The syndrome of primary aldosteronism

Superselective adrenal arterial embolization for primary aldosteronism without lateralized aldosterone secretion: an efficacy and safety, proof-of-principle study

Superselective adrenal arterial embolization (SAAE) appears to be beneficial in primary aldosteronism (PA) patients with lateralized aldosterone secretion (unilateral PA). As confirmed by adrenal vein sampling (AVS), nearly 40% of PA patients would be PA without lateralized aldosterone secretion (bilateral PA). We aimed to investigate the efficacy and safety of SAAE on bilateral PA. We identified 171 bilateral PA patients from 503 PA patients who completed AVS. Thirty-eight bilateral PA patients received SAAE, and 31 completed a median 12-month clinical follow-up. The blood pressure and biochemical improvements of these patients were carefully analyzed. 34% of patients were identified as bilateral PA. Plasma aldosterone concentration, plasma renin activity, and aldosterone/renin ratio (ARR) were significantly improved 24-h after SAAE. SAAE was associated with 38.7% and 58.6% of complete/partial clinical and biochemical success within a median 12-month follow-up. A significant reduction in left ventricular hypertrophy was shown in patients who obtained complete biochemical success compared with partial/absent biochemical success. SAAE was associated with a more apparent nighttime blood pressure reduction than daytime blood pressure reduction in patients with complete biochemical success. No major adverse safety events related to SAAE were reported during the intraoperative, postoperative, and follow-up periods. SAAE was associated with blood pressure and biochemical improvements in part of bilateral PA and appeared safe. The biochemistry success was accompanied by improved cardiac remodeling and a more prominent decrease in nocturnal blood pressure. This study was part of a trial registered with the Chinese Clinical Trial Registry, number ChiCTR2100047689.

Evaluation of the Saline Infusion Test and the Captopril Challenge Test in Chinese Patients With Primary Aldosteronism

CONTEXT

The aim of this study was to determine whether the diagnosis cutoff values associated with the saline infusion test (SIT) and captopril challenge test (CCT) in the Endocrine Society guidelines are applicable to Chinese subjects.

OBJECTIVE AND DESIGN

We performed a head-to-head comparison of the SIT and CCT among Chinese subjects with primary aldosteronism (PA) and essential hypertension (EH).

PARTICIPANTS AND SETTING

One hundred sixty-four hypertensive patients were enrolled.

INTERVENTION

All participants underwent both the SIT and CCT.

MAIN OUTCOME MEASURES

The plasma aldosterone concentration (PAC) and plasma renin activity were measured before and after the SIT and CCT. The degree of PAC decline after CCT was calculated.

RESULTS

This study included 115 PA and 49 EH subjects. The prevalence of hypokalemia was 74.8% in the PA group. Supine PACs in the EH and PA groups were 15.1 ± 4.7 mmol/L and 30.4 ± 12.1 mmol/L. Post-SIT PACs were 8.8 ± 1.7 ng/dL and 22.7 ± 10.2 ng/dL in the EH and PA groups. The degree of PAC decline after CCT was 17.7% and 14.2% in the EH and PA groups; post-CCT PACs were 11.7 ± 3.3 ng/dL and 25.9 ± 10.6 ng/dL. PAC values of 11.2 ng/dL and 16.7 ng/dL after the SIT and CCT represented the optimal cutoff values for PA diagnosis. The post-SIT and post-CCT area under the receiver operating characteristic curve values were 0.972 [95% confidence interval (CI) = 0.934 to 0.991] and 0.933 (95% CI = 0.883 to 0.966).

CONCLUSIONS

Post-SIT and post-CCT PACs, but not the degree of PAC suppression, were both reliable for PA diagnosis. However, the optimal cutoffs were slightly higher in Chinese subjects than those recommended by the Endocrine Society.

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.

Treatment of primary aldosteronism: Where are we now?

Primary aldosteronism (PA) is an important cause of secondary hypertension, is being increasingly diagnosed and may account for more than 10% of hypertensive patients, both in primary care and in referral centers. Aldosterone excess is associated with adverse cardiovascular, renal and metabolic effects that are in part hypertension-independent. Laparoscopic adrenalectomy remains the mainstay of treatment for unilateral forms of PA, whereas medical treatment is recommended for bilateral forms of PA. However, a favourable surgical outcome depends on several factors and many patients are not suitable for this treatment. On the other hand, surgery in patients considered to have bilateral PA may contribute to better blood pressure control. In this review, established and novel strategies for the management of different types of PA are discussed.

