the BHS (British Hypertension Society). RESULTS The mean serum TSH and FT4 were respectively 6.9 +/- 2.2 microUI/ml and 1.1 +/- 0.2 ng/dl in SH patients. Although there was no difference in the mean values of systolic and diastolic blood pressure between the two groups, there was a positive correlation between the mean values of diastolic blood pressure (DBP) and serum TSH levels in SH patients (r:0.477; p = 0.004). These correlations were detected at daytime (r:0.498; p = 0.002) and sleep-time (r:0.322; p = 0.032) measurements. CONCLUSION The blood pressure was not different between patients with or without SH; however, the results suggest that the progression of subclinical hypothyroidism to higher levels of TSH may increase the cardiovascular risk by increasing diastolic blood pressure.