Pathology - S2B1 - 4 Vascular and Infectious
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- What could cause a vasospasm in the lungs?
- amphetamines (cocaine)
- What are Pulmonary Infarcts most commonly the result of?
- Pulmonary Thromboembolism
- 75% of pulmonary infarcts invlove which part of the lungs?
- Lower lobes b/c perfusion is greater than ventilation in the lower lobes
- What is the most common origin of Pulmonary Thromboembolisms?
- Femoral Vein = deep veins in legs
- Macroscopically, what is the classic appearance of Pulmonary Infarcts?
-
Hemorrhagic infarct, which extends to the periphery of the lung as a wedge - What can happen if the hemorrhagic infart extends to the pleural surface?
- can be covered by Fibrinous exudate and cause Pleural friction rub
- When an infarct is caused by a septic embolus, a septic infarct may occur and evolve into what?
- Abscess
- What is the classic triad associated with Pulmonary Embolism?
-
1. Dyspnea (shortness of breath)
2. Pleuritic chest pain
3. Hemoptysis
**most patients are extremely dyspneic** - List risk factors for pulmonary thromboembolism (6)
-
1. Cancer (Trousseau syndrome = pancreatic carcinoma cancer cells release thromboplastin)
2. Cardiac disease
3. Obesity
4. Prolonged bed rest
5. Acute paraplegia
6. oral contraceptive use - What is Homan's sign?
- Use to check for Deep vein thrombosis --> pain in the calf is produced by passive dorsiflexion of the foot
- What is the underlying principle of order of scanning in the V/Q scan?
-
-1st scan using isotope with smallest dose or lowest energy to avoid down-scatter of higher energy isotope
-scan with highest energy isotope last - When doing the V/Q scan, which imaging when done first can be cost effective?
- Perfusion because if it is normal, a ventilation study is not needed to assess for pulmonary emboli
- To determine the etiology of a perfusion defect, what 2 things are needed?
-
1. ventilation study
2. CXR - A V/Q mismatch suggest (V/Q is infinite)?
- Pulmonary embolism
- A V/Q match suggests?
- parenchymal disease
- What is the risk of performing an angiogram in trying to detect the presence of Pulmonary Thromboembolism?
- the radiographic contrast itself can cause thrombosis
- What are Interstitial Pneumonias usually caused by? (2)
-
1. viral infections
2. Mycoplasma pneumonia - Define Bronchopneumonia
-
-patchy consolidation centered around small bronchi
-PMN reaction - What is the cause of Bronchopneumonia?
- inhalation/aspiration, mostly bacteria, some fungi
- Define Lobar Pneumonia
-
-homogenous
-identical involvement of alveoli, same time and same extent
-intra-alveolar exudate resulting in consolidation - What is the most common cause of Lobar Pneumonia?
-
Strep pneumo
*Klebsiella also - List the 4 stages in Lobar Pneumonia
-
1. congestion
2. red hepatization
3. gray hepatization
4. resolution - Describe the Congestion phase of Lobar Pneumonia
-
- heavy, boggy, red lung = active hyperemia
- histologically = vascular engorgement, intra-alveolar fluid with few NO and often the presence of numerous bacteria - Describe the Red Hepatization phase of lobar pneumonia
-
- lobe is distinctly red, firm, and airless, with a liver-like consistency
- Histo = alveolar spaces are filled with RBC's, PMN's, and fibrin - Describe the Gray Hepatization phase of Lobar pneumonia
-
-grayish,brown dry surface
- Histo = disintegration of RBC's and the persistence of fibrinopurulent (Fibrin + Neutrophils) exudate within air spaces - Expected oropharyngeal flora in ~20% of adults
- Strep pneumo
- Normally sensitive to penicillin, but drug resistance is emerging
- Strep pneumo
- With this bacteria, African-Americans have a 3-5 fold higher incidence of bacteremia than whites and rates of invasive disease are also exceptionally high among Native Americans
- Strep pneumo
-
What is the name of the vaccine available for adults against Strep pneumo?
What type of vaccine? -
Pneumovax
Polysaccharide vaccine that covers most of the bacteremic strains of pneumococcus -
Name of Strep pneumo vaccine given to children?
Vaccine properties? -
Prevenar
Heptavalent vaccine linked to Diphtheria toxin - Classically "lancet-shaped" gram + diplococcus with a capsule
- Strep pneumo
- What are most Gram - pneumonias due to?
- Endogenous aspiration of oropharyngeal flora
- Eponymic name is Friedlander's pneumonia
- Klebsiella
- Encapsulated organism, 10% of all nosocomial pneumonias
- Klebsiella
- Gram -, fat rod surrounded by a mucoid capsule
- Klebsiella
- Most common gram - causing lobar pneumonia and typical pneumonia in elderly patients in nursing homes
- Klebsiella
- Common cause of Pneumonia in Alcoholics
- Klebsiella
- Pneumonia associated with blood-tinged, thick, mucoid sputum; lobar consolidation and abscess formation simulating TB
- Klebsiella
- Intracelluar organism that requires anti-microbial drugs with good cytoplasmic penetration, such as Macrolides
- Legionella
- Infection from inhalation of aerosol from contaminated stored water, most often in air-conditioning systems
- Legionella
- Detected by Immunofluorescence of sputum
- Legionella
- Inoculated on Charcoal Yeast extract plates
- Legionella
- Stained with Dieterle silver stain
- Legionella
- Gram - rod with green sputum (pyocyanin)
- P. aeruginosa
- Common colonizer of CF patients
- P. aeruginosa
- Pneumonia from this bacteria is often associated with infarction due to vessel invasion
- P. aeruginosa
- Mucoid colonies in chronically infected patients make eradication impossible
- P. aeruginosa
- Definition: a localized collection of pus in the lung resulting from liquefactive necrosis of lung tissue
- Lung Abscess
- List 4 bacteria that frequently cause abscesses
-
1. S. aureus ***
2. Pseudomonas
3. Klebsiella
4. Proteus - List 4 mechanisms that can lead to Lung Abscesses
-
1. aspiration of infected material, especially Gram - and anaerobes in patients with dental caries
2. Antecedent primary bacterial infection
3. Septic embolism
4. obstruction secondary to neoplasm - Definition: local aggregations of macrophages that become epithelioid cells
