Primary Aldosteronism Diagnosis and Management: A Clinical Approach

A study on the early metabolic effects of salt and fructose consumption: the protective role of water

Increasing serum osmolality has recently been linked with acute stress responses, which over time can lead to increased risk for obesity, hypertension, and other chronic diseases. Salt and fructose are two major stimuli that can induce acute changes in serum osmolality. Here we investigate the early metabolic effects of sodium and fructose consumption and determine whether the effects of sodium or fructose loading can be mitigated by blocking the change in osmolality with hydration. Forty-four healthy subjects without disease and medication were recruited into four groups. After overnight fasting, subjects in Group 1 drank 500 mL of salty soup, while those in Group 2 drank 500 mL of soup without salt for 15 min. Subjects in Group 3 drank 500 mL of 100% apple juice in 5 min, while subjects in Group 4 drank 500 mL of 100% apple juice and 500 mL of water in 5 min. Blood pressure (BP), plasma sodium, and glucose levels were measured every 15 min in the first 2 h. Serum and urine osmolarity, serum uric acid, cortisol, fibroblast growth factor 21 (FGF21), aldosterone, adrenocorticotropic hormone (ACTH) level, and plasma renin activity (PRA) were measured at the baseline and 2 h. Both acute intake of salt or fructose increased serum osmolality (maximum ∼4 mOsm/L peaking at 75 min) associated with a rise in systolic and diastolic BP, PRA, aldosterone, ACTH, cortisol, plasma glucose, uric acid, and FGF21. Salt tended to cause greater activation of the renin-angiotensin-system (RAS), while fructose caused a greater rise in glucose and FGF21. In both cases, hydration could prevent the osmolality and largely block the acute stress response. Acute changes in serum osmolality can induce remarkable activation of the ACTH-cortisol, RAS, glucose metabolism, and uric acid axis that is responsive to hydration. In addition to classic dehydration, salt, and fructose-containing sugars can activate these responses. Staying well hydrated may provide benefits despite exposure to sugar and salt. More studies are needed to investigate whether hydration can block the chronic effects of sugar and salt on disease.

Increased daytime and awakening salivary free aldosterone in essential hypertensive men

Background

While aldosterone plays an important role in blood pressure regulation, its role in essential hypertension (EHT) remains unclear. Here, we systematically investigated the secretion of biologically-active free aldosterone in saliva in response to awakening (AldAR) and during the day (AldDay) in EHT compared to normotensive controls (NT).

Methods

In 30 men with EHT and 30 age-matched NT, AldAR saliva samples were collected immediately after awakening and 15, 30, 45, and 60 min thereafter and AldDay samples were collected from 08:30-22:00 h on two consecutive days.

Results

Over the course of the day, men with EHT had higher repeated AldDay levels compared to NT (p = .002) with higher concentrations in the morning hours (p's ≤ .047), a steeper decline over the course of the day (p's ≤ .018), and similar concentrations in the evening (p's ≥ .21). Regarding AldAR, we observed higher concentrations in EHT at awakening (p = .017) and borderline higher concentrations at 15 min (p = .086). No differences were found 30-60 min after awakening (p's ≥ .34). Analyses with repeated and aggregated AldAR levels resulted in borderline significantly higher free aldosterone in EHT (p's ≤ .077). Complementary analyses confirmed linear associations between higher blood pressure and higher AldAR and AldDay levels.

Conclusions

Our data point to elevated salivary free aldosterone secretion in EHT over the course of the day, particularly in the morning hours. As the free aldosterone fraction is considered biologically active, our data may point to a biological mechanism underlying EHT.

Characterization of a Biochemical Mouse Model of Primary Aldosteronism for Thermal Therapies

Introduction

Aldosterone-producing adenoma (APA) is the most common cause of endocrine-related hypertension but surgery is not always feasible. Current medical interventions are associated with significant side effects and poor patient compliance. New APA animal models that replicate basic characteristics of APA and give physical and biochemical feedback are needed to test new non-surgical treatment methods, such as image-guided thermal ablation.

Methods

A model of APA was developed in nude mice using HAC15 cells, a human adrenal carcinoma cell line. Tumor growth, aldosterone production, and sensitivity to angiotensin II were characterized in the model. The utility of the model was validated via treatment with microwave ablation and characterization of the resulting physical and biochemical changes in the tumor.

