Pathology/clinical/diseases Flashcards
What is the pulmonary lobule?
Lung tissue surrounded by interlobular septae
What is pulmonary acinus?
The lung parenchyma distal to a terminal bronchiole
What is pulmonary interstitium?
The connective tissue in the alveolar and interlobular septae, and around vessels and airways
What are the 3 types of emphysema and their characteristics?
- Centrilobular (proximal acinar) most common in clinic – upper lobe predominance – black due to cigarette smoking
- Panlobular (panacinar) less common – lower zone predominance, whole of acinus is affected, then whole lobule – alpha 1 antitrypsin (antiprotease) deficiency (gene PiMM - 90% population- or PiZZ)
- Paraseptal (distal acinar) – subpleural distribution, really close to the pleura – not common – upper lobe
What is Bronchiolitis?
- An inflammation of the bronchioles, is associated with cigarette smoking, is characterized by
- mural chronic inflammation
- mural fibrosis
- epithelial goblet cell hyperplasia and luminal mucus accumulation = lumen obstruction
What’s a clear symptom of chronic Bronchitis?
- Expectoration (coughing up) of mucous on most days for at least 3 consecutive months for at least 2 years
What is Bronchiectasis?
- An irreversible dilation of a portion of the bronchial tree
- often grouped with COPD because there’s a lot of mucus in the airways and distal bronchiolitis
- 3 types (based on morphology)
- Cylindrical
- Varicose
- Saccular
What is the DEFINITION of COPD?
A common, preventable, and treatable disease that is characterized by persistent respiratory symptoms (breathless, cough, sputum) and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases.
What is the epidemiology of COPD?
- Major public health problem (1/10 men, 1/13 women over 40 y.o.
- mortality rate of COPD is increasing
- most admissions to hospitals (burden to the health system)
What are the risk factors of COPD?
- Cigarette or environmental smoke
- Occupational dust and chemicals
- Pollution
- Genes
- Infections
- Lung development
- Asthma
Describe the pathophysiology of COPD.
calculate airflow limitation by using a volume/tine graph. If your FEV1/FVC is ↓ 0,7 and stays this way after administration of bronchodilator.
Key pathophysiological mechanism of dyspnea in COPD =
- Exhaling each breath requires time, but airflow limitation slows exhalation
- With insufficient time to exhale each breath, one breathes in before exhalation is complete
- This results in hyperinflation
- Breathing at a higher lung volume (hyperinflation) requires more effort
How do you diagnose COPD?
- Symptoms (dyspnea, chronic cough, sputum)
- Exposure to risk factors (tobacco, occupation, pollution)
- Spirometry (FEV1/FVC < 0.7 post bronchodilator) : REQUIRED TO ESTABLISH DIAGNOSIS
When diagnosing and/or evaluating a patient with COPD, there are some essential things we need to assess. What are those things ?
In that case, is spirometry enough to quantify the disease impact on patient lives ?
- Presence of persistent airflow limitation
- the severity of airflow limitation
- symptoms and exarcerbation risk (really important in order to caracterize the disease, is the patient breathless only during exercise, when he walks, too breathless to leave the house, etc.)
Spirometry is then not enough to quantify the disease impact on patient lives : symptoms severity, disability and risk of exacerbation.
What are the goals of management of COPD?
- Alleviate breathlessness and other respiratory symptoms
- Prevent disease progression
- Treat exacerbations and complications
- Reduce the frequency and severity of exacerbations
- Improve exercise tolerance, physical activity
- Improve health status
- Reduce mortality
- Assess and manage co-morbidities
What are the interventions with COPD?
-
Smoking cessation
- if you quit smoking, you slow down the course of the disease (the slope is less severe, but you can never come back to what you were before smoking)
- Vaccination
- Bronchodilators
- Anti-inflammatories
- Anti-microbials
- Pulmonary rehabilitation (self-management, exercise, cessation)
- Supplemental oxygen
- Assisted ventilation
- Surgical: lung volume reduction, transplant
What is acute exacerbations in COPD?
Exacerbation and symptom burdens are important to characterize the disease.
Definition of exacerbation = Sustained (≥48 h, différencie acute exacerbation from the normal day-to-day variations in COPD symptoms) worsening of dyspnea, cough or sputum production that induces :
- an increase on the use of regular medications
- Supplementation with additional medications.
Exacerbation impacts all aspects of this vicious cycle and contribute to impired HRQL and more rapid decline of lung function over time
What constitutes and characterizes asthma?
Asthma is a chronic inflammatory disorder associated with reversible airway obstruction, bronchial hyper-responsiveness, and airway inflammation
- Variable degree of airway obstruction
- Airway inflammation
- Bronchial hyperresponsive
What are the inflammatory components of asthma sensitive to steroid?
