IM- CAP Flashcards
Results from the proliferation of microbial pathogens at the alveolar level and the host’s response to those pathogen
Pathophysiology of community acquired pneumonia
What are the Most common mode of transmission?
o Aspiration from the oropharynx (Sleep, decreased sensorium)
o Inhaled as contaminated droplets
o Via hematogenous spread or contagious extension from an infected pleural or mediastinal space
What are the mechsnical factors in regards to host defense from CAP?
- Hair and turbinates of the nares
- Branching architecture of the tracheobronchial tree
- Gag reflex and the cough mechanism
- Normal flora adhering to mucosal cell of the oropharynx (prevents pathogenic bacteria from binding)
have intrinsic opsonizing properties or antibacterial or antiviral activity
Surfactant proteins A and D
Initiate host inflammatory response
o Fever (TNF IL 1) o Pheripheral leukocytosis and increased purulent secretions (chemokines: IL8, GCSF)
- Hemoptysis
- Rales
- Radiologic infiltrates
- Hypoxemia
Alveolar capillary leak
- decrease compliance due to capillary leak
- hypoxemia
- increased respiratory drive
- increase secretions
- occasionally infection-related bronchospasm
Dyspnea
Rarely evident in clinical or autopsy specimens bc of the rapid transition to 2nd phase
Edema
- Presence of proteinaceous
- Exudate- and often of bacteria- in the alveoli
Edema
Erythrocytes in the cellular intraalveolar exudate (red)
Red hepatization
more important from the standpoint of host defense in the stage of red hepatization
Neutrophil influx
occasionally seen in pathologic specimens collected during the phase of red hepatization
Bacteria
No new erythrocytes are extravasating and those already present have been lysed and degraded, turning Gray
Gray Hepatization
predominant cell in the phase of gray hepatization
Neutrophil
Abundant in the gray hepatization
Fibrin deposition
corresponds with successful containment of the infection → improve gas exchange
Gray hepatization
Debris of neutrophils, bacteria and fibrin has been cleared, as has the inflammatory response
Resolution phase
dominant cell type in alveolar space during resolution phase
Macrophage reappearance
2 pathogens that causes the typical penumonia
o Streptococcus pneumonia
o H. Influenzae
3 pathiogens that causes the atypical pneumonia?
o Mycoplasma pneumoniae
o Chlamydia pneumoniae
o Legionella pneumoniae
What are the clinical manifestestation of Pneumonia?
- frequently febrile with tachycardia or may have a history of chills and or/sweats
What is the quality of cough in Pneumonia?
productive/non-productive
In Atypical Pneumonia, Up to _____ of patients may have gastrointestinal symptoms such as nausea, vomiting, and or/diarrhea
20%
Its other symptoms may include fatigue, headache, mylagias and athralgias
Atypical pneumonia
Crackles, bronchial breath sounds, and possibly a pleural ____ may be heard on auscultation
Friction rub
In Pneumonia, severly ill pt may have ___ and evidence of ______
Septic shock and organ failure
Can CAP be diagnostically accurately with history and PE alone?
No
Accuracy of predicting CAP by physicians’ clinical judgment is between ________ (Grade B)
60-70%
essential in the diagnosis of CAP
Chest x ray
- Assess severity
- Differentiate pneumoniae from other condition
- For prognostication
Chest radiograph
remains the reference dx standard for pneumonia
new parenchymal infiltrate in the chest radiograph
should be done in patient suspected with CAP to confirm dx
Chest x ray
Can we do not do CXR?
Yes
What specific views of CXR should be requested?
Standing (1) posteroanterior and (2) lateral views of the chest in full inspiration (Grade A)
Can CXR be “normal” in a patient with suspected pneumonia?
YES! Consider as “radiologic lag”
- Not routinely done
- Minimal role
- Non-resolving or progressive pneumonia
CT Scan
In Gram- staining and culture of sputum of CAP, Sputum should be
▪ >25 Neutrophils
▪ <10 Squamous Epithelial Cells
What does the blood culture in CAP yields?
disappointingly low
Only approximately _____ of cultures of blood from pt hospitalized w/ CAP are positive
5-14%
Most frequently isolated pathogens in CAP
S. pneumoniae
allow narrowing of antibiotic therapy in appropriate cases.
Susceptibility data
no longer considered de rigueur for all hospitalized CAP patient
Blood culture
Disadvantages of Antigen test, PCR, Serology
o Not cost effective
▪ Low yield pf blood cultures (5 to 15%)
▪ Poor quality of samples in respiratory specimens o Availability of the tests
Antibiotic should be initiated _____ when diagnosis is made
ASAP
The choice of oral antibiotics ff initial parenteral therapy is based on:
o Available culture results o Antimicrobial spectrum o Efficacy o Safety o Cost
Dosage of Amoxicillin-clavulznic acid
625 mg TID or 1gm BID
Dosage of Azithromycin
500 mg OD
Cefixime
200 mg BID
Cefuroxime Axetil
500 mg BID
Cefpodoxime Proxetil
200 mg BID
Levofloxacin
500-750 mg OD
Moxifloxacin
400 mg OD
Sultamicilin
750 mg BID
