question concerning COPD

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Does anyone know the pathophys behind the reason COPD pt's are at an increased risk for respiratory infections? Does it have to do with a lesser ability to mobilize and cough up secretions? or because of areas of collapsed alveoli? or does it have to do with less macrophages in the lungs? can't find the reason anywhere. I would appreciate an answer if you know it.

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Specializes in med/surg, telemetry, IV therapy, mgmt.

does anyone know the pathophys behind the reason copd pt's are at an increased risk for respiratory infections? weakened defense system does it have to do with a lesser ability to mobilize and cough up secretions? not really. the built up mucus and debris in the alveoli and bronchioles provide a medium for an invading microbe to flourish. or because of areas of collapsed alveoli? i would say no; exposure to dusts upon which microbes could hitch a ride into the alveoli and get trapped is a portal of entry, but that could happen to a normal person as well. or does it have to do with less macrophages in the lungs? yes, they are the first to arrive on the scene of the microbe's portal of entry as part of the inflammatory response. the fighting of infection always begins with the onset of the inflammatory response. but, since the inflammatory response is already chronic and ongoing in copd, the number of white cells in the local area of the lungs is going to be compromised. if an invading microbe makes its way into the internal lung tissues, the lung needs to call up for reinforcements as its own supply of macrophages gets used up. depending on how depleted the body's store of wbcs are (the copd may have put a great strain on the supply) and how good the person's nutrition and circulation is will determine the response. if the patient has been on corticosteroids or other drugs that effect any part of the immune system's integrity to maintain and replenish itself, the inflammatory response is going to be impaired. can't find the reason anywhere. i would appreciate an answer if you know it.

i think that what you need to do is look first at the pathophysiology of infection itself. specific elements must be present for an infection to exist:

  • a causative agent (a microbe which can be bacteria, fungi, virus, or protozoa)
  • weakened defense mechanisms that impairs the body's ability to recognize and/or fight the pathogen(s)
    • weak immune system (immunodeficiency or immunocompromise) that is due to genetic defect, aging, previous infection, malnutrition, chronic stress, diabetes, renal failure, cirrhosis, and the effects of drugs like corticosteroids and chemotherapy.
      • impaired function of the wbcs
      • low levels of t and b cells
        • presence of certain environmental factors
          • poor hygiene - dirty skin surfaces and crevices are a harbor for microbes
          • malnutrition - the body needs nutrients, vitamins and minerals to synthesize proteins; protein malnutrition interferes with the synthesis of antibodies needed to attack microbe invasion.
          • inadequate physical barriers - breaks in the skin
          • emotional and physical stressors - accidents
          • chronic diseases - cause impaired or altered anatomy and physiology that interrupt natural barriers allowing microbes entry into the body
          • medical and surgical treatments - interrupt natural barriers allowing microbes entry into the body
          • inadequate immunization

with copd you have a susceptible host, one who has weakened defense mechanisms. as above, in chronic diseases (copd is among the chronic diseases) you have immunodeficiency (low levels of t cells) because of the chronic inflammation present in the respiratory track. additionally, the patient may be on long-term corticosteroid therapy for the chronic inflammation. corticosteroids alter the body's response to infection and cause masking of the signs and symptoms of each specific infection. here are links to two previous threads with the pathology you need:

there is a collection of the various disease pathophysiologies that have been posted on the student forums on this post:

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