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Medical Why do doctors assume pneumonia is bacterial?

  1. Jul 13, 2018 #1
    I had pneumonia once, it was mild enough(just felt like I had the flu for a month) that I did not go to the doctor because I figured it was viral. I didn't have a stethoscope but just having the flu for a month made me think that it was probably viral pneumonia(unlikely that I would get 1 virus right after another with the same symptoms, especially since I stayed indoors that entire month). I have had crackling lungs other times but no fever.

    My dad, he was ill last year and it was getting worse and he had these coughing fits. My Momma asked me about what would be causing the coughing fits and I said "It could be pneumonia so they would do a culture, if the culture comes back positive, it is bacterial and he would be put on antibiotics, if the culture comes back negative, it is viral and you just treat the symptoms.

    Well, it turned out that my dad did not have a culture done(which I was kind of annoyed about) and the doctor just put him on antibiotics after he got diagnosed with pneumonia and bronchitis. This I view as bad practice. The doctor just assumed it was bacterial when it easily could have been viral. Putting someone on antibiotics without doing a culture first increases antibiotic resistance(which is a major problem, especially with bacteria that cause pneumonia) and destroys the microbiome(which can be a major problem).

    So why do doctors just assume that if someone comes in with pneumonia, it is bacterial? If I was diagnosing pneumonia, I would go through the effort of doing a culture that way I know what is causing it and only give antibiotics if the culture comes back positive, not just give antibiotics after I found out that the person has pneumonia.
     
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  3. Jul 13, 2018 #2

    fresh_42

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    That should be the official way. Unfortunately many doctors find it easier to prescribe antibiotics and hope for the best. The correct way, even if it was a bacterial infection would require to determine which antibiotic would work best. But broadband is easier.

    The reason presumably is the following: If it's viral, we can't do a lot anyway, and if it's bacterial, then save lab costs and prescribe a tricycline.

    This habit is unfortunately wide spread, and we start to pay the costs in terms of resistant germs.
     
    Last edited: Jul 13, 2018
  4. Jul 13, 2018 #3

    Ryan_m_b

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    Whilt antibiotic resistance is a consideration it has to be balanced against the risk of harming a patient by not prescribing them. If the doctor waits for confirmation by culture it would likely be a few days before the results came back, during this time the patient could have worsened and pneumonia can be fatal. By prescribing antibiotics if the condition is bacterial the patient receives treatment immediately. If it is viral then the worsening of the condition will be diagnostically informative, allowing the doctor to make a decision about the next option.
     
  5. Jul 13, 2018 #4

    Bystander

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    Up to a week, as of this past spring, plus pulmonary "edema," shortness of breath, painful breathing, pleurisy, and the fact that the culture sample is drawn in an outpatient surgical procedure, draining the lung(s), which is not free.
     
  6. Jul 13, 2018 #5

    CWatters

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    According to the UK NHS it's "usually caused by a bacterial infection"...

    https://www.nhs.uk/conditions/pneumonia/

    Elsewhere it said viral pneumonia can also trigger bacterial pneumonia.
     
  7. Jul 13, 2018 #6

    TeethWhitener

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    There are a lot of problems with OP’s post.
    If you didn’t see a doctor, who made this diagnosis? Are you a doctor? Did you self-diagnose?
    Why are you asking quasi anonymous strangers on an internet physics forum rather than the doctor that made the diagnosis? Wouldn’t they be in a better position to answer your question?
    Well, if you diagnosed yourself with pneumonia above, did you do a culture on yourself? Did you demand a doctor do one?

    If you get bitten by a bat, the doctor is likely to immediately vaccinate you against rabies, even without running any tests. Why? Because rabies untreated is fatal, and the risk of an adverse vaccine reaction is far outweighed by the risk of death without a vaccine. As for pneumonia, lower respiratory infections are the #8 top cause of death in the US.

    Are antibiotics overprescribed? Sure, but it’s a known problem that many doctors fight against. I had pneumonia last year and the doctor prescribed a fluoroquinolone antibiotic without doing a culture. Why? Because while penicillin-resistant pneumococcal pneumonia shows a significant prevalence, fluoroquinolone-resistant pneumococcal pneumonia is far rarer. To essentially accuse your doctor of malpractice without having clarified your concerns with them seems grossly irresponsible.
     
  8. Jul 14, 2018 #7
    When I was a kid ('60s), the ear doc did his own petri dish culture and checked it with a microscope. The whole procedure took no more than 10 minutes, including a few minutes of incubation time. He had the right gear and didn't need to send out to a lab somewhere else. He said he already knew it was bacterial, but he needed to make sure it wasn't a resistant strain, so he'd done a qualitative test; if it had been resistant, he'd have done more tests.
     
  9. Jul 14, 2018 #8

    256bits

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  10. Jul 14, 2018 #9
    To be on the safe side if its viral antibiotics wont do anything but if you wait and its bacterial you can die (my uni pals brother presented with flu symptoms and was dead within a week)

    I must have had so much penicillin as a kid (60s 70s) Drs just gave it out to get rid of you worried mothers.
     
  11. Jul 14, 2018 #10

    jim mcnamara

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    As stated, this is impossible. The generation time for the majority of human bacterial pathogens is on the order of 20 minutes or more. So, for the record, I would guess we should rule out culturing bacteria. It would take a lot longer than 10 minutes to get a negative/positive result. We have no way to know what the physician actually accomplished.
    Example pathogen: http://textbookofbacteriology.net/S.pneumoniae.html shows ~20 minutes at 37°C.
     
