The doctor may have done so either a) because there’s an expectation to Do Something, or b) because of a combination of factors to do with that patient’s history.
Bronchitis CAN lead to a secondary infection. If it’s been going on for a while without getting better, that might be a clue that this has, in fact, happened. Some patients are more susceptible to this happening - e.g. I have asthma, and a respiratory virus can either cause a flare (in which case, a burst of steroids can make a huge difference), or settle in the lungs and allow nasty stuff to start brewing - in which case, steroids won’t help me much, while antibiotics do.
I have actually NEVER had a doctor attempt to do any kind of culture or test to determine whether I had a bacterial infection. I wish they would, actually - I’m not big on unnecessary antibiotics.
it’s been somewhat interesting to see different doctors’ biases toward one approach or the other. Once, 12 or 13 years back, I started going downhill over a weekend. I called my doctor’s on-call service, got a colleague who was covering for her, described the asthma symptoms flaring, and his reaction to the suggestion of prednisone was “Oh NOOOOOES!!! I’ve seen patients break hips after doing this too often!”. He prescribed an antibiotic, which I picked up and started; it maybe helped a little but 3 days later I was getting worse again. I called MY doctor, who sent a prescription for steroids, and also a different antibiotic. Oh, and yeah, too-frequent use of steroids is a risk factor for osteoporosis, but every 2-3 years for an asthma flare, not so likely. I honestly don’t know of the antibiotics were appropriate, in this scenario, I think the steroids definitely were. This is the closest I’ve come to the scenario described by the OP.
Another time, I had some kind of cold that had caused coughing - but I wasn’t really in any kind of respiratory distress… however, my voice completely left the premises and it felt like someone was jabbing daggers into my eardrums. The doc at urgent care said antibiotics were almost certainly not appropriate (and I agreed with her 100%) but did give me a short course of steroids. Spot-on - it just felt like there was pure inflammation going on from the virus.
But about 5 years back, I had a cold that turned into bronchitis, and after 2 weeks I was not improving - in fact I was getting worse. I went to urgent care (next door to my primary care’s office) and was given oral steroids. For a regular asthma flare, that would have made a significant difference within 24 hours - but 2 days later, I was WORSE. I went back - and they gave me MORE steroids (injection, this time). And, very reluctantly, a scrip for some kind of antibiotic “don’t fill it until tomorrow”.
Well, when I started the antibiotics, I started feeling better 24 hours later. I think I mentioned that on the boards once before, and the response was “it takes several days for xx to have any effect, it was probably just the steroids finally kicking in”… but knowing my own pattern and response to such in the past, I’m leaning toward the antibiotics being the winner (though I think the 'roids were appropriate also). I really think that the doctors (it was a different person, the 2 visits) were following the guidelines of assuming it’s viral, but not using their judgment in my specific situation.
Re purulent sputum (yellow or green): I thought that had largely been discounted as a signal that things had gone bacterial?
It’s a pity there aren’t more ways to at least mitigate the misery-making symptoms of a respiratory infection. OTC cough suppressants don’t do a hell of a lot; prescription ones do seem to help (me, at least) a bit, but with a productive cough, you don’t WANT to suppress it that much. Sneezing and sniffling isn’t much fun, but is not nearly as soul-destroying as the kind of cough that keeps you from sleeping for 2 days straight. If there was some better way of handling that sort of thing, I’d bet there would be less demand for unnecessary antibiotics.