Hyperaldosteronism: recent concepts, diagnosis, and management

Hypokalemic Paraparesis Progressing to Quadriparesis in a Case of Intradural Spinal Tumor

Introduction

This study aims to present a case of spinal intradural tumor with paraparesis referred for surgery, which later progressed to quadriparesis and subsequently found to have hypokalemia due to primary hyperaldosteronism causing a clinical dilemma.

Case Report

A 46-year-old male was referred for surgery from peripheral center with a diagnosis of an intradural tumor at L1. The patient presented to us with paraparesis, which progressed to quadriparesis. On evaluation, the patient was found to have low serum potassium levels of 1.6 mmol/L with hypertension. The plasma aldosterone-renin was elevated which was suggestive of primary hyperaldosteronism. Further, investigations in the form of CT abdomen suggested the presence of a right adrenal adenoma. The patient was diagnosed with hypokalemia-induced quadriparesis and treated conservatively with potassium supplementation and later spironolactone. The patient recovered completely in 72 h and was able to walk independently before discharge.

Conclusion

Spinal tumor may not always be the cause for patient's paraparesis; non-spinal factors such as hypokalemia should be kept in mind. The presence of intradural spinal tumor with hypokalemia may cause decision dilemma regarding treatment and interdisciplinary approach is recommended to facilitate the treatment.

Review: Aldosterone — the future challenge in cardiovascular disease?

Mineralocorticoid receptor activation plays a key role in cardiovascular disease and hypertension, which are particularly prevalent in diabetes mellitus; secondary hyperaldosteronism contributes to cardiac failure. Major intervention trials in heart failure have demonstrated unequivocal benefit from aldosterone receptor antagonism. Focused experimental studies in humans and in animal models of hypertension have shown that aldosterone blockade improves a number of pathogenic abnormalities including vascular endothelial dysfunction and altered baroreflex function, and prevents the development of cardiac hypertrophy and renal histological damage. Based on recent outcomes studies, the challenge is now to transfer the experimental evidence into clinical M practice.

Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis

The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na⁺ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na⁺ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na⁺ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure.

Hypertension caused by primary hyperaldosteronism: increased heart damage and cardiovascular risk

INTRODUCTION AND OBJECTIVES

Primary hyperaldosteronism is the most common cause of secondary hypertension. Elevated aldosterone levels cause heart damage and increase cardiovascular morbidity and mortality. Early diagnosis could change the course of this entity. The objective of this report was to study the clinical characteristics, cardiac damage and cardiovascular risk associated with primary hyperaldosteronism.

METHODS

We studied 157 patients with this diagnosis. We analyzed the reason for etiological investigation, and the routinely performed tests, including echocardiography. We used a cohort of 720 essential hypertensive patients followed in our unit for comparison.

RESULTS

Compared with essential hypertensive patients, those with hyperaldosteronism were younger (56.9 [11.7] years vs 60 [14.4] years; P<.001), had higher blood pressure prior to the etiological diagnosis (136 [20.6] mmHg vs 156 [23.2] mmHg), more frequently had a family history of early cardiovascular disease (25.5% vs 2.2%; P<.001), and had a higher prevalence of concentric left ventricular hypertrophy (69% vs 25.7%) and higher cardiovascular risk. Specific treatment resulted in optimal control of systolic and diastolic blood pressures (from 150.7 [23.0] mmHg and 86.15 [14.07] mmHg to 12.69 [15.3] mmHg and 76.34 [9.7] mmHg, respectively). We suspected the presence of hyperaldosteronism because of resistant hypertension (33.1%), hypokalemia (38.2%), and hypertensive crises (12.7%). Only 4.6% of these patients had been referred from primary care with a suspected diagnosis of hyperaldosteronism.

CONCLUSIONS

Hyperaldosteronism should be suspected in cases of resistant hypertension, hypokalemia and hypertensive crises. The diagnosis of hyperaldosteronism allows better blood pressure control. The most prevalent target organ damage is left ventricular hypertrophy.

