Some considerations about evolution of idiopathic primary aldosteronism

Syndromes that Mimic an Excess of Mineralocorticoids

Pseudohyperaldosteronism is characterized by a clinical picture of hyperaldosteronism with suppression of renin and aldosterone. It can be due to endogenous or exogenous substances that mimic the effector mechanisms of aldosterone, leading not only to alterations of electrolytes and hypertension, but also to an increased inflammatory reaction in several tissues. Enzymatic defects of adrenal steroidogenesis (deficiency of 17α-hydroxylase and 11β-hydroxylase), mutations of mineralocorticoid receptor (MR) and alterations of expression or saturation of 11-hydroxysteroid dehydrogenase type 2 (apparent mineralocorticoid excess syndrome, Cushing's syndrome, excessive intake of licorice, grapefruits or carbenoxolone) are the main causes of pseudohyperaldosteronism. In these cases treatment with dexamethasone and/or MR-blockers is useful not only to normalize blood pressure and electrolytes, but also to prevent the deleterious effects of prolonged over-activation of MR in epithelial and non-epithelial tissues. Genetic alterations of the sodium channel (Liddle's syndrome) or of the sodium-chloride co-transporter (Gordon's syndrome) cause abnormal sodium and water reabsorption in the distal renal tubules and hypertension. Treatment with amiloride and thiazide diuretics can respectively reverse the clinical picture and the renin aldosterone system. Finally, many other more common situations can lead to an acquired pseudohyperaldosteronism, like the expansion of volume due to exaggerated water and/or sodium intake, and the use of drugs, as contraceptives, corticosteroids, β-adrenergic agonists and FANS. In conclusion, syndromes or situations that mimic aldosterone excess are not rare and an accurate personal and pharmacological history is mandatory for a correct diagnosis and avoiding unnecessary tests and mistreatments.

Polycystic ovary syndrome: Implications of measurement of plasma aldosterone, renin activity and progesterone

A positive correlation between aldosterone, inflammatory parameters, blood pressure and metabolic abnormalities in polycystic ovary syndrome (PCOS) has been reported in the early estrogenic phase. The aim of the study was to measure plasma aldosterone, plasma renin activity (PRA) and progesterone on the 21st day of the cycle, in women with PCOS and to consider the interrelationships between these hormones. Sixty-six consecutive normal BMI women with PCOS (median age 24 years, range 21-28 years) and 53 age- and body mass index-matched healthy controls were enrolled in the study. Aldosterone, aldosterone/PRA ratio (ARR) and Homeostasis Model Assessment (HOMA) index were significantly higher (p<0.0001) in PCOS women than controls. Positive correlations were found in PCOS but not in controls between (i) progesterone and aldosterone, (ii) aldosterone and PRA, (iii) PRA and progesterone. Mean blood pressures were within the normal range but significantly higher in PCOS than controls. The increase of plasma aldosterone, ARR and blood pressure in PCOS compared with controls is consistent with an increased mineralocorticoid effector mechanism in PCOS; prolonged therapy with spironolactone could counteract both the hyperandrogenism and reduce future cardiovascular risk.

Spontaneous remission of idiopathic aldosteronism after long-term treatment with spironolactone: results from the German Conn's Registry

CONTEXT

Primary aldosteronism (PA) is mainly caused by aldosterone-producing adenoma and idiopathic bilateral adrenal hyperplasia (IHA). Recently, spontaneous resolution of IHA has been described.

OBJECTIVE

We aimed to determine the frequency of spontaneous remission of PA during long-term treatment with mineralocorticoid receptor (MR) antagonists.

DESIGN, SETTING AND PATIENTS

Thirty-seven patients of the Munich PA registry with IHA treated by MR antagonists were investigated. The patients were identified retrospectively by chart review and prospectively assessed by clinical and biochemical means.

