Flashcards in Pulmonary Host Defense Deck (23):
4 ways that the mechanical protection of the upper airway can be impaired?
Altered consciousness. (esp. aspiration)
Intubation / tracheostomy. (allows microbes deep into lungs)
Altered adhesive properties of resp. mucosa.
3 aspects of mechanical protection in the lower conducting airways?
Bronchial branching -> turbulent flow -> better particle trapping.
What can happen if you chronically suppress coughing?
Recurrent right middle lobe infections..
Things that impair the bronchial branching mechanical protection of the lower airways?
CF -> diffuse bronchiectasis (dilation)
Post-pneumonia, TB, pertussis -> focal bronchiectasis
Typical cause defects in mucous protection?
Common causes of airway clearance defects?
Tumors, foreign bodies blocking airway.
Voluntary cough suppression.
What fails to happen in CF, leading to defective lower airway defenses?
Impaired Cl- secretion -> impaired water secretion -> ciliary defect.
Also, defensins aren't secreted due to osmotic defects.
How does cavitary TB, even if treated, predispose to future infections?
Old cavities don't get drained well, so can be invaded by things like aspergillus.
Epithelial cells in the airway have TLRs and secrete innate defense moecules.
What does neutropenia particularly predispose to?
Gram negative pneumonia and invasive aspergillosis.
2 causes of desquamated / injured respiratory epithelium?
What does this predispose to particularly?
Airway burns / smoke inhalation, post-influenza.
Causes susceptibility to bacterial pneumonia, esp. Strep pneumo and Staph.
Collectins, complement, and things like transferrin are important.
If you're complement deficient, one has recurrent pyogenic infections with encapsulated organisms.
What organisms are Abs / B cells most important for controlling?
Which organ is very important for clearing these opsonized organisms?
Encapsulated bacteria (S. pneumo, H. flu, meningococcus).
The spleen is particularly important - sickle cells pts with functional asplenia are predisposed to these.
5 acquired causes of Ab dysfunction?
(quantitative or functional?)
Multiple myeloma (quantitative and functional).
Nephrotic syndrome (quantitative).
Sickle cell (functional and asplenia).
AIDS (functional, though there's often an ineffective hypergammaglobulinemia).
3 common causes of cell-mediated immune defects?
AIDS, corticosteroids, immunosuppression.
3 common fungal lung infections seen in cell-mediated immune deficiency?
Pneumocystis jiroveci (PCP).
2 viral lung infection that commonly seen in cell-mediated immune deficiency?
CMV, Kaposi's sarcoma (HHV-8).
3 bacterial lung infections commonly seen in cell-mediated immune deficiency?
Nocardia. (first time I've heard of this one...)
Must an infection in a patient with an immunodeficiency get be caused by an opportunistic organism?
Of course not. Just because the boards questions will be structured as such, immunosuppressed people still get infections with S. pneumo, and it's worse.
Typical, non-immunocompromised presentation of lung TB?
Upper lobe, cavitary.
Atypical patterns of TB that can be seen in immunocompromised patients?
Non-cavitary, lower lobe, adenopathy only, milliary (disseminated), extrapulmonary.
Review: what do you seen in TB histology?
Acid fast bacilli.
Granulomas with giant cells (assuming CD4's intact enough to do this).