Diagnostic Imaging Pathways - Hyperaldosteronism (Primary Suspected)
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This pathway provides guidance on the imaging of adult patients with biochemically confirmed primary hyperaldosteronism.
Date reviewed: October 2017
Date of next review: October 2020
Published: February 2018
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The relative radiation level (RRL) of each imaging investigation is displayed in the pop up box.
SYMBOL | RRL | EFFECTIVE DOSE RANGE |
![]() | None | 0 |
![]() | Minimal | < 1 millisieverts |
![]() | Low | 1-5 mSv |
![]() | Medium | 5-10 mSv |
![]() | High | >10 mSv |
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Teaching Points
Teaching Points
- Indications for screening of suspected hyperaldosteronism
- Hypokalaemic hypertension
- Resistance / Refractory hypertension
- Presence of an incidentally detected adrenal mass
- Family history of hypertension
- Biochemical confirmation of primary hyperaldosteronism must be confirmed prior to imaging
- CT of the adrenals is the initial imaging modality for localisation of biochemically proven primary hyperaldosteronism
- Adrenal vein sampling should be undertaken to assess for a surgical remedial cause of primary hyperaldosteronism
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Primary Hyperaldosteronism
- The incidence of hyperaldosteronism as a cause for hypertension is believed to be more common than previously thought. 2-10% of patients with hypertension have hyperaldosteronism 1-3
- Imaging is used for localisation of a biochemically proven abnormality 1, 4, 5
- The most important distinction to be made is between the two most common causes of primary hyperaldosteronism 1, 4, 6
- Aldosterone producing adenoma (APA) - one third of cases of primary hyperaldosteronism
- Bilateral adrenal hyperplasia or idiopathic hyperaldosteronism (IHA) - two thirds of cases of primary hyperaldosteronism
- Aldosterone producing adenoma is treated surgically and bilateral adrenal hyperplasia is treated medically 1, 4
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Screening for Primary Hyperaldosteronism
- Plasma aldosterone concentration to plasma renin activity ratio (PAC/PRA) is regarded as the screening test of choice for primary hyperaldosteronism (PA) 1,2
- Biochemical diagnosis of primary hyperaldosteronism must be established prior to performing imaging studies to avoid unnecessary surgery because 3% to 7% of patients over the age of 50 have non-functioning adrenal nodules ("incidentalomas") 7
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Confirmatory Testing
- A number of further tests are available to confirm the diagnosis of primary hyperaldosteronism. These include 8
- Normal saline infusion – most commonly used
- Fludrocortisone suppression test
- Oral sodium loading
- In clinical practice however, a properly performed plasma aldosterone:renin concentration (PAC / PRA) particularly in the absence of medications likely to cause false results (such as B-blockers and diuretics) is normally sufficient to make the diagnosis
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Computed Tomography (CT)
- Initial imaging modality of choice for localisation of biochemically proven primary hyperaldosteronism 1, 4
- Computed Tomography has been shown to have a sensitivity of 50-60% in the detection of adenoma 9-11
- Magnetic Resonance Imaging has been shown to have a comparable sensitivity of 70% in detecting adenoma, with a specificity of 100% 12
- Advantages - non-invasive, can be used in the assessment of adrenal incidentalomas and is useful in mapping the position of veins prior to adrenal vein sampling 13
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Adrenal Vein Sampling (AVS)
- Most reliable method to localise the lesion resulting in primary hyperaldosteronism, and will dictate further management 2, 9, 10, 13-15
- Concordance between computed tomography and adrenal vein sampling for the assessment of primary hyperaldosteronism is poor 2, 13