The prevalence of a raised aldosterone–renin ratio (ARR) among new referrals to a hypertension clinic

The wider application of the plasma aldosterone to renin activity ratio (ARR) test has led independent groups to report a 10-fold or higher prevalence in the detection and prevalence of primary aldosteronism than previously suggested, although such figures have been contested. We determined the prevalence of a raised ARR in an unselected group of patients who were referred to the hypertension clinic at Aberdeen Royal Infirmary. Over a 4-month period, all newly referred patients had an ARR, urea and electrolytes, and 24-h ambulatory blood pressure monitoring (ABPM) performed in addition to a detailed clinical examination. One hundred and twenty-two patients (mean age 51 +/- 16 years) were examined over the study period; 57 (47%) were receiving no anti-hypertensive medication, 32(26% of total) had a normal 24-h ABPM of which 15 patients were receiving antihypertensive medication ("controlled" hypertensives) and 17(14%) were receiving no anti-hypertensive medication ("white-coat hypertensives). Twenty patients (mean age 58 +/- 11 years) were found to have a raised ARR (> 750), of which 10 patients were receiving beta-blocker therapy as part of their anti-hypertensive regimen. Patients with a raised ARR were more likely (odds ratio 3.6, 95% confidence interval 1.2-13.2, p < 0.05) to be classified as a "non-dipper" compared with those whose blood pressure fell at night. The proportion of newly referred hypertensive patients with a raised ARR is still significant and confirms that of previous studies The ratio appears to be significantly driven by a suppressed renin value and further investigation is required to clarify the status of those patients receiving anti-hypertensive medications, particularly beta-blockers.

Role of radiology in the management of primary aldosteronism

The diagnosis of primary aldosteronism, the most common form of secondary hypertension, is based on clinical and biochemical features. Although radiology plays no role in the initial diagnosis, it has an important role in differentiating between the two main causes of primary aldosteronism: aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH). This distinction is important because APAs are generally managed surgically and BAH medically. Adrenal venous sampling is considered the standard of reference for determining the cause of primary aldosteronism but is technically demanding, operator dependent, costly, and time consuming, with a low but significant complication rate. Other imaging modalities, including computed tomography, magnetic resonance imaging, and adrenal scintigraphy, have also been used to determine the cause of primary aldosteronism. Cross-sectional imaging has traditionally focused on establishing the diagnosis of an APA, with that of BAH being one of exclusion. A high specificity for detecting an APA is desirable, since it will avert unnecessary surgery in patients with BAH. However, an overreliance on cross-sectional imaging can lead to the incorrect treatment of affected patients, mainly due to the wide variation in the reported diagnostic performance of these modalities. A combination of modalities is usually required to confidently determine the cause of primary aldosteronism. The quest for optimal radiologic management of primary aldosteronism continues just over a half century since this disease entity was first described.

Secondary hypertension: current diagnosis and treatment

Secondary hypertension affects a small but significant number of the hypertensive population and, unlike primary hypertension, is a potentially curable condition. The determinant for workup is dependent on the index of suspicion elicited during patient examination and treatment. Specific testing is available and must be balanced depending on the risk and cost of the workup and treatment with the benefits obtained if the secondary cause is eliminated. This article reviews common manifestations, workup, and the current treatments of the common causes of secondary hypertension.

The pharmacological treatment of primary aldosteronism

Aldosterone is increasingly considered to have a fundamental role in the pathophysiology of cardiovascular disease. Primary aldosteronism is a much more common cause of secondary hypertension than once suspected, accounting for approximately 10% of cases. Screening for primary aldosteronism should be considered even in the presence of normokalaemia. The non-classical effects of aldosterone, some of which are transcription-independent, may be of similar or greater importance than its traditional effects on the kidney. Treatment of primary aldosteronism should be specific and aim to ameliorate all hormone-related effects of aldosterone, not just the most obvious manifestation of hypertension. Mineralocorticoid antagonism, shown to lead to significant additional survival advantage in heart failure, offers the best prospect for achieving therapeutic goals. For the increasing proportion of patients with primary aldosteronism suitable for long-term medical treatment, mineralocorticoid receptor blockade (better tolerated with eplerenone) should be considered the most appropriate choice of treatment, pending the development of better alternatives.

