A case of primary aldosteronism due to unilateral adrenal hyperplasia.

The case of a patient with primary aldosteronism due to unilateral adrenal hyperplasia (UAH) is reported. A 43-year-old man with an 8-year history of hypertension presented at our institution with hypokalemia, increased plasma aldosterone concentration (PAC), and suppressed plasma renin activity (PRA). An abdominal CT scan showed almost normal adrenal glands with slight enlargement in the left gland. 131I-Norcholesterol adrenal scintigraphy under dexamethasone suppression showed bilaterally decreased uptake. To rule out idiopathic hyperaldosteronism, an adrenal vein sampling before and after ACTH stimulation was performed and a left-sided lateralization of PAC was observed. A left adrenalectomy was performed, and the patient had a good clinical and biochemical response. Micronodular hyperplasia was discovered in the adrenal gland histologically, and in the immunohistochemical analysis, positive staining for 3beta-hydroxysteroid dehydrogenase in micronodular lesions confirmed the diagnosis of UAH. Although UAH is a rare subset of primary aldosteronism, it is surgically correctable as a unilateral autonomous aldosterone-producing lesion. Careful investigations, including bilateral adrenal vein sampling, should be performed for the diagnosis.     

A rare case of ACTH-independent macronodular adrenal hyperplasia associated with aldosterone-producing adenoma

A 52-year-old man was evaluated for incidentally discovered bilateral adrenal masses. He had drug-resistant hypertension but lacked Cushingoid features. Endocrinological tests revealed autonomous secretion of cortisol and aldosterone with suppressed plasma ACTH and renin activity. A selective adrenal venous sampling demonstrated aldosterone hypersecretion from the left adrenal vein. The clinical diagnosis of subclinical Cushing's syndrome due to ACTH-independent macronodular adrenal hyperplasia (AIMAH) associated with primary aldosteronism was made, and he underwent left adrenalectomy; the resected adrenal lesion was consistent with the pathological diagnosis of AIMAH coexistent with aldosterone-producing adenoma (APA). This is a very rare case of AIMAH with concomitant unilateral APA, whose hypertension improved after surgery.     

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     

New diagnostic procedure for primary aldosteronism: adrenal venous sampling under adrenocorticotropic hormone and angiotensin II receptor blocker--application to a case of bilateral multiple adrenal microadenomas.

Formerly, the incidence of primary aldosteronism (PA) among patients with hypertension was believed to be less than 1%. However, recent studies have suggested a much higher incidence of 6.59%-14.4% among such patients. These findings suggest that many cases of PA caused by small aldosterone-producing adenoma (APA) or idiopathic hyperaldosteronism (IHA) have not been properly diagnosed. To make a more accurate diagnosis in such cases, we developed a new diagnostic procedure for localization of PA, namely, adrenal venous sampling under continuous infusion of adrenocorticotropic hormone (ACTH) and administration of angiotensin II receptor blocker (AVS with ACTH and ARB). Here, we confirm the efficacy of this procedure in the case of a 37-year-old male suspected of having PA. The anticipated diagnosis of PA was based on the presence of hypokalemia, low plasma renin activity (PRA), elevated plasma aldosterone concentration (PAC) and left adrenal mass. However, AVS with ACTH and ARB revealed the presence of bilateral multiple adrenal microadenomas. In the new AVS method, neither ACTH nor the renin-angiotensin system (RAS) exert any influence on the plasma aldosterone level, and a more accurate aldosterone secretary state and a more accurate assessment of the aldosterone secretion of both adrenal glands can be recognized than by conventional AVS. Use of this new method should enable identification of additional cases of APA among patients diagnosed with essential hypertension.     

Detecting and treating primary aldosteronism: primary aldosteronism.