- Granulomatous inflammation = granuloma
- What are 3 causes of granulomatous inflammation in the lungs
-
1. Mycobateria
2. Dimorphic fungi
-Histoplasma
-Coccidioides
-Blastomyces
3. Sarcoidosis - What is the initial focus of Tuberculosis in primary infection?
- Ghon Complex
- What is a Ghon Complex?
-
1. Parenchymal subpleural lesion
2. enlarged hilar lymph nodes
*both contain tuberculous granulomas - Describe Miliary Tuberculosis
- Secondary TB with the presence of multiple, small tuberculous granulomas in many organs, which result from the hematogenous spread of bacteria
- Name 5 complications of TB
-
1. cavitation
2. hemorrhage
3. bronchopleural fistulas
4. Bronchopneumonia
5. Aspergillomas - With Tuberculosis, swallowed sputum may lead to ________
- GI TB
- This complication of TB is particularly a problem in children and the immunosuppressed
- TB meningitis
- List 3 common causes of diffuse infiltrate in IC'ed hosts
-
CMV
PCP
Drug reaction - List 3 common causes of focal infiltrates in IC'ed hosts
-
Gram - rods
S. aureus
Aspergillus - Fruiting body and narrow-angled, branching septate hyphae
- Aspergillus
- Non-invasive "fungus ball", occupies a previously existing anatomical space, such as a sinus cavity or abscess cavity
- Aspergilloma
- Most common opportunistic infection in AIDS patients
- Pneumocystis carinii
- Replicates in the human lung, with a complicated life cycle that includes formation of intra-alveolar CYSTS
- Pneumocystis carinii
- Most of the population is infected by age 5 with this organism
- PCP
- What is PCP probably acquired from?
- Aerosolized mouse or rat urine
- What drug is given prophylactically for PCP when CD4 counts drop below 200
- Trimethoprim-Sulfamethoxazole
- What do CXR's look like with PCP?
- Patchy, pneumonia, with a characteristic "ground-glass" appearance
- Budding yeast with narrow-based buds
- Cryptococcus neoformans
- Systemic fungi surrounded by a thick capsule
- Cryptococcus
- Is ubiquitous in the environment, preferring alkaline bird droppings as its habitat
- Cryptococcus neoformans
- Usually causes meningitis in IC'ed, but primary lung disease may occur
- Cryptococcus neoformans
- What test is useful in detecting Cryptococcus in normal hosts?
- Antigen testing of the CSF
- What test is adequate for detecting Cryptococcus in IC'ed host?
- India Ink prep
- Dimorphic large yeast with Broad-based budding
- Blastomyces dermitidis
-
What is this showing? -
Saddle embolus originating from the deep veins of the leg
-straddles right and left pulmonary artery = sudden death - Why are small Pulmonary Infarcts "Hemorrhagic" or "red" infarcts?
-
The lung has a dual blood supply
-Pulmonary Artery
-Bronchial arteries -
What is this picture showing? -
Bronchopneumonia
-pathy areas where PMN's are within tiny bronchioles -
What are these microbes? - Strep pneumo
-
What is this showing?
What is the most likely cause? -
Lower Lobe consolidation
Pneumococcus -
What is this showing? -
Lobar Pneumonia
-if the bronchi were filled with pus = Bronchopneumonia, but since they are spared it is Lobar -
What is the likely cause of this? How do you know? -
Klebsiella
-consolidation + abscesses -
This person contracted 5-lobe consolidation by working in the produce section with water mist sprayers - Legionella
-
What microbe?
What are these 2 stains? -
Legionella
Immunofluorescence
Dieterle Silver -
What microbe?
What are these 2 stains? -
Legionella
Immunofluorescence
Dieterle Silver -
What are the 3 associations here? -
1. P. aeruginosa
2. Cystic Fibrosis
3. Bronchiectasis -
What organisms typically cause this? -
1. S. aureus
2. Klebsiella
3. Aerobic and anaerobic streptococci
4. Gram - organisms - What is a Simon focus?
-
Granuloma at the lung apex in Secondary Pulmonary TB
-occurs at apex due to high O2 tension -
What is this microbe? - Cytomegalovirus
- When does Invasive (disseminated) Aspregillosis usually only occur?
- Immunocompromised
-
What is this? - Aspergilloma
-
What is shown here? - Aspergilloma
-
What is this?
In culture, what do the hyphae look like? -
Aspergillus
Acute (<45 degrees) branching Septate Hyphae -
This was from an Immunocompromised patient.
What pathogen? - Invasive Aspergillosis
-
What pathogen?
How do you know? -
Invasive Aspergillosis
Acutely branching septate hyphae -
What pathogen?
What does it usually cause?
How are you exposed to it? -
-Cryptococcus neoformans = narrow-based budding
-Meningitis in IC'ed
-Pigeon excreta -
What pathogen is this?
Who does it usually affect? -
Pneumocystis carinii
IC'ed = AIDS -
What is this showing?
How do you know? -
Bronchopneumonia
Patchy areas of pulmonary consolidation