Week 5 resp Flashcards
Describe restrictive lung complaince in terms of FEV1, FVC and their ratio
Low FEV1 and LOW FVC but FEV1/FVC is normal ratio
What is the interstitum?
The connective tissue space around the airways and vessels - The space between the basement membranes of the alveolar walls
What material reduces the compliance of the lung and impaedes the elasticity of the alveoli?
Collagen
Describe the characteristics of restrictive lung disease
Reduced gas transfer
Diffusion abnormalities
Ventilation/Perfusion imbalances
small airways are affected by pathology
Is there airflow limitation in restrictive lung disease
Nope
What are the clinical presentations for restrictive lung disease
Discovery of abnormal CXR
Dyspnoea
resp failure - type 1
HF
What are 3 chronic outcomes from a parenchymal (intersitial) lung injury
Usual interstitial pneumonitis
Granulomatous responses
Other patterns
What does DAD stand for?
Diffuse alveolar damage
What is DAD associated with?
major trauma Chemical injury/toxic inhalation Circulatory shock Drugs Infection Autoimmune disease Radiation However can still be idiopathic
Describe the exudative stages of DADs
within first 7 days
Oedema and hyline membranes
- Oedema: arises immediately. vessels become massively leaky, moreso than in a normal response (typically gone by day 3)
- Hyline membranes: arise after a day, decreased to half its peak value by 7 days. Contain lots of proteins
Describe the proliferative stage of Dads
A combination of interstitial fibrosis and interstitial inflammation
What are the histological features of DADs
Protein rich oedema
Fibrin
Hyaline membranes
Denuded basement membranes
What is the most common interstitial lung disease?
Sarcoidosis
Apart from sarcoidosis what is the other granulomatous response?
Hypersensitivity pneumonitis
Describe the histopathology of sarcoidosis
Epitheloid and giant cell granulomas
necrosis/Caseation very unusual - Differentiates from TB
Little lymphoid infiltrate
Variable associated fibrosis
Describe the presentation of sarcoidosis
- Young adult: Acute arthralgia, arythema nodosum, Bilateral hilar lymphadenopathy
- Incidental Abnormal CXR: No symptoms
- SOB, cough and abnormal CXR
What is the treatment for sarcoidosis
Corticosteroids
Describe the acute presentation for hypersensitivity pneumonitis
Fever, dry cough, myalgia
Chills, 4-9 hours after Ag exposure
Crackles, tachypnoea, wheeze
Precipitating antibody
What is the chronic presentation of hypersensitivity pneuomonitis
Malaise, SOB, Cough
Low grade illness
Crackles and some wheeze
[Can lead to rep failure, gas transfer low, history important]
What type of hypersensitivity causes hypersensitivity pneuomnitis?
immune complex mediated combined Type II and Type IV hypersensitivity reaction
Hypersensitivty pneumonitis is said to cause Bronchiolitis obliterans, what does this mean?
Inflammatory obstruction of bronchioles, these bronchioles become damaged and ingflamed by chemical particles or respiratory infections. Features extensive scarring that blocks airways.
What are the casues of usual interstitial pneomonitis?
Connective tissue diseases: scleroderma and rheumatoid disease Drugs Asbestos Viruses Idiopathic/Cryptogenic reasons
Describe the interstitium of a patient with UIP
Patchy chronic inflammation
Type 2 pneumocytes hyperplasia
Smooth muscle and vascular proliferation
Proliferating fibroblastic foci
What are Proliferating Fibroblastic Foci
nodules of fibrous tissue in the walls of the alveoli, reflect the severity of the disease
What is the clinical presentation of idiopathic pul fibrosis?
Dyspnoea, cough
Basal crackles, cyanosis, clubbing
Prognosis for idiopathic pul fibrosis?