- Adrenal vein sampling is a sensitive test to differentiate aldosterone-producing adenoma (APA) from bilateral hyperplasia 10, 14, 15
- The aldosterone to cortisol ratio in both adrenal veins is compared. If one side has a concentration more than 2 times the other side, then APA is diagnosed; bilateral adrenal hyperplasia is the diagnosis by default 15
- When successful, AVS unequivocally establishes the presence or absence of unilateral aldosterone production, thus clarifying the choice of therapy - medical or surgical 1
- Disadvantages - invasive, highly operator-dependent, not widely available and carries a finite risk of venous thrombosis, adrenal haemorrhage, and adrenal insufficiency 2
References
References
Date of literature search: September 2017
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Thakkar RB, Oparil S. Primary aldosteronism: a practical approach to diagnosis and treatment. J Clin Hypertens (Greenwich). 2001;3(3):189-95. (Review article). View the reference
- Buffolo F, Monticone S, Williams TA, Rossato D, Burrello J, Tetti M, et al. Subtype Diagnosis of Primary Aldosteronism: Is Adrenal Vein Sampling Always Necessary? International Journal of Molecular Sciences. 2017;18(4):848. (Review article). View the reference
- Gordon RD, Stowasser M, Tunny TJ, Klemm SA, Rutherford JC. High incidence of primary aldosteronism in 199 patients referred with hypertension. Clin Exp Pharmacol Physiol. 1994;21(4):315-8. (Level II evidence). View the reference
- Ganguly A. Primary aldosteronism. N Engl J Med. 1998;339(25):1828-34. (Review article). View the reference
- Stowasser M, Gordon RD. Primary Aldosteronism: Changing Definitions and New Concepts of Physiology and Pathophysiology Both Inside and Outside the Kidney. Physiol Rev. 2016;96(4):1327-84. (Review article). View the reference
- Iacobone M, Citton M, Viel G, Rossi GP, Nitti D. Approach to the surgical management of primary aldosteronism. Gland Surg. 2015;4(1):69-81. (Review article). View the reference
- Bornstein SR, Stratakis CA, Chrousos GP. Adrenocortical tumors: recent advances in basic concepts and clinical management. Ann Intern Med. 1999;130(9):759-71. (Review article). View the reference
- Schirpenbach C, Reincke M. Screening for primary aldosteronism. Best Pract Res Clin Endocrinol Metab. 2006;20(3):369-84. (Review article). View the reference
- Doppman JL, Gill JR, Jr., Miller DL, Chang R, Gupta R, Friedman TC, et al. Distinction between hyperaldosteronism due to bilateral hyperplasia and unilateral aldosteronoma: reliability of CT. Radiology. 1992;184(3):677-82. (Level II evidence). View the reference
- Harper R, Ferrett CG, McKnight JA, McIlrath EM, Russell CF, Sheridan B, et al. Accuracy of CT scanning and adrenal vein sampling in the pre-operative localization of aldosterone-secreting adrenal adenomas QJM: An International Journal of Medicine. 1999;92(11):643-50. (Level III evidence) View the reference
- Dunnick NR, Leight GS, Jr., Roubidoux MA, Leder RA, Paulson E, Kurylo L. CT in the diagnosis of primary aldosteronism: sensitivity in 29 patients. AJR Am J Roentgenol. 1993;160(2):321-4. (Level III evidence). View the reference
- Sohaib SA, Peppercorn PD, Allan C, Monson JP, Grossman AB, Besser GM, et al. Primary hyperaldosteronism (Conn syndrome): MR imaging findings. Radiology. 2000;214(2):527-31. (Level IV evidence). View the reference
- Kempers MJ, Lenders JW, van Outheusden L, van der Wilt GJ, Schultze Kool LJ, Hermus AR, et al. Systematic review: diagnostic procedures to differentiate unilateral from bilateral adrenal abnormality in primary aldosteronism. Ann Intern Med. 2009;151(5):329-37. (Review article). View the reference
- Magill SB, Raff H, Shaker JL, Brickner RC, Knechtges TE, Kehoe ME, et al Comparison of adrenal vein sampling and computed tomography in the differentiation of primary aldosteronism. J Clin Endocrinol Metab. 2001;86(3):1066-71. (Level III evidence). View the reference
- Mayo-Smith WW, Boland GW, Noto RB, Lee MJ. State-of-the-art adrenal imaging. Radiographics. 2001;21(4):995-1012. (Review article). View the reference
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