Clinical and biochemical characteristics of normotensive patients with primary aldosteronism: a comparison with hypertensive cases

Primary Aldosteronism Prevalence - An Unfolding Story

Primary aldosteronism (PA) is characterized by dysregulated, renin-independent aldosterone excess. Long perceived as rare, PA has emerged as one of the most common causes of secondary hypertension. Failure to recognize and treat PA results in cardiovascular and renal complications, through processes mediated by both direct target tissue insults and indirectly, by hypertension. PA spans a continuum of dysregulated aldosterone secretion, which is typically recognized in late stages after treatment-resistant hypertension and cardiovascular and/or renal complications develop. Determining the precise disease burden remains challenging due to heterogeneity in testing, arbitrary thresholds, and populations studied. This review summarizes the reports on PA prevalence among the general population and in specific high-risk subgroups, highlighting the impact of rigid versus permissive criteria on PA prevalence perception.

Frequently asked questions and answers (if any) in patients with adrenal incidentaloma

PURPOSE

Adrenal incidentalomas (AIs) are incidentally discovered adrenal masses, during an imaging study undertaken for other reasons than the suspicion of adrenal disease. Their management is not a minor concern for patients and health-care related costs, since their increasing prevalence in the aging population. The exclusion of malignancy is the first question to attempt, then a careful evaluation of adrenal hormones is suggested. Surgery should be considered in case of overt secretion (primary aldosteronism, adrenal Cushing's Syndrome or pheochromocytoma), however the management of subclinical secretion is still a matter of debate.

METHODS

The aim of the present narrative review is to offer a practical guidance regarding the management of AI, by providing evidence-based answers to frequently asked questions.

CONCLUSION

The clinical experience is of utmost importance: a personalized diagnostic-therapeutic approach, based upon multidisciplinary discussion, is suggested.

Autonomous Aldosterone Secretion as a Subclinical Form of Primary Aldosteronism: Pathogenesis and Clinical Significance

In recent years, a substantial prevalence of primary aldosteronism (PA) has been demonstrated in both normotensive and mildly hypertensive cohorts. Consequently, a classic presentation of the syndrome, i. e. moderate-to-severe and resistant hypertension with concomitant hypokalemia, should be considered a tip-of-the-iceberg phenotype of a wide PA spectrum. Its entire range encompasses the non-classic clinical forms of mild hypertension and prehypertension but also several biochemical presentations, including patients who meet PA screening and confirmation test criteria, as well as those with either of them and those with other parameters indicating mineralocorticoid excess. In the current review, research insights on the pathogenetic background and clinical significance of autonomous aldosterone secretion (AAS) are presented, which is defined as a constellation of either: 1) normotension, normokalemia, a positive PA screening (high aldosterone-to-renin ratio) and/or confirmation test, or 2) hypertension, normokalemia and a positive PA screening but negative confirmation test. For this purpose, a literature search of the PubMed database was conducted. Advances in immunohistochemistry and genetic sequencing of isolated adrenal cells are provided as probable morphologic basis of the wide range of aldosterone secretion autonomy. Also, the role of corticotropin as an aldosterone secretagogue is discussed. To date, clinical studies depict consequences of subclinical PA phenotypes, such as increased mortality and risk of developing hypertension, impaired arterial and kidney function, association with metabolic syndrome and age, as well as osteoporosis.

Nearly fatal hypokalaemia due to non-hypertensive primary hyperaldosteronism in the post partum

A previously healthy postpartum 33-year-old woman was admitted at the emergency department after two episodes of syncope. In the waiting room, she collapsed, ventricular fibrillation was detected, and she was reanimated by electric cardioversion. At admission, she was conscient, with blood pressure of 102/74 mm Hg and heart rate of 78 bpm. In the laboratory workup, severe hypokalaemia was found (K⁺ 1.77 mEq/L). Abdominopelvic CT revealed a 27 mm nodule in the right adrenal gland. High aldosterone and low plasma renin levels were detected, and the diagnosis of primary hyperaldosteronism was made, although she never had hypertension. Posteriorly, a cosecretion of aldosterone and cortisol was found. Two months after admission, the patient remained stable with normal K⁺ levels under spironolactone and a right adrenalectomy was performed. The cure of primary hyperaldosteronism and a partial adrenal insufficiency were confirmed. K⁺ levels and blood pressure remained normal without treatment and 10 months after surgery hydrocortisone was suspended.