<5 years
Describe type 1 resp failure
PaO2 <8kPa (PaCO2 normal or low)
Describe type 2 resp failure
PaCO2 >6.5 kPa (PaO2 usually low)
What is the resut of alveolar hypoventilation on PACO2 and PAO2 ?
Hypoventilation increases the PACO2 and therefore decreases PaCO2
Increased PACO2 takes up space in the alveoli and therefore causes PAO2 and PaO2 to fall
How can you correct a fall in PaO2 due to hypoventilation?
Raising the FIO2
What is the commones cause of hypoxaemia clinically?
V/Q mismatch
Why is normal V/Q ration 0.8?
Normally breath 4 l/min. CO is 5 l/min so normal V/Q is 4/5 or 0.8
How can you treat hypoxaemia due to low V/Q?
Increase in FIO2
What are the pleural cases of restrictive lung disease
Pleural effusion
Pneumothorax
Pleural thickening - asbestos related pneumonia
What are the skeletal causes of restrictive lung diseases
Kyphoscoliosis
Ankylosing spondylitis
Thoracoplasty
Rib fractures- soreness
What are the muscular causes of restrictive lung disease
Amyotrophic lateral sclerosis
Obesity - sub diaphragmatic - diaphragm can’t fall properly
Pregnancy - sub diaphragmatic
What is sarcoidosis?
Multisystem granulomatosus disease of unknown cause
What is the histological hallmark of sarcoidosis
Non-cesating granuloma
What are the clinical signs of sarcoidosis
Eythrma nodosum
Typically who gets sarcoidosis?
Adults < 40
Women > men
World wide
When would you treat sarcoidosis with NSAIDS?
Erythema nodosum/arthralgia
When would you treat sarcoidosis with Topical steroids?
Skin lesions/anterior uveitis/Cough
When would you treat sarcoidosis with systemic stroids?
Cardiac, neurologica, eye disease not responding to topical Rx, hypercalcaemia
What is the typical presentation for idiopathic pul fibrosis
Crhonic SOB and cough
Typically 60-70 years old, commoner in men
Failed Rx for LVF or infection
Clubbed and crackles
How does fibrotic tissue vary in the lung?
Usually most prominent in the peripheral tissue, central tissue is usually unaffected- worsens as severity of the condition increases
How do large shunts respond to increases in FlO2?
Poorly, dont do it pal
What is FLO2?
The fraction of inspired air which is oxygen
Define obstructive sleep apnoea
Recurrent episodes of upper airway obstruction leading to apnoea during sleep
Describe the presentation of obstructive sleep apnoea
Usually associated with heavy snoring
Typically un-refreshing sleep
Daytime somnolenece/Sleepiness
Poor daytime concentration
What score in the epworth questionare is considered abnormal?
11 or higher
Describe the severity of sleep apnoea with reference to the desaturation rate/AHI
0-5: normal
5-15: Mild
15-30: Moderate
>30: severe
Describe the treatment for sleep apnoea
Identify and discourage exacerbating factors (wieght, alcohol)
diagnose and treat possible endocrine disorders
Mandibular repositioning splint
Define narcolepsy
A chronic sleep disorder characterised by overwhelming daytime drowsiness and sudden attacks of sleep
What are the clinical features of narcolepsy
Cataplexy - where person suddenly collapses and seems to be asleep but is aware of what is going on around them
Excessive daytime somnolence
Hypnagogic/Hyponopomic hallucinations
Sleep paralysis
What is the treatment for narcolepsy
Modafinil
Dexamphetamine
Venlafzine
Sodium Oxybate
Define chronic ventilatory failure
Defined by the following factors:
- elevated pCO2 (>6kPa)
- PO2 <8kPa
- Normal blood pH
- Elevated bicarbonate (HC03)
What are the symptoms of chronic ventilatory failure
SOB Orthopnoea Ankle swelling Morning headache Reccurent chest infections Disturbed sleep
What are the 5 stages in the normal growth and development of the lungs
Embryonic Pseudoglandular Canalicular Saccular Alveolar
Describe the embryonic stage of lung development
3-8 weeks
- Lung bud starts to develop as resp diverticulum from the foetal foregut
- At 5 weeks 2 primary lung buds visible