Results

The APA model showed rapid and relatively homogeneous growth. The tumors produced aldosterone and steroid precursors in response to angiotensin II challenge, and plasma aldosterone levels were significantly higher in tumor bearing mice two hours after challenge verses non-tumor bearing mice. The model was useful for testing microwave ablation therapy, reducing aldosterone production by 80% in treated mice.

Conclusion

The HAC15 model is a useful tumor model to study and develop localized treatment methods for APA.

Imaging Concordance With Vein Sampling for Primary Aldosteronism: A Cohort Study and Literature Review

INTRODUCTION

Adrenal venous sampling (AVS) is used to distinguish unilateral from bilateral aldosterone hypersecretion as a cause of primary aldosteronism (PA). Unilateral disease is treated with adrenalectomy and bilateral hypersecretion managed medically.

METHODS

We performed a single institution retrospective cohort study of adult patients undergoing adrenalectomy for PA from July 2013 to June 2022. Concordance of imaging findings with AVS was evaluated. Statistical analysis was performed with Mann-Whitney U and chi-squared Fisher's exact. Literature review performed via triple method search strategy.

RESULTS

Twenty-one patients underwent AVS and adrenalectomy for PA. Two patients did not have imaging findings and 19 were localized with an adenoma. For patients with image localization, AVS was concordant in nine, discordant in four, and nondiagnostic in six. For patients with discordant findings, age range was 35.8 to 72.4 y compared with concordant patient age range of 49.8 to 71.7 y. Overall discordance between imaging results and AVS was 40%. The aldosterone level was associated with concordance with a median of 52 ng/dL compared with 26 ng/dL if discordant (P = 0.002). There was a significant reduction in antihypertensive medications for the entire cohort from a median of three medications (interquartile range 2-4) to 1 medication (interquartile range 1-2), P < 0.001.

CONCLUSIONS

In this cohort, 40% of patients with selective AVS had discordant imaging and AVS results. Aldosterone level was associated with concordance. Hypertension was significantly improved with a median decrease of two antihypertensives. Our results support performance of AVS on all candidates for adrenalectomy for PA.

What We Know about and What Is New in Primary Aldosteronism

Primary aldosteronism (PA), a significant and curable cause of secondary hypertension, is seen in 5-10% of hypertensive patients, with its prevalence contingent upon the severity of the hypertension. The principal aetiologies of PA include bilateral idiopathic hypertrophy (BIH) and aldosterone-producing adenomas (APAs), while the less frequent causes include unilateral hyperplasia, familial hyperaldosteronism (FH) types I-IV, aldosterone-producing carcinoma, and ectopic aldosterone synthesis. This condition, characterised by excessive aldosterone secretion, leads to augmented sodium and water reabsorption alongside potassium loss, culminating in distinct clinical hallmarks: elevated aldosterone levels, suppressed renin levels, and hypertension. Notably, hypokalaemia is present in only 28% of patients with PA and is not a primary indicator. The association of PA with an escalated cardiovascular risk profile, independent of blood pressure levels, is notable. Patients with PA exhibit a heightened incidence of cardiovascular events compared to counterparts with essential hypertension, matched for age, sex, and blood pressure levels. Despite its prevalence, PA remains frequently undiagnosed, underscoring the imperative for enhanced screening protocols. The diagnostic process for PA entails a tripartite assessment: the aldosterone/renin ratio (ARR) as the initial screening tool, followed by confirmatory and subtyping tests. A positive ARR necessitates confirmatory testing to rule out false positives. Subtyping, achieved through computed tomography and adrenal vein sampling, aims to distinguish between unilateral and bilateral PA forms, guiding targeted therapeutic strategies. New radionuclide imaging may facilitate and accelerate such subtyping and localisation. For unilateral adrenal adenoma or hyperplasia, surgical intervention is optimal, whereas bilateral idiopathic hyperplasia warrants treatment with mineralocorticoid antagonists (MRAs). This review amalgamates established and emerging insights into the management of primary aldosteronism.

