Respiratory Flashcards
(95 cards)
1
Q
What causes respiratory distress syndrome in newborns?
A
Lack of surfactant
No reduction in surface tension, so smaller alveoli collapse
2
Q
What is diffuse lung fibrosis?
A
Replacement of normal capillaries, alveoli and healthy interstitium with more interstitial tissue
3
Q
What is the effect of pulmonary fibrosis.
A
Thickened capillary membrane increases diffusion distance for O2 and CO2
Impairs has exchange
4
Q
What are the symptoms of pulmonary fibrosis?
A
Breathlessness
Dry cough
5
Q
What is a sign of pulmonary fibrosis?
A
Bilateral reduction in chest expansion
6
Q
What is emphysema?
A
Abnormal, permanent enlargement of air spaces distal to terminal bronchiole
Reduced elasticity due to destruction of elastin
Large air spaces causes reduced surface area for gas exchange
7
Q
What is the most common cause of emphysema?
A
COPD
8
Q
What occurs in carbon monoxide poisoning?
A
Hb has a v high affinity for CO
Unaffected subunits of Hb gain a higher affinity for O2, so they don’t give it up at tissues
9
Q
What is type 1 respiratory failure?
A
pO2 <8kPa
O2 sats <90%
pCO2 normal or low
10
Q
What is type 2 respiratory failure?
A
Low pO2
High pCO2
11
Q
What are some causes of hypoxia?
A
Low inspired O2 due to environmental problem Right to left shunt Hypoventilation V/Q mismatch Diffusion defect
12
Q
What are some causes of acute hypoventilation?
A
Opiate overdose
Head injury
V severe acute asthma attack
13
Q
What are some effects of acute hypoxaemia?
A
Impaired CNS function
Cyanosis
Cardiac arrhythmias
Hypoxic vasoconstriction of pulmonary vessels
14
Q
What are some effects of acute hypercapnia?
A
Respiratory acidosis
Impaired CNS function
Peripheral vasodilation
Cerebral vasodilation
15
Q
What are some effects of chronic hypoxaemia?
A
Increased EPO => raise Hb
Increase 2,3-BPG
Chronic vasoconstriction to under-perfused areas => pulmonary hypertension, cor pulmonale
16
Q
What are occurs in chronic hypercapnia?
A
CO2 diffuse into CSF => lowers pH
Low pH damages neurones, so need to compensate
Choroid plexus secretes HCO3- into CSF to bring pH to normal
Although pCO2 is high, central chemoreceptors no longer respond to it
17
Q
What is asthma?
A
A chronic inflammatory airway disease characterised by intermittent airway obstruction and hyper-reactivity
18
Q
What is the pathophysiology of asthma?
A
Chronic inflammation driven by TH2
Release of cytokines attracts and activates mast cells and eosinophils
Activation of B cells => IgE production
19
Q
What changes to airways in asthma result in airway obstruction?
A
Mucosal oedema Infiltration of inflammatory cells Over production of mucus Smooth muscle contraction Shedding of epithelium
20
Q
What are symptoms of asthma?
A
Dry, nocturnal cough
Wheeze
Breathlessness
Tight chest
21
Q
What are signs of asthma?
A
High resp rate High pulse Low O2 sats Bilateral wheeze Atopy - eczema, hayfever
22
Q
In asthma, what are the effects on gas exchange?
A
Airway narrowing => reduced ventilation of affected alveoli => V/Q mismatch
23
Q
What are signs and symptoms of acute severe asthma attacks?
A
Pt can’t complete full sentences Wheezing Hypoxic (sats still >92%) Tachypnoeic >25 Tachycardia >110bpm
24
Q
What are signs and symptoms of a life threatening asthma attack?
A
Exhaustion Silent chest due to little airflow Altered consciousness Central cyanosis Reduced resp effort Bradycardia Hypotension O2 sats <92%
25
What is COPD?
Obstruction to airflow
| Umbrella term for emphysema and chronic bronchitis
26
What occurs in emphysema?