Primary aldosteronism (PA) is the most common cause of mineralocorticoid hypertension. Different studies, using the plasma aldosterone concentration to plasma renin activity ratio (PAC/PRA) for the screening of patients with hypertension, have shown a marked increase in the detection rate of PA. Idiopathic bilateral adrenal hyperplasia (IHA) and aldosterone-producing adrenal adenoma (APA), are the leading causes of primary aldosteronism. Glucocorticoid-remediable aldosteronism (GRA), also called familial hyperaldosteronism type I, familial hyperaldosteronism type II and carcinomas are rare causes of PA. Patients with hypertension and hypokalemia, those with a family history of hypertension and stroke at an early age, or patients with medication-resistant hypertension should be screened for PA using the PAC/PRA ratio. If a high ratio is found, a sodium loading test or a captopril test is warranted to confirm the diagnosis. Adrenal gland imaging is important in subtype differentiation (APA vs IHA). Adrenal venous sampling should be used when other tests prove inconclusive. Genetic testing has facilitated detection of GRA. Surgery is considered the treatment of choice for patients with APA, while bilateral hyperplasia subtypes are treated medically. Normalization of aldosterone levels or aldosterone receptor blockade are necessary to prevent the morbidity and mortality associated with hypertension, hypokalemia, and cardiovascular damage.     

Unique cases of unilateral hyperaldosteronemia due to multiple adrenocortical micronodules, which can only be detected by selective adrenal venous sampling

Primary aldosteronism is classified as aldosterone-producing adenoma (APA), idiopathic hyperaldosteronism (IHA), unilateral adrenal hyperplasia (UAH), primary adrenal hyperplasia (PAH), adrenal cancer, and glucocorticoid-remediable aldosteronism. We describe here 4 cases of primary aldosteronism due to unilateral hyperaldosteronemia, demonstrating unique histopathologic findings, such as unilateral multiple adrenocortical micronodules in the affected adrenals. Thirty-three patients with primary aldosteronism were consecutively admitted; 27 of them were treated by unilateral adrenalectomy. Four of them also had unilateral adrenal hypersecretion of aldosterone by selective adrenal venous sampling and adrenocortical multiple micronodules without an adenoma. These patients had hyporeninemic hyperaldosteronism with normokalemic hypertension. In these patients, furosemide plus upright test failed to increase plasma renin activity (PRA); the ratio of plasma aldosterone concentration (PAC) to PRA at 90 minutes after captopril administration was similar to that in patients with IHA and APA. Aldosterone concentrations were increased in each unilateral adrenal vein, and poorly encapsulated multiple adrenocortical micronodules from 2 to 3 mm in diameter were microscopically detected in the resected adrenal glands. Immunohistochemical analysis of steroidogenic enzymes, including cholesterol side chain cleavage, 3beta-hydroxysteroid dehydrogenase, 21-hydroxylase, 17alpha-hydroxylase, and 11beta-hydroxylase, indicated that the cortical cells within these micronodules were active in aldosterone production, while the non-nodular zona glomerulosa cells were inactive. We conclude that the clinical and pathologic characteristics of our 4 cases with unilateral multiple adrenocortical micronodules (UMN) are distinct from those of APA, IHA, UAH, and PAH. Furthermore, unilateral hyperaldosteronemia induced by UMN may be frequently misdiagnosed, because standard imaging tests, which cannot always detect tiny abnormalities of adrenals, showed "normal adrenal glands" in these patients. Thus, primary aldosteronism due to UMN should be carefully examined for differential diagnosis of each form of hyperaldosteronemia.     

Correctable subsets of primary aldosteronism. Primary adrenal hyperplasia and renin responsive adenoma

Among 154 cases of primary aldosteronism seen in the General Clinical Research Center at San Francisco General Hospital, twelve patients did not fulfill established characteristics of an aldosterone producing adenoma (APA) or idiopathic hyperaldosteronism (IHA). Eight patients had nodular adrenocortical hyperplasia; plasma and urinary aldosterone were elevated and responses to stimulatory and suppressive maneuvers demonstrated the same autonomy seen in patients with APA. This subset is designated primary adrenal hyperplasia. Four additional patients also had elevated aldosterone levels that were responsive to these maneuvers, similar to IHA, but had unilateral tumors. This group has been designated as aldosterone-producing renin-responsive adenoma. Eleven patients had unilateral adrenalectomy and one preferred prolonged spironolactone therapy, resulting in a sustained cure or amelioration of hypertension, hypokalemia and normalization of aldosterone production.     