Treating Primary Aldosteronism-Induced Hypertension: Novel Approaches and Future Outlooks

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased morbidity and mortality when compared with blood pressure-matched cases of primary hypertension. Current limitations in patient care stem from delayed recognition of the condition, limited access to key diagnostic procedures, and lack of a definitive therapy option for nonsurgical candidates. However, several recent advances have the potential to address these barriers to optimal care. From a diagnostic perspective, machine-learning algorithms have shown promise in the prediction of PA subtypes, while the development of noninvasive alternatives to adrenal vein sampling (including molecular positron emission tomography imaging) has made accurate localization of functioning adrenal nodules possible. In parallel, more selective approaches to targeting the causative aldosterone-producing adrenal adenoma/nodule (APA/APN) have emerged with the advent of partial adrenalectomy or precision ablation. Additionally, the development of novel pharmacological agents may help to mitigate off-target effects of aldosterone and improve clinical efficacy and outcomes. Here, we consider how each of these innovations might change our approach to the patient with PA, to allow more tailored investigation and treatment plans, with corresponding improvement in clinical outcomes and resource utilization, for this highly prevalent disorder.

Laparoscopic sleeve gastrectomy followed by laparoscopic adrenalectomy for patients with obesity and primary aldosteronism: Report of two patients

INTRODUCTION AND IMPORTANCE

Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Surgical treatment of unilateral PA usually resolves excessive aldosterone secretion. Obesity is an independent factor for postoperative persistent hypertension for patients with unilateral PA. Laparoscopic sleeve gastrectomy has become popular due to its efficacy in resolving obesity. A specific strategy might to be needed for patients with unilateral PA and obesity.

CASE PRESENTATION

Two males with PA and obesity (Body Mass Index: BMIs of 35.9 and 39.0, respectively) were referred for evaluation. Both patients had hypertension caused by PA and obesity. We performed laparoscopic sleeve gastrectomy (LSG) prior to adrenalectomy to avoid persistent postoperative hypertension and perioperative obesity related comorbidities. LSG could lead to decreasing of BMIs to 27.7 and 32.1. Comorbidities associated with obesity were also resolved in both patients. Laparoscopic adrenalectomy was then safely performed in these two patients with PA.

CLINICAL DISCUSSIONS

Patients with PA developing resistant hypertension were estimated to be 20 % of those who underwent adrenalectomy. Decreased BMI can be an independent preoperative determinant for successful outcome after adrenalectomy regarding hypertension. We need to review with special care the preoperative BMI and the nature of hypertension before performing surgery on patients with unilateral PA.

CONCLUSIONS

A successful strategy was used to treat two obese patients with unilateral PA who underwent laparoscopic adrenalectomy after LSG to minimize complications associated with obesity-related comorbidities.

Primary Aldosteronism: A Pragmatic Approach to Diagnosis and Management

Primary aldosteronism is a prevalent but underdiagnosed cause of hypertension, contributing to increased cardiovascular and cerebrovascular events and end-organ damage independent of blood pressure. Prompt diagnosis and treatment with targeted surgical or medical therapy reduce the risk of complications and improve prognosis. This review outlines a practical approach to diagnosis and management of primary aldosteronism for global practitioners.

Cardiovascular Remodeling in Chronic Mineralocorticoid Excess

Primary hyperaldosteronism typically leads to resistant hypertension, hypokalemia, and metabolic alkalosis. Excess aldosterone secretion by the adrenal glands may lead to heart failure with preserved ejection fraction. Potassium-sparing diuretics and aldosterone antagonists directed to lower excess aldosterone levels may help treat the associated heart failure and lead to control of blood pressure, resulting in improved outcomes. We report a case of a 55-year-old male with poorly controlled hypertension and newly symptomatic heart failure with preserved ejection fraction in the setting of excess aldosterone activity and an adrenal adenoma suggesting primary aldosteronism-induced diastolic heart failure. The biochemical evaluation revealed elevated plasma aldosterone concentrations with low plasma renin activity, diuretic-induced hypokalemia, and metabolic alkalosis. A progressively enlarging left adrenal adenoma was found on abdominal imaging along with resistant hypertension despite the use of multiple antihypertensive medications. Medical management targeted to lower excess aldosterone levels with the use of aldosterone antagonists helped us achieve better blood pressure control and resolution of symptoms of diastolic dysfunction. Treating the underlying pathology helped us improve overt heart failure and may suggest that goal-directed therapy towards the inciting factors may potentially lead to a path to reverse the heart failure symptoms clinically.

