Primary hyperaldosteronism Patient Information
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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
What are the symptoms of Primary hyperaldosteronism
Common Symptoms
Common symptoms of primary hyperaldosteronism (PA) include:
- Headaches
- Facial flushing
- Weakness
- Visual impairment
- Impaired consciousness
- Seizures (hypertensive encephalopathy)
- Constipation
- Increased urinary frequency and thirst (Polyuria and polydipsia)
- Weakness
Less Common Symptoms
Less common symptoms of Conn's syndrome (primary hyperaldosteronism) include:
- Paralysis
- Racing of the heart(Palpitations)
- Abdominal fullness/constipation(Ileus)
What causes Primary hyperaldosteronism
Common Causes
Common causes of primary hyperaldosteronism (PA) may be divided into:
- Adrenal causes:
- Aldosterone-secreting adrenal adenoma (APA-benign tumor, 50-60%)
- Idiopathic hyperaldosteronism (IHA-Bilateral hyperplasia of the adrenal gland, 40-50%)
- Extra-adrenal causes
- Ectopic secretion of aldosterone (ovaries and kidneys)
Less Common Causes
Less common causes of primary hyperladosteronism include:
- Familial hyperaldosteronism type I (glucocorticoid-remediable aldosteronism [GRA])
- Familial hyperaldosteronism II (the familial occurrence of APA or bilateral idiopathic hyperplasia or both)
- Familial hyperaldosteronism type III (associated with the germline mutation in the KCNJ5 potassium channel)
- Pure aldosterone-producing adrenocortical carcinomas
- Unilateral adrenal hyperplasia
When to seek urgent medical care?
Call for an appointment with your health care provider if you develop symptoms of hyperaldosteronism. Elevated blood pressure may increase the risk of strokes and may cause problems with normal functioning of the heart.
Diagnosis
Laboratory findings consistent with the diagnosis of primary hyperaldosteronism include plasma aldosterone to renin activity ratio (PAC/PRA) of >30, 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.
Plasma Aldosterone to Renin Ratio (PAC/PRA)
Protocol
- Drugs that affect the renin–angiotensin-aldosterone axis should be stopped before testing, such as: beta-blockers, ACE inhibitors, ARBs (angiotensin receptor blockers), renin inhibitors, dihydropyridine calcium channel blockers, and central alpha2-agonists, for about fourteen days, and spironolactone, eplerenone, amiloride, and triamterene, and loop diuretics for about twenty eight days.
- The test should be conducted between 8 a.m. and 10 a. m. The patient is advised to stay upright for 2 hours prior to testing, and then sit for about 10 minutes before testing.
Interpretation
- Primary hyperaldosteronism (Conn's syndrome) is associated with an increased aldosterone levels (PAC) in plasma along with suppressed renin concentration (PRA) due to feedback inhibition of aldosterone on renin levels in the plasma.
- A PAC/PRA ratio of >30 is a strong evidence of primary hyperladosteronism and value >50 is considered diagnostic in the presence of resistant hypertension, hypokalemia and metabolic alkalosis.
Confirmatory Tests
After preliminary testing for primary hyperaldosteronism via PAC/PRA ratio, any one of the following tests may be performed in order to confirm the diagnosis:
1. Fludrocortisone suppression test (FST)
- This is the gold standard test for confirmation of primary hyperaldosteronism.
- Patient is given a synthetic mineralocorticoid (9-[alpha]-fludrocortisone acetate 0.1 mg every six hours) and sodium chloride [slow-release sodium 30 mmol (1.75 g) three times daily].
- Plasma aldosterone level is measured in the a.m. after four days of administration.
- A value of > 6 ng / dl and simultaneous PRA levels < than 1.0 ng / ml / hour, confirm primary hyperaldosteronism.
2. Intravenous saline load test (SLT)
- Patient is infused with two liters of NaCl 0.9% for fours hours.
- Plasma aldosterone more than 10 ng / dl is confirmatory, normally aldosterone would be suppressed to below 5 ng / dl.
3. Oral sodium loading test
- This test has a sensitivity and specificity of >90%
- Patient is fed a high sodium diet, of approximately 218 mmol / day, for three days.
- On the third day, a 24-hour urine sample is collected.
- Normal suppression is defined as post-test 24-hour urinary aldosterone excretion less than 12 μg / day and a urinary sodium excretion of more than 200 mmol / day.
4. Captopril challenge test
- Positive test for primary hyperaldosteronism is defined as a PAC / PRA > 30, measured two hours after the administration of 25 mg or 50 mg of captopril with patients in the sitting position.
- Reserved for patients with reduced cardiac or renal function.
Less Common Tests
- Frusemide upright posture test
- 24-hour urinary aldosterone
- Losartan test
Subtype Classification
Once the diagnosis of primary hyperaldosteronism is confirmed, a subtype classification is required as the management may vary based on the etiology.