Update in primary aldosteronism

It is now widely recognized that primary aldosteronism (PA) is much more common than previously thought, accounting for up to 5-10% of hypertensives, and that aldosterone excess has adverse cardiovascular consequences that go above and beyond hypertension development. These findings have precipitated a marked resurgence of research activity, most of which has supported the concept that PA plays an important role in cardiovascular disease states and should be systematically sought and specifically treated, and the development of an Endocrine Society clinical guideline for the case detection, diagnosis, and management of this common, specifically treatable, and potentially curable condition. Areas of recent, topical research include: 1) the demonstration of excess morbidity in patients with PA compared with other forms of hypertension, confirming the clinical relevance of non-blood pressure-dependent adverse effects of aldosterone excess; 2) the further demonstration that this excess morbidity and mortality are ameliorated with specific (but not nonspecific antihypertensive) therapy directed against aldosterone excess, confirming the importance of detection and diagnosis of PA to enable optimal specific management; 3) the development of new treatment strategies; 4) an ongoing appraisal and refinement of diagnostic approaches including screening, subtype differentiation, and new assay development; and 5) further insights into the importance and nature of genetic factors related to the development of PA.

Role of unilateral adrenalectomy in bilateral primary aldosteronism: a 22-year single center experience

OBJECTIVE

The aim of the study was to examine blood pressure and biochemical responses to unilateral adrenalectomy in patients with bilateral primary aldosteronism (PA) and identify predictive parameters.

CONTEXT

PA considered due to bilateral autonomous production of aldosterone is usually treated medically. Unilateral adrenalectomy has been considered ineffective. Because quality outcome data are lacking and medical treatment may cause adverse effects or fail to control hypertension, defining the role for unilateral adrenalectomy in bilateral PA is an important clinical issue.

DESIGN AND SETTING

Between 1984 and 2004, 51 of 684 patients diagnosed with bilateral PA underwent unilateral adrenalectomy. This report is based on the records of the 40 considered suitable for inclusion, who were followed for at least 12 (median, 56.4) months.

RESULTS

Hypertension was cured in 15% of patients and improved in 20%, usually within 1 yr of unilateral adrenalectomy. The proportion with controlled hypertension was significantly (P < 0.001) higher after adrenalectomy (65%) than before (25%). Mean systolic (P < 0.001) and diastolic (P < 0.001) blood pressure, left ventricular mass index (P < 0.05), plasma upright aldosterone (P < 0.05), and aldosterone/renin ratio (P < 0.001) fell. Serum creatinine independently predicted hypertension cure.

CONCLUSION

Although this retrospective analysis of patients from a single center does not permit prediction of response rates among patients diagnosed elsewhere, it suggests that unilateral adrenalectomy can be beneficial in some patients with apparent bilateral PA and should not be dismissed as a treatment option.

Anesthesia management of familial dysautonomia

Familial dysautonomia (FD) is an autosomal recessive inherited disorder, predominantly affecting the Ashkenazi Jewish population that is characterized by sensory and autonomic neuropathy. The protean manifestations and perturbations result in high morbidity and mortality. However, as a result of supportive measures and centralized care, survival has improved. As surgical options are increasing to symptomatically treat FD, anesthesiologists need to be familiar with this disorder. Because the Dysautonomia Center at NYU Medical Center is a referral center for FD patients, we have attained considerable anesthetic experience with FD. This article reviews clinical features of FD that could potentially affect anesthetic management and outlines our present practices.