SFE/SFHTA/AFCE consensus on primary aldosteronism,part 4: Subtype diagnosis

To establish the cause of primary aldosteronism (PA), it is essential to distinguish unilateral from bilateral adrenal aldosterone secretion, as adrenalectomy improves aldosterone secretion and controls hypertension and hypokalemia only in the former. Except in the rare cases of type 1 or 3 familial hyperaldosteronism, which can be diagnosed genetically and are not candidates for surgery, lateralized aldosterone secretion is diagnosed on adrenal CT or MRI and adrenal venous sampling. Postural stimulation tests and ¹³¹I-norcholesterol scintigraphy have poor diagnostic value and ¹¹C-metomidate PET is not yet available. We recommend that adrenal CT or MRI be performed in all cases of PA. Imaging may exceptionally identify adrenocortical carcinoma, for which the surgical objectives are carcinologic, and otherwise shows either normal or hyperplastic adrenals or unilateral adenoma. Imaging alone carries a risk of false positives in patients over 35 years of age (non-aldosterone-secreting adenoma) and false negatives in all patients (unilateral hyperplasia). We suggest that all candidates for surgery over 35 years of age undergo adrenal venous sampling, simultaneously in both adrenal veins, without ACTH stimulation, to confirm the unilateral form of the hypersecretion. Sampling results should be confirmed on adrenal vein cortisol assay showing a concentration at least double that found in peripheral veins. Aldosterone secretion should be considered lateralized when aldosterone/cortisol ratio on the dominant side is at least 4-fold higher than contralaterally.     

Preclinical Cushing's syndrome due to ACTH-independent bilateral macronodular adrenocortical hyperplasia with excessive secretion of 18-hydroxydeoxycorticosterone and corticosterone

A 64-year-old woman developed hypertension and hypokalemia, due to ACTH-independent bilateral macronodular adrenocortical hyperplasia (AIMAH) with excessive secretion of 18-hydroxydeoxycorticosterone and corticosterone. Plasma cortisol did not show a diurnal rhythm, and was not suppressed by dexamethasone (8 mg). Plasma cortisol responded to ACTH and was increased by hypoglycemia without modifying ACTH levels. Radiological studies demonstrated that adrenal glands were enlarged with macronodules. Although the patient exhibited a low plasma renin activity and aldosterone levels, hypokalemia and hypertension were observed. Hormonal findings would support the hypothesis that the tumor of AIMAH originated from cells of the upper zona fasciculata.     

Aldosterone receptors in different types of primary hyperaldosteronism

The number of mineralocorticoid-binding sites on mononuclear leukocytes and plasma aldosterone (aldo) concentrations were measured in patients with different types of primary hyperaldosteronism. Patients with unilateral adenoma and patients with bilateral adrenal hyperplasia had a significantly lower (P less than 0.001) mean number of binding sites for aldo [144 +/- 36 (+/- SD; n = 6) and 140 +/- 28 sites/cell (n = 4), respectively] compared with normal subjects (292 +/- 110 sites/cell; n = 25). In four patients with dexamethasone-suppressible hyperaldosteronism, mineralocorticoid-binding sites in mononuclear leukocytes were normal (291 +/- 108 sites/cell). In all patients undergoing surgery for unilateral adenoma, the receptors normalized 3 months after the operation. In two patients the reduction in receptors persisted for a short time after surgery even though the plasma aldo level had already normalized. We conclude that mineralocorticoid excess produces down-regulation of mineralocorticoid receptors, which, in turn, might contribute to the genesis of the aldo escape phenomenon.     