Tests useful in assessing subtypes are:
1. Computed Tomography (CT)
- A high-resolution CT (HRCT) scan with contrast, has a high sensitivity (78%) and specificity (75%) for detection of adrenal masses (inluding aldosterone producing adenomas-APAs)
- CT scan is best when used for adrenal adenomas > 2cm but accuracy decreases if the mass is < 1cm.
- A unilateral lesion exceeding 4 cm suggests possible carcinoma
- Moreover, it cannot distinguish between a functional APA and a non-secreting adrenal adenoma (incidentaloma).
2. Magnetic Resonance Imaging (MRI)
- Sensitivity of 70 to 100% in detecting APA, depending on the size of the lesion, being greatest for lesions > 2 cm.
- Limitations are similar to that of CT scan.
3. Adrenal venous sampling (AVS)
- Gold standard test for subtype classification.
- It has a high sensitivity (95%) and specificity (100%) for the detection of unilateral aldosterone excess but is highly expertise dependent.
- AVS can be performed using any of the three protocols:
- (a) Unstimulated sequential or simultaneous bilateral AVS
- (b) Unstimulated sequential or simultaneous bilateral AVS followed by bolus cosyntropin-stimulated sequential or simultaneous bilateral AVS
- (c) Continuous cosyntropin infusion with sequential bilateral AVS.
- Plasma aldosterone collected from the adrenal veins is corrected to its respective plasma cortisol, measured as a ratio (PAC / cortisol ratio)
- A gradient of > 4:1, points towards unilateral aldosterone secreting adenoma and < 3 : 1 suggests bilateral adrenal hyperplasia.
4. Posture stimulation test
- May be used when AVS is equivocal.
- It is based on the principal that PAC in patients with aldosterone producing adenoma (APA) there is a diurnal variation and is relatively unchanged by changes in the angiotensin II levels being under ACTH control, whereas, bilateral adrenal hyperplasia (IHA) is affected heavily by a small change in the angiotensin II, due to standing.
5. Iodocholesterol scintigraphy (NP-59 scan)
- 6 beta- 131I iodomethyl-19-norcholesterol (NP-59), was introduced in 1977 for the diagnosis for primary aldosteronism.
- The NP-59 scan is performed with dexamethasone suppression.
- It is not very useful in identifying micro adenomas of the adrenals (<1.5cm).
6. 18-Hydroxycorticosterone levels
- Less accurate than other tests.
- Hydroxylation of corticosterone leads to the formation of 18-hydroxycorticosterone.
- Historically, it was used to differentiate APA from bilateral adrenal hyperplasia.
- Supine plasma 18-hydroxycorticosterone levels > 100 ng/dl at 8 a.m., suggest aldosterone producing adenoma (APA).
Treatment options
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. The following medications may be used depending on the situation:
- Mineralocorticoid receptor antagonists (Spironolactone, Potassium Canrenoate, Eplerenone)
- Potassium sparing diuretics (Amiloride, Triamterene)
- Calium channel blockers (Amlodipine, Nifedipine)
- ACE inhibitors (Lisinopril, Captopril)
- Angiotensin receptor blockers (Valsartan, Candesartan, Losartan)
- Dexamethaspne therapy (For familial hyperaldosteronism type I)
Surgery
Surgery is the mainstay of treatment for unilateral adrenal hyperplasia, aldosterone producing adenomas (APAs), adrenal carcinoma, ectopic ACTH, renin, and deoxycorticosterone secreting tumors. Laproscopic adrenalectomy may cure the disease.
Post Surgical Prognosis
Good prognosis after adrenalectomy depends on:
- Good response to medical therapy with spironolactone
- Young age
- Decreased duration of hypertension
- Preoperative use of two or fewer antihypertensive agents
Diseases with similar symptoms
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
- Renin-secreting tumors
Where to find medical care for primary hyperaldosteronism
What to expect?(Outlook/Prognosis)
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.
- Adrenalectomy lowers long-term all-cause mortality from primary hyperaldosteronism.
Patients undergoing unilateral adrenalectomy for unilateral adenoma
- Adrenalectomy leads to cure of hypertension in 50% to 60% of patients.
- Blood pressure typically becomes normal after 1 to 6 months of the procedure.
- Treatment leads to a significant increase in quality of life and improved cardiovascular outcomes.
Patients receiving aldosterone antagonist medications
- Hypertension is controlled in majority of the patients.
- Improvements are not as significant as after unilateral adrenalectomy for lateralizing lesions.
Patients with FH-I undergoing treatment with glucocorticoid medications
- Hypertension in familial hyperaldosteronism type I (FH-I) is usually of early onset and may be severe enough to cause early death, usually from hemorrhagic stroke, unless specifically treated.[20]
- Treatment with glucocorticoids, given in low doses is usually effective in controlling hypertension and consequently preventing stroke.