restrictive lung diseases Flashcards
what is meant by the interstitium of lung?
connective tissue space around alveoli
what are some clinical symptoms caused by interstitial lung diseases?
reduced lung compliance
low FEV1 and FVC but usually normal ratio
reduced gas transfer
ventilation perfusion imbalance
how would restrictive interstitial lung disease discovered?
usually by imaging but can also present in patients as dyspnoea upon exertion and at rest as disease progresses
what are the 3 main types of interstitial lung disease ?
sarcoidosis
diffused alveolar damage (DAD)
hypersensitivity pneumonitis
what are the histological features of DAD?
fibrin
protein rich oedema
hyaline membranes
whats DAD associated with?
chemical injury
circulatory shock
drugs
infections/viruses
what are the histological features of sarcoidosis?
giant granuloma formation
what causes hypersensitivity pneumonitis caused?
hypersensitive reaction to organic molecules or antigens
eg. animals, birds & micro-organisms
whats really important about hypersensitivity pneumonitis?
taking a history to find out if the patient has been exposed to organic molecules or antigens
where does hypersensitivity pneumonitis begin ?
centriacinar region
what could hypersensitivity pneumonitis present as?
acute pneumonia but it is more chronic and it gradually deteriorates lung function
what do interstitial lung diseases end in?
end stage fibrosis
whats the normal PaO2 and PaCO2 range?
PaO2- 10.5-13.5kPA
PaCO2- 4.8-6kPA
what stats would define type 1 and 2 respiratory failure?
type 1- PaO2 < 8kPA (PaCO2 normal or low)
type 2- PaCO2 > 6.5kPA (PaO2 low)
what are some causes of hypoxaemia?
ventilation/perfusion imbalance
diffusion impairment
alveolar hypoventilation
shunt
what is the most common clinical cause for hypoxaemia?
ventilation/perfusion imbalance
what is meant by diffusion impairment?
does not change CO2 levels
takes longer for blood and alveolar air to equilibrate
whats the difference in the ventilation of abnormal alveoli between ventilation/perfusion imbalance and shunt?
ventilation/perfusion imbalance- some ventilation of abnormal alveoli
shunt- no ventilation of abnormal alveoli
how would you clinically define restriction?
forced vital capacity <80%
low spirometry volumes
what body parts cause restrictive lung disease?
lungs
pleura
skeletal
muscle
what are the lung causes for restrictive lung disease?
IPF
sarcoidosis
hypersensitivity pneumonitis
what are the pleural causes for restrictive lung disease?
effusions
pneumothorax
pleural thickening
what are the skeletal causes for restrictive lung disease?
kyphoscoliosis
rib fractures
ankylosing spondylitis (kampoura)
what does a granuloma look like in histology?
rugby ball shaped collection of seeds
what tests would you do to diagnose sarcoidosis?
pulmonary function tests bloods urinalysis ECG eye exam
whats the treatment for sarcoidosis?
in increasing severity: -NSAIDS(non steroidal anti-inflammatories)
- topical steroids
- systemic steroids
whats a significant clinical symptom of IPF?
crackles and clubbing
w=how would IPF be treated?
usually palliative can be given oral anti-fibrotics and some patients may be eligible for transplant
what is obstructive sleep apnoea syndrome?
recurrent episodes of upper airway obstruction leading to apnoea during sleep, associated with heavy snoring, daytime sleepiness an poor concentration
how would OSAS be diagnosed?
clinical history and examination
epworth questionnaire (score of >11 is abnormal)
overnight sleep study
whats the treatment for OSAS?
- identify exacerbating factors eg. weight reduction, avoidance of alcohol, diagnose and treat endocrine disorders if present
- continuous positive airway pressure (CPAP)
- mandibular repositioning splint
what are the clinical features of narcolepsy?
cataplexy
excessive daytime somnolence
hallucinations
sleep paralysis
how would you confirm a narcolepsy diagnosis?
polysonography
multiple sleep latency test (MSLT)
low orexin levels in CSF
what medications would be given to treat narcolepsy?
modafixil
dexamphetamine
venlafaxine (for cataplexy)
what are the clinical sats signs of chronic ventilatory failure?
elevated pCO2
pO2<8kPA
normal blood pH
elevated bicarbonate (HCO3)
whats the aetiology for chronic ventilatory failure ?
airway disease
chest wall abnormalities
respiratory muscle weakness
central hypoventilation
what are the symptoms for chronic ventilatory failure?
breathlessness while standing up and lying flat ankle swelling morning headache recurrent chest infections disturbed sleep
what would be a key examination finding of chronic ventilatory failure?
paradoxical abdominal wall motion and ankle oedema
whats the treatment for chronic ventilatory failure?
non invasive ventilation
oxygen therapy
what tests would you carry out to support a chronic ventilatory failure diagnosis?
lung function tests ad assessment of hypoventilation
eg. lying/standing VC, early morning ABG, overnight oximetry
when are congenital abnormalities picked up?
they are present at birth and can be picked up at antenatal screenings (ultrasound,MRI) or in the newborn period
laryngomalacia
abnormal collapse of larynx
presents with stridor, worse when feeding
usually improves within the first year
concern if it