An additional child case of an aldosterone-producing adenoma with an atypical presentation of peripheral paralysis due to hypokalemia

Aldosterone-producing adenoma, which is characterized by hypertension, hypokalemia, and elevated aldosterone levels with suppressed plasma renin activity, is a rare condition during childhood and is also potentially curable. To the best of our knowledge, nearly 25 cases of childhood aldosterone-secreting adenoma have been reported in the literature to date. Here we describe a 13-yr-old girl with primary hyperaldosteronism secondary to aldosterone-secreting adenoma. The patient was admitted to our hospital with the neuromuscular complaints of muscle weakness and inability to walk due to hypokalemia. She had been misdiagnosed as having hypokalemic periodic paralysis 2 months before admission and her symptoms had radically improved with potassium supplementation. However, her blood pressure levels had increased and her symptoms reappeared 2 days prior to being observed during hospitalization in our institution. Laboratory examinations revealed hypokalemia (2.1 mEq/l), and increased serum aldosterone levels with suppressed plasma renin activity. Abdominal ultrasonography and abdominal magnetic resonance imaging revealed left adrenal mass. Laparoscopic adrenalectomy was performed and histopathological examinations showed benign adrenal adenoma. Serum aldosterone levels and blood pressure levels returned to normal after surgical intervention. This case demonstrates the importance of a systemic evaluation including blood pressure monitorization of children with hypokalemia as intermittent hypertension episodes may be seen; cases without hypertension may be misdiagnosed as rheumatological or neurological disorders such as hypokalemic periodic paralysis, as in our case.     

Variant of pre-clinical Cushing's syndrome: hypertension and hypokalemia associated with normoreninemic normoaldosteronism.

The case of a 48-year-old woman with a left adrenocortical adenoma and showing hypokalemia, hypertension and normoreninemic normoaldosteronism is reported. Basal plasma adrenocorticotrophic hormone (ACTH) and cortisol levels were within the reference ranges. The patient's plasma cortisol level decreased insufficiently at night, and was insufficiently decreased by nighttime administration of dexamethasone. She showed no Cushingnoid stigmata. Iodocholesterol scintigraphy revealed tumor-sided uptake alone. The plasma dehydroepiandrosterone-sulfate level was low-to-normal for her age. Metabolic alkalosis and increased potassium clearance after sodium thiosulfate loading were revealed. The plasma aldosterone level was within the normal range, but it was statistically higher than the range for patients with pre-clinical Cushing's syndrome. However, peripheral plasma renin activity (PRA) increased normally after the patient resumed an upright posture following furosemide administration. After adenomectomy the hypokalemia and hypertension were resolved, and the plasma ACTH, cortisol, and PRA remained within the reference ranges. The plasma aldosterone level decreased slightly, but also remained within the reference range after adenomectomy. Paradoxical hyperplasia in the non-neoplastic adrenal glomerulosa zone, which indicates primary aldosteronism, and slight atrophy of the non-neoplastic adrenal cortex, which indicates pre-clinical Cushing's syndrome, were demonstrated. These findings satisfied the criteria of pre-clinical Cushing's syndrome, but did not completely satisfy those of primary aldosteronism. However, the level of CYP11 B2 mRNA in the tumor was in the lower-limit of the range for adenomas associated with primary aldosteronism and was higher than the ranges for adenomas associated with pre-clinical Cushing's syndrome and overt Cushing's syndrome. Based on these results, this case was suspected to constitute a variant of pre-clinical Cushing's syndrome with slight hypersecretion of aldosterone.     

Primary hyperaldosteronism: A missed diagnosis in ‘essential hypertensives’?