Destruction of terminal bronchioles and airspaces
Leads to loss of alveolar surface area
Causes destruction of supporting tissue surrounding small airspaces => collapse of airways during expiration
Loss of elastic tissue causes hyperinflation of lungs
27
What is chronic bronchitis?
Chronic mucus hypersecretion
Caused by inflammation of large airways => proliferation of mucus producing cells
Airflow obstruction is due to remodelling and narrowing of airways
28
What causes COPD?
Mostly caused by smoking
Other causes include:
α1-antitrypsin deficiency
Occupational exposure
Pollution
29
What are some symptoms of COPD?
Productive cough
Progressive breathlessness
Exacerbations are associated with increased breathlessness, cough and sputum production
30
What are some signs of COPD?
```
Pursed lip breathing
Tachypnoea
Use of accessory muscles
Hyperinflation (barrel chest)
Wheezing
```
31
What is the management of COPD?
```
Smoking cessation
Bronchodilators => symptomatic relief
Antimuscarinics
Steroids => reduce inflammation
Mucolytics => reduce sputum thickness
```
32
What is bronchiectasis?
Chronic dilatation of one or more bronchi
| Bronchi also have poor mucus secretion which predisposes to infection
33
What are symptoms of bronchiectasis?
```
Chronic cough
Daily sputum production
Breathless on exertion
Intermittent haemoptysis
Chest pain
Wheeze
```
34
What are the causes of bronchiectasis?
Post infective; whooping cough, TB
Immune deficiency
Mucociliary clearance defects; CF
35
What is the management of bronchiectasis?
Physio/airway clearance
Sputum sampling
Exclude immunodeficiency
Flu vaccine
36
What are common causative organisms of bronchiectasis?
```
Haemophilus influenzae
Pseudomonas aeruginosa
Streptococcus pneumoniae
Aspergillus
Candida albicans
```
37
What is cystic fibrosis?
Mutation in CFTR gene from an autosomal recessive condition
Leads to ineffective cell surface chloride transport
Results in thick dehydrated body fluids in organs which express the CFTR gene
38
What is the presentation of cystic fibrosis?
Meconium ileus - bowel obstruction, delay in passing meconium
Intestinal malabsorption- deficiency in pancreatic enzymes
Chest infections
39
What are some complications of CF?
```
Lungs - bronchiectasis, pneumothorax
Upper resp tract - chronic sinusitis, nasal polyposis
Pancreas - DM, pancreatic insufficiency
Liver - cirrhosis
Biliary tree - gallstones
Repro - male infertility
```
40
What are some organisms that cause lower respiratory tract infections?
```
Common;
Viridans streptococci
Neisseria
Anaerobes
Candida
```
Less common;
Streptococcus pneumoniae
Streptococcus pyogenes
Haemophilus influenzae
41
What are usual defences of the respiratory tract?
Ciliated columnar epithelium and nasal hairs
Cough and sneeze reflexes
Lymphoid follicles of pharynx and tonsils
IgA and IgG
42
What are some examples of LRTIs?
```
Bronchitis
Bronchiolitis
Bronchiectasis
Pneumonia
Empyema
Lung abscess
```
43
What occurs in acute bronchitis?
Inflammation of medium sized airways
Most commonly caused by S. pneumoniae
Symptoms;
Cough, fever, sputum production, SoB
Treat;
Bronchodilation, physiotherpy, maybe abx
44
What is pneumonia?
Inflammation of the alveoli
Consolidation of lungs seen on CXR
45
How does pneumonia present?
Fever
Cough
Pleuritic chest pain
SoB
46
How is pneumonia classified?
Clinical setting;
Community or hospital acquired
Presentation;
Acute or chronic
Lung pathology;
Lobar, bronchopneumonia or interstitial pneumonia
47
What organisms commonly cause community acquired pneumonia?
```
Streptococcus pneumoniae
Haemophilus influenzae
Staphylococcus aureus
Moraxella catarrhalis
Klebsiella pneumoniae
```
48
What are symptoms of community acquired pneumonia?