  12. Jul 14, 2018 #11
    Sorry rid of you/your worried mothers!

    not you worried mothers! got in enough trouble with stuff like that already!!!
     
  13. Jul 14, 2018 #12

    jim mcnamara

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    The best answers have already been given. Physcians are the ultimate pragmatists. The question the doc has to deal with: what is the probability that this patient will get worse or die if I fail to use treatment X? If the doc has experience with an ailment like this then they know ahead of time what is the best choice for you.
    (they all do, BTW) It is part and parcel of their job. It is why they are interns after med school.

    The question is not: will this one treatment alter the extant bacterial population?

    @caters - your question has a lot of assumptions that would benefit from a tune up.

    Also, completely deregulated access to what should be a regulated prescription drug, coupled with completely improper monitored patient compliance and prescription practices by poorly trained personnel is common in some countries. It is no accident that some of the more recent TB variants first arose in India.
    Discussion: https://www.tbfacts.org/drug-resistant-tb-india/ -- see the section 'Treatment of multiple drug resistant TB in India'

    Less technical example:
    Before Juarez Mexico became a war zone, I purchased drugs there, like Humulin (insulin) for my kids at ~20% of the US cost, in a pharmacy that was a short walk over the border into Juarez. No prescription required. I got a big list of drugs the pharmacist said she had on hand. Any others she had to order would have been awkward for us living 205 miles North of the border.
     
  14. Jul 14, 2018 #13

    TeethWhitener

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    There are, for example, rapid strep tests, but these are antigen-antibody assays, not cultures. Cultures generally take a few days at least.
     
  15. Jul 14, 2018 #14

    jim mcnamara

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    @TeethWhitener - I think sysprog was referring to the 1960's. I do not know if those physician-office-ready antigenic tests were available back then.
     
  16. Jul 14, 2018 #15
    I questioned the doc about that at the time. He explained that it wasn't necessary to wait for a full-duration incubation, because he was testing only for resistance to penicillin. He had prepared the petri dish with 2 areas: one pre-treated with penicillin; the other not. All he had to do then was scratch the sample across the plate, untreated side first, and incubate only long enough to enable him to determine microscopically whether the treated side exhibited strong inhibition of growth compared to the untreated side. If it did, he could infer that no especially resistant bacterium was present, and that the tentatively contemplated prescription would probably be appropriately effective.
     
  17. Jul 16, 2018 #16
    On re-reading this: "... If it did, he could infer that no especially resistant bacterium was present, ...", I think that would be better stated as: "... If it did, he could infer that a not especially resistant bacterium was present, ..." -- it's possible that some less rapidly growing and/or less populous resistant bacteria could have been present. I vaguely recall that the doc told me that, just in case, he always put the test dishes back into the incubator until the next day, before he ran them through the autoclave. Presumably, some of any bacteria present in the sample would be partway through their generative cycle, which would allow earlier detection of growth, but earlier for some than for others.
     
  18. Jul 16, 2018 #17

    Ryan_m_b

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    Either we're missing something to this story (a possibility given that this was nearly 60 years ago) or what your doctor did was nonsense. Bacterial cultures take hours to grow before you can start seeing inhibition of the CFUs and are usually best left for longer (i.e. overnight). I'm also skeptical that using a light microscope on a bronchoalveolar lavage sample (required for pneumonia testing) one would be able to identify infectious bacteria as opposed to random populations of harmless lung flora.
     
  19. Jul 16, 2018 #18
    I understand that the thread topic specifies pneumonia, but nothing I said in my posts indicated that the sample in my case was from "bronchoalveolar lavage" or that the testing was for pneumonia. I did say that it was an "ear doc". The sample was a nasal maxillary sinus smear. He had a probe device with a maybe 5" platinum wire with a hook at the end that he spun a swab onto from a cotton dispenser. He inserted it via my nostril.

    Among the things the ear doc said, when I asked about the rapidity of the result, were that the test was qualitative, and that he was using it to confirm what he already thought was the case. I mentioned in my second post in this thread that I vaguely recalled that he would leave the dish incubating until the next day just in case. Apparently he didn't need to wait very long in order to find what he was looking for. My impression was that he had found the first signs of a growth pattern to be similar to those of others he had recently encountered.
     
  20. Jul 17, 2018 #19
    Having gone through a good part of December in the hospital with pneumonia, I am aware that there is something missing from what has been said. I had viral pneumonia and was treated for bacterial pneumonia and released. I was back three days later for another week and they sorted out that it was viral. The treatment was steroids to control the inflammation so my body could recover. It is correct that the body must defeat the virus but the inflammation can be controlled so the body can do it's job. Just for info, I was dealing with the effects of immunotherapy that had taken out my adrenal system so I was particularly vulnerable. It took over two months for the problem was totally understood.
     
  21. Jul 17, 2018 #20
    A good clinical exam with the history will often provide clues to the nature of the infection, bacterial infections are often associated with greater fluid buildup in the lungs and more localized changes in lobar pneumonia. In the UK Drs also have access to a continuously updated database of what infections are doing the rounds and their sensitivity patterns. I noticed the word bronchitis, I don't know the age of the person but in the elderly this is associated with re-occuring bacterial infections. Pneumonia is a common cause of death even now and delaying treatment is risky.
     
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