Background: It has been recognised recently that primary hyperaldosteronism may be more common than previously thought, the frequency of diagnosis being improved by screening using a plasma aldosterone concentration to renin activity ratio. Aims: To determine the frequency of primary hyperaldosteronism, screening with both plasma aldosterone to renin concentration (PRC) and activity (PRA) ratios, in normokalaemic subjects previously diagnosed as having essential hypertension. Methods: Plasma potassium, aldosterone and PRCs and PRA and blood pressure (BP) were measured in 74 hypertensive subjects previously diagnosed by one physician as having essential hypertension. A normal range for plasma aldosterone/renin ratios was determined in 147 control subjects. Hypertensive subjects with elevated aldosterone/renin ratios were further assessed for primary hyperaldosteronism using saline loading and fludrocortisone suppression. Those in whom plasma aldosterone concentration exceeded 140 pmol/L after suppression tests underwent adrenal vein sampling for measurement of aldosterone and Cortisol concentrations as well as adrenal CT scanning to diagnose the cause of primary hyperaldosteronism. The main outcome measures were a diagnosis of aldosterone producing adenoma or bilateral adrenal hyperplasia based upon adrenal vein sampling. Results: Four subjects (5%) had an elevated plasma aldosterone to renin ratio using PRC and six (8%) using PRA. Two subjects (2.7%) in this selected population had primary hyperaldosteronism, both of whom had BP > 160/110 mmHg at the time of testing. Conclusions: The frequency of normokalaemic primary hyperaldosteronism appears to be greater than previously thought, though the true incidence in the general population of hypertensive subjects remains unknown. The sensitivity of diagnosis (but not specificity) may be improved by measurement of the plasma aldosterone/renin ratio and PRC is at least as adequate as PRA for this process.     

Primary hyperaldosteronism without suppressed renin due to secondary hypertensive kidney damage

Primary hyperaldosteronism is characterized by high plasma and urinary aldosterone and suppressed PRA. Renin suppression is due to aldosterone-dependent sodium retention and mild extracellular volume expansion. We observed three patients with primary hyperaldosteronism, severe refractory hypertension, and normal to high normal PRA levels whose aldosterone/renin ratios were still elevated because of disproportionately high aldosterone levels. All available medical data on the patients as well as publications on the aldosterone/renin relationship in primary hyperaldosteronism were reviewed to explain the unusual findings. In one patient, histologically proven renal arteriolosclerosis was the probable cause of the escape of PRA from suppression by an aldosterone-producing adenoma. In the other two patients, hypertensive kidney damage due to primary hyperaldosteronism was the most likely explanation for the inappropriately high PRA, as in patient 1. All patients had high normal or slightly elevated serum creatinine levels and responded to 200 mg spironolactone/day with increased serum creatinine and hyperkalemia. Hyperkalemia was probably due to a decreased filtered load of sodium and a spironolactone-induced decrease in mineralocorticoid function. Two patients were cured of hyperaldosteronism by unilateral adrenalectomy but still need some antihypertensive therapy, whereas one patient has probable bilateral adrenal disease, with normal blood pressure on a low dose of spironolactone. In patients with severe hypertension due to primary hyperaldosteronism, PRA can escape suppression if hypertensive kidney damage supervenes. An increased aldosterone/PRA ratio is still useful in screening for primary hyperaldosteronism. These patients may respond to spironolactone therapy with a strong increase in serum creatinine and potassium. Early specific treatment of primary hyperaldosteronism is therefore indicated, and even a patient with advanced hypertension will profit from adrenalectomy or cautious spironolactone treatment.     

Plasma aldosterone response to ACTH in primary aldosteronism and in patients with low renin hypertension.

ACTH alpha 1-24 was infused at incremental rates of 12.5-200 mIU/30 min in dexamethasone-suppressed hypertensive patients on a regular sodium diet. The plasma aldosterone response to this stimulus in 8 patients with hyperaldosteronism due to an adrenal aldenoma and 11 with adrenal hyperplasia was significantly greater at all infusion rates (P less than 0.05) when compared with the response in 6 normal subjects on a similar diet. This responsiveness to ACTH in the patients with primary hyperaldosteronism was similar to that of the normal subjects on a low sodium diet. Twelve patients with low renin and 6 patients with normal renin essential hypertension were similarly studied. There was no significant difference in the median aldosterone response between these 2 groups and the normal subjects on a normal diet, but the response was significantly lower compared with that in patients with primary hyperaldosteronism. These data show that patients with hyperaldosteronism from an adrenal adenoma or hyperplasia have a consistent and exaggerated response to ACTH. The hyper-responsiveness is not apparently shared by the majority of patients with low renin essential hypertension and does not support the concept that this group is an intermediate form of primary aldosteronism. Individual patients within this group, however, may have such a response and might be identified by this type of testing.     