Normotensive presentation in primary aldosteronism: A report of two cases

Normotensive patients with primary aldosteronism (PA) are relatively rare. Herein, we report two patients with normotensive PA and present a literature review to improve an understanding of the disease. Patient 1, a 56-year-old man, presented with recurrent hypokalemia that lasted for more than 2 years. Patient 2 was a 33-year-old man who presented with sexual dysfunction and was diagnosed with a prolactinoma combined with adrenal insufficiency and hypogonadism. Neither of these patients had hypertension that was detectable on repeated manual measurements. In both patients, a typical biological profile of PA was demonstrated that included hypokalemia with kaliuresis, elevated plasma aldosterone concentration (PAC), suppressed plasma renin concentration, and a high aldosterone-to-renin ratio. Both patients did not have sufficiently suppressed PAC on the saline infusion test, confirming the diagnosis of PA. Computed tomography of the adrenal gland and adrenal venous sampling suggested an aldosteronoma, which was confirmed by lateralized hypersecretion of aldosterone. After removal of the benign adenoma, the biochemical abnormalities were corrected. As hypertension is not necessarily a sign of PA, we propose that all patients with hypokalemia should be screened for PA in order to prevent cardiovascular complications while balancing economics and effectiveness.

Recent Development toward the Next Clinical Practice of Primary Aldosteronism: A Literature Review

For the last seven decades, primary aldosteronism (PA) has been gradually recognized as a leading cause of secondary hypertension harboring increased risks of cardiovascular incidents compared to essential hypertension. Clinically, PA consists of two major subtypes, surgically curable and uncurable phenotypes, determined as unilateral or bilateral PA by adrenal venous sampling. In order to further optimize the treatment, surgery or medications, diagnostic procedures from screening to subtype differentiation is indispensable, while in the general clinical practice, the work-up rate is extremely low even in the patients with refractory hypertension because of the time-consuming and labor-intensive nature of the procedures. Therefore, a novel tool to simplify the diagnostic flow has been recently in enormous demand. In this review, we focus on recent progress in the following clinically important topics of PA: prevalence of PA and its subtypes, newly revealed histopathological classification of aldosterone-producing lesions, novel diagnostic biomarkers and prediction scores. More effective strategy to diagnose PA based on better understanding of its epidemiology and pathology should lead to early detection of PA and could decrease the cardiovascular and renal complications of the patients.

Adrenal Incidentaloma

An adrenal incidentaloma is now established as a common endocrine diagnosis that requires a multidisciplinary approach for effective management. The majority of patients can be reassured and discharged, but a personalized approach based upon image analysis, endocrine workup, and clinical symptoms and signs are required in every case. Adrenocortical carcinoma remains a real concern but is restricted to <2% of all cases. Functional adrenal incidentaloma lesions are commoner (but still probably <10% of total) and the greatest challenge remains the diagnosis and optimum management of autonomous cortisol secretion. Modern-day surgery has improved outcomes and novel radiological and urinary biomarkers will improve early detection and patient stratification in future years to come.

Normotensive hypokalemic primary hyperaldosteronism mimicking clinical features of anorexia nervosa in a young patient: A case report

RATIONALE

The typical clinical presentations of patients with primary aldosteronism (PA) include generalized weakness, fatigue, high blood pressure, and potassium deficiency. However, normotensive PA is rare. Therefore, an atypical presentation of normal blood pressure is a challenge for the diagnosis and treatment of PA.

PATIENT CONCERNS

A 43-year-old, thin, and tall woman (body mass index, 18.6 kg/m) with generalized weakness for 1 day presented to our emergency department, where hypokalemia was a significant finding. The initial diagnosis was anorexia nervosa with the evidence of renal potassium wasting with low urinary sodium and chloride levels, metabolic alkalosis, normal blood pressure, and low body mass index. However, neither vomiting features nor other specific induced vomiting features were noted.

DIAGNOSES

The laboratory examination revealed high plasma aldosterone level, low plasma renin activity, and extremely high aldosterone-to-renin ratio indicating the diagnosis of PA, confirmed via adrenal computed tomography.

INTERVENTIONS

Surgical adrenalectomy was performed. Pathological diagnosis was a benign cortical adenoma.

OUTCOMES

Patient's serum potassium level and hormonal status became normalized after surgical removal of adrenal adenoma. She fully recovered without any further sequelae.