```
SoB
Cough +/- sputum
Fever
Rigours
Pleuritic chest pain
Malaise
Nausea and vomiting
```
49
What are signs of pneumonia?
```
Pyrexia
Tachycardia
Tachypnoea
Cyanosis
Dullness to percussion
Bronchial breathing
Crackles
```
50
What is atypical pneumonia?
Caused by organisms without a cell wall
| Therefore requires abx which act on protein synthesis
51
What is hospital acquired pneumonia?
Pneumonia which occurs after >48 hrs in hospital
```
Common organisms:
Staph aureus
Pseudomonas
H influenzae
Fungi eg Candida
```
52
What is aspiration pneumonia?
Aspiration of endogenous or exogenous secretions into the respiratory tract
Common in pts with neurological dysphagia, epilepsy, alcoholics or drowning
Often caused by a mixed infection;
Viridans streptococci and anaerobes
Treated w/ co-amoxiclav
53
How is pneumonia prevented?
Immunisation - flu vaccine
Chemoprophylaxis - oral penicillin/erythromycin for pts w/ high risk of LRTI
Smoking cessation
54
What are the stages of pneumonia?
1) Congestion; days 1 - 2
2) Red hepatisation; days 3 - 4
3) Grey hepatisation; days 5 - 7
4) Resolution; day 8 - 3 weeks
55
What happens in the congestion stage of pneumonia?
Blood vessels and alveoli fill with excess fluid
56
What happens in the red hepatisation phase of pneumonia?
Exudate (RBCs, neutrophils and fibrin) fill air spaces => more solid
Appearance resembles liver
57
What happens in the grey hepatisation stage of pneumonia?
Tissue is still firm
| Colour change due to break down of RBCs in exudate
58
What happens in the resolution stage of pneumonia?
Exudate is digested, ingested or coughed up
59
What is tuberculosis?
A common worldwide bacterial infection
| Affects the lungs, and can progress so affect other systems
60
What bacteria causes TB?
Mycobacterium tuberculosis - most common
M bovis
M africanum
61
Describe the structure of the bacteria causing TB
Non-motile rod shaped
Obligate anaerobe
Cell wall contains lots of fatty acids and glycolipids - gives structural rigidity and staining characteristics (acid fast, red in Ziehl-Neelsen stain)
62
How is TB spread?
Inhalation
63
What is the natural history of TB?
Primary TB
Latent TB
Reactivation
64
What occurs in primary TB?
Macrophage ingests mycobacterium
Mycobacterium produces proteins which inhibit lysosomal breakdown
Mycobacterium proliferates
A granuloma is produced to inhibit spread of infection
Caseous necrosis occurs in the granuloma - Ghon focus
This caseating tissue can spread to hilar lymph nodes
65
What occurs post-primary TB infection?
Fibrosis of Ghon complex => Ranke complex
Most often TB is killed off
Other times it can remain still viable, but walled off
66
What are some risk factors for reactivation of TB?
```
AIDS
Substance abuse
Corticosteroids
Organ transplant
Diabetes mellitus
Low BMI
```
67
When should you suspect TB?
Non-UK born, recent migrants or travel
HIV or other immunosuppressed states
Homeless
Close contact w/ TB pts
68
What are symptoms of pulmonary TB?
```
Fever
Night sweats
Weight loss
Anorexia
Tiredness/malaise
Haemoptysis
Breathlessness
```
69
What are signs of pulmonary TB?
Crackles in affected lobe
Signs of effusion if pleura is involved
Extensive disease can show signs of cavitation and fibrosis
70
What is the treatment for TB?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
These are given for two months, then rifampicin and isoniazid for a further four months
71
What is miliary TB?
Spread of the bacilli through the blood causing a widespread infection
Occurs in either primary infection or reactivation
72
What can miliary TB affect?
Headache; meningeal involvement
Pericardial or pleural effusion
Ascites
Retina; choroid tubercles
73
How is active TB diagnosed?