Inappropriate elevation of the aldosterone/plasma renin activity ratio in hypertensive patients with increases of 11-deoxycorticosterone and 18-hydroxy-11-deoxycorticosterone: a subtype of essential hypertension?

Among 436 patients with hypertension unrelated to any renal lesion, renovascular damage, pheochromocytoma, Cushing's syndrome or hyperthyroidism, 15 patients had low plasma renin activity (PRA) and elevated plasma aldosterone concentrations in the upright position and resultant high aldosterone/PRA ratios: 8 with aldosterone-producing adenoma (APA; group 1) and 7 with idiopathic hyperaldosteronism (IHA; group 2). Thirty-nine patients had suppressed PRA in the presence of normal plasma aldosterone levels and moderately elevated aldosterone/PRA ratios (group 3). Thirty of them had elevated plasma 11-deoxycorticosterone (DOC) and 18-hydroxy-11-deoxycorticosterone (18-OH-DOC) concentrations (group 3a) and 9 of them had normal levels of those mineralocorticoids (group 3b). The rest of them (382 patients) had low aldosterone/PRA ratios (group 4). Adrenal scintigraphy with dexamethasone pretreatment revealed [13I]-cholesterol accumulation not only in patients with APA (unilateral) or IHA (bilateral), but also in patients of group 3a (bilateral). In patients in groups 3a and 3b adrenal size (especially thickness), as measured by computed tomography (CT scan), was enlarged, as in patients with IHA (group 2), and was significantly greater than in patients of group 4 (p less than 0.001). Spironolactone reduced blood pressure in all tested patients of group 3a, and the removal of adrenal tumor or hyperplastic tissue normalized blood pressure in patients of groups 1, 2 and 3a. Excised adrenal glands exhibited cortical hyperplasia with or without nodular hyperplasia in patients of group 3a. Good agreement was found between the actual size of the excised tissue and the measurement obtained by CT scan. Since beta-endorphin and beta-lipotropin were depressed in patients of group 3a, it is suggested that an unknown pituitary substance stimulates the adrenal cortex to release too large amounts of DOC and 18-OH-DOC and inappropriate secretion of aldosterone.     

Low-renin ("primary") hyperaldosteronism. Differential diagnosis and distinction of sub-groups within the syndrome.

Hypokalemia in a hypertensive patient is commonly diuretic-induced. However, if hypokalemia persists after stopping diuretic therapy, possible mineralocorticoid excess, including primary hyperaldosteronism, must be considered. Hypertension with secondary hyperaldosteronism may occur with malignant-phase hypertension and with renal or renovascular disease. However, secondary hyperaldosteronism is associated with raised circulating levels of renin and angiotensin II, while in primary hyperaldosteronism plasma concentrations of renin and angiotensin II are inappropriately low.Hypertension and hypokalemia may also be associated with an excess of a mineralocorticoid other than aldosterone. Syndromes associated with an apparently isolated excess of 11-deoxycorticosterone, of 18-hydroxy-11-deoxycorticosterone and of corticosterone have been described. Plasma renin may be suppressed as in primary hyperaldosteronism, but aldosterone values are normal or low. Hypertension, hypokalemia, and renin suppression may also occur in Cushing's syndrome, associated with abnormalities of corticosteroid synthesis and during ingestion of licorice-containing drugs. Again, aldosterone values are normal or low.Once the diagnosis of primary hyperaldosteronism has been confirmed, the rare cases of glucocorticoid-remediable hyperaldosteronism and hyperaldosteronism associated with adrenal or ovarian carcinoma must be excluded. There-after, it is necessary to distinguish between the two commonest forms, a unilateral adrenocortical adenoma and bilateral hyperplasia of the zona glomerulosa. The statistical technique of quadric analysis used prospectively has correctly predicted adrenal pathology in 23 of 24 patients. Other methods for differentiating the two groups include comparisons of aldosterone response to sodium loading, comparison of postural and diurnal changes in plasma aldosterone, adrenal venography, and examination of the adrenal glands by ultrasound and by scintillation scanning.     