The epithelial sodium channel in inflammation and blood pressure modulation

A major regulator of blood pressure and volume homeostasis in the kidney is the epithelial sodium channel (ENaC). ENaC is composed of alpha(α)/beta(β)/gamma(γ) or delta(δ)/beta(β)/gamma(γ) subunits. The δ subunit is functional in the guinea pig, but not in routinely used experimental rodent models including rat or mouse, and thus remains the least understood of the four subunits. While the δ subunit is poorly expressed in the human kidney, we recently found that its gene variants are associated with blood pressure and kidney function. The δ subunit is expressed in the human vasculature where it may influence vascular function. Moreover, we recently found that the δ subunit is also expressed human antigen presenting cells (APCs). Our studies indicate that extracellular Na+ enters APCs via ENaC leading to inflammation and salt-induced hypertension. In this review, we highlight recent findings on the role of extra-renal ENaC in inflammation, vascular dysfunction, and blood pressure modulation. Targeting extra-renal ENaC may provide new drug therapies for salt-induced hypertension.

Diagnostic value of the fractional excretion of urine potassium for primary aldosteronism

Background

Primary aldosteronism (PA) is a common form of secondary hypertension, which usually manifests low blood potassium levels. The fractional excretion of urine potassium (FEK) has been proposed as a useful tool to measure urinary potassium excretion. However, the role of the FEK in PA remains unclear. In the current study, we assessed the diagnostic value of FEK in PA.

Methods

A total of 155 hypertension patients were included in this cross-sectional study, of which 62 were confirmed by a positive screening test for PA. We collected the serum, 24-hr urine samples, and spot urine samples to evaluate the diagnostic value of the spot and 24-hr FEK in the diagnosis of PA and renal potassium loss compared to other indices. The sensitivity and specificity of the related diagnostic indexes were analyzed using receiver operating characteristic (ROC) curves, and the optimal cut-point value of the diagnostic index was determined according to the Youden index (YI) (sensitivity + specificity - 1). Correlation analysis was performed between the spot FEK and 24-hr FEK using Pearson's correlation coefficient.

Results

The spot FEK (7.3 vs. 5.9) and 24-hr FEK (9.3 vs. 8.0) levels were statistical differences between the PA and essential hypertension groups. PA patients had a significant tendency to lose potassium through the kidneys. We found that FEK from spot urine distinguished renal potassium loss with a sensitivity of 86.7% and a specificity of 87.1% at a cut-off of 9.8%. The sensitivity and specificity of the spot FEK in screening PA were 51.6% and 76.3%, respectively.

Conclusions

FEK is significantly related to renal potassium loss. Spot FEK and 24-hr FEK performed a certain diagnostic value for PA, which may be potential indicators for the differential diagnosis of PA.

Diagnostic evaluation for adrenal tumors - What does the urologist need to know about endocrine metabolic work up?

PURPOSE OF REVIEW

Adrenal lesions are commonly discovered on abdominal imaging studies, whereas some patients with adrenal tumors present with symptoms of homonal excess. They are categorized as either hormone active or inactive and either as benign or malignant. This review is focused on the endocrine work up in patients with adrenal tumors. Knowledge of the use and limitations of hormonal assessment is essential for propper interpretation of the obtained test results. This article reviews which diagnostics are necessary to identify adrenal masses requiring treatment.

RECENT FINDINGS

Delayed hormonal assessment is not uncommon and associated with delayed treatment. The endocrine work up is guided by data from prospective and retrospective observational studies. Adrenal tumors include a wide spectrum of diseases and as a principle, most patients require biochemical testing to select the appropriate treatment.

SUMMARY

The most important factor for the outcome in the management of adrenal masses is, beside the exclusion of malignancy, a structured evaluation of the patients endocrine status.