Familial hyperaldosteronism

Primary aldosteronism (PAL) may be as much as ten times more common than has been traditionally thought, with most patients normokalemic. The study of familial varieties has facilitated a fuller appreciation of the nature and diversity of its clinical, biochemical, morphological and molecular aspects. In familial hyperaldosteronism type I (FH-I), glucocorticoid-remediable PAL is caused by inheritance of an ACTH-regulated, hybrid CYP11B1/CYP11B2 gene. Genetic testing has greatly facilitated diagnosis. Hypertension severity varies widely, demonstrating relationships with gender, affected parent's gender, urinary kallikrein level, degree of biochemical disturbance and hybrid gene crossover point position. Analyses of aldosterone/PRA/cortisol 'day-curves' have revealed that (1) the hybrid gene dominates over wild type CYP11B2 in terms of aldosterone regulation and (2) correction of hypertension in FH-I requires only partial suppression of ACTH, and much smaller glucocorticoid doses than those previously recommended. Familial hyperaldosteronism type II is not glucocorticoid-remediable, and is clinically, biochemically and morphologically indistinguishable from apparently sporadic PAL. In one informative family available for linkage analysis, FH-II does not segregate with either the CYP11B2, AT1 or MEN1 genes, but a genome-wide search has revealed linkage with a locus in chromosome 7. As has already occurred in FH-I, elucidation of causative mutations is likely to facilitate earlier detection of PAL and other curable or specifically treatable forms of hypertension.

Aldosterone excess: a rare non-nephrophathic cause of hypertension in type I diabetes

The aetiology of hypertension in type 1 diabetes is commonly due to the presence of diabetic nephrology. A rare case of hypertension in a patient with type 1 diabetes and no proteinuria is reported, where the investigation of borderline hypokalaemia allowed us to make a diagnosis of hyperaldosteronism due to bilateral adrenocortical hyperplasia. Secondary causes of hypertension should always be considered in all diabetic patients, particularly in the absence of clinical proteinuria.

Algorithms for diagnosing some electrolyte disorders

The differential diagnosis of electrolyte disorders has traditionally been framed in terms of pathophysiology, and analysis of clinical problems has usually proceeded in the same way. However, easier access to rapid-response laboratory analysis has prompted physicians who encounter patients with serious electrolyte abnormalities to try to establish the cause by quickly obtaining further simple tests. In that vein, this article and the algorithms that are presented are intended to assist the preliminary laboratory differential diagnosis of low and high serum levels of sodium, potassium, and calcium.

Flow diagrams for the diagnosis of acid-base disorders

This article discusses flow diagrams and tables intended to provide a systematic approach to the rapid laboratory differential diagnosis of acid-base disorders in the emergency department.

Primary aldosteronism: difference in clinical presentation and long-term follow-up between adenoma and bilateral hyperplasia of the adrenal glands

Since 1974 primary aldosteronism has been diagnosed in 71 patients in our outpatient clinic. Thirty-four patients had a unilateral aldosterone-producing adenoma, whereas bilateral adrenal hyperplasia was diagnosed in 37 patients. Although at the time of diagnosis the mean potassium values were lower and mean aldosterone levels were higher in patients with an adenoma, as compared to those with bilateral hyperplasia, these laboratory data did not allow us to differentiate between the two leading causes of primary aldosteronism in the individual patient due to pronounced overlap of laboratory values between the two groups. During the first few years, a successful differential diagnosis was made by adrenal phlebography and separate sampling of plasma aldosterone in both adrenal veins; later non-invasive imaging techniques such as computed tomography and radionuclide scanning were used. The best results were obtained in patients with adenoma who underwent adrenalectomy. Fifty-six percent of these patients were clinically and biochemically cured; 28% were improved and had normal blood pressure values during drug treatment. In contrast, patients with bilateral hyperplasia were treated pharmacologically, but only in half of the patients could normal blood pressure values be achieved. Two thirds of the male patients developed gynecomastia during spironolactone treatment. As expected, unilateral adrenalectomy was unsuccessful in the 7 patients with bilateral hyperplasia who underwent surgery. Our results confirm that surgical treatment of adrenal adenomas and drug treatment of bilateral hyperplasias are the appropriate therapy in primary aldosteronism. A differential diagnosis cannot be made on the basis of clinical and non-invasive laboratory data alone; imaging techniques have to be included in the diagnostic process.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and pathological diversity of primary aldosteronism, including a new familial variety

