Excel and DAX formulas for counting distict patient vists with variables

I need an excel formula and a separate DAX formula to count a large dataset of patient visits among many other data points. The count needs to be able to count only the patient account numbers that have charged dollar amounts against the account number by service date month of visit . Distinct count will not work. The account number is shown many times in one month's period since the patient will have many records in the charge month for multiple procedure codes, payment and adjustment activity. Distinct count would work if the patient was only seen once that month, but in the case the patient is seen a few times in a month. I need to be able to see the total visits by month and year and also be able to slice the data.