Combined primary aldosteronism and Cushing's syndrome due to a single adrenocortical adenoma complicated by Hashimoto's thyroiditis

A 43-year-old Japanese woman presented hypertension, hypokalemia and typical Cushingoid signs. Autonomous secretion of both aldosterone and cortisol was shown. Abdominal computed tomography demonstrated a single tumor in the right adrenal gland, which established the diagnosis of combined primary aldosteronism and Cushing's syndrome. The resected tumor was a golden yellow-colored adenoma (diameter 4.3 cm) which expressed P450(aldo) and P450(11beta), causing oversecretion of both hormones from this adenoma. After tumor resection, overproduction of both hormones disappeared and she developed adrenal insufficiency, suggesting the strong suppression of normal adrenal function. This case was complicated by Hashimoto's thyroiditis.     

PRE-OPERATIVE LOCALIZATION OF ALDOSTERONE-SECRETING ADRENAL ADENOMAS

Techniques for pre-operative localization of aldosterone-secreting adrenal adenomas were studied in thirty-seven patients, each with hypertension and biochemical evidence of primary hyperaldosteronism and each later having adrenal surgery (thirty-two adenomas, five bilateral adrenal hyperplasia). Bilateral adrenal vein catheterization was attempted in all cases; it was successful on the left side in all patients and in 92% of cases on the right. Adrenal vein plasma samples were obtained from the left side in 92% and from the right in 73% of cases. Adrenal vein plasma aldosterone measurements correctly indicated the presence of tumour in twenty-eight cases but falsely predicted unilateral adenoma in two cases of bilateral adrenal hyperplasia. Adrenal venography also correctly predicted unilateral adrenal adenomas in twenty-six cases but falsely suggested the presence of tumour in three cases of bilateral adrenal hyperplasia. Computed tomography (CT) was used in the last eight cases. In seven instances the predictions (six adenomas, one bilateral adrenal hyperplasia) were confirmed at surgery. However, the remaining patient harboured an adenoma 20 mm in diameter which was not detected by CT although diagnosed both by adrenal venography and adrenal vein aldosterone measurements. Ultrasound detected adenoma in only three of twenty-two cases examined. Although further comparative studies of the type described here are required, the results of computed tomography are promising and suggest that this non-invasive technique might well become the first choice procedure in localizing aldosterone-secreting adenomas.     

Primary aldosteronism due to unilateral adrenal hyperplasia: report of two cases and review of the literature

Unilateral adrenal hyperplasia (UAH) is a rare, surgically correctable subset of primary aldosteronism (PA), which shows similar endocrine features to aldosterone-producing adenoma (APA). We report here two Japanese patients with UAH. Case 1 was a 62-year-old man with a four-year history of hypertension. Hypokalemia and suppressed plasma renin activity (PRA) with elevated plasma aldosterone concentration (PAC) were observed, while no adrenal nodules were identified by abdominal computed tomographic (CT) scan. Adrenal scintigraphy did not reveal definite localization. The selective adrenal-vein sampling for determinations of PAC showed an over-functioning left adrenal gland, and a left adrenalectomy was performed. Diffuse micronodular adrenocortical hyperplasia was observed. Case 2 was a 61-year-old man with a six-year history of hypertension. At the first visit to our hospital, hypokalemia and suppressed PRA with elevated PAC were observed. An abdominal CT scan showed a left adrenal mass 1.5 cm in diameter, while adrenal scintigraphy did not reveal definite laterality. A left adrenalectomy was performed, and three macronodules and diffuse micronodular adrenocortical hyperplasia were observed. Hypokalemia, hypertension and endocrine data became normal, and both patients have been well with no signs of recurrence for eight years (case 1) and seven months (case 2) after surgery. Clinical characteristics and endocrine features of UAH are also reviewed.