- eosinophils
- mast cells
- Th2-lymphocytes
- dendritic cells
- IL-4, IL-5, IL-13,
- IgE
What are the inflammatory components of asthma NOT sensitive to steroid?
- Th17 lymphocytes
- neutrophils
When should an M.D. suspect asthma?
- Recurrent episodes of wheezing
- Troublesome cough, especially at night
- Cough or wheeze after exercise
- Cough, wheeze or chest tightness after exposure to airborne allergens or pollutants
- Prolonged cough or wheeze following a respiratory infection. Colds “go to the chest” or take more than 10 days to clear.
What triggers asthma?
-
Respiratory tract infections.
- Rhinovirus is by far the number 1 trigger for asthma exacerbation.
-
Allergens
- human dust mite, fungal spores, animal danders, cockroach, pollens
-
Pollutants, irritants
- smoke, perfumes, cleansing agents
-
Medications
- aspirin, beta blockers (blood pressure, angina, arrhythmia)
-
Physical factors
- exercise, cold air
-
Physiological factors
- stress, gastro-œsophageal reflux, sinus disease, obesity, pregnancy
How is asthma diagnosed?
- History and patterns of symptoms
- Measurements of lung function
- Spirometry (OBLIGATOIRE POUR UN DIAGNOSTIC)
- Peak expiratory flow (if impossible to do spirometry)
- Measurement of airway responsiveness
- Following the administration of a bronchodilator such as salbutamol, an improvement in FEV1 of at least 12% and at least 200ml within 30 minutes.
- We administrate histamine or methacholine and see how you respond
- Measurements of inflammatory status of the airways (sputum analysis with hypertonic saline)
What are the long term goals of asthma management?
- Achieve and maintain control of symptoms
- Maintain normal activity levels, including exercise
- Maintain pulmonary function as close to normal levels as possible
- Prevent asthma exacerbations
- Avoid adverse effects from asthma medications
- Prevent asthma mortality
What types of medication are used to treat asthma? Is there another way to treat it ?
-
Medication
- blue/green puffers : bronchodilators («ols, «iums»)
-
rescue medication
- short-acting bronchodilator agents (SABA)
-
controller medication
-
long-acting bronchodilators (LABD)
- LABA (beta2-agonist)
- LAMA (anticholinergics muscarinic)
-
long-acting bronchodilators (LABD)
-
rescue medication
- orange/red/purple puffers : controllers
- Inhaled corticosteroids (ICS) «-ides, -ones »
- ICS-LABA (combination therapy)
- oral medication : controllers
- anti-IgE
- prednisone (oral corticosteroid)
- blue/green puffers : bronchodilators («ols, «iums»)
- Non-medication (stop exposure, lifestyle)
What are the 2 less common (oral corticosteroids) treatment only used for severe asthma?
- Prednisone: very cheap and effective for SHORT periods of time because a lot of side effects
- Monoclonal antibodies: very expensive
What are the Canadian Asthma Consensus Guidelines criteria for acceptable control of asthma?
- Daytime symptoms < 4 days/week
- Night-time symptoms < 1 night/week
- Normal physical activity
- Mild, infrequent exacerbations
- No absenteeism due to asthma
- Fewer than 4 doses/week of SABA needed
- FEV1 or PEF >85% of personal best or greater (ideally 90%)
- Diurnal variability in PEF less than 15%
- What are the 2 main caracteristic of COPD ?
- It’s a slowly progressive disorder resulting from __________ and/or ______________
- Main caracteristics :
- Increased airway resistance to airflow
- decreased lung/chest wall elastic recoil
- It’s a slowly progressive disorder resulting from emphysema and/or irreversible reduction in the caliber of the small airways (non-respiratory bronchioles) aka bronchiolitis
What is emphysema ?
- A condition of the lung characterized by abnormal and permanent enlargement of airspaces accompanied by the destruction of alveolar walls without significant fibrosis
- explain the pathogenesis of emphysema
- Why is cigarette smoke a risk factor for emphysema
- Neutrophils in the lungs die and release proteolytic enzymes (proteases) that can digest elastin and collagen, and then destroy the underlying lung. Macrophages produce the same thing in the alveoli.
- naturally, the body uses serum alpha 1 antiproteases produced by the liver to block the effect of those proteases (there’s a balance)
- Cigarette smoke lead to an increase of neutrophils in lung tissue, delay their transit, augment the amount of neutrophil elastase and increase the neutrophil elastase release leading to a debalancement of this equilibrum leading to ephysema
what’s a bullae ?
When the cystic spaces of emphysema becomes larger than a centimeter = bullae in the case of paraseptea emphysema
In COPD, by what is caused the airway limitation ?
