Aldosterone-producing tumors (Conn's syndrome)

Primary aldosteronism: molecular medicine meets public health

Primary aldosteronism is the most common single cause of hypertension and is potentially curable when only one adrenal gland is the culprit. The importance of primary aldosteronism to public health derives from its high prevalence but huge under-diagnosis (estimated to be <1% of all affected individuals), despite the consequences of poor blood pressure control by conventional therapy and enhanced cardiovascular risk. This state of affairs is attributable to the fact that the tools used for diagnosis or treatment are still those that originated in the 1970-1990s. Conversely, molecular discoveries have transformed our understanding of adrenal physiology and pathology. Many molecules and processes associated with constant adrenocortical renewal and interzonal metamorphosis also feature in aldosterone-producing adenomas and aldosterone-producing micronodules. The adrenal gland has one of the most significant rates of non-silent somatic mutations, with frequent selection of those driving autonomous aldosterone production, and distinct clinical presentations and outcomes for most genotypes. The disappearance of aldosterone synthesis and cells from most of the adult human zona glomerulosa is the likely driver of the mutational success that causes aldosterone-producing adenomas, but insights into the pathways that lead to constitutive aldosterone production and cell survival may open up opportunities for novel therapies.

Screening of primary aldosteronism by clinical features and daily laboratory tests: combination of urine pH, sex, and serum K

OBJECTIVE

To develop and validate a scoring system for selection of patients who should proceed to endocrinologic examinations of primary aldosteronism in newly diagnosed hypertensive patients.

METHODS

A multivariate logistic regression analysis for primary aldosteronism was undertaken by use of seven possible primary aldosteronism markers, age less than 40 years, female sex, moderate-to-severe hypertension, hypokalemia, serum Na minus Cl at least 40 mmol/l, serum uric acid 237.92 μmol/l or less (4.0 mg/dl), and urine pH (U-pH) at least 7.0, in consecutive outpatients newly diagnosed with hypertension. The diagnostic criteria of primary aldosteronism were plasma aldosterone concentration-to-plasma renin activity ratio [ARR, (ng/dl)/(ng/ml per h)] at least 20 and at least one positive result in four types of challenge tests.

RESULTS

Of 130 patients, 24 were diagnosed with primary aldosteronism. The area under the receiver operating characteristic curve (AUC) for a logistic model incorporating all possible primary aldosteronism markers was 0.73 [95% confidence interval (CI): 0.61-0.85]. Removing high U-pH, female sex, and hypokalemia from the full model decreased the AUC by 0.059, 0.035, and 0.011, respectively. We devised pH of urine, female sex, low serum K (PFK) score, in which one point each was assigned to high U-pH, female sex, and hypokalemia. The prevalences of primary aldosteronism in patients with 0, 1, 2, and 3 points were 11, 14, 42, and 60%, respectively. In external validation datasets (n = 106), AUC of PFK score was significantly higher than that of hypokalemia alone (0.73, 95% CI: 0.63-0.83 vs. 0.53, 95% CI: 0.44-0.63, P < 0.01).

CONCLUSION

PFK score may be a better parameter than hypokalemia alone for identifying patients with a high probability of having primary aldosteronism.

Idiopathic hyperplasia of the adrenal gland behaving like an aldosterone producing adenoma

Primary hyperaldosteronism (adrenal adenoma and idiopathic hyperplasia) is a disorder with hypertension, hypokalemia, elevated serum aldosterone and suppressed plasma renin activity. Hyperplasia is managed medically whereas adenomas are treated surgically. Selective adrenal venous catheterization and aldosterone measurement is a useful tool in making the distinction in 95% of cases. We report a case of bilateral idiopathic hyperplasia of the adrenal glands adequately treated with medications for 6 years followed by worsening. Selective catheterization was consistent with a right sided adenoma. Surgical removal of the right adrenal gland alleviated her symptoms. Pathological examination showed focal nodular hyperplasia. We propose that in the course of the disease the focal hyperplastic nodule became autonomous and behaved like an adenoma. Monitoring of patients with adrenal hyperplasia for recurrence of symptoms is prudent as surgery is beneficial in patients who develop an autonomous nodule.

Primary aldosteronism. Results of surgical treatment

SUMMARY BACKGROUND DATA

Management of primary hyperaldosteronism has undergone dramatic changes in the past 40 years. This retrospective study was carried out to review our recent surgical experience and to identify potential factors associated with postoperative persistent hypertension.

METHODS

Forty-six patients who had adrenal surgery for primary hyperaldosteronism from 1983 to 1994 were included in the study.

RESULTS

Periodic paralysis occurred in 12 (26%) patients. Hypertension and hypokalemia (mean serum potassium, 2.2 + 0.5 [+ standard deviation (SD) mmol/L) were present in all patients. Postural study was diagnostic in 85% (23 of 27). Computed tomography scan correctly localized the tumor in all except 1 patient, and venous sampling was performed in 11 patients. There was no operative mortality, and complications developed in six patients (13%), including one patient requiring re-exploration for hemostasis. All patients had a histologically documented adenoma. During a mean follow-up of 51 months, 34 (77%) of the 44 patients required no further antihypertensive treatment. Two patients were lost to follow-up. Age, response to spironolactone treatment, and blood pressure on discharge were risk factors identified for persistent hypertension.

CONCLUSION

Primary hyperaldosteronism due to aldosterone-producing adenoma can be diagnosed and localized expeditiously, whereas surgical treatment can be performed safely. Hypokalemia may be cured by surgical treatment, although persistent hypertension, usually of a mild degree, still occurs in selected patients.

Adrenal adenocarcinoma: a review of 53 cases

PROBLEM

Fifty-three patients (30 men, 23 women) with histologically proven adrenal carcinoma were reviewed. Nineteen (36%) had endocrine manifestations from functioning tumors. Arteriography was positive in 95% (19/20), CT scan in 94% (17/18), and ultrasound in 92% (12/13). Seventy-six percent of the patients, at the time of diagnosis, were stage III and IV. Most common metastatic sites were the liver, lymph nodes, bone, and lungs. Local recurrence developed in 39% of cases (15/38).

METHOD

Forty-one patients underwent an operation. Complete surgical removal of all gross tumor was achieved in 24 patients.

RESULT

The overall median survival time was 8 months, and the estimated 5-year survival rate 19%. There were significant differences in survival between the various stages (P = 0.01) and between the group of patients who underwent complete excision of the tumor and those with incomplete resection (P = 0.002).

CONCLUSIONS

Complete surgical excision offers the best prospect for long-term survival in localized adrenal carcinoma.