Imaging Pearls ❯ Adrenal ❯ Hyperaldosteronism
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- “Primary aldosteronism (PA) has been reported in 3% to 10% of hypertensive patients.16 Once PA is diagnosed, mineralocorticoid antagonists can be used to effectively manage PA-related hypertension and hypokalemia. Primary aldosteronism may be caused by an aldosterone-secreting adenoma, unilateral adrenal hyperplasia, or bilateral adrenal hyperplasia, and adrenal venous sampling (AVS) may be necessary for lateralization. After adrenalectomy, the majority of patients with PA have either complete or partial clinical success, with less than 20% requiring the same or higher doses of medication postoperatively. Studies to date have assessed cost and quality-of-life outcomes after adrenalectomy via laparoscopy, and whether similar conclusions can be made using other minimally invasive surgical approaches is not yet known.”
American Association of Endocrine Surgeons Guidelines for Adrenalectomy: Executive Summary
Linwah Yip, et al.
JAMA Surg. doi:10.1001/jamasurg.2022.3544 Published online August 17, 2022. - “Adrenal metastasis commonly occurs in patientswith malignancy from the lung, kidney, breast, melanoma, and colon but may occur from many other primary sites. While there are currently no established criteria guiding patient selection for adrenal metastasectomy, consideration should be given to pathology, synchronous vs metachronous presentation, disease free interval, and tumor size to help select appropriate surgical candidates. Adrenal metastasectomy may be more difficult because of reaction from systemic treatment but can be performed either open or minimally invasive with equivalent oncologic outcomes.”
American Association of Endocrine Surgeons Guidelines for Adrenalectomy: Executive Summary
Linwah Yip, et al.
JAMA Surg. doi:10.1001/jamasurg.2022.3544 Published online August 17, 2022. - “We recommend that allpatientswith an adrenal incidentaloma 1 cm or larger undergo biochemical testing for autonomous cortisol secretion. Patients with hypertension or hypokalemia also require biochemical evaluation for primary aldosteronism. Patients with adrenal imaging findings that have noncontrast CT with HU greater than 10 should undergo evaluation for pheochromocytoma.”
American Association of Endocrine Surgeons Guidelines for Adrenalectomy: Executive Summary
Linwah Yip, et al.
JAMA Surg. doi:10.1001/jamasurg.2022.3544 Published online August 17, 2022. - Primary Aldosteronism: Causes
- aldosterone-producing adenoma
- bilateral adrenal hyperplasia
- aldosterone-producing adrenal carcinoma
- ectopic aldosterone secretion from the kidneys or ovaries
- Familial causes - Primary Aldosteronism: Facts
Primary hyperaldosteronism (PA) is an under-diagnosed cause of hypertension. The presentation is classically known to occur as a patient with hypertension and hypokalemia. - Primary aldosteronism is aldosteronism caused by autonomous production of aldosterone by the adrenal cortex (due to hyperplasia, adenoma, or carcinoma). Symptoms and signs include episodic weakness, elevated blood pressure, and hypokalemia. Diagnosis includes measurement of plasma aldosterone levels and plasma renin activity. Treatment depends on cause. A tumor is removed if possible; in hyperplasia, spironolactone or related drugs may normalize blood pressure and eliminate other clinical features.
Merck Manual - “Rare germline variants of CYP11B2 (encoding aldosterone synthase), CLCN2 (encoding voltage-gated chloride channel ClC2), KCNJ5, CACNA1H (encoding a subunit of T-type voltage-gated calcium channel CaV3.2), and CACNA1D have been reported in different subtypes of familial hyperaldosteronism. Collectively, these studies suggest that primary aldosteronism is largely due to genetic mutations in single genes, with potential implications for diagnosis and therapy.”
Genetic causes of primary aldosteronism
Eric Seidel, Julia Schewe, and Ute I. Scholl
Experimental & Molecular Medicine (2019) 51:131
- Primary Aldosteronomas: Facts
• First described by Conn in 1955
• Age at presentation is between 30-50 years and and more common in woman
• Characterized by hypertension, suppressed plasma renin activity and increased aldosterone secretion
• Two thirds of patients have bilateral idiopathic hyperaldosteronism and approximately one third have aldosterone producing adenomas - “Primary aldosteronism is defined as the inappropriate autonomous hypersecretion of aldosterone in the absence of activation of the renin-angiotensin-aldosterone axis. Primary aldosteronism is the most common cause of secondary hypertension and is estimated to be responsible for 5%–20% of all cases of hypertension.”
Role of Radiology in the Management of Primary Aldosteronism Patel SM et al. RadioGraphics 2007; 27:1145–1157 - “Primary aldostenonism, or Conn’s
cause of hypertension. Approximately
have a benign aldosterone-secreting
of the remaining patients have bilateral adrenal hyperplasia. Adrenal carcinoma has been reported as a cause of Conn’s syndrome, but this is rare.”
