Arterial hypertension and thyroid disorders: What is important to know in clinical practice?

Blood pressure in hyperthyroid cats before and after radioiodine treatment

BACKGROUND

Hyperthyroid cats commonly have systemic hypertension, with a reported prevalence of 7% to 48%. Although hypertension might be expected to resolve once treatment restores euthyroidism, it can persist or only first develop after treatment.

OBJECTIVES

To determine the proportion of hyperthyroid cats with hypertension (systolic blood pressure [SBP] ≥160 mm Hg), persistence or first development of hypertension after successful radioiodine treatment, and correlation of post-treatment hypertension with azotemia or hypothyroidism.

ANIMALS

Four hundred one hyperthyroid nonazotemic cats were included in the study.

METHODS

Prospective, cross-sectional and before-and-after studies. All hyperthyroid cats had SBP measured by Doppler; 255 had SBP rechecked 6 months after successful radioiodine (131I) treatment.

RESULTS

Of untreated hyperthyroid cats, 108/401 (27%) were hypertensive. A higher proportion of hypertensive cats were nervous/excited compared with normotensive cats (47% vs 12%; P < .001). Of the initially hypertensive cats, 87/108 cats were reexamined after 131I treatment; 43/87 (49%) cats normalized SBP, whereas 44/87 (51%) remained hypertensive. Of the initially normotensive cats, 16/168 (9.5%) first developed hypertension after successful 131I treatment. 7/60 (12%) of the 131I-treated hypertensive cats were azotemic and 9/60 (15%) were hypothyroid. A higher proportion of cats remaining hypertensive had nervous/excited demeanor than did normotensive cats (50% vs 17%; P < .001).

CONCLUSIONS/CLINICAL IMPORTANCE

Hypertension, when present, resolves in many hyperthyroid cats after successful treatment. Hyperthyroid cats uncommonly develop new hypertension after treatment. Persistent or newly detected hypertension was unrelated to azotemia or iatrogenic hypothyroidism. More frequently perceived nervousness/anxiety in radioiodine-treated hypertensive cats suggests that many of these cats might have "situational" hypertension, as hyperthyroid-induced hypertension should resolve after treatment.

Thyroid Hormone Resistance Syndrome: From Molecular Mechanisms to Its Potential Contribution to Hypertension

Thyroid hormone resistance (THR) is a rare inherited disorder that affects approximately one in every 40,000 live births. This condition arises from a mutation in the thyroid hormone receptor β, leading to reduced responsiveness of target tissues. It can result in a combination of hypothyroidism and hyperthyroidism symptoms in different tissues. The thyroid hormone is crucial for controlling blood pressure, and even small changes in its levels can have an effect on vascular resistance, cardiac performance, and heart rhythm. Both hypo- and hyperthyroidism have been associated with elevated blood pressure, underscoring the significant link between thyroid hormone sensitivity and vascular function. Considering thyroid hormone sensitivity is essential in clinical practice, particularly when managing patients with hypertension, to ensure personalized and effective treatment approaches. Monitoring thyroid function is essential during the diagnosis of hypertension, as thyroid dysfunction can often be corrected to normalize blood pressure. It's crucial to distinguish between essential hypertension and hypertension associated with a thyroid abnormality in THR. The mechanisms behind the development of hypertension in THR include reduced nitric oxide production, dysregulation of the renin-angiotensin-aldosterone system, impaired endothelial function, and mutations in the deiodinases. Physicians should understand the underlying mechanisms of THR and identify new therapeutic targets for hypertension in THR.

Secondary hypertension as a cause of treatment resistance

In secondary hypertension, elevated blood pressure is caused by a known and/or potentially treatable underlying disease.Although the prevalence of secondary hypertension depends on the patient population and the thoroughness of applied diagnostic approaches, arterial hypertension is classified in 90 to 95% as primary in nature. In young patients, individuals without a family history of hypertension, late onset of hypertension or worsening of a previous well-controlled hypertension as well as in patients who have a difficult to treat hypertension, the prevalence of secondary hypertension is significantly higher.Because the identification and the specific therapy of secondary hypertension may result in normalisation or improvement of elevated blood pressure in many cases, a targeted diagnostics is of great importance.

Association of periodontitis, missing teeth, and oral hygiene behaviors with the incidence of hypertension in middle-aged and older adults in Korea: A 10-year follow-up study

BACKGROUND

The relationship between periodontitis and hypertension remains controversial. This study aimed to investigate the association of periodontitis, missing teeth, and oral hygiene behaviors with the incidence of hypertension.

METHODS

A total of 104,349 participants were selected from the National Health Insurance System-Health Screening cohort. Incident hypertension and periodontitis were diagnosed based on the patients' clinical records and health examinations. A multivariable Cox proportional hazards regression analysis was performed after adjusting for socioeconomic factors, coexisting disease, and health behaviors.