1. Of 93 patients with primary aldosteronism seen during a 20 year period, 52 had an aldosterone-producing adenoma (APA) removed (five more await surgery), 14 had bilateral adrenal hyperplasia (BAH), three had glucocorticoid-suppressible hyperaldosteronism (GSH), one had adrenal carcinoma and 18 are yet to be categorized. 2. Seventy-three presented with hypertension and hypokalaemia. Others had markedly suppressed renal venous plasma renin activity (PRA) or elevated plasma aldosterone (PA)/PRA ratio, in new or resistant hypertensives. 3. The PA/PRA ratio was the most reliable screening test. 4. Diagnosis depended on the failure of suppression of aldosterone by salt loading and fludrocortisone. 5. Differentiation of BAH from APA depended on adrenal venous sampling comparing adrenal and peripheral venous PA/cortisol ratios. 6. A new familial variety of primary aldosteronism is described, with two affected members in each of three families. 7. Primary aldosteronism should be looked for in resistant and low-renin hypertension as well as in hypertension with hypokalaemia, and other family members should have PA/PRA measured if they are hypertensive.

Primary aldosteronism: diagnosis and treatment

The syndrome of primary aldosteronism produces few signs or symptoms. The diagnosis should be suspected when either spontaneous hypokalemia or easily provoked hypokalemia is found in a patient with hypertension. Hypokalemia in association with inappropriate kaliuresis, low plasma renin activity, and a high plasma aldosterone concentration/plasma renin activity ratio are the findings on initial screening tests that should suggest primary aldosteronism. The diagnosis must be confirmed by demonstrating nonsuppressible aldosterone excretion in conjunction with normal cortisol excretion. The choice of therapy is based on distinguishing unilateral from bilateral adrenal disease. With a unilateral adrenal adenoma, surgical removal reverses the hypokalemia and frequently cures the hypertension. In most patients with bilateral adrenal hyperplasia who are treated surgically, however, hypertension persists; thus, the initial treatment in these patients should be pharmacologic.

Clinical implications of primary aldosteronism with resistant hypertension

Twenty-eight patients with resistant hypertension were found to have primary aldosteronism; 25 had solitary adenoma and 3 had adrenal hyperplasia. All were severely hypertensive despite receiving three or more antihypertensive agents, including conventional doses of diuretics, sympatholytics, and vasodilators. Hypervolemia (24 patients) or normovolemia (2 patients) despite severe diastolic hypertension was the hallmark in 26 patients. Adequate salt and water depletion alone with spironolactone (200 mg/day) and hydrochlorothiazide (50-100 ng/day) reduced arterial pressure in all. Twenty-two patients had surgical removal of a solitary adenoma. Over 1 to 2 years of follow-up, 13 were normotensive without medication, and six required hydrochlorothiazide and three hydrochlorothiazide plus a beta-blocker to normalize blood pressure. Blood pressure response to surgery had no relation to either duration or severity of hypertension. Six patients (three with hyperplasia, three with adenoma) have continued diuretic therapy and are normokalemic and normotensive. These results indicate that primary aldosteronism can be associated with sever and drug-resistant hypertension, that maintained hypervolemia is the reason for resistance to therapy, that sustained volume depletion is the most important therapeutic goal for these patients, and that cure can be achieved despite prolonged and severe hypertension.

Therapeutic results of primary aldosteronism with special reference to renal or renovascular lesions

A study was made of 9 patients with primary aldosteronism due to aldosterone-producing adenoma (APA) and 8 subjects with idiopathic adrenal hyperplasia (IHA) to clarify the pathogenesis of sustained hypertension after surgical or non-surgical treatment. Following each treatment, a complete improvement of hypertension was obtained in 12 patients (6 APA, 6 IHA), while 5 (3 APA, 2 IHA) showed still hypertensive status. Renal or renovascular lesions were prominent only in the hypertension-unchanged group. Under regular sodium diet, the ratio of urinary excretion of sodium to creatinine of this hypertensive group was significantly lower than that of the hypertension-improved group. However, the results of other renal function tests were similar in both groups. After respective treatments, suppressed plasma renin activity and elevated plasma aldosterone concentration were improved in all patients. In addition, patients of both groups showed normal response of the renin-aldosterone system following diuretic and dietary induced sodium and volume depletion. Based on these findings, renal or renovascular lesions appear to play an important role in the pathogenesis of maintenance of hypertension in this disorder after respective treatments.