CT in the Diagnosis of Primary Aldosteronism: Sensitivity in 29 Patients Dunnick NR et al. AJR 1 993;160:321-324 - “APAs are benign adrenocortical neoplasms associated with pathologic aldosterone excess. At gross examination, they are usually yellow, round or oval, and typically less than 2 cm in size, with a significant proportion less than 1 cm. APAs can occur in any age group but are often found in younger patients ( 40 years old).”
Role of Radiology in the Management of Primary Aldosteronism Patel SM et al. RadioGraphics 2007; 27:1145–1157 - “If an adrenal nodule or mass is seen in one adrenal gland but the contralateral gland appears normal, surgery should be considered for the resection of an APA. In older patients, however, owing to the higher prevalence of bilateral (nodular) hyperplasia, the clinician may prefer to use AVS prior to surgery to confirm the diagnosis of an APA.”
Role of Radiology in the Management of Pri- mary Aldosteronism Patel SM et al. RadioGraphics 2007; 27:1145–1157 - Aldosteronomas: CT Appearance
• Can be either due to aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia (BAH)
• aldosterone-producing adenoma (APA) are usually unilateral and 2cm or less in size
• aldosterone-producing adenoma (APA) can be bilateral and the site of the tumor may require venous sampling - Primary Aldosteronomas: CT Findings
Usually unilateral but may be bilateral
• Mean diameter is 1.5 to 2.0 cm
• No significant enhancement
• Sensitivity for localizing a Primary Aldosteronomas with CT is 82-90%
• Key is thin section CT on current state of the art scanner - “ A 100% specificity for diagnosing bilateral adrenal hyperplasia was achieved with a mean adrenal limb width greater than or equal to 5 mm and 100% sensitivity with a mean width greater than 3 mm.”
Role of Radiology in the Management of Primary Aldosteronism Patel SM et al. RadioGraphics 2007; 27:1145-1157 - “In the setting of hyperaldosteronism (Conn's syndrome), the absence of an adenoma traditionally suggested adrenal hyperplasia as the cause. With improved CT resolution, gland measurements have proven useful. Lingam et al. revealed that the medial and lateral limbs were significantly larger in hyperplasia. A cutoff of 5 mm was 47% sensitive and 100% specific; using a 3-mm cutoff, sensitivity was 100% and specificity, 54%. In comparison, the absence of an adenoma at imaging was 93.3% sensitive and 84.6% specific.”
Adrenal Imaging with MDCT: Nonneoplastic Disease Johnson PT, Horton KM, Fishman EK AJR 2009;193: 1128-1135 - “Cushing syndrome (CS) is a constellation of clinical signs and symptoms resulting from chronic exposure to excess cortisol, either exogenous or endogenous. Exogenous CS is most commonly caused by administration of glucocorticoids. Endogenous CS is subdivided into two types: adrenocorticotropic hormone (ACTH) dependent and ACTH independent.”
Cushing Syndrome: Diagnostic Workup and Imaging Features, With Clinical and Pathologic Correlation Wagner-Bartak NA et al. AJR 2017; 209:19–32
- “Laparoscopic unilateral adrenalectomy for PHA cured or improved hypertension in 84 % of patients. Preoperative AVS is mandatory for surgical decision making if the CT scan shows bilateral or no lesions associated with PHA.”
Is Adrenal Venous Sampling Mandatory before Surgical Decision in Case of Primary Hyperaldosteronism-
Pirvu A et a.
World J Surg. 2014 Jan 31. [Epub ahead of print] - “Of the 62 patients who underwent a unilateral adrenalectomy, 46 (74 %) had an adrenal adenoma, 14 (22 %) a hyperplasia, and the adrenal gland was normal in two cases. Hypertension was cured in 24 cases (38 %), and 28 patients (45 %) showed improvement with a reduction in AM. Predictive factors for a cure were gender, age, number of preoperative AMs, preoperative arterial systolic blood pressure, and plasma renin activity.”
Is Adrenal Venous Sampling Mandatory before Surgical Decision in Case of Primary Hyperaldosteronism-
Pirvu A et a.
World J Surg. 2014 Jan 31. [Epub ahead of print] - Primary Aldosteronomas: Facts
- First described by Conn in 1955
- Age at presentation is between 30-50 years and and more common in woman
- Characterized by hypertension, suppressed plasma renin activity and increased aldosterone secretion
- Two thirds of patients have bilateral idiopathic hyperaldosteronism and approximately one third have aldosterone producing adenomas - Primary Aldosteronism: Other Causes
- Primary unilateral adrenal hyperplasia
- Pure aldosterone secreting adrenal cortical carcinoma
- Familial hyperaldosteronism - Primary Aldosteronomas: CT Findings
- Usually unilateral but may be bilateral
- Mean diameter is 1.5 to 2.0 cm
- No significant enhancement
- Sensitivity for localizing a Primary Aldosteronomas with CT is 82-90%
- Key is thin section CT on current state of the art scanner - “ 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).”