LESSONS

It is too early to rule out PA based on the presence of normal blood pressure in a patient with metabolic alkalosis and renal wasting hypokalemia. Moreover, PA should be considered in a normotensive patient with an unknown hypokalemic etiology to avoid delayed diagnosis and treatment.

The spectrum of low-renin hypertension

Low-renin hypertension (LRH) is a frequent condition in patients with arterial hypertension, accounting for 30% of patients. Monogenic forms can cause LRH in a minority of cases. However, in the large majority of patients, LRH is caused by the combined effects of congenital and acquired factors, comprising dietary habits. Several genetic variants have been proposed as co-factors in the pathogenesis of LRH with normal-low serum aldosterone. Emerging evidences support the hypothesis that a large proportion of LRH with normal-high serum aldosterone is associated with subclinical primary aldosteronism (PA). The recent identification of aldosterone-producing cell clusters (APCCs) as the possible cause of subclinical PA, further supported the concept of a continuous spectrum of autonomous aldosterone secretion, from subclinical forms towards overt PA. In this review we describe the main aspects of LRH, focusing on molecular basis, clinical risk profile and patients' management.

Association of Papillary Thyroid Carcinoma with Primary Aldosteronism

Objective The association of primary aldosteronism (PA) with thyroid disease has already been suggested. The aim of this study was to examine the presence of PA in patients with papillary thyroid carcinoma (PC) and to characterize such PC patients with PA. Methods We examined the presence of PA in 81 consecutive patients with PC, whose random sitting blood pressure (BP) was ≥140/90 mmHg in the office (n= 68), who had an incidental adrenal tumor or adrenal enlargement (n=9), or who showed hypokalemia (n=4). Thirty-one of these 81 patients had been treated with anti-hypertensive drugs. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were first measured before operation in 16 patients and after operation in 65 patients. PA was diagnosed according to the guidelines of the Japan Endocrine Society. Results Forty patients with PC with a random PAC/PRA ratio of over 200 were subjected to a further study (12 of these patients had been treated with anti-hypertensive drugs). Ultimately, 15 patients with PC were diagnosed with PA. Adrenal venous sampling was done in 9 out of 15 patients with PC associated with PA. No patients were diagnosed as having unilateral lesions. Among the 15 patients, white-coat hypertension was observed in 5 patients, and normotension was observed in 1 patient. Conclusion These findings suggest that the prevalence of PA may be high among patients with PC. An active examination is needed to detect PA, as its signs and symptoms may be mild in patients with PC associated with hypertension.

A Rare Aldosterone-Producing Adenoma Detected by 68Ga-pentixafor PET-CT: A Case Report and Literature Review

Context: Primary aldosteronism represents an important and common cause of hypertension and is characterized by autonomous aldosterone secretion that results in severe hypertension and hypokalemia. Nonetheless, its manifestations are atypical in some cases, which renders its diagnosis difficult. Case Description: Presented in this report is a Chinese female patient with blood pressure in the high-normal range, and her parathyroid hormone was significantly elevated. Elevated plasma aldosterone concentration plus suppressed plasma rennin activity was suggestive of primary aldosteronism. ⁶⁸Ga-pentixafor positron emission tomography/computed tomography revealed an aldosterone-producing adenoma, which was globally the second of its kind ever reported so far. Moreover, the tumor was located in an extremely rare area. Conclusions: Patients with primary aldosteronism may present with normal or high-normal blood pressure and a significantly elevated parathyroid hormone. ⁶⁸Ga-pentixafor PET/CT is potentially a helpful tool for the non-invasive characterization of patients with primary aldosteronism.

Primary aldosteronism in the primary care setting

PURPOSE OF REVIEW

The aim of the present manuscript is to provide an overview of the most updated studies on the prevalence of primary aldosteronism in primary care and to compare these figures with the actual rate of diagnosis in clinical practice and with the prevalence of primary aldosteronism in specific subgroup of patients.

RECENT FINDINGS

Over the last 20 years the clinical spectrum of low renin hypertension and primary aldosteronism has changed dramatically. Once considered only in the presence of severe hypertension and hypokalemia, it is now well known that primary aldosteronism is not uncommon even in patients with mild forms of hypertension and/or normokalemia. Moreover, recent evidence points toward a large proportion of normotensive study participants as being affected by subclinical primary aldosteronism, which represents a strong risk factor for incident hypertension. Moreover, primary aldosteronism patients are exposed to an increased risk of cardio and cerebrovascular events and metabolic comorbidities compared with patients affected by essential hypertension. Disappointingly, primary aldosteronism remains a largely underdiagnosed and undertreated disorder.

