How much time does dr. spend on hyperaldosteronism in medical school?

Very variable: The amount of time a student spends on one of the thousands of diseases is quite variable: maybe one hour if he never sees a patient with that disease; maybe 1 month if he takes an elective in which there are many patients with that disease.

Not much: The training to manage hyperaldosteronism takes place more through sub specialties, nephrology and endocrinology, post internal medicine residency training.

a few minutes: Common endocrine diseases, such as hypothyroidism and diabetes, get good coverage in medical school. Keep in mind that medical school gives students a general overview of common diseases. The less common endocrine diseases are generally not given much time in school, but much more in internal medicine residencies, and again much more in endocrine fellowships. You need to see an endocrinologist.