Lecture 4: Pneumonia Flashcards
What # cause of death is pneumonia for infectious causes of death?
1!
Also 2nd most common cause for hospitalization
Define pneumonia.
Inflammation of the lung parenchyma, resulting in consolidation of the affected part.
Describe the 5 pathophysiological steps of pneumonia, beginning with infection.
- Infection of the lung
- Inflammatory response
- Alveolar edema and exudate formation
- Alveoli and respiratory bronchioles fill up
- Consolidation of lung tissue.
What is the most common causative organism
of community acquired pneumonia?
Strep pneumo.
What is the most common cause of hospital acquired pneumonia?
Pseudomonas aeruginosa
What are the 3 classifications for pneumonia?
- Anatomic location (on radiograph)
- Mechanism of acquisition (aspiration vs vent vs etc)
- Setting of acquisition (CAP vs HAP vs VAP)
What is the primary causative organism of lobar pneumonia?
Strep pneumo accounts for 95% of causative organisms.
Lobar is the usual CAP.
Which lung is typically more affected in lobar pneumonia?
R lobe.
RLL specifically, due to proximity to the R main bronchus.
What lobe does klebsiella typically affect and why?
RUL due to an alcoholic passing out and aspirating.
What lung fields does legionella tend to appear in?
Lower lung fields.
How does a lobular/bronchopneumonia typically appear on CXR?
- Patchy appearance
- Peribronchial thickening
- Poorly defined air-space opacities
Destructive pneumonia that is not isolated.
Typically will lead to abscesses, cavitation, necrosis, and pleural effusions.
What are the more causative organisms for lobular pneumonia?
- Staph Aureus (MRSA)
- Strep
- H flu
- Klebsiella
- P aeruginosa
Staph is very common in COPD patients as well.
Define interstitial pneumonia.
- Focal or diffuse
- Edema and inflammatory cellular infiltrate into the interstitium
- Appears as fluffy clouds around the lung.
- Ground-glass appearance
- Bilateral and symmetric.
Will usually begin with viral prodrome => ARDS
What is aspiration pneumonia?
Inhalation of oropharyngeal secretions, gastric contents, or colonized organisms.
What are the two most common sites of infiltration for aspiration PNA?
- RLL: most common due to vertical orientation of RMB.
- RUL: most common in alcoholics who aspirate in a prone position.
Why is aspiration PNA pathophysiology more concerning than normal lobar CAP?
Formation of cavities and necrosis.
What is VAP?
Ventilator acquired PNA, which occurs 48hrs+ mechanical ventilation via ET tube or tracheostomy.
What is the main concern with organisms in VAP?
Multi drug resistance.
Need to cover MRSA, pseudomonas, and other G-.
Why does VAP occur?
Inability to cough and naturally clear airway, so bacteria can contaminate and colonize.
What counts as CAP vs nosocomial?
- CAP: OP or within 48 hrs of admittance.
- Nosocomial: everything else :)
HCAP refers to within 48 hrs of admittance even thought it is also CAP.
HAP is 48hrs post admission.
VAP is 48 hrs post intubation OR within 48hrs of extubation.
Where is most CAP treated?
Outpatient
What are the most common causes of viral pneumonia?
- Influenza
- RSV
- Parainfluenza
- Adenovirus
For pneumonia, what do sputum colors generally correlate with in terms of bacterial etiology?
- Rust colored: strep pneumo
- Green: pseudomonas, H flu, and other pneumococci
- Red currant jelly: Klebsiella
- Foul-smelling: Anaerobes
What are the additional symptoms of PNA?
- Fever (80%)
- Dyspnea (45-70%)
- Pleuritic chest pain (30%)
- Sweats
- Chills (40-50%)
- Rigors (15%)
- N/V/D
- AMS
What is the gold standard for diagnosing PNA?
Infiltrate on CXR.
Definitively can say someone has PNA. Unknown etiology.
What organisms can an urine antigen test detect for pneumonia etiologies?
- Strep pneumo
- Legionella
Only checks for 1 serotype group of legionella
Test is very sensitive and specific for legionella.
Generally reliable and can detect post ABX therapy.
What PSI and CURB-65 scores indicate outpatient treatment?
- PSI of 2 or lower.
- CURB-65 of 1 or lower.
PSI is more extensive, but CURB-65 is shorter.
What is CURB 65 criteria?
