Path of Infectious and Non-infectious Flashcards
Pneumonia is responsible for what fraction of death in the US?
1/6
True or false: the lower airways are usually sterile
True
True or false: we all regularly aspirate
True–though it is minute
What is the technical definition of pneumonia?
Infection of the lung parenchyma
What are the two major lifestyle factors that predispose people to pneumonia?
EtOH
Smoking
What is the usual cause of acute pneumonia?
Pyogenic bacteria
What is pneumonitis?
Usually not pyogenic—often viral or d/t to mycoplasma
What are the common causes of chronic pneumonias?
TB
Fungi
Parasites
What are the five physiological changes that predispose to developing pneumonia?
- Loss of cough reflex
- Injury to mucociliary escalator
- LOF of macrophages
- Pulmonary edema and congestion
- Accumulated secretions
What are the two ways to classify pneumonia?
Etiological agent or clinical setting
True or false: you can get pneumonia from sepsis
True
CAP is usually caused by what infectious type of agent?
Bacterial
Atypical pneumonia is usually caused by what infectious agent?
Viruses
Aspiration pneumonia is usually caused by what?
Bacteria and chemicals
What are the usual causes of chronic pneumonias?
mycobacteria
True or false: Legionnaires disease is classified as a CAP
True
Which lobes of the lung are most often affected by aspiration?
Lower lobes or right middle
What are the two morphological patterns of bacterial pneumonia?
Bronchopneumonia and lobar pneumonia
What is lobar pneumonia?
Consolidation of an entire lobe or large portion of a lobe
What is bronchopneumonia?
Patchy consolidation in one or more lobes
What does the pneumonia pattern depend on?
Bacterial virulence and host resistance
What are the lung sounds with lobar pneumonia?
Rales
What are the gross findings of bronchopneumonia?
Dispersed, elevated 3-4 cm lesions of palpable consolidation
What are the histological findings of bronchopneumonia?
Acute PMN filled exudate filling airspaces and airways
90-95% of lobar pneumonia is caused by what pathogen?
Strep pneumoniae
What is the progression of lobar pneumonia?
Congestion
Red hepatization
Gray hepatization
Resolution
What causes the red hepatization in the lungs with pneumonia?
Confluent exudation with RBCs, fibrin in alveolar spaces
What causes the grey hepatization in the lungs with pneumonia?
RBCs break down, exudate remains
What is involved in the resolution phase of lobar pneumonia?
Exudate enzymatically digested
What happens if the pneumonia does not resolve? Why?
Scarring d/t degradation from enzymatic destruction
What are the four major indications that you should hospitalize a patient with pneumonia?
- severe dyspnea
- Empyema
- Underlying disease
- Severe systemic ssx
What are the pleural consequences of pneumonia? (3)
Pleuritis
Pleural effusion
Bronchopleural fistulas
What are the localized complications from pneumonia?
Abscesses
Empyema
What is type I respiratory failure?
Low O2, but CO2 not elevated
What are the heart sequelae of pneumonia? (3)
A-fib
Pericarditis
Myocarditis
What is atypical pneumonia?
Lack of alveolar exudate in most, with increased WBCs
Which WBC is increased markedly with atypical pneumonia (usually)?
Lymphocytes
Monocytes
What is the “proper” name for primary atypical pneumonia?
Interstitial pneumonitis
What are the CXR findings of atypical pneumonia?
Patchy Interstitial changes
What are the usual bacteria that cause atypical pneumonia?
Mycoplasma
Chlamydia
What are the ssx of atypical pneumonia?
Pharyngitis with URI like ssx
What are the classic ssx of mycoplasma pneumoniae?
Bad, persistent cough
What are the primary viral causes of atypical pneumonia?
Influenza A and B
RSV
Adenovirus
What is the common pathogenic mechanisms for viral pneumonia?
Attachment of organism to the respiratory epithelium, leading to necrosis of cells and an inflammatory response
If sputum changes from green to yellow, what should you suspect?
Bacterial pneumonia superimposed by a viral one
What is the usual clinical course of atypical pneumonia?
Usually resolves spontaneously
What are the severe sequelae of atypical pneumonia?
ARDS
What is the typical histopathology of atypical pneumonia?
Interstitial pneumonia with mononuclear infiltrates and diffuse alveolar damage
What are the two major granulomatous diseases that affect the lung?
Sarcoidosis
Hypersensitivity pneumonitis
What is the pulmonary eosinophilia?
a disease in which an eosinophil, a type of white blood cell, accumulates in the lung d/t some insult (meds, parasites, environmental triggers etc)
What is sarcoidosis?
Systemic disease of unknown etiology, but causes granulomas
What are the most frequent targets of sarcoidosis?
Lung and/or hilar lymph nodes
What is the classic patient to be affected by sarcoidosis?
Young, AA females
True or false: sarcoidosis is a disease of exclusion
True
What is the most common manifestation of sarcoidosis?
Asymptomatic
What are the usual ssx of pulmonary involvement with sarcoidosis?
Insidious onset of TB-like ssx
What is needed for a diagnosis of sarcoidosis? (3)
Biopsy showing:
- Non-caseating granulomas
- Special stains
- Culture
What are the lab findings of acute sarcoidosis? (3)
Increased IgG, Ca, and ACE
What are the cells that are involved with sarcoidosis? Where do they accumulate?