Pathophysiology of bilateral hyperaldosteronism

PURPOSE OF REVIEW

Renin-independent aldosterone production from one or both affected adrenal(s), a condition known as primary aldosteronism (PA), is a common cause of secondary hypertension. In this review, we aimed to summarize recent findings regarding pathophysiology of bilateral forms of PA, including sporadic bilateral hyperaldosteronism (BHA) and rare familial hyperaldosteronism.

RECENT FINDINGS

The presence of subcapsular aldosterone synthase (CYP11B2)-expressing aldosterone-producing micronodules, also called aldosterone-producing cell clusters, appears to be a common histologic feature of adrenals with sporadic BHA. Aldosterone-producing micronodules frequently harbor aldosterone-driver somatic mutations. Other potential factors leading to sporadic BHA include rare disease-predisposing germline variants, circulating angiotensin II type 1 receptor autoantibodies, and paracrine activation of aldosterone production by adrenal mast cells. The application of whole exome sequencing has also identified new genes that cause inherited familial forms of PA.

SUMMARY

Research over the past 10 years has significantly improved our understanding of the molecular pathogenesis of bilateral PA. Based on the improved understanding of BHA, future studies should have the ability to develop more personalized treatment options and advanced diagnostic tools for patients with PA.

A narrative review of Hyporeninemic hypertension-an indicator for monogenic forms of hypertension

BACKGROUND AND OBJECTIVE

While the role of the renin-angiotensin-aldosterone system (RAAS) in the development of hypertension is well known, the significance and contribution of low renin hypertension is often overlooked. RAAS stimulation results in more tubular absorption of sodium and water along the nephron, contributing to a higher circulating vascular volume. In addition, members of the RAAS system, such as angiotensin II, have direct effects on vascular vasoconstriction, the heart, aldosterone synthesis in the adrenal glands, the sympathetic nervous system, and the central nervous system. This has resulted in a line of antihypertensive therapeutics targeting RAAS with angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and renin inhibitors, which prevent conversion of angiotensinogen to angiotensin. While general practitioners and nephrologists are well aware of the causes and the long-term consequences of elevated renin and aldosterone levels, the opposite situation with low renin and/or low aldosterone levels is frequently underappreciated. The objective of this review is to provide insight to the less common forms of hyporeninemic hypertension.

METHODS

We searched the PubMed online library for keywords related to hyporeninemic hypertension and focused on the pediatric population. For pathophysiology we focused on literature of the last 5 years.

KEY CONTENT AND FINDINGS

The low renin and aldosterone levels may be indicators of inherited (especially when associated with hypokalemia), monogenic forms of hypertension stimulating excessive tubular sodium and water absorption which subsequently results in plasma volume expansion and hypertension. These forms of hypertension require frequently specific forms of therapy. This underlines the importance of the practitioner to be familiar with these rare diseases.

CONCLUSIONS

In this review article, we outline the different forms of hypertension characterized by low renin/low aldosterone and low renin/high aldosterone levels, how to diagnose these forms of hypertension, and how to treat them.

Progress on Genetic Basis of Primary Aldosteronism

Primary aldosteronism (PA) is a heterogeneous group of disorders caused by the autonomous overproduction of aldosterone with simultaneous suppression of plasma renin activity (PRA). It is considered to be the most common endocrine cause of secondary arterial hypertension (HT) and is associated with a high rate of cardiovascular complications. PA is most often caused by a bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenoma (APA); rarer causes of PA include genetic disorders of steroidogenesis (familial hyperaldosteronism (FA) type I, II, III and IV), aldosterone-producing adrenocortical carcinoma, and ectopic aldosterone-producing tumors. Over the last few years, significant progress has been made towards understanding the genetic basis of PA, classifying it as a channelopathy. Recently, a growing body of clinical evidence suggests that mutations in ion channels appear to be the major cause of aldosterone-producing adenomas, and several mutations within the ion channel encoding genes have been identified. Somatic mutations in four genes (KCNJ5, ATP1A1, ATP2B3 and CACNA1D) have been identified in nearly 60% of the sporadic APAs, while germline mutations in KCNJ5 and CACNA1H have been reported in different subtypes of familial hyperaldosteronism. These new insights into the molecular mechanisms underlying PA may be associated with potential implications for diagnosis and therapy.