- Later divide into lobar buds (3 on right 2 on left)
- Like cell from gut, derived from endoderm
- Blood vessels and stuff are derived from endoderm
Describe the pseudoglandular stage of lung development
5-17 weeks
- Rapid branching of airways
- will be 16-25 primitive segmental bronchi which will continue to elongate and wider in later phases
- Development of specialised cells (cillia)
Describe the Canalicular stage of lung development
16-26 weeks
- When lungs develop distal architecture
- Terminal bronchiole, alveolar sacks and capillaries form gas exchange units
- Type 1 and 2 pneumocytes are formed
- In later stages, presence of gas exchange units make possible for premature delivery and survive with support - described as the limit of viability
Describe the Saccular stage of lung development
24-38 weeks
- Bronchioles elongate and interstitial tissue between sacs reduce
- Alveolar sacs grow in size and become well formed
- More surfactant is produced
- Alveolar walls become thinner
Describe the alveolar stage of lung development
36 weeks, term and beyond
Can sustain breathing without support
Describe laryngomalacia
Floppiness of airway - Dynamic abnormal collapse of voicebox
- Commonly seen in infants
- Presents with stridor, worse with feeding when upset/excited
- Will improve within first year
- Concern if affects feeding, growth or causes apnoeas
Describe tracheomalacia
Floppiness of trachea
- Can be isolated in healthy infants
- Associated with genetic conditions
- May be caused by external compression
Describe the presentation of tracheomalacia
- Barking cough
- Recurrent ‘croup
- Breathless on exertion
- Stridor/wheeze
Describe the management of tracheomalacia
Includes physio and abx when unwell
Natural history resolution within time
Describe a tracho-oesphagoeal fistula
- Abnormal conenction between trachea and oesophagus
- Majority have associated oesophageal atresia
- Associated with genetic conditions
- May be diagnosed anteneally or postnatally
What is the presentation of a tracho-oesphagoeal fistula
- Choking
- Colour change
- Cough with feeding
- Unable to pass NG
What is the treatment of a tracho-oesphagoeal fistula
- Surgical repair
- Complications include:
tracheomalacia
Strcutres due to narrowing of oesophagus
Leak
Reflux
Describe congenital pulmonary airway malformations
Abnormal non functioning lung tissue
- 80% detected antenatally
- Occur sparodically
- May resolve in utero
- Conservative management if asymptomatic
- Surgical intervention may be required
- Possible risk of malignant change
Describe a conegntial diaphragmatic hernia
= when diaphragm doesnt close
- CDH affects 1 in 2500 births
- Usually left side > right side
- Most diagnosed antenatally
- Some cases diagnosed late
- Managment = surgical repair
- Prognosis depends on degree of lung hpoplasia
Describe the genetics of CF
Single gene disorder - autosomal recessive - most common in caucasians
How many people ae carriers of CF?
1 in 25 people
How does CF occur?
Due to mutation in the transmembrane conductance regular protein which is coded on chromosome 7
What is the implications of abnormal transport of chloride and sodium?
- reduced airway surface liquid
- Thick sticky mucous
- Shearing
- Impaired bacterial killing via neutrophils
How many classes of Cf are there?
6
Describe the 6 classes of CF
Class 1-3 is severe deisease
Class 4-6 is milder
Describe the antenatal testing methods in CF
= Preimplantation genetic diagnosis
Chorionic villous sampling
Amniocentesis
Describe the neonatal screening for CF
Nowborn bloodspot (day 5_ - Gurthie test Sweat testing - measures onc. of chloride excreted in sweat elevated in CF - Tests usually repeated to confirm - Less reliable in adults
Describe the parameters of the results of a sweat test for CF
30-59 = inconclusive
<30 in infant over 6 months old = probably not CF
60 or over = CF
What are the different systems affected by CF?
