Chapter 15: Pulmonary Pathology (Singh) Flashcards
(99 cards)
What are the two major requirements for normal fetal lung development to occur?
- space in the thoracic cavity
- ability to inhale
- chest wall needs to move
- need enough material to be present (amniotic fluid)
What is the difference between type 1 and type 2 pneumocytes?
What are Alveolar pores of Kohn?
Type 1: facilitate gas exchange
Type 2: produce surfactant, create new Type 1 cells
APK: allow air to move between alveoli but can allow bacteria/cells/exudate to travel between as well
Pulmonary Hypoplasia
What are two main causes of disease (RS/II) and when does immediate death occur?
- Reduced space in thoracic cavity
- diaphragmatic hernia (lungs cannot push solid organs)
- Impaired Inhalation
- Oligohydramnios = not enough amniotic fluid
- airway malformation (tracheal stenosis)
- chest wall motion disorder
immediate death occurs in neonatal period if LUNG WEIGHT < 40%
What is Potter Sequence and what is it associated with?
P - pulmonary hypoplasia O - oligohydramnios (trigger) T - twisted face T - twisted skin E - extremity defects R - renal agenesis (renal failure)
associated with pulmonary hypoplasia due to dec. production of amniotic fluid
Foregut Cysts
What are they and how can you differentiate a respiratory/esophageal/gastroenteric cyst?
What are their 3 main complications (R/I/C) and how are they cured?
- detached outpouchings of foregut seen along hilum and mediastinum
R - lined by respiratory epithelium
E - lined by squamous tissue
G - lined by glandular tissue
C: rupture, infection, airway compression
- EXCISION is curative
Congenital Pulmonary Adenomatoid Malformation (CPAM)
What is it, how does it interact with the tracheobronchial tree, and what are complications of development?
- arrested development of pulmonary tissue with formation of intrapulmonary cystic masses (would produce tissue mass of level of differentiation)
- DOES communicate with tracheobronchial tree
- can be detected with Fetal US and is DEADLY due to hydrops or pulmonary hypoplasia (also gets infected)
- CAN REMOVE in utero to help save lung function
Pulmonary Sequestrations
What are they and where do they most commonly occur at?
What are their two major characterizations? (NC/IA)
- nonfunctioning lung tissue that forms an abberrant accessory lung bud (usually LEFT LOWER LOBE)
C: does NOT communicate with tracheobronchial tree and has independent arterial supply
- can be either intralobar or extralobar
What is the difference between Intralobar vs Extralobar Pulmonary Sequestrations? (ILS vs ELS)
Which one presents with congenital anomalies?
ILS: presents in older children/adults
- lack of airway perfusion = abscess formation
- infection due to under oxygenation
ELS: presents after birth with CONGENITAL anomalies
- has its own PLEURAL LINING
- seen as mass lesions in chest/abdomen
What is Atelectasis and what is the difference between Resorption, Compression, and Contraction types?
- acquired failure of expansion of lung parenchyma
Re: airway obstruction with resorption of air reducing lung expansion
Com: accumulated material in pleural cavity compresses the lung parenchyma
Con: fibrotic/innate restrictive process in pleura restricting lung expansion
What is the most common cause of Pulmonary Edema and what does it look like histologically?
MCC: left-sided heart failure
Histo: PINK interstitial fluid in alveolar spaces
What are examples of these causes of Pulmonary Edema:
- “Pushing Out” of fluid (HF/VO/PVO)
- “Leaking Out” of fluid (HA/NS/LD)
- Alveolar Wall injury (P/S/S/A)
- Unsure mechanisms (N/A)
- left-sided HF, volume overload, pulmonary V. obstruction
- hypoalbuminemia, nephrotic syndrome, liver disease
- bacterial pneumonia, sepsis, smoking, aspiration
- neurogenic, high altitudes
What are “heart failure cells” and what are they associated with?
- scattered hemosiderin-laden macrophages that accumulate in the alveoli
- associated with congestive heart failure that backs up and causes pulmonary edema in the lungs (microhemorrhages)
What are the 4 criteria you must have in order to have a CLINICAL DIAGNOSIS of Acute Respiratory Distress Syndrome? (AO/H/BI/NC)
- abrupt onset of symptoms
- can be in hospital or as out-patient
- hypoxemia (PaO2/FiO2 < 200; ALI only < 300)
- bilateral infiltrates
- non-cardiac in nature
- basically make sure that heart failure is NOT the cause
How does Acute Respiratory Distress Syndrome (ARDS) tend to develop?