Screening for primary aldosteronism: hypokalemia in hypertensive patients

A serum potassium determination is usually recommended for new hypertensive patients as a screening test for primary aldosteronism and as a baseline for drug therapy. Since hypokalemia is not specific for aldosteronism, the authors assessed its use and limitations as a screening test in nine reported studies of 303 patients with aldosterone-producing adenomas (n = 252) or adrenal hyperplasia (n = 51). The optimal potassium cutoff level and the predictive ability of hypokalemia to detect aldosteronism were analyzed in a primary care setting with different diseases, test characteristics, and prevalences. Optimal screening for primary aldosteronism occurred at serum potassium less than 3.2 mEq/l in a primary care, low-prevalence population, and at higher potassium levels in higher-prevalence populations. Other screening tests, such as urinary aldosterone levels and plasma renin activity, showed lower individual test performance characteristics, but when combined were similar in performance to serum potassium measurement.

May a lymphocytic infiltration have a pathogenic role in an aldosterone-producing adrenal tumor?

A 38-year-old woman is described to have a primary hyperaldosteronism due to an aldosteronoma with foci of lymphocytic infiltration. The finding suggests: a concomitant lymphoid adrenalitis; or, an immunological attack to neoplastic cells. The hypothesis is that there may be a relationship in the association. The lymphocytic infiltrates could have a pathogenic role in the development of the aldosterone-producing adrenocortical neoplasm by interrupting some inhibitory mechanism(s) of the cells that secrete aldosterone.

Differential acute effects of aldosterone, dexamethasone, and hyperkalemia on distal tubular potassium secretion in the rat kidney

To determine the specific effects on renal potassium transport of acute elevations in plasma aldosterone, dexamethasone, and potassium concentrations, we studied adrenalectomized rats prepared such that each factor could be varied independently. Clearance data alone could not be used to deduce the underlying tubular transport effects, however, since infusion of each of these agents was associated with a marked change in urinary flow rate, which may itself have influenced potassium excretion. We therefore used a technique of continuous microperfusion, in vivo, of single superficial distal tubules to evaluate potassium secretion at constant luminal flow rate during each experimental maneuver. Acute aldosterone infusion was associated with a 90% stimulation of potassium secretion by microperfused tubules. However, total kidney sodium excretion and urinary flow rate were markedly reduced, and these factors opposed the direct tubular action of aldosterone, resulting in no net change in the amount of potassium excreted into the final urine. Conversely, dexamethasone had no direct effect on potassium secretion by single microperfused tubules, but it caused a sharp increase in urinary flow and sodium excretion, and secondarily enhanced urinary potassium excretion by 50%. Hyperkalemia per se stimulated renal potassium excretion both via a direct tubular effect and by increasing urinary flow rate. We conclude that urinary potassium excretion after infusion of each of these agents represents the net result of direct tubular effects and secondary flow-mediated changes.

Primary hyperaldosteronism in childhood due to unilateral macronodular hyperplasia. Case report

We present the first report of primary hyperaldosteronism in childhood due to unilateral macronodular hyperplasia. A 10-year-old white boy with severe hypertension (150/100 mm Hg), hypokalemia (1.4 mEq/liter), and suppressed plasma renin activity (PRA) (less than 0.1 ng/ml/hr) demonstrated fixed PRA and aldosterone (aldo) levels that did not change with alteration of dietary sodium. The paradoxical decrease in serum aldo on assumption of upright posture suggested a tumor. Prolonged ACTH administration produced a continuous rise in blood pressure, but a transient rise in aldo. A minimal decrease in urinary aldo during dexamethasone administration was noted, excluding dexamethasone-suppressible hyperaldosteronism. Blood pressure normalized with spironolactone. Computerized transaxial tomography, iodocholesterol scanning, and adrenal venography were not diagnostic of a discrete adrenal lesion. Although hyperplasia is more common than an adenoma as a cause of hyperaldosteronism in childhood, a tumor was predicted, since adrenal vein hormone sampling with ACTH stimulation lateralized aldosterone secretion unequivocally to the left adrenal gland. However, left adrenalectomy revealed macronodular hyperplasia. Postoperatively, there was reversal of hypertension, hypokalemia, and hyperaldosteronism. Thus, in childhood, unilateral hypersecretion of aldosterone may result from nodular hyperplasia, rather than a discrete adenoma.