- ↓ lung elastic recoil pressure : reduces the driving pressure flow because of the destruction of the elastic alveolar walls
- ↓ airway tethering : destruction of elastic recoil leads to narrower luments = increased resistance to airflow
- augmentation of airway resistance (e.g. mucus plugging) : the airways are narrowed by remodelling or mucus
- dynamic compression of the airways
On what is based pharmacologic therapies in the case of COPD ?
On symptoms and exacerbation risk
Appart from medications, what are the possible treatment for COPD ?
-
patient-tailored multi-component intervention (cornerstone of managing COPD)
- exercise training
- disease education
- self-managment
- smoking cessation
- long-term oxygen therapy to achieve a saturation of >90%
what’s the eiology and who do you manage exacebation in COPD ?
- etiology
- infectious (70%)
- bacterial
- viral
- non-infectious (30%)
- pollution
- non-compliance
- pulmonary embolism
- unknown
- infectious (70%)
- management
- antibiotic and corticosteroids are key component of acute COPD exacerbation
What is the prevalence of asthma in Canada ?
- 8,4% canadians older than 12 y.o
- 12% in canadian children
- asthma prevalence has increased over time in adults
How do the component of airway inflammation determine response to therapy ?
Dépendamment si les cells/mediators sont sensible ou non aux stéroides, les course of treatments peuvent être différents pour régler des symptomes différents
how can you mesure lung function to do an asthma diagnosis ?
- PEAK EXPIRATORY FLOW
- if you have a low liability = athma bad
- SPIROMETRY
- obligatoire pour un diagnosis
- key points
- FEV1 and PEF are decreased
- FVC is decreased or unchanged
- FEV1/FVC is decreased
What criteria determine significant reversibility in airflow after bronchodilator administration ?
- Following the administration of a bronchodilator such as salbutamol, an improvement in FEV1 of at least 12% and at least 200ml within 30 minutes.
- Examples:
- FEV1 improves from 1 liter to 1.15 liters after a bronchodilator: not significant bronchodilation
- FEV1 improves from 2 liters to 2.25 liters after a bronchodilator: significant bronchodilation
- Examples:
how do we classify asthma severity ?
by what kind of medication the patient takes to get as good as he can be
Why do ICS is still used today ? What’s the ideal dose ?
- dose-response effect
- asthma mortality rate is reduced with each additionnal cartridge of ICS used and 3 month after stopping the treatment
- asthma exacerbations is reduced. The effect is dose-dependant as weel ad higher ICS doses are more effective
- the ideal dose is 500 mcg daily (1 inhalation twice a day of any of the ICS)
What do we do if high dose ICS don’t work in patient with asthma ?
- add LABA in adults only (rather than upping the ICS dose)
What factors are associated with more severe athsma and a poor response ?
- female
- obesity
- smoking
diffenrentiate asthma and COPD on those clinical features
- age onset
- smoking history (pre-onset)
- allergy
- airflow obstruction
- FEV1 reversibility
- noctural symptoms
- dyspnea
- corticosteroid responsivness
What treatment is longer: TB or non-tuberculous mycobacterial disease?
Non-tuberculous mycobacterial disease is longer (2 years) therefore the compliance is very low.
What promotes and inhibits sleep ?
- Ascending arousal system (monoaminergic, orexinergic) promotes wakefulness
- Inhibition of arousal system by ventro-lateral pre-optic (VLPO) area promotes sleep
- Sleep-wake neuronal systems project to respiratory control centres
What is Obstructive apnea-hyopopnea?
An upper airway collapse during sleep that has many determinants and causes.
What are the causes of Central apnea-hypopnea?
- Hypercapnic
- “Idiopathic”
- Central nervous system lesions
- Congestive Heart Failure: Cheyne-Stokes Respiration: the feed-back is impaired
What is the treatment of Treatment of Cheyne-Stokes Respiration?
Adaptive Servo-Ventilation
What sleeping disorder is associated with severe cardio-vasculaire complications ?
Obstructive apnea-hyopopnea is associated with:
- Hypertension
- Arrhythmias
- Acute coronary events
- Transient ischemic attack/Stroke
- Pulmonary Hypertension
- Congestive Heart Failure
- Increased mortality
Who plays the role of central regulators of hemostasis ?
endothelial cells
What does an endothelial cell injury cause?
- Release endothelin
- Release/activation of pro-coagulants (eg. tissue factor, aka factor III)
What are the 3 elements that control the balance CLOT/BLEEDING in both hemostasis and thrombosis?
- Endothelial cells and vascular wall
- Platelets
- Coagulation cascade
Main steps of hemostasis after injury occurs?
- Arteriolar Vasoconstriction
- Primar hemostasis (formation of initial platelet plg)
- Secondar hemostasis (stabilization of platelet plug)
- Fibrinolysis and dissolution
What causes vasoconstriction?
