Milk duct infection?

I am 56 and was diagnosed with Mastitis in right breast. What causes that at my age? After a round of antibiotics, the redness was gone but the pain and swelling was still there. I was finally sent for a mammogram (the pain was so bad I was screaming and crying), diagnostic mammogram, and ultrasound. The mammogram came out ok, but the ultrasound show a build-up of fluid in a duct. When the needle aspiration was done 4 days ago, the doctor could not completely get all the fluid out as it was very thick and wouldn't go up the needle. The fluid was yellow and bloody. Is that significant? Also, how long does it take for the fluid to be analyzed. The doctor said that it may not be enough and if that is the case, then I would have to come back in for another procedure.
Is there a reason to worry about the appearance of the fluid and what would the next step be?

[japdip]

When Mastitis occurs in post menopausal women it is because the ducts become clogged with dead skin cells or other debris causing the infection. This can be a chronic condition. If all the fluid / pus wasn't removed I would think possibly a ductal lavage might be done ... a catheter inserted in the duct and the blockage "washed" out so to speak. The length of time for the fluid to be analyzed would depend on the institution; just looking at the cells under the microscope should only take 3-5 days for the report to reach your Dr. but if a culture is done it would be longer.  Regards ....

[momelke]

Thanks for answering and the great info. The doctor said they would be doing a check under the microscope and doing a culture. My next appointment is Jan. 15th. I'm supposed to get the results then. I guess I'm still in pain because all of it was not removed. I'm also having radiating pain to the top of the breast. I'm guessing it is from the aspiration which was done at the 8 o'clock position. I suppose that's not too bad considering they had to keep putting in an anesthetic (5x) and use 2-3 different size needles to even penetrate it.