The changing clinical spectrum of primary aldosteronism

In a prospective study of 80 patients with primary aldosteronism (70 with adenoma and 10 with hyperplasia), "refractory" hypertension, hyperkinetic circulation, and hypovolemia were frequent occurrences. We found that measurements of serum potassium concentration and plasma renin activity were inadequate screening tests because of high rates of false-positive and false-negative results. The demonstration of excessive aldosterone production after three days of salt loading provided the best sensitivity (96 percent) and specificity (93 percent) in identifying patients with primary aldosteronism. Severe, persistent hypokalemia, increased plasma 18-hydroxycorticosterone values, and an anomalous postural decrease in the plasma aldosterone concentration, when present, provided the best indicators of the presence of an adenoma. Of three localizing procedures (selective adrenal venography, adrenal computed tomographic scan, and adrenal venous sampling for plasma aldosterone concentration) the measurement of adrenal venous plasma aldosterone concentration yielded 100 percent accuracy. These results indicate a wider clinical spectrum in primary aldosteronism than previously described. They also show that nonsuppressible aldosterone production is its most important diagnostic hallmark and the single best diagnostic screening procedure, and that adrenal venous sampling for plasma aldosterone concentration remains the most precise technique for identification and localization of tumors.

Unilateral hypersecretion of aldosterone associated with adrenal hyperplasia as a cause of primary aldosteronism

In 3 patients with longstanding hypertension and spontaneous or diuretic-induced hypokalemia, the diagnosis of primary aldosteronism was established by the dual criteria of non-suppressible plasma aldosterone level and suppressed plasma renin activity. Preoperative studies of the etiology for the hyperaldosteronism using the postural plasma aldosterone test and adrenal venous steroid measurements gave conflicting results. On the basis of the differential adrenal venous steroid content, which suggested an unilateral adrenal source for the aldosterone hypersecretion, presumed to be adrenal adenoma, each patient was operated upon. In each case the excised adrenal revealed adenomatous or macronodular hyperplasia. Reinvestigation of the patients 3 to 12 months after the adrenalectomy showed that the dynamics of the renin-aldosterone axis was now restored to the normal state even though the patients remained hypertensive. These findings indicate that unilateral hypersecretion of aldosterone associated with adrenal hyperplasia can occur in some patients with primary aldosteronism simulating that due to an aldosteronoma. Such observations also raise questions about the pathogenesis of the adrenal hyperplasia and seem to add further complexity to the evaluation of patients with hyperaldosteronism.

Evolution of the surgical management of primary aldosteronism

During the past two decades 50 patients were operated on for primary aldosteronism. Diagnosis was based on high aldosterone excretion or secretion during a high sodium intake and, more recently, low stimulated plasma renin activity. Computed tomography and adrenal venography with selective adrenal vein catheterization for determination of aldosterone/cortisol ratios were helpful in the distinction between adenoma and bilateral hyperplasia. As a result of preoperative localization, unilateral posterior or flank approach to the adrenal has replaced transabdominal as the approach of choice. Overall in-hospital mortality in this series was 10% and occurred exclusively with a transabdominal approach in the early part of the series. Adrenalectomy has been curative in 66% of patients with adenoma and in 38% of patients with hyperplasia which includes patients with adenomatous (dominant macroscopic adenoma, 1 cm or greater) hyperplasia when the cure rate was 75%. Currently, only patients who have unilateral adrenal hyperfunction, who respond to spironolactone with a fall in blood pressure, and who are a good operative risk are considered for operation by posterior or flank approach. These guidelines for the management of primary aldosteronism, used since 1974, have been associated with an excellent response (92%), zero mortality and reduced morbidity.

Hyperreninemia and hyperaldosteronism in sickle cell anemia

Fourteen patients with sickle cell anemia, ages 6 to 20 years, were studied while ingesting high- and low-sodium diets. Although none of the patients had excessive urinary loss of sodium, the majority had elevated plasma renin activities and aldosterone secretion rates. The PRA was higher in patients over 10 years of age; ASR in patients receiving the high-sodium diet increased with age. Patients with sickle cell anemia appeared to compensate for urinary sodium loss between crises. The mechanism of this loss could be a defect in the function of either the distal tubule or the loop of Henle.

