Primary hyperaldosteronism overview
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Differentiating Primary Hyperaldosteronism from other Diseases |
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Diagnosis |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Syed Hassan A. Kazmi BSc, MD [2]
Overview
Historical Perspective
Primary hyperaldosteronism (Conn's syndrome) was described for the first time by the Polish internist Michał Lityński.[1] In 1955, Dr Jerome W. Conn the American endocrinologist first described the condition and named it Conn's syndrome. [2][3] Over the last few decades other more rare type of primary hyperaldsoteronism have also been described.[4][5] From 1960s to early 1970s, its techniques of diagnosis and treatment were greatly improved by the availability of spironolactone, realization of the renin-angiotensin-aldosterone system, and progress in laboratory tests and adrenal venous sampling.
Pathophysiology
Conn's syndrome (primary hyperaldoseronism-PH) features overproduction of aldosterone despite suppressed plasma renin activity (PRA). The resulting Na+ retention produces hypertension, and elevated K+ excretion may cause hypokalemia. Patients with Conn's syndrome due to primary hyperaldosertonism may have an aldosterone producing adrenocortical adenoma (APA)- Classically referred to as Conn's syndrome, [2], a unilateral hyperplasia, idiopathic hyperaldosteronism (IHA, also known as bilateral adrenal hyperplasia).[3],, familial forms (familial hyperaldosteronism types I, II, and III) have also been described, ectopic secretion of aldosterone (The ovaries and kidneys are the 2 organs described in the literature that, in the setting of neoplastic disease, can be ectopic sources of aldosterone, but this is a rare occurrence)
Causes
Common causes of primary hyperaldosteronism include aldosterone-secreting adenoma, bilateral hyperplasia of the adrenal glands and ectopic secretion of aldosterone from ovaries and kidneys. Less common causes of primary hyperaldosteronism include familial hyperaldosteronism types I-III, pure aldosterone-producing adrenocortical carcinomas and unilateral hyperplasia of the adrenal gland.
Differentiating Primary Hyperaldosteronism from other diseases
Primary hyperaldosteronism must be differentiated from other diseases that cause hypertension and hypokalemia such as renal artery stenosis, cushing's syndrome, congenital adrenal hyperplasia, Liddle's syndrome, diuretic use, licorice ingestion and renin-secreting tumors.
Epidemiology and Demographics
Worldwide, the prevalence of primary hyperaldosteronism (PA) ranges from a low of 10,000 per 100,000 persons with hypertension to a high of 35,000 per 100,000 persons with hypertenion when aldosterone/renin ratio is used as a screening tool.[1] There is no racial predilection for primary hyperaldosteronism.
Screening
According to the Endocrine Society Clinical Practice Guideline, screening for hyperaldosteronism is performed by checking the plasma aldosterone to renin ratio (PAC/PRA).[1]
Natural History, Complications and Prognosis
If left untreated, patients with primary hyperaldosteronism may progress to develop stroke, coronary artery disease, and renal insufficiency with associated proteinuria. APAs continue to grow slowly over time. The aldosterone production likely correlates with the size of the adenoma. Primary hyperladosteronism can be progressive leading to increased severity of disease. Common complications of primary hyperaldosteronism include left ventricular hypertrophy due to chronic hypertension, atrial fibrillation, myocardial infarction, stroke, proteinuria and metabolic syndrome. The prognosis of primary hyperaldosteronism is good with treatment. Without treatment, primary hyperaldosteronism will result in hypertension with resultant hypertension-related complications, which may be a major cause of morbidity and mortality among patients.
Diagnosis
History and Symptoms
The hallmark of primary hyperaldosteronism is resistant hypertension. A positive history of sponatneous or unprovoked hypokalemia and treatment-resitant/refractory hypertension are suggestive of primary hyperaldosteronism. The most common symptoms of primary hyperaldosteronism include headaches, facial flushing, vision changes and weakness.
Physical Examination
Patients with primary hyperaldosteronism usually appear well. Physical examination of patients with primary hyperaldosteronism is usually remarkable for high blood pressure, tachycardia, and an S4 maybe heard on auscultation of the precordium suggesting left ventricular hypertrophy secondary to increased afterload due to hypertension.
Laboratory Findings
Laboratory findings consistent with the diagnosis of primary hyperaldosteronism include plasma aldosterone to renin activity ratio (PAC/PRA) of >30[1], serum aldosterone value of > 6 ng / dl and simultaneous PRA levels < than 1.0 ng / ml / hour after fludrocortisone supression test, or a plasma aldosterone more than 10 ng / dl on saline infusion test or on oral sodium loading test, the post-test 24-hour urinary aldosterone excretion less than 12 μg / day and a urinary sodium excretion of more than 200 mmol / day. The adrenal venous sampling test is gold standard for subtype classification of primary hyperaldosteronism.
CT scan
CT scan may aid in visualizing adrenal adenomas for lesions that are amenable to surgery.[1][2]
MRI
MRI may be used for diagnosing adrenal adenomas when the attenuation on CT is <30 HU.
Other Imaging Findings
There are no other imaging findings associated with primary hyperaldosteronism.
Other Diagnostic Studies
There are no other diagnostic studies associated with primary hyperaldosteronism.
Treatment
=Medical Therapy
The optimal therapy for primary hyperladosteronism depends on the etiology of hyperaldosteronism. Medical therapy is indicated for bilateral adrenal hyperplasia, and all ambiguous causes of primary hyperaldosteronism.
Surgery
Surgery is the mainstay of treatment for unilateral adrenal hyperplasia, aldosterone producing adenomas (APAs), adrenal carcinoma, ectopic ACTH, renin, and deoxycorticosterone secreting tumors.
Primary Prevention
There is no primary prevention for primary hyperaldosteronism.
=Secondary Prevention
There is no secondary prevention for primary hyperaldosteronism.