SUMMARY

These recent findings further highlight the importance of widening the spectrum of patients who should be screened for primary aldosteronism, to reduce the cardiovascular risk associated with this medical condition.

Primary aldosteronism as a cause of secondary osteoporosis

OBJECTIVE

Patients with primary aldosteronism (PA) have a high prevalence of osteoporosis (OP) and fractures (Fx). We evaluated the presence of PA in patients admitted to our metabolic bone disease outpatient clinic.

DESIGN

Study conducted on an in- and outpatient basis in a referral Italian endocrinology unit.

METHODS

A total of 2632 patients were evaluated. 2310 were excluded because they were taking drugs known to affect bone or mineralocorticoids metabolism or were diagnosed to have a secondary cause of osteoporosis. The remaining 322 subjects (304 females, 18 males) took part in the study. Bone mineral density (BMD) and thoracic and lumbar spine vertebral morphometry were performed by dual X-ray absorptiometry. All patients were screened for PA with aldosterone-to-renin ratio. In those who had positive results, confirmatory tests were performed.

RESULTS

Among 322 subjects, 213 were osteoporotics and 109 were not. PA was diagnosed in eleven out of 213 osteoporotic patients (5.2%) and one out of 109 non-osteoporotic subjects (0.9%, P = 0.066). PA was observed in the 26.1% of patients with the concomitant presence of osteoporosis, hypertension and hypercalciuria. Compared with patients without PA, patients with PA had mean values of urinary calcium excretion, 4.8 ± 2.5 mmol/day vs 7.6 ± 3.2 mmol/day, P < 0.001 and serum PTH levels, 5.4 pmol/L vs 7.3 pmol/L, P < 0.01, significantly higher.

CONCLUSIONS

PA should be considered among the causes of secondary OP.

Case detection and diagnosis of primary aldosteronism - The consensus of Taiwan Society of Aldosteronism

BACKGROUND/PURPOSE

Even though the increasing clinical recognition of primary aldosteronism (PA) as a public health issue, its heightened risk profiles and the availability of targeted surgical/medical treatment being more understood, consensus in its diagnosis and management based on medical evidence, while recognizing the constraints of our real-world clinical practice in Taiwan, has not been reached.

METHODS

The Taiwan Society of Aldosteronism (TSA) Task Force acknowledges the above-mentioned issues and reached this Taiwan PA consensus at its inaugural meeting, in order to provide updated information of internationally acceptable standards, and also to incorporate our local disease characteristics into the management of PA.

RESULTS

When there is suspicion of PA, a plasma aldosterone to renin ratio (ARR) should be obtained initially. Patients with abnormal ARR will undergo confirmatory laboratory and image tests. Subtype classification with adrenal venous sampling (AVS) or NP-59 nuclear imaging, if AVS not available, to lateralize PA is recommended when patients are considered for adrenalectomy. The strengths and weaknesses of the currently available identification methods are discussed, focusing especially on result interpretation.

CONCLUSION

With this consensus we hope to raise more awareness of PA among medical professionals and hypertensive patients in Taiwan, and to facilitate reconciliation of better detection, identification and treatment of patients with PA.

A Normotensive Patient with Primary Aldosteronism

This study was to report a case of normotensive patient with primary aldosteronism who was admitted to our department recently. The patient was a 33-year-old male with right adrenal incidentaloma, but without any symptom. He has no history of hypertension, and blood pressure was normal when measured at multiple time points during hospitalization stay. The 24-hour ambulatory blood pressure prompted a normal blood pressure with the existence of circadian rhythm. The patient was diagnosed with primary aldosteronism by screening and confirmatory test. Due to the absence of symptom, surgery was not preferred. Blood pressure was found to be normal with the 2-month follow-up from discharge until now.