RESULTS

The mean age of the participants was 51.1 years (range, 40-79 years) at baseline, and 55.1% were men. A total of 52,855 incident hypertension cases were identified during the median follow-up period of 9.6 years. Among the participants, periodontitis (hazard ratio [HR]: 1.02, 95% confidence interval [95% CI]: 1.00-1.04), number of missing teeth (for ≥15 group, HR: 1.40, 95% CI: 1.29-1.52), dental scaling (HR: 0.93, 95% CI: 0.91-0.95), and tooth brushing frequency (for ≥3 group, HR: 0.85, 95% CI: 0.83-0.88) were significantly associated with incident hypertension after full adjustments for covariates. While periodontitis was significantly associated with incident hypertension (HR: 1.04, 95% CI: 1.02-1.06) in the middle-aged group (40-64 years), the effect was insignificant in the older group (≥65 years).

CONCLUSION

Oral inflammation could contribute to the incidence of hypertension; thus, efforts to reduce oral inflammation should be encouraged. Future intervention studies are warranted to determine whether oral health care could be beneficial in the management of hypertension. This article is protected by copyright. All rights reserved.

Hypertension and Hyperthyroidism: Association and Pathogenesis

Hypertension can cause significant morbidity and reduced life expectancy. Most patients with hypertension have primary hypertension; however, 10 to 15% of patients have secondary hypertension. Endocrine disorders explain approximately 10% of hypertension in all patients, and thyroid disorders account for approximately 1% of cases with hypertension. Hyperthyroidism can cause increased cardiac output, increased systolic blood pressures, and increased levels of renin, angiotensin, and aldosterone. Treatment of hyperthyroidism can cure hypertension in some patients. Consequently, identification of patients with secondary hypertension potentially has important benefits, and understanding secondary hypertension provides a framework for investigating the pathophysiology of hypertension. Clinicians should consider the possibility of hyperthyroidism in patients with hypertension, even in those of more advanced age.

Hyperthyroidism

Hyperthyroidism is a condition where the thyroid gland produces and secretes inappropriately high amounts of thyroid hormone which can lead to thyrotoxicosis. The prevalence of hyperthyroidism in the United States is approximately 1.2%. There are many different causes of hyperthyroidism, and the most common causes include Graves' disease (GD), toxic multinodular goiter and toxic adenoma. The diagnosis can be made based on clinical findings and confirmed with biochemical tests and imaging techniques including ultrasound and radioactive iodine uptake scans. This condition impacts many different systems of the body including the integument, musculoskeletal, immune, ophthalmic, reproductive, gastrointestinal and cardiovascular systems. It is important to recognize common cardiovascular manifestations such as hypertension and tachycardia and to treat these patients with beta blockers. Early treatment of cardiovascular manifestations along with treatment of the hyperthyroidism can prevent significant cardiovascular events. Management options for hyperthyroidism include anti-thyroid medications, radioactive iodine, and surgery. Anti-thyroid medications are often used temporarily to treat thyrotoxicosis in preparation for more definitive treatment with radioactive iodine or surgery, but in select cases, patients can remain on antithyroid medications long-term. Radioactive iodine is a successful treatment for hyperthyroidism but should not be used in GD with ophthalmic manifestations. Recent studies have shown an increased concern for the development of secondary cancers as a result of radioactive iodine treatment. In the small percentage of patients who are not successfully treated with radioactive iodine, they can undergo re-treatment or surgery. Surgery includes a total thyroidectomy for GD and toxic multinodular goiters and a thyroid lobectomy for toxic adenomas. Surgery should be considered for those who have a concurrent cancer, in pregnancy, for compressive symptoms and in GD with ophthalmic manifestations. Surgery is cost effective with a high-volume surgeon. Preoperatively, patients should be on anti-thyroid medications to establish a euthyroid state and on beta blockers for any cardiovascular manifestations. Thyroid storm is a rare but life-threatening condition that can occur with thyrotoxicosis that must be treated with a multidisciplinary approach and ultimately, definitive treatment of the hyperthyroidism.

Hypertension in Thyroid Disorders

Arterial hypertension represents a major global health concern; more than one fourth of the population is affected by high blood pressure. Albeit the underlying cause of the disease remains unclear in the vast majority of the cases, ~10% are of secondary origin. Endocrine disorders are common illnesses and some of them may lead to elevated blood pressure, among which thyroid diseases are of high prevalence and often overlooked, especially in mild cases. Overt and subclinical hyper- and hypothyroidism can both lead to (mostly mild) hypertension; however, the underlying mechanisms are only partially understood. The results of clinical studies are often controversial. During the past decades, some genetic mutations in the hypothalamus-pituitary-thyroid axis with cardiovascular consequences were revealed. Atherosclerotic changes resulting from lipid abnormalities due to thyroid dysfunction also affect the vasculature and can cause elevated blood pressure. The review gives a synopsis of our knowledge how thyroid hormone metabolism and functional thyroid diseases affect the cardiovascular system, their negative impact and causative role in the development of hypertension.

