Conn’s syndrome:

Excessive production of mineralocorticoids most commonly from an adenoma.
Clinical features
Hypertension is the main and often the only symptom. 
There is severe muscle weakness in some patients due to hypokalemia. Because of high aldosterone levels in the blood act on the kidney to increase the loss of mineral potassium in the urine. This in turn may lead to a fall in blood potassium, resulting in tiredness, muscle weakness, passing large volumes of urine (polyuria), especially at night (nocturia).
Diagnosis and Tests
A 24 hour urine collection for potassium is the best screening test.
Saline Infusion test is confirmatory. 
Aldosterone levels and renin levels- aldosterone level is elevated and renin level is low or undetectable.
Mild hypernatremia, metabolic alkalosis.