Progress in aldosteronism: a review of the prevalence of primary aldosteronism in pre-hypertension and hypertension

Primary aldosteronism (PA) secondary to excessive and/or autonomous aldosterone secretion from the renin-angiotensin system accounts for ∼10% of cases of hypertension and is primarily caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenomas (APAs). Although the diagnosis has traditionally been supported by low serum potassium levels, normokalaemic and even normotensive forms of PA have been identified expanding further the clinical phenotype. Moreover, recent evidence has shown that serum aldosterone correlates with increased blood pressure (BP) in the general population and even moderately raised aldosterone levels are linked to increased cardiovascular morbidity and mortality. In addition, aldosterone antagonists are effective in BP control even in patients without evidence of dysregulated aldosterone secretion. These findings indicate a higher prevalence of aldosterone excess among hypertensive patients than previously considered that could be attributed to disease heterogeneity, aldosterone level fluctuations related to an ACTH effect or inadequate sensitivity of current diagnostic means to identify apparent aldosterone excess. In addition, functioning aberrant receptors expressed in the adrenal tissue have been found in a subset of PA cases that could also be related to its pathogenesis. Recently a number of specific genetic alterations, mainly involving ion homeostasis across the membrane of zona glomerulosa, have been detected in ∼50% of patients with APAs. Although specific genotype/phenotype correlations have not been clearly identified, differential expression of these genetic alterations could also account for the wide clinical phenotype, variations in disease prevalence and performance of diagnostic tests. In the present review, we critically analyse the current means used to diagnose PA along with the role that ACTH, aberrant receptor expression and genetic alterations may exert, and provide evidence for an increased prevalence of aldosterone dysregulation in patients with essential hypertension and pre-hypertension.

Pathophysiology, diagnosis, and treatment of mineralocorticoid disorders

The renin-angiotensin-aldosterone system (RAAS) is a major regulator of blood pressure control, fluid, and electrolyte balance in humans. Chronic activation of mineralocorticoid production leads to dysregulation of the cardiovascular system and to hypertension. The key mineralocorticoid is aldosterone. Hyperaldosteronism causes sodium and fluid retention in the kidney. Combined with the actions of angiotensin II, chronic elevation in aldosterone leads to detrimental effects in the vasculature, heart, and brain. The adverse effects of excess aldosterone are heavily dependent on increased dietary salt intake as has been demonstrated in animal models and in humans. Hypertension develops due to complex genetic influences combined with environmental factors. In the last two decades, primary aldosteronism has been found to occur in 5% to 13% of subjects with hypertension. In addition, patients with hyperaldosteronism have more end organ manifestations such as left ventricular hypertrophy and have significant cardiovascular complications including higher rates of heart failure and atrial fibrillation compared to similarly matched patients with essential hypertension. The pathophysiology, diagnosis, and treatment of primary aldosteronism will be extensively reviewed. There are many pitfalls in the diagnosis and confirmation of the disorder that will be discussed. Other rare forms of hyper- and hypo-aldosteronism and unusual disorders of hypertension will also be reviewed in this article.

NP-59 SPECT/CT imaging in stage 1 hypertensive and atypical primary aldosteronism: a 5-year retrospective analysis of clinicolaboratory and imaging features

OBJECTIVE

We retrospectively analyzed all primary aldosteronism (PA) patients undergoing NP-59 SPECT/CT imaging with regard to their clinicolaboratory and imaging features, investigation, and outcomes.

MATERIAL AND METHODS

11 PA patients who presented to our hospital for NP-59 SPECT/CT imaging between April 2007 and March 2012 and managed here were analyzed.

RESULTS

Among 11 PA patients, eight (73%) had stage 1 hypertension, three (27%) stage 2 hypertension, four (36%) normal plasma aldosterone concentration, nine (82%) nonsuppressed plasma renin activity (PRA), six (55%) normal aldosterone-renin-ratio (ARR), eight (73%) serum potassium ≧3 mEq/L, seven (64%) subclinical presentation, seven (64%) negative confirmatory testing, and four (36%) inconclusive results on CT scan and seven (64%) on planar NP-59 scan. All 11 (100%) patients had positive results on NP-59 SPECT/CT scan. Two (18%) met typical triad and nine (82%) atypical triad. Among nine atypical PA patients, three (33%) had clinical presentation, six (67%) subclinical presentation, six (67%) negative confirmatory testing, and four (44%) inconclusive results on CT scan and six (67%) on planar NP-59 scan. All patients had improved outcomes. Significant differences between typical and atypical PA existed in PRA and ARR.

CONCLUSIONS

NP-59 SPECT/CT may provide diagnostic potential in stage 1 hypertensive and atypical PA.

