If you're still coughing with thick green phlegm even after a course of antibiotics, then you definitely should get your nose and sinuses carefully examined by your friendly ENT specialist who can insert a flexible tiny endoscope/camera into your nose to take a look. I would say that this is one of the more common problems that patients come to see me for, with many patients already having been seen by their Respiratory/Chest specialist.
Bronchitis is a chest infection which may be due to a constant drip of infected mucus flowing down from the back of your nose onto your airway and into your lungs. So it is important to find out where the original true source of your infection is arising from, so that we can treat it effectively. Although it may occasionally be helpful to take a culture swab from your nose, we don't often find that it will change the treatment course because the "bugs" grown are those which we know to commonly cause nose and sinus infections. The antibiotics we usually prescribe already cover these "bugs". In addition, as you have already had a course of antibiotics, the culture swab may often not grow any "bug" at all and come back as "negative".
We may have to arrange a CT scan of your sinuses to see if they are hiding a pool of stagnant trapped infected mucus. We may then prescribe a longer course of antibiotics like Augmentin or Klacid which is best used to treat sinus infections. Sea salt alkaline nasal douches and nasal steroid sprays (Nasonex or Avamys) with antihistamine medications (Aerius or Xyzal) will also be prescribed for you to help clear the trapped nasal secretions.
If things still don't improve with your nose and sinuses, then you may need to undergo minimally invasive surgery to unblock the drainage pathways of your sinuses to wash them out thoroughly. This is called Functional Endoscopic Sinus Surgery (FESS) where the surgery is done through the nasal passages under guidance of a special endoscope/camera. This procedure is quite safe and may done as a daycase.
Hope you feel better soon with the right combination of meds, Cherie!
