Lower RT Infections Part 1 Flashcards
4 pathogens of CAP found in the mouth and URT
Strep pneumoniae
Haemophilus influenzae
Moraxella
Mycoplasma
2 ways pneumonia happens
Lower RT is usually sterile
Aspiration
Inhalation by droplet/aerosol transmission
3 defence mechanisms of the lungs
Mucus and mucociliary clearance
Cough
Humoral and cellular immunity
4 droplet bacteria vs 3 droplet nuclei bacteria
Droplet: Influenza, Group A strep, Mycoplasma, Neisseria meningitidis
Nuclei: Measles, TB, Varicella
Top 3 typical bacteria that cause CAP (and what is their morphology)
Strep pneumoniae (gram + cocci in pairs) H. influenzae (gram - coccobacilli) Moraxella catarrhalis (gram - diplococci)
Top 2 atypical causes of CAP
Mycoplasma pneumoniae Chlamydophila pneumoniae (gram - obligate intracellular bacteria)
Legionella pneumoniae
Rare cause of pneumonia
Can be severe though!
Causes outbreaks
Doesn’t gram stain well
Most common cause of pneumonia in children 1mo to 5yrs
Viral!!
Hospital acquired pneumonia
- what is it
- what pathogens are most likely
Pneumonia occurring >48 hours after hospital admission
Strep pneumo and Haemophilus are still most likely
Also S aureus, Pseudomonas, and Enterobacteraciae
Ventilator associated pneumonia
Pneumonia occurring >48 hours after intubation
Even more likely to be resistant to nosocomial organisms
What two categories are usually found in
1. acute
2. chronic
pneumonias
- Bacterial or viral
2. Mycobacterial, fungal
4 things to look for on clinical presentation for pneumonia
Cough (+/- purulent sputum)
Fever
Shortness of breath (decline in oxygenation)
Abnormal lung exam (rales, rhonchi, dullness to percussion)
3 things to look for on Lab data for pneumonia
Elevated WBC count
Abnormal chest x-ray
Resp sample: sputum, bronchoalveolar lavage, tracheal aspiration
2 problems with sputum
Obtaining a good lower RT sample is difficult
Good samples can show more than one organism or no organism (doesnt stain)
2 things you should have in a good sputum sample
Less than 10 squamous epithelial cells
Many polymorphonuclear lymphocytes
Sputum gram stain and culture should only be performed in which 4 conditions
When a good quality sample can be obtained
For hospitalized patients with severe underlying lung disease
For patients who have failed antibiotic therapy, or in whom antibiotic resistance is suspected
For patients with suspected TB
When do you do blood cultures?
Only for hospitalized patients with severe CAP
Because they have low sensitivity after antibiotics are started
3 problems with serology
Delay in diagnosis
Variable sensitivity
Cross-reactivity
2 pathogens that have urine antigen testing
Legionella Strep pneumo (not routine)
Pros and cons to urine antigen testing
Pros: more sensitive and specific than sputum gram stain and culture, urine more readily available, immediate results, still works after antibiotics started
Cons: sensitivity less in patients without bacteremia, can’t do antibiotic susceptibility testing
3 times that identifying the specific organism actually becomes important
Resistant bacteria
Bacteria not covered by standard empiric therapy (staph, pseudomonas)
Non-bacterial pathogen (influenza season, immune suppressed)
Antibiotics that work against common bacteria
- which bacteria
- 6 drugs
- Strep pneumo, H influenzae (+ or - beta lactamase), Moraxella
- Amox-clav, Cefuroxime, Ceftriaxone, Doxy, Levofloxavin, and Moxifloxacin (but the fluoros are second line)
5 antibiotics that work against bacteria without a cell wall or intra-cellular organisms
Clarithromycin Azithromycin Doxycycline Levofloxacin Moxifloxacin NO BETA LACTAMS
CAP
- Mild/moderate drugs
- Severe drugs
- Doxy, or Amox-clav and macro/doxy
2. Ceftriaxone and doxy or ceftriaxone and azithromycin
How long do you treat
- CAP
- HAP or VAP
- 5 days
2. 7 days
6 main bacteria that cause HAP or VAP
Strep pneumo H influenzae Staph aureus (including MRSA) Pseudomonas Enteric gram - bacteria Anaerobes
Drugs for VAP or HAP
Pip-taxo Meropenem/imipenem Cefepime/ceftazidime Ciprofloxacin/levofloxain One of those plus or minus Vancomycin (MRSA) or Linezolid
CRB-65 Score
Prognosis score
Confusion, resp rate (> 30), BP ( < 90/60), age (> 64)
All those are 1 point
If you get greater than 1, hospitalize