Diagnosis and management of primary aldosteronism: an updated review

Primary aldosteronism (PA) is the most common secondary form of arterial hypertension, with a particularly high prevalence among patients with resistant hypertension. Aldosterone has been found to be associated with cardiovascular toxicity. Prolonged aldosteronism leads to higher incidence of cardiac events, glomerular hyperfiltration, and potentially bone/metabolic sequels. The wider application of aldosterone/renin ratio as screening test has substantially contributed to increasing diagnosis of PA. Diagnosis of PA consists of two phases: screening and confirmatory testing. Adrenal imaging is often inaccurate for differentiation between an adenoma and hyperplasia, and adrenal venous sampling is essential for selecting the appropriate treatment modality. The etiologies of PA have two main subtypes: unilateral (aldosterone-producing adenoma) and bilateral (micro- or macronodular hyperplasia). Aldosterone-producing adenoma is typically managed with unilateral adrenalectomy, while bilateral adrenal hyperplasia is amenable to pharmacological approaches using mineralocorticoid antagonists. Short-term treatment outcome following surgery is determined by factors such as preoperative blood pressure level and hypertension duration, but evidence regarding long-term treatment outcome is still lacking. However, directed treatments comprising of unilateral adrenalectomy or mineralocorticoid antagonists still potentially reduce the toxicities of aldosterone. Utilizing a physician-centered approach, we intend to provide up-dated information on the etiology, diagnosis, and the management of PA.

Current status and controversies in adrenal incidentalomas

Adrenal incidentalomas (AI) are serendipitously discovered lesions during abdominal imaging studies that need to be investigated for evidence of hormonal hypersecretion and/or malignancy. Because imaging modalities can reliably identify lesions that carry a high risk of malignancy, we focus on the identification of hypersecretory lesions and those with subclinical activity, particularly Cushing syndrome. Because diverse diagnostic tests and cut-offs are employed, the prevalence of hypersecretory AI varies widely, and there is controversy regarding their long-term sequelae. In this article we provide information regarding current radiological means to define the nature of AI, and the most appropriate biochemical tests for delineating hypersecretory states. We also discuss the duration and intensity of AI follow-up as well as the identification of AI that require specific therapeutic intervention.

Adrenal incidentaloma

Adrenal incidentaloma is a common clinical problem and its prevalence, in radiological studies, comes close to that of autoptic data as a result of imaging technological advances. The diagnostic challenge is to distinguish the majority of benign lesions from other masses, either malignant or hormone secreting, which require further therapy. The imaging evaluation (unenhanced CT and MRI) can differentiate malignant to benign lesions because the benign lesions have high lipid content. All patients should be tested for hypercortisolism and pheochromocytoma whereas aldosteronism should be tested in hypertensive patients only. The optimal diagnostic management for adrenal incidentaloma is still controversial, and the endocrinologist must devise a cost-effective approach taking into account the extensive endocrine work-up and imaging investigations that may be necessary. A tailored strategy may be based on the selection of patients at increased risk who require a careful and extensive follow-up among the vast majority of patients who require a simplified follow-up.

Subclinical primary aldosteronism

Screening for primary aldosteronism was historically recommended in patients with moderate to severe and/or resistant hypertension. Patients with mild hypertension and normotensive subjects were therefore excluded from the screening. However, a considerable number of normotensive individuals without hypokalaemia may have subclinical forms of primary aldosteronism. In this review, we describe evidence supporting the idea that primary aldosteronism is not only confined to patients with moderate to severe and/or resistant hypertension, but also exists in patients with mild hypertension and even in those with normotension. We discuss possible aetiologies, screening and diagnostic techniques and treatment options of the normotensive form of primary aldosteronism. The natural history, adverse effects and best treatment of this disease still remain to be resolved. The long-term follow-up studies of normotensive primary aldosteronism patients who receive neither adrenal surgery nor treatment with mineralocorticoid receptor antagonists might help to solve these problems.

