Singh Pathology of Respiratory System #4 Flashcards
What is the most common cause of sepsis and septic shock?
Pneumonia
What are the stages of lobar pneumonia?
- Congestion with vascular engorgement
- Red hepatization with red cells and inflammation
- Grey hepatization with inflammation and debris
- Resolution with fibrosis and macrophage clean up
Complications of lobar pneumonia?
Abscess
Empyema
Bacteremia
What is the most common cause of community acquired pneumonia?
- Streptococcus pneumoniae
- pairs and chains of lancet shaped gram positive diplococci
What are 3 other bacterial causes of CAP besides S.pneumonia? What are their characteristics?
- Haemophilus influenzae
- virulent pneumonia in kids
- S. aureus
- abscess forms
- IV drug user
- K. pneumoniae
- alcoholics
- currant jelly sputum
What characterizes typical pneumonia?
- abrupt onset
- respiratory sx predominate
- Consolidation on CXR
- Older adults or young kids
What characterizes Atypical (walking) pneumonia?
- Slow onset
- Systemic symptoms predominate
- Patchy infiltrates on CXR
- Young adults teens
What bacteria are responsible for atypical pneumonia?
- Mycoplasma pneumoniae
- Legionella pneumophila
- Chlamydia pneumonia
- Chlamydia psittaci
Describe Legionella pneumophila?
- Gram negative bacillus
- Gros in warm freshwater
- air conditioning units
- misters
- hot tubs
- Airborne
What is the most common viral CAP?
- Influenza
What two proteins make up influenza virus?
- Hemagglutinin
- attaches to cells
- Neuraminidase
- allows release of replicated virus from cell
What is antigenic drift?
- minor changes to proteins that are just enough to allow increased spread (epidemic)
- Similar enough to original virus to allow for some immunity
What is antigenic shift?
- Genomic alterations with major resulting change to protein structures
- Naïve immunity for almost all people
- Pandemics
- Picked up from animal gene products
What kind of virus is COVID-19?
Positive sense ssRNA
How does COVID 19 lead to ARDS?
Induces a cytokine storm
How does COVID 19 induce coagulopathy? How do you test for it?
- Venous and arterial thrombi
- Megakaryocyte activation
- D dimer predictive value
What causes neonatal bacterial pneumonia?
- Group B strep
- Gram - bacilli
- Listeria
What are the viral and bacterial causes of pneumonia in kids less than 1 month old?
- RSV
- Parainfluenza virus
- Influenza A and B
- Adenovirus
- Rhinovirus
- S. pneumoniae
- H. influenzae
- M. catarrhalis
- S. aureus
Signs and sx of influenza?
- Abrupt onset
- Fever 3-4 days
- Severe aches
- Chills
- Fatigue and weakness
- Headache common
Which type of viral class has the most direct route to viral proteins?
- ssRNA + sense virus
- they go straight to ribosome and begin translation
RSV Pneumonia symptoms?
- paramyxovirus
- Rhinorrhea and cough
- Wheezing dyspnea
- Tachypnea
- Cyanosis
Presentation of bacterial pneumonia?
- Abrupt onset
- Not associated with epidemics
- may have bacteremia
- High grade fever
- Crackles
- Lobar or consolidated appearance
- May involve pleura
Viral presentation of pneumonia?
- gradual onset
- epidemics are common
- Not associated with viremia
- No fever or low grade
- Wheezes
- Diffuse infiltrates on CXR
- Doesn’t involve pleura
- Self limiting
Complication of pneumonia?
- Lung abscess
- Aspiration
Why would the right middle and lower lobes be preferentially afcted?
- The right main bronchi has a steeper slope making it more favorable for anything to fall that way
What is a ghon complex?
Caseating granulomata is found in the hilar lymph nodes and at the parenchyma
What diseases cause pulmonary granulomatas?
- TB
- Sarcoidosis
- Hypersensitivity pneumonia
- Vasculitis (GPA)
What is chronic pneumonia? What is the biggest cause?
- Pneumonia lasting for months in a immunocompetent patient
- Fungal infections are the most common cause
- Histoplasma
- Blastomycosis
- Coccidiomycosis
Histoplasma Capsulatum, where is it endemic and what is the characteristic?
- Endemic in Midwest and Caribbean (ohio and mississippi river valleys)
- Characteristic yeast shows pumpkin seed morphology
- Subclinical infection with granulomatous response
- calcification or coil lesion on CXR
Blastomyces dermatitides endemic and characteristics?
- Endemic in ohio and mississippi river valley
- Infections gives granulomatous response
- Characteristic yeast shows broad based buds
Coccidiodes immitis?
- Endemic in SW US and Mexico
- Granulomatous response with eosinophils
- Subclinical and self limited
- Can produce disseminated infection especially with immunocompromised
Pneumocystis jiroveci (carinii) pneumonia characteristics?
- Opportuinistic fungal infection
- AIDS defining illness
- Characteristic cup shaped yeast forms
- can be diffuse or focal
CMV Pneumonia?
- Opportunistic viral infection
- AIDS defining illness
- Characteristic inclusions in image “Cowdry”
Mycobacterium avium complex?
- Immunocompromised or elderly
- Thin mycobacteria seen as slender red forms on acid fast staining