Management of Patients With Glucocorticoid-Related Diseases and COVID-19

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a global health crisis affecting millions of people worldwide. SARS-CoV-2 enters the host cells by binding to angiotensin-converting enzyme 2 (ACE2) after being cleaved by the transmembrane protease serine 2 (TMPRSS2). In addition to the lung, gastrointestinal tract and kidney, ACE2 is also extensively expressed in endocrine tissues, including the pituitary and adrenal glands. Although glucocorticoids could play a central role as immunosuppressants during the cytokine storm, they can have both stimulating and inhibitory effects on immune response, depending on the timing of their administration and their circulating levels. Patients with adrenal insufficiency (AI) or Cushing's syndrome (CS) are therefore vulnerable groups in relation to COVID-19. Additionally, patients with adrenocortical carcinoma (ACC) could also be more vulnerable to COVID-19 due to the immunosuppressive state caused by the cancer itself, by secreted glucocorticoids, and by anticancer treatments. This review comprehensively summarizes the current literature on susceptibility to and outcome of COVID-19 in AI, CS and ACC patients and emphasizes potential pathophysiological mechanisms of susceptibility to COVID-19 as well as the management of these patients in case of SARS-CoV-2. Finally, by performing an in silico analysis, we describe the mRNA expression of ACE2, TMPRSS2 and the genes encoding their co-receptors CTSB, CTSL and FURIN in normal adrenal and adrenocortical tumors (both adenomas and carcinomas).

Performance of the Aldosterone to Renin Ratio as a Screening Test for Primary Aldosteronism

CONTEXT

The aldosterone to renin ratio (ARR) is the guideline-recommended screening test for primary aldosteronism. However, there are limited data in regard to the diagnostic performance of the ARR.

OBJECTIVE

To evaluate the sensitivity and specificity of the ARR as a screening test for primary aldosteronism.

METHODS

We searched the MEDLINE, Embase, and Cochrane databases until February 2020. Observational studies assessing ARR diagnostic performance as a screening test for primary aldosteronism were selected. To limit verification bias, only studies where dynamic confirmatory testing was implemented as a reference standard regardless of the ARR result were included. Study-level data were extracted and risk of bias and applicability were assessed using the QUADAS-2 tool.

RESULTS

Ten studies, involving a total of 4110 participants, were included. Potential risk of bias related to patient selection was common and present in half of the included studies. The population base, ARR positivity threshold, laboratory assay, and reference standard for confirmatory testing varied substantially between studies. The reported ARR sensitivity and specificity varied widely with sensitivity ranging from 10% to 100% and specificity ranging from 70% to 100%. Notably, 3 of the 10 studies reported an ARR sensitivity of <50%, suggesting a limited ability of the ARR to adequately identify patients with primary aldosteronism.

CONCLUSIONS

ARR performance varied widely based on patient population and diagnostic criteria, especially with respect to sensitivity. Therefore, no single ARR threshold for interpretation could be recommended. Limitations in accuracy and reliability of the ARR must be recognized in order to appropriately inform clinical decision-making.

Chronic kidney disease in adrenal disorders

PURPOSE OF REVIEW

This review will focus on hypertension due to underlying adrenal disorders in chronic kidney disease (CKD). Diagnosis of adrenal hypertension and particularly primary aldosteronism (PA) in CKD is frequently not pursued. We outline limitations that advanced kidney disease poses on the diagnostic work up of these disorders and provide a framework for approaching CKD patients suspected of having an adrenal disorder. Recognition of these disorders is important as they are often underdiagnosed which leads to poorer outcomes.

RECENT FINDINGS

Adrenal disease associated with hypertension in CKD is most commonly due to PA whereas pheochromocytoma and Cushing's disease are important but less common. Diagnosis of these diseases is important as their identification leads to better blood pressure control and can possibly mitigate the risk of progression of CKD. Work up and treatment of PA has been shown to be safe and is associated with less antihypertensive medication requirement for the associated hypertension and slower progression of CKD.

SUMMARY

This chapter summarizes the importance of recognizing adrenal hypertension in CKD and reinforces the need for physicians to pursue these diagnoses in CKD patients as this is safe and improves both BP control and delays progression of CKD.