Prevalence of primary aldosteronism among prehypertensive and stage 1 hypertensive subjects

Recent studies have reported a high prevalence of primary aldosteronism among patients with severe hypertension. However, the prevalence of this disease among normotensive and mildly hypertensive patients has not been determined. The aim of this study was to examine the prevalence of primary aldosteronism among prehypertensive and stage 1 hypertensive subjects. A total of 292 adult subjects with hypertension or prehypertension was screened for primary aldosteronism. Subjects with a plasma aldosterone concentration (ng per 100 ml) to plasma renin activity (ng ml(-1) h(-1)) ratio (ARR) above 20 underwent confirmatory captopril suppression testing. A total of 54 subjects (18.5%) had an ARR above 20. A captopril suppression test was performed in 17 of 54 subjects with probable primary aldosteronism. The test confirmed the diagnosis of primary aldosteronism in 11 (64.7%) of 17 patients, giving a least prevalence of 3.8% for this disease. The 11 patients with primary aldosteronism had a mean ± s.d. systolic blood pressure of 139 ± 4 mm Hg, diastolic blood pressure of 95 ± 10 mm Hg and serum potassium of 4.46 ± 0.48 mEq l(-1) at the time of screening test. The prevalence of primary aldosteronism as could be assessed in this study was at least 6.8% in prehypertensive patients, 3.3% in stage 1 hypertensive patients and 3.1% in stage 2 hypertensive patients. In conclusion, this study suggests a high prevalence of primary aldosteronism among prehypertensive and stage 1 hypertensive Japanese patients. Significant numbers of prehypertensive individuals may have subclinical forms of this disease.

Aldosterone-producing adenoma and other surgically correctable forms of primary aldosteronism

Surgically correctable forms of primary aldosteronism are characterized by unilateral aldosterone hypersecretion and renin suppression, associated with varying degrees of hypertension and hypokalemia. Unilateral aldosterone hypersecretion is caused by an aldosterone-producing adenoma (also known as Conn's adenoma and aldosteronoma), primary unilateral adrenal hyperplasia and rare cases of aldosterone-producing adrenocortical carcinoma. In these forms, unilateral adrenalectomy can cure aldosterone excess and hypokalemia, but not necessarily hypertension. The prevalence of primary aldosteronism in the general population is not known. Its prevalence in referred hypertensive populations is estimated to be between 6 and 13%, of which 1.5 to 5% have an aldosterone-producing adenoma or primary unilateral adrenal hyperplasia. Taking into account referral biases, the prevalence of surgically correctable primary aldosteronism is probably less than 1.5% in the hypertensive population and less than 0.3% in the general adult population. Surgically correctable primary aldosteronism is sought in patients with hypokalemic, severe or resistant forms of hypertension. Recent recommendations suggest screening for primary aldosteronism using the aldosterone to renin ratio. Patients with a raised ratio then undergo confirmatory suppression tests. The differential diagnosis of hypokalemic hypertension with low renin includes mineralocorticoid excess, with the mineralocorticoid being cortisol or 11-deoxycorticosterone, apparent mineralocorticoid excess, pseudo-hypermineralocorticoidism in Liddle syndrome or exposure to glycyrrhizic acid. Once the diagnosis is confirmed, adrenal computed tomography is performed for all patients. If surgery is considered, taking into consideration the clinical context and the desire of the patient, adrenal vein sampling is performed to detect whether or not aldosterone hypersecretion is unilateral. Laparoscopic surgery for unilateral aldosterone hypersecretion is associated with a morbidity of about 8%, with most complications being minor. It generally results in the normalization of aldosterone secretion and kalemia, and in a large decrease in blood pressure, but normotension without treatment is only achieved in half of all cases. Normotension following adrenalectomy is more frequent in young patients with recent hypertension than in patients with long-standing hypertension or a family history of hypertension.

[Primary hyperaldosteronisms: from diagnosis to treatment]

Primary hyperaldosteronism is a growing cause of apparently essential hypertension (until 15 % of patients with hypertension). Primary hyperaldosteronism can now be recognized even for patients without hypertension or hypokaliemia. Paradoxically normal levels of aldosterone when serum renin levels and/or plasmatic renin activity and/or kaliemia are low, lead to suggest primary hyperaldostéronism. High values of aldosterone/renin or aldosterone/PRA favour the diagnosis. Adrenal scanography (fine slices) has to be performed, and confronted with one functional procedure (adrenal iodocholestérol uptake after dexamethasone, or sampling of adrenal venous blood for aldosterone measurement) only if surgery is suggested. When hypersecretion is unilateral or largely predominant in one size, surgery is very useful, when hypertension or hypokaliemia are poorly controlled, when medications are unwell tolerated, especially in men.