What is disrupted in its early stages?
What does it lead to the development of and what does it look like histologically?
- begins in the BLOOD VESSELS = inc. capillary permeability allowing fluid to leak into alveoli (edema)
- due to DISRUPTED VE-cadherin bonds
- endothelium becomes activated, allowing neutrophils to accumulate in alveoli along with fluid, leading to the development of HYALINE MEMBRANES
- requires edema + fibrin + cell debris
- hyper-pink outline around alveolar membrane
- causes DECREASED AERATION = hypoxemia
What is PaO2 and FiO2?
P = partial pressure of oxygen
- measure with arterial blood gas
F = calculate based on what patient is breathing
- normal room air is = 21%
What are the 3 major stages of ARDS (E/P/F) and how are they characterized?
What are the two possible resolutions of ARDS?
- Exudative - edema, hyaline membrane, neutrophils
- 40% of patients die in this phase
- Proliferative - fibroblasts, early fibrosis, organizing pneumonia
- Fibrotic - extensive fibrosis, loss of normal alveolar architecture
Resolution: either restoration of normal structure and function or DESTRUCTION/DISTORTION that is IRREVERSIBLE
How is ARDS pathologically diagnosed and what is the name for this condition?
- called DIFFUSE ALVEOLAR DAMAGE (DAD)
- requires hyaline membranes, interstitial edema, and epithelial necrosis
What is the difference between Restrictive and Obstructive Lung diseases?
How do FEV1, FVC, and TLC change in both of these diseases?
Restrictive = restriction of overall volume of lung(s)
- also called INTERSTITIAL LUNG DISEASE
- due to fibrosis of alveolar walls
- normal FEV1/FVC, dec. TLC and FVC
Obstructive = hyper-expanded lungs
- dec. flow
- low FEV1/FVC, dec. FEV1, inc. TLC
- dec. ratio is MOST RELIABLE statistic
What are 3 common examples of Obstructive Lung Disease? (B/E/A)
Which ones are most often caused by smoking?
chronic Bronchitis, Emphysema, and Asthma
bronchitis and emphysema (COPD) are most often caused by smoking
Chronic Bronchitis
How does it develop, what is used to make the diagnosis, and what does it look like histologically?
D: mucus hypersecretion in response to smoking causes inflammation and damaged cilia, which can then be infected (thick muscle wall with mucus dec. lumen size)
Dx: pt. with PERSISTENT cough with sputum production of 3 months out of 2 consecutive years
H: mucous gland hyperplasia with damaged airway epithelium
Chronic Bronchitis
What are its 3 major complications? (C/B/D)
- carcinoma (from squamous metaplasia that becomes dysplastic)
- bronchiectasis
- death from respiratory infection
Emphysema
How is it generated, how does it present clinically, and where does it occur at?
- caused when chronic bronchitis reaches terminal bronchiole, causing alveolar sac to collapse
CP: enlarged lungs on CXR (super black) with flattened diaphragm and “barrel chest” with inc. AP diameter
- diminished breath sounds, prolonged exp. wheeze
- PFTs show obstructive pattern (looks like a CHAIR)
emphysema is an IRREVERSIBLE airspace enlargement occurring DISTAL to terminal bronchiole
How does a Chronic Bronchitis pt. differ in presentation compared to an Emphysema pt.?
CB = BLUE BLOATERS (clinical diagnosis)
- overweight and cyanotic
- elevated hemoglobin lvls (trying to compensate)
- peripheral edema and rhonchi/wheezing
E = PINK PUFFERS (pathological diagnosis)
- permanent enlargement/destruction of airspaces
- older/thin with severe dyspnea
- dec. breath sounds
Alpha-1 Antitrypsin Deficiency
What is it and how does it develop, what kind of emphysema does it cause, and where is this condition seen in lungs?
What genetics are associated with this disease and how can it be screened? What is the classic pt. presentation?
- lack of a1-antitrypsin due to mutations trapping them in liver (liver damage), unable to prevent Neutrophil Elastase from damaging alveoli = PANACINAR EMPHYSEMA (panacinar enlargement)
- panacinar because alveoli are soaked in elastase
- seen in LOWER lung due to gravity (more prominent at the base of the lung)
G: pts. homozygous for PiZZ (Pi on C 14, Z allele associated with dec. circulating a1-AT)
- serum test for a1-AT is primary means of diagnosis
pt: young 30 yo smoker with obstructive lung disease