CXR
Samples; sputum, pus, biopsy
Ziehl-Neelson stain; rapid direct microscopy for acid fast bacilli, TB shows up red
74
How is latent TB diagnosed?
Mantoux test - tuberculin skin test
However can have a false positive in pts who have had BCG
75
What is a pneumothorax?
Presence of air in the pleural space resulting in a collapsed lung
76
What are the symptoms of a pneumothorax?
```
Sudden onset chest pain
Sharp, localised pain
Tachycardia
Tachypnoea
Cough
```
77
What is a primary spontaneous pneumothorax?
Rupture of an underlying small sub-pleural bulla
| Most commonly occurs in young, thin, tall males with no predisposing factors
78
What causes a secondary pneumothorax?
Underlying lung disease; COPD, asthma, bronchiectasis
Trauma; fractured rib punctures pleura
High pressure ventilation
79
What is a tension pneumothorax?
Occurs when air enters the pleural cavity, but cannot escape due to a flap which closes on expiration
80
What are some signs of a tension pneumothorax?
```
Tachycardia
Hypotension
Raised JVP
Deviated trachea
Displaced apex beat
Silent breath sounds
Hyper-resonance on percussion
```
81
What are some symptoms of a tension pneumothorax?
Severe distress and dyspnoea
Pleuritic chest pain
Fatigue
82
What is a pleural effusion?
Accumulation of fluid in the pleural space
| Either failure of absorption, or overproduction of the fluid
83
How does a failure of absorption cause a pleural effusion?
Most commonly due to hypoproteinaemia (liver failure, nephrotic syndrome)
Congestive heart failure
Lymphatic obstruction
84
How does overproduction of fluid cause a pleural effusion?
Increased capillary permeability
| Inflammation; infection or pulmonary infarct
85
What are some signs and symptoms of a pleural effusion?
```
Chest pain
Dry cough
Fever
Orthopnea
SoB
Difficult taking deep breaths
Persistent hiccups
```
86
What is a pulmonary embolus?
Part of a thrombus from the venous system which has broken off, travelled through the right side of the heart and lodges in the pulmonary arteries
87
What are some risk factors for thromboembolism?
```
Smoking
Pregnancy
Obesity
Prolonged immobilisation
Cancer
Contraceptive pill
```
88
Describe the pathophysiology of PE
Right ventricular overload;
Increase in pulmonary artery pressure => right ventricular dilatation and strain
Release of NA and adrenaline to try to maintain systemic circulation => pulmonary artery vasoconstriction
Respiratory failure;
Areas of V/Q mismatch
Low right ventricle output
Pulmonary infarction;
Small distal emboli => alveolar haemorrhage
Causes haemoptysis, pleuritis and small pleural effusion
89
What are some signs and symptoms of a PE?
```
Dyspnoea
Pleuritic chest pain
Cough
Haemoptysis
Unilateral leg pain
```
Tachycardia
Low BP
Raised JVP
90
What are some differential diagnoses for a PE?
```
Pneumothorax
Pneumonia
Pleurisy
MSK chest pain
MI
Pericarditis
```
91
What are the investigations and findings for a PE?
Blood gases; hyperventilation => respiratory alkalosis (hypoxaemia, hypocapnia)
CXR; mostly normal, used to exclude other diagnoses eg pneumonia
ECG; can have evidence of RV strain, although mostly just get sinus tachycardia
D dimer
92
What is the treatment for a PE?
Oxygen
| Immediate heparinisation
93
How does heparin reduce mortality from a PE?
Stops propagation of the thrombus and allows the fibrinolytic system to lyse the thrombus
Reduces frequency of further pulmonary embolism
Does not dissolve the clot
94
How are high risk PE pts treated?
```
Haemodynamic support
Respiratory support
Exogenous fibrinolytics
Percutaneous catheter directed thrombectomy
Surgical pulmonary embolectomy
```
95
What treatment is there for PE pts after initial heparinisation?
Oral anticoagulant eg warfarin, rivaroxaban