Role of Radiology in the Management of Primary Aldosteronism
Patel SM et al.
RadioGraphics 2007; 27:1145-1157 - “ Primary aldosteronism is defined as the inappropriate autonomous hypersecretion of aldosterone in the absence of activation of the renin-angiotensin-aldosterone axis. Primary aldosteronism is the most common cause of secondary hypertension and is estimated to be responsible for 5%-20% of all cases of hypertension.”
Role of Radiology in the Management of Primary Aldosteronism
Patel SM et al.
RadioGraphics 2007; 27:1145-1157 - “ A 100% specificity for diagnosing bilateral adrenal hyperplasia was achieved with a mean adrenal limb width greater than or equal to 5 mm and 100% sensitivity with a mean width greater than 3 mm.”
Role of Radiology in the Management of Primary Aldosteronism
Patel SM et al.
RadioGraphics 2007; 27:1145-1157 - “ Our new AVS (adrenal vein sampling) protocol resulted in a marked improvement in BAVS. AVS influenced management in a third of patients with primary aldosteronism. Surgical decision making cannot be made solely on the basis of cross sectional imaging.”
Modification of the protocol for selective adrenal venous sampling results in both a significant increase in the accuracy and necessity of the procedure in the management of patients with primary aldosteronism
Harvey A et al.
Surgery 2012;152:643-651 - “ Of the 86 AVS performed on 84 patients with PA, 82 had BAVC. AVS altered the management in 26 of 84 (31%) patients. Despite clear unilateral findings on imaging in 45 patients, AVS demonstrated bilateral adrenal hyperplasia in 10 and contralateral disease in 3. AVS confirmed unilateral PA in 5 patients with equivocal <1cm nodules. In 4 of 25 patients with normal adrenal glands, AVS demonstrated localization.”
Modification of the protocol for selective adrenal venous sampling results in both a significant increase in the accuracy and necessity of the procedure in the management of patients with primary aldosteronism
Harvey A et al.
Surgery 2012;152:643-651 - “ If CT scans of patients with Conn’s syndrome show a focal mass, ipsilateral adrenalectomy can be performed with the expectation of cure. If no mass is found, adrenal venous sampling can be used to detect an adenoma not shown on CT.”
CT in the Diagnosis of Primary Aldosteronism: Sensitivity in 29 Patients
Dunnick NR et al.
AJR 1993;160:321-324 - “Fourteen of 17 aldosteronomas were detected on CT scans (sensitivity, 82%). Adrenal tumors were not seen on CT scans in any of the 12 patients with hyperplasia, although the glands appeared diffusely enlarged in only seven of these patients. In no case was an adrenal tumor seen on CT scans that was not found at surgery (positive predictive value, 100%).”
CT in the Diagnosis of Primary Aldosteronism: Sensitivity in 29 Patients
Dunnick NR et al.
AJR 1993;160:321-324 - “ The adrenal glands in patients with bilateral adrenal hyperplasia were significantly (p < 0.05) larger than those in patients with aldosterone-producing adenoma or in healthy control subjects. A sensitivity of 100% was achieved when a mean limb width of greater than 3 mm was used to diagnose bilateral adrenal hyperplasia, and a specificity of 100% was achieved when the mean limb width was 5 mm or greater.”
CT of primary hyperaldosteronism (Conn's syndrome): the value of measuring the adrenal gland
Lingam RK et al.
AJR 2003 Sep;181(3);843-9 - “In patients with primary hyperaldosteronism, adrenal limb measurements on CT can aid in differentiating bilateral adrenal hyperplasia from aldosterone-producing adenoma because the adrenal glands in bilateral adrenal hyperplasia are larger.”
CT of primary hyperaldosteronism (Conn's syndrome): the value of measuring the adrenal gland
Lingam RK et al.
AJR 2003 Sep;181(3);843-9 - “In the setting of hyperaldosteronism (Conn's syndrome), the absence of an adenoma traditionally suggested adrenal hyperplasia as the cause. With improved CT resolution, gland measurements have proven useful. Lingam et al. revealed that the medial and lateral limbs were significantly larger in hyperplasia. A cutoff of 5 mm was 47% sensitive and 100% specific; using a 3-mm cutoff, sensitivity was 100% and specificity, 54%. In comparison, the absence of an adenoma at imaging was 93.3% sensitive and 84.6% specific.”
Adrenal Imaging with MDCT: Nonneoplastic Disease
Johnson PT, Horton KM, Fishman EK
AJR 2009;193: 1128-1135