Long-Term Results of Adrenalectomy in Patients with Aldosterone-Producing Adenomas: Multivariate Analysis of Factors Affecting Unresolved Hypertension and Review of the Literature

The long-term surgical cure rate of patients with primary aldosteronism varies widely, and causes of persistent hypertension are not completely established. We reviewed retrospectively charts from 98 patients (range, 19–70 years old) with aldosterone-producing adenomas who underwent unilateral adrenalectomy. At a median follow-up of 81 months (range, 18–186 months), the mean blood pressure values improved in 95 out of 98 (96.9%) patients, although hypertension was cured only in 71 out of 98 (72.4%) patients. Multivariate analysis using a logistic regression model adjusted for duration of follow-up showed that only age of the patients and duration of the disease independently correlated with unresolved hypertension. The cumulative odds ratio (OR), obtained using the logistic regression function, was 5.38 (95% CI 1.78–16.22), and the OR of single variables were 1.32 (95% CI 0.36–19.83) and 4.56 (95% CI 1.41–14.78), respectively. By using discriminant analysis to derive a classification function for the prediction of unresolved hypertension, a maximum predictive power of 75 per cent was achieved. In conclusion, in patients with an aldosterone-producing adenoma undergoing surgery, the combination of age and duration of hypertension gave the best predictive power of a linear classification function and represented the main independent risk factors affecting hypertension cure rate.

Hyperaldosteronism and pheochromocytoma: new tricks and tests

Hyperaldosteronism, previously thought to represent only 1% to 2% of cases of hypertension, may cause as much as 25% of hypertension in a primary care setting. The renin/aldosterone ratio is the best test for initial screening, followed by localization if possible. Aldosterone antagonists, such as spironolactone, and surgery are the mainstays of treatment. Pheochromocytomas are rare, but because they are a curable cause of hypertension and potentially fatal if not found, important to diagnose. Clinical presentation is variable; however, if symptoms are present, they usually include hypertension, hyperhydrosis, headaches, or palpitations sometimes occurring in dramatic fashion. Once a diagnosis is entertained, appropriate laboratory confirmation is essential. Positive laboratory confirmation then leads to localization of the tumor for eventual surgical removal. New biochemical tests and imaging procedures are making the difficult job of diagnosing and finding these tumors.

Non-invasive adrenal imaging in primary aldosteronism. Sensitivity and positive predictive value of radiocholesterol scintigraphy, CT scan and MRI

The aim of this study was to evaluate the sensitivity and positive predictive value (PPV) of dexamethasone-suppression norcholesterol scintigraphy (NCS), computed tomography (CT) scanning and magnetic resonance imaging (MRI) in patients with primary aldosteronism (PA) who had undergone unilateral adrenalectomy. A series of 49 patients with confirmed PA was reviewed. There were 18 (36.7%) men and 31 (63.3%) women, with a median age of 47 years (range, 23-66 years). NCS was performed in all patients, and 46 (93.9%) and 31 (63.2%) underwent CT scan and MRI, respectively. Final pathology showed an aldosterone-producing adenoma in 45 (91.8%) patients, unilateral nodular cortical hyperplasia (NCH) in two (4.1%) and unilateral microscopic cortical hyperplasia (MCH) in two (4.1%). No aldosterone-producing carcinoma or bilateral adenomas were found. The greatest diameter of the removed adrenal tumour was in the range 8-40 mm (median, 14 mm). The PPV of adrenal imaging was 97.6% for NCS, 85.0% for CT scan (P=0.04) and 83.3% for MRI (P=0.03), and the sensitivity was 85.4%, 85.0% and 74.1%, respectively (P=NS). The age and the main biochemical parameters did not differ significantly (P=NS) between patients with true positive and false negative results of the imaging procedures. NCS accurately depicted all patients with NCH and MCH, whilst CT scan and MRI failed to diagnose such unilateral adrenal gland hyperfunction in two and three patients, respectively. The overall sensitivity of combined NCS and CT scan was 100%. In conclusion, in patients with PA, both NCS and CT scan are necessary to confirm the exclusive unilateral adrenal hyperfunction and, subsequently, to establish the appropriate treatment.