Pancreatic insufficiency
Diabetes
Lung infection and bronchiectasis
Describe pancreatic insuffiency within CF
The pancreas produces enzymes that digest food. lack of these enzymes leads to malabsorption, abnormal stools and a general failure to thrive girlie.
- There are 6 classes of CF - thus 6 levels of pancreatic function
- Class 1-3 are pancreatic insufficient
- Class 4-6 have some pancreatic function
- Only need about 5% of CFTR function to have sufficient function and be asymptomatic
Describe what reccurrent chest infections may occur as a result of CF
Pneumonia
Bronchiectasis
Scarring
Abscesses
Why do pulmonary infections occur in CF?
- There is abnormal electrolyte transport across the cell membrane
- Dehydration of airway surface layer (water layer which allows muccous of to slide easily up airway to be coughed up
- Thus there is a decreased mucocillary clearance
- Mucous sticks to mucosal surface and causes shearing damage
- This causes increased bacterial adherance and decreased bacterial killing
What is the overarching effect of reccurent resp infections in CF
Cause progressive respiratory decline due to progressive bronchiectasis -> chronic sputum production
Is nail clubbing present in CF
It CAN BE
Describe the management of pancreatic insufficiency in CF
- Need to boost nutrition
- Can replace enzymes with CREON -> need to tkae 30-40 per day so tend to dak handful with meals
- Given high energy diet plus calorie supplement drinks
- Given nutritional suppliments: Fat soluble vitamin and mineral supplements
Describe the management of the respiratory features of CF
- Mucous obstruction inflammation: Airway clearance via physiotherapy, mucolytics and bronchodilators
- Chronic infection: abx
- Increased inflammation: Azithromycin
- Fibrosis/Scarring/Bronchiectasis: supportive treatment and management of symptoms
What are other aspects of CF
Diabetes
Osteoporosis
Pneumothorax
Haemoptysis
Describe the aspect of diabetes in CF
- type of diabetes and management differs from non CF patients
- Joint diabeteic/CF clinicls and CF dietician vital
- Type 2 is the commonest type seen in CF
[not enough insulin from pancreas or insulin not working properly] - type 1 is very rare in CF
[no insulin made]
Describe the aspect of osteoporosis in CF
- BMD falls in patients with CF
- Slower gain, faster loss, worse the sicker you are
- increased risk of fractures
- May exclude lung transplant
- Treatement = bone protection drugs, wieght bearing exercises
Describe haemoptysis as an aspect of CF
= Bronchial wall destruction causing coughing up of blood
- Minor haemoptysis is very common (60%) - blood streaking, no specific treatment
- Massive haemoptysis in 1% of pts each year: May be preceded by ‘gurgling’ in chest. Admit patients with this and resus. May need bronchial angiogram and embolisation
Describe the pathophysiology of a pul embolism
Thrombus form sin the venous system. usually in deep veins of the legs and embolisms to the pulmonary arteries
What are the symptoms for a pulmonary embolism
pleuritic chest pain, cough and haemoptysis
Isolate acute dysponea
Syncope or cardiac arrest (MASSIVE PE)
What are the signs of a PE
- Pyrexia, pleural rub, stony dullness to percussion at base (pleural effusion)
- Tachycardia, tachypnoea, hypoxia
- Tachycardia, hypotension, tachypnoea, hypoxia
What is the treatment for PE
Oxygen
Low molecule weight heparin eg dalteparin
Warfarin
Direct oral anticoagulants (DOAC): Rivaroxaban, apixaban
Thrombolysis: Alteplase (rt-PA)
Pulmonary embolectomy
What is pulmonary hypertension
Elevated blood pressure in the arterial tree
Defined as a mean pul artery pressure of >25mmHg
Either primary or secondary to other conditions