- Confusion of new onset
- Blood Urea Nitrogen > 19mg/dL or 7mmol/L
- RR >= 30 bpm
- BP < 90 SBP or DBP <=60
- Age of 65 or more.
Predicts 30day mortality.
2 or more = inpatient.
How long should ABX be used for outpatient CAP?
- 5-7 days at minimum.
- 48-72 hrs post afebrile is recommended.
What are the additional treatments for CAP?
- Rest/hydration
- Analgesics (acetaminophen or ibuprofen)
- Expectorants (guaifenesin)
- Steroids (debateable)
What is the empiric treatment for regular outpatient CAP?
- Amoxicillin 1g PO TID
- Azithromycin 500mg PO 1 dose + 250mg PO daily for 4 days
- Clarithomycin 500mg PO BID or ER 1000mg PO q24hr (bad in h flu and mcat)
- Doxycycline 100mg PO BID
No comorbidities
No factors for MDR strep pneumo
No ABX in 3 months
What is the modified empiric treatment for outpatient CAP with prior ABX use or comorbidities?
- Azithro/Claritho + beta lactam
- Respiratory fluoroquinolone (levofloxacin or moxi)
What is the treatment for standard IP CAP?
Same as OP w/ comorbidities.
- Macrolide + beta lactam (azithro + rocephin)
- Respiratory fluoroquinolone
What is the treatment for ICU CAP?
- Rocephin + azithromycin
- Levo/moxi + Rocephin
- Levo + aztreonam (for PCN allergy)
Who is pneumococcal vaccination indicated for?
Age >=65 or any chronic illness that increases CAP risk.
In HIV patients, what other organism is highly likely to cause PNA?
Pneumocystis jirovecii
In transplant patients, what are some more common causative organisms that can result in PNA?
- Fungi
- Nocardia
- CMV
What risk factors are associated with nosocomial pneumonia?
- ABX in last 3 months
- Acute hospitalization > 2 days in past 3 months
- Nursing home
- Home infusion therapy
- Dialysis in past 30 days
- Wound care
- Family member w infection
- Immunosuppressed
What 3 factors distinguish nosocomial PNA from CAP?
- Different infectious causes
- Different ABX susceptibility
- Different underlying health conditions
What is the concern with causative organisms in nosocomial pneumonia?
Drug resistance.
What is the initial treatment for nosocomial pneumonia?
Empiric ABX followed by targeted therapy once cultures result.
For a patient with a low risk for drug-resistant bacteria, what is the treatment for nosocomial PNA?
- Levofloxacin
- Piptazo
- Cefepime
For a patient with high risk for MDR pathogens resulting in nosocomial PNA, what is the treatment protocol?
- Antipseudomonal + carbapenem + beta-lactam
- Antipseudomonal fluoroquinolone + aminoglycoside
- MRSA coverage
1 from each category.
What demographic is most susceptible to klebsiella and what is the hallmark finding of a klebsiella PNA?
- Alcoholics who aspirate after passing out.
- Red-currant like jelly sputum.
- Ground-glass opacity on CT (100%)
A patient with a history of COPD presents with PNA and it is cultured. Culture reveals a gram positive bacteria that tends to clump and is shaped like a sphere. What is the most likely causative organism?
Staphylococcal pneumonia.
What is the primary treatment for staphylococcal pneumonia?
- Clindamycin
- IP Vancomycin
What are the characteristics of mycoplasma?
- Smallest living organism
- No cell wall
- Causes atypical pneumonia usually.
What is unique about mycoplasma pneumonia?
- Intractable, non-productive cough.
- CXR is generally normal.
- Potentially a bullous myriginitis in TM.
What drug classes treat mycoplasma pneumonia?
- Macrolides
- Fluoroquinolones
What is different between bacterial and viral pneumonia?
Viral pneumonia generally is nonproductive with their cough.
What is the treatment for viral pneumonia?
Supportive care.
What is unique about PJP?
Unicelluar fungal infection that does not respond to antifungals.
What labs are elevated and abnormal diagnostics in PJP?
- Serum LDH
- Serum Beta-D-glucan
- CXR: diffuse, bilateral interstitial infiltrates
- CT: Hallmark ground glass opacities
What is the treatment for PJP?
- ART (anti-retroviral therapy)
- Bactrim
What is the prophylaxis for PJP and the cell count?
< 200 cell count with bactrim.