Renal changes in primary aldosteronism

The clinical presentations and renal biopsy specimens of 18 patients with primary aldosteronism were reviewed to determine the characteristic pathologic features of the kidney in this syndrome. All patients were hypertensive with a mean blood pressure of 192 nm. Hg systolic and 122 mm. Hg diastolic. The average duration of hypertension was 6.88 years. The mean serum potassium was 2.88 mEq. per l. and the mean plasma carbon dioxide was 31.4 mEq. per l. A significant history of urinary tract disease was noted in 8 patients. Laboratory and diagnostic studies evaluating renal structure and function were abnormal in 11 patients. Renal biopsies from all 18 individuals showed evidence of parenchymal damage. Hypertensive and hypokalemic changes were the most significant abnormalities and were considered moderate to severe in 78 and 89 per cent of the patients, respectively. Histologic evidence of pyelonephritis was noted in 2 patients only and no renal specimens contained characteristic changes of metabolic alkalosis. The preoperatively hypertensive and renal evaluations did not reflect the severity of the renal changes noted histologically. The extent of renal injury caused by hypertension and hypokalemia in these patients emphasizes the consequences of primary aldosteronism. Early diagnosis and treatment of this disorder are essential if these consequences are to be avoided.

A perspective on aldosterone abnormalities

Not all the varied clinical disorders in which aldosterone and the mineralocorticoid hormones are involved have been reviewed. Only those disorders in which the mineralocorticoid hormones and their regulatory factors are the principal cause of the biochemical and clinical abnormalities have been examined. These are many and varied. Appreciation of the extent and magnitude of their involvement in the regulation of blood pressure, body fluids, and electrolyte composition continues to grow. The major direct clinical impact of the mineralocorticoid hormones appears to be in two areas: hypertension and potassium homeostasis. Their part in the mosaic of hypertension is established in primary hyperaldosteronism, but they also appear to affect and modify the hypertensive process in primary or essential hypertension. The probe continues. Hypoaldosteronism is more than the rare occurrence associated with Addison's disease. It may be the clue to the presence of nonaldosterone mineralocorticoid excess syndromes, and is obviously of critical importance in an increasing number of patients with chronic renal failure of varied aetiologies.

Primary aldosteronism. A study in contrasts

Two patient with primary aldosteronism, one with a solitary adrenal adenoma and the other with bilateral nodular hyperplasia, are described. Both patients showed the classic features of primary aldosteronism in electrolyte and hormone patterns, but there were important differences in the biochemistry of their excised adrenal tissue. In addition, the injection of plasma from the patient with bilateral adrenal hyperplasia into the sheep's transplanted adrenal gland elicited a definite aldosterone secretory response, but there was no aldosterone response to the injection of plasma from the patient with a solitary adrenal adenoma. The findings support the hypothesis that an extra-adrenal stimulus may contribute to the pathogenesis of bilateral adrenal hyperplasia.

Scintigraphy with 131I-19-iodocholesterol in adrenal disease

Adrenal scintigraphy after i.v. injection of 131I-19-iodocholesterol has been performed in 4 patients with primary aldosteronism, 5 with Cushing's syndrome and 1 patient with phaeochromocytoma. In primary aldosteronism a unilaternal adrenocortical adenoma was demonstrated in 2 patients, while the method failed in 1 patient to visualize a tumour that was localized by measurements of aldosterone concentrations in the adrenal veins and by adrenal venography; in 1 patient none of the methods demonstrated a tumour. In Cushing's syndrome, adrenal scinitgraphy indicated bilateral adrenocortical hyperplasia in 1 patient and visualized the tumour in 2 patients with adrenocortical adenoma. In all patients with Cushing's syndrome due to unilateral adrenocortical tumour, the accumulation of radioactivity in the contralateral adrenal was suppressed. However, a delayed and slight accumulation of the isotope in the suppressed gland contralateral to an adrenocortical carcinoma was misinterpreted and led to exploration on the wrong side since the tumour did not concentrate radioactivity at all. The method failed in 1 patient to localize the adrenocortical tissue responsible for the relapse of Cushing's syndrome after bilateral adrenalectomy for hyperplasia. In the patient with phaeochromocytoma, no radioactivity was found on the tumour. It is conculded that adrenal scintigraphy is a safe and valuable method for localization of adrenal tumours and their differentiation from adrenocortical hyperplasia. Some diagnostic pitfalls do, however, exist, as demonstrated in this series of patients.