Mood Disorders in Uncontrolled Hypertension Despite Multiple Anti-Hypertensive Medications: Searching for a Link

INTRODUCTION

Resistant hypertension is a clinical condition in which blood pressure (BP) control is not achieved under a pharmacological therapy including a diuretic and at least two additional antihypertensive drug classes.

AIM

To discuss an unusual presentation of uncontrolled hypertension despite multiple anti-hypertensive medications.

METHODS AND RESULTS

A 46-year-old woman presented with resistant hypertension (HT) and with a long history of polydipsia, polyuria, weight loss and psychiatric symptoms (sudden onset of personality disorder with free anxiety, negativism and asthenia) unsuccessfully treated with antidepressant drugs. Tests for secondary HT showed a marked increase of serum renin and aldosterone both in clinostatic (342 pg/ml and 907 pmol/l, respectively) and orthostatic posture (351 pg/ml and 2845 pmol/l, respectively), hypokalemia (2.9 mmol/l) and macroalbuminuria (431 mg/day). Diagnostic examinations also revealed a focal stenosis of approximately 70 % of the proximal right renal artery with post-stenotic dilation. After percutaneous balloon angioplasty and stent implantation, BP was normalized with 5 mg/day amlodipine and psychiatric symptoms suddenly disappeared.

CONCLUSIONS

Psychopathological symptoms are rare at the onset of hyperaldosteronism, and their aetiology is not well defined. A proper diagnostic and therapeutic process is mandatory in order to get the recommended therapeutic targets in short-midterm improving long-term prognosis. We also suggest not considering depressed or treat with antidepressant agents a young hypertensive subject with uncontrolled hypertension despite multiple anti-hypertensive medications without having ruled out a secondary form of hypertension.

Low serum free thyroxine concentrations associate with increased arterial stiffness in euthyroid subjects: a population-based cross-sectional study

Some studies suggest that even in euthyroid subjects, thyroid function may affect arteriosclerotic risk factors. We aimed to determine whether thyroid hormones or thyroid autoantibodies are associated with arterial stiffness in middle-aged and elderly Chinese subjects with euthyroidism. A cross-sectional, population-based study was conducted in Nanjing, China. A total of 812 euthyroid subjects (mean age [56.75 ± 8.34] years; 402 men) without vascular disease and major arteriosclerotic risk factors were included. Clinical factors, oral glucose tolerance test results, homeostasis model assessment for insulin resistance (HOMA-IR) results, and serum levels of lipids, free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and thyroid autoantibodies were measured. Arterial stiffness was assessed using brachial-ankle pulse wave velocity (baPWV). In Pearson correlation analyses, baPWV correlated inversely with FT4 (r = -0.146, P < 0.001), but not with FT3 (r = 0.008, P = 0.816) or TSH (r = 0.055, P = 0.118). Subsequently, a multiple stepwise regression analysis revealed a significant and independent association of FT4 with baPWV in euthyroid subjects (β = -0.076, P = 0.005). After adjusting for potential cardiovascular risk factors, mean diastolic blood pressure (DBP), HOMA-IR, and baPWV levels decreased across increasing FT4 quartiles (DBP, P < 0.001; HOMA-IR, P < 0.001; baPWV, P = 0.003). No difference in baPWV was observed between the positive and the negative thyroid antibody groups (15.23 ± 3.30 m/s vs. 15.73 ± 3.05 m/s, P > 0.05). FT4 levels were inversely associated with arterial stiffness in euthyroid subjects. A prospective study is warranted to validate whether subjects with low-normal FT4 levels have a high incidence of cardiovascular disease.

Cardioprotective properties of citicoline against hyperthyroidism-induced reperfusion damage in rat hearts

Hyperthyroidism represents an increased risk factor for cardiovascular morbidity, especially when the heart is subjected to an ischemia/reperfusion process. The aim of this study was to explore the possible protective effect of the nucleotide citicoline on the susceptibility of hyperthyroid rat hearts to undergo reperfusion-induced damage, which is associated with mitochondrial dysfunction. Hence, we analyzed the protective effect of citicoline on the electrical behavior and on the mitochondrial function in rat hearts. Hyperthyroidism was established after a daily i.p. injection of triiodothyronine (at 2 mg/kg of body weight) during 5 days. Thereafter, citicoline was administered i.p. (at 125 mg/kg of body weight) for 5 days. In hyperthyroid rat hearts, citicoline protected against reperfusion-induced ventricular arrhythmias. Moreover, citicoline maintained the accumulation of mitochondrial Ca(2+), allowing mitochondria to reach a high transmembrane electric gradient that protected against the release of cytochrome c. It also preserved the activity of the enzyme aconitase that inhibited the release of cytokines. The protection also included the inhibition of oxidative stress-induced mDNA disruption. We conclude that citicoline protects against the reperfusion damage that is found in the hyperthyroid myocardium. This effect might be due to its inhibitory action on the permeability transition in mitochondria.