MAIN OUTCOME MEASURES

Complete remission of IHA was defined as normal aldosterone to renin ratio (ARR), normal suppression test and normalization of hypokalaemia in the presence of normal blood pressure. Partial remission was defined as normalization of normal ARR, normal suppression test and normalization of hypokalaemia in the presence of persistent hypertension.

RESULTS

The mean period of MR antagonist treatment was 5·8 ± 0·7 years in the patients. We identified two of 37 (5·4%) patients with spontaneous remission: one with complete remission and one with partial remission.

CONCLUSION

Remission of IHA in PA may occur in some patients after long-term mineralocorticoid antagonist treatment.

Verification and evaluation of aldosteronism demographics in the Taiwan Primary Aldosteronism Investigation Group (TAIPAI Group)

OBJECTIVE

Current data on primary aldosteronism (PA) from Asian populations are scarce. This cohort study clarifies the attributes of patients with PA in a typical Chinese population.

DESIGN

An observational cohort study.

METHODS

The records of patients referred to the Hypertension Clinic from a multi-centre registration in Taiwan from January 1995 to December 2007 were reviewed. All patients with PA were classified into two subtypes: aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism (IHA); their characteristics were compared.

RESULTS

Our cohort consisted of 346 patients with PA, 255 with APA and 91 with IHA. The initial hypokalaemia (59% in APA vs. 27.5% in IHA, p < 0.0001) and transtubular potassium gradient (TTKG) (6.30 ± 2.41 in APA vs. 4.91 ± 2.03 in IHA, p = 0.01) were higher in the APA group. Baseline plasma aldosterone concentration (PAC) was also significantly different between the two subgroups (49.96 ± 38.15 ng/dl in APA vs. 34.24 ± 21.47 in IHA, p < 0.0001).

CONCLUSIONS

In typical Chinese PA patients, the APA subgroup had a higher proportion of hypokalaemia with elevated TTKG and higher PAC as compared with the IHA subgroup. This largest Asian database also demonstrated major differences between the Caucasian and Chinese populations including female predilection, frequent hypokalaemia, and common paralytic myopathy.

[Insulin resistance as a mechanism of adaptation during human evolution]

The recent application of concepts of evolution to human disease is proving useful to understand certain pathophysiological mechanisms of different entities that span genomic alterations of immunity, respiratory and hormone function, and the circulatory and neural systems. However, effort has concentrated on explaining the keys to adaptation that define human metabolism and, since the early 1960s, several theories have been developed. This article reviews some of the hypotheses postulated in recent years on the potential benefit of insulin resistance and discusses the most recent knowledge. The concept of the thrifty gene seems to have been definitively refuted by current knowledge. The current paradigm describes an interaction between the metabolic and the immune systems resulting from their coevolution, promoted by evolutionary pressures triggered by fasting, infection and intake of different foods. The activation and regulation of these ancient mechanisms in integrated and interdependent areas defines insulin resistance as a survival strategy that is critical during fasting and in the fight against infection. The relationship with some components of the diet and, particularly, with the symbiotic intestinal microflora points to new paradigms in understanding the pathophysiology of obesity, metabolic syndrome and type 2 diabetes mellitus.

A patient with concurrent primary aldosteronism and Page kidney

The ratio of aldosterone-to-renin activity is currently recommended as a screening test for primary aldosteronism (PA). There are many factors interfering the interpretation of aldosterone-renin ratio (ARR) and could hamper in-time diagnosis of PA. Here, we first report a patient with underlying Page phenomenon and an accidentally disclosed adrenal incidentaloma. High renin secretion from Page phenomenon had masked higher ARR into normal ARR obscuring the diagnosis of PA. However, adrenal venous sampling (AVS) confirmed the autonomous aldosterone secretion with left adrenal vein plasma aldosterone concentration (PAC) 124.1 ng/dl and a lateralization ratio 3.3. AVS may discriminate masked PA due to high renin secretion from Page kidney. It is suggested that clinicians should cautiously interpret aldosterone-renin ratio and consider diagnostic AVS if hyperaldosteronism is highly suspected especially in the background of other secondary hypertension.