CD4+ T cells in the lung interstitium and alveoli
What are the cytokines release by the CD4+T cells in sarcoidosis? (4)
IL-2
IFN-gamma
IL-8
TNF
What do the IL-2 and IFN-gamma do in sarcoidosis?
Increase T cell expansion
What do IL-8 and TNF do in sarcoidosis?
Recruitment of additional T cells and monocytes
What causes the skin manifestations of sarcoidosis?
Peripheral anergy of CD4+ T cells
What type of antibody is upregulated with Sarcoidosis?
IgG
What are the HLA genotypes that are associated with sarcoidosis?
HLA A1 and B8
What is Mikulicz syndrome?
a type of benign enlargement of the parotid and/or lacrimal glands. 2/2 sarcoidosis
What is the defining characteristic of sarcoidosis?
Well formed noncaseating granulomas
What are the long term sequelae of sarcoidosis?
Fibrosis and honeycomb lung
Where does sarcoidosis granulomas forms in the long?
Along the lymphatic pathways
What is contained within granulomas in sarcoidosis?
Tight, clustered epithelioid histiocytes rimmed by outer zone of CD4+ T cells
What are the histological findings of sarcoidosis?
PMNs infiltrating the alveolar septa
What are the “potato” nodes in sarcoidosis?
Large granulomas
What are the schumann bodies that can be seen with sarcoidosis?
Little lamellated calcified structures in giant cells
What are the asteroid bodies that are found in sarcoidosis?
Star-shaped eosinophilic bodies made of compressed intermediate filaments
What is the clinical course of sarcoidosis?
very good with steroids
What type of sarcoidosis is more likely to become progressive?
Pulmonary disease without adenopathy
What percent of patients with sarcoidosis die? COD?
10-15%–pulmonary fibrosis or cor pulmonale
What is hypersensitivity pneumonitis?
usually an occupational disease resulting from an increased susceptibility to inhaled antigens
What type of pulmonary disease is hypersensitivity pneumonitis?
Interstitial, restrictive disease
What lung structure is primarily involved in hypersensitivity pneumonitis?
Alveoli
What usually causes hypersensitivity pneumonitis?
- Spores of thermophilic bacteria
- Fungi
- Animal proteins
- bacterial products
How do you avoid progression of hypersensitivity pneumonitis?
Remove the antigen early
What are the acute ssx of hypersensitivity pneumonitis?
Large exposure to antigen that causes SOB
What are the ssx of chronic hypersensitivity pneumonitis?
Insidious onset of SOB, cough, and fatigue
Respiratory failure eventually
What type of hypersensitivity reaction is hypersensitivity pneumonitis? (early and later)
Type III early
Type IV later
What are the BAL findings with hypersensitivity pneumonitis?
Increased T cells (both CD4 and CD8)
What are the serum findings with hypersensitivity pneumonitis?
Specific antibodies
What is the sequelae of type IV hypersensitivity prolonged hypersensitivity pneumonitis?
Non-caseating granuloma
What is Farmer’s lung?
Hypersensitivity pneumonitis caused by spores of thermophilic actinomyces in hay
What is Pigeon breeder’s lung?
Hypersensitivity pneumonitis caused by proteins from bird feathers
What is humidified or air conditioners lung?
Hypersensitivity pneumonitis caused by thermophilic bacteria
What type of cells are high with acute Hypersensitivity pneumonitis ?
PMNs in the interstitium
What are the primary cells types that are found with chronic Hypersensitivity pneumonitis?
Mononuclear cells
What are the characteristics of the granulomas formed from Hypersensitivity pneumonitis?
Noncaseating that are loose and poorly formed
What happens in the later stages of Hypersensitivity pneumonitis?
Interstitial fibrosis
What fraction of patients with Hypersensitivity pneumonitis will have intra-alveolar infiltrate?
Greater than 2/3 of pts
What are the CXR findings of Hypersensitivity pneumonitis?
Increased lung markings
What is silo filters disease?
AN occupational lung disease from NO/NO2 that is often sound in silos. This can lead to pulmonary edema in minutes, or chronic widespread bronchiolitis with scar tissue
What is the major cells that are upregulated with smoking?
Macrophages
What is desquamative interstitial pneumonia?
a form of idiopathic bronchitis featuring elevated levels of macrophages.
It is associated with patients with a history of smoking.
What is the survival rate of desquamative interstitial pneumonitis with steroid use?
100%
What is pulmonary alveolar proteinosis?
A rare lung disease in which abnormal accumulation of pulmonary surfactant occurs within the alveoli, interfering with gas exchange.
What is the stain that is used to highlight the acellular surfactant in pulmonary alveolar proteinosis?
PAS+
What are the ssx of pulmonary alveolar proteinosis?
Thick white sputum that is gelatinous
Progressive SOB cyanosis, respiratory insufficiency
What happens to the alveolar walls with pulmonary alveolar proteinosis?
Minimal inflammation
True or false: there is a high rate of progression to pulmonary fibrosis with pulmonary alveolar proteinosis?
False–very rare
What is the treatment for pulmonary alveolar proteinosis?
Lavage