Endothelin released because of the injury
Who is responsible for the vasoconstriction?
Smooth muscle cells
What are the 3 main steps of primary hemostasis?
Platelet adhesion, activation and aggregation
What are the 2 roles of initial platelet plug?
Form hemostatic plug that seals vascular defects
Provide surface to recruit & concentrate activated coagulation facotrs
What is a platelet?
Anucleate fragment from megakaryocyte that circulate in blood
What are the 3 components of platelet adhesion
- Adhesion via special receptors (glycoprotein 1b) on von Willebrand factor (on exposed ECM)
- Other receptors link to other platelets via platelet-fibrinogen complex
- Continues until platelets fill vascular defects
Describe platelet activation.
- Platelets undergo irreversible shape change after adhesion
- Granules secretion for coagulation & wound headling (calcium: required for several coagulation factors & thromboxane a2: activate additional nearby platelets & role in platelet aggregation)
ALso, wound healing allows re-endothelialisation of vessels.
Platelet aggregation
Shape changes in platelets –> allow for binding to fibrinogen with receptors on other platelets
Leads to aggregation to fill defect & finish forming primary plug
Increasing surface area available for interaction with coagulation factors for secondary hemostasis
In a normal Platelet-Endothelial Interaction, who vasodilates and usually inhibit platelet aggregation?
Prostaglandin PGI2 & NO - synthetized by normal endothelium.
In the platelet-endothelial interaction, during an endothelial injury/thrombosis, who vasoconstricts & enhance platelet aggregation?
TxA2 - synthetized by activated platelets
What drug can help inhibit platelet aggregation?
Cyclo-oxygenase inhibitor, ex ASA (aspirin)
Short definition of secondary hemostasis
Local activation of coagulation cascade (stabilization of platelet plug)
What is the end result of the coagulation cascade, a pathway of multiple factors acting in concert?
Activation of thrombin, which cleaves fibrinogen and forms an insoluble fibrin polymer.
Thrombin also activates more platelets to reinforce plug.
What does fibrin polymerization do?
It leads to cementing the platelets into a definitive secondary hemostatic plug that is more large and stable than the first one; contains entrapped red cells and leukocytes.
What is the only thing we need to know about the coagulation cascade?
A successive series of amplifying enzymatic reactions.
Where do the coagulation factors assemble on a platelet?
On the phospholipid surface
Why is it important to control the coagulation factors?
To prevent inappropriate and potentially dangerous clotting elsewhere in the vascular tree.
How is coagulation restricted to sites of injury? 3 choses
- Blood flow washes away coagulations factors & platelets to limit size of platelet plug
- Limiting enzymatic activation to phospholipid surfaces provided by activated platelets or injured endothelium
- Normal endothelial cells have surface receptors/proteins that are natural anticoagulants (antithrombin iii, protein C)
What other cascade is activated by platelet plug formation? (We say it’s the end-product of the coagulation cascade)
Fibrinolytic cascade
What is the role of fibrinolytic cascade?
Limits the size of the clot and contributes to its later dissolution.
- Largely done with enzymatic activation of plasmin, which breaks down fibrin.
- Plasmin generated from plasminogen, by plasminogen activators
What is the Thrombosis Virchow’s Triad
Endothelial injury/dysfunction
Hypercoagulability
Abnormal blood flow
What bacterial product can be use to lyse clots?
Streptokinase
What will we find in blood that could help us diagnose abnormal thrombotic state and why?
Elevated levels of FSPs: fibrin split products. Something that is produced when fibrinolysis happens.
What can be 2 characteristics of a dysfunctional endothelium?
- More procoagulant factors (ex,tissue factor)
- Less antifibrinolytic factors (ex,thrombomodulin, PGI2, t-PA)
What can cause an endothelial injury/dysfunction in a thrombosis?
- Myocardial infarction
- Atherosclerosis
- Traumatic/inflammatory injury(vasculitis)
- Hypertension
- Turbulent blood flow
- Bacterial products
- Radiation injury
- Metabolic abnormalities (Hypercholesterolemia,homocystinuria)
- Toxins(cigarette smoking)
In a normal blood flow, what is the type of flow and where are platelets/blood cells ?
Laminar blood flow and found in the center of the lumen
(Plasma is on the sides)
Why does abnormal blood flow lead to coagulation?
Because it activates the endothelial cells because of the flow-induced changes in endothelial gene expression
2 types of abnormal blood flow ? What are they factor for ?
- statis (something physically blocks the flow)
- factor for venous blood clots
- turbulence (clotthing factors are on th e border instead of the middle where they usually are)
- factor for cardiac and arterial thrombi
What does turbulence flow cause?
Countercurrents and local pockets of stasis –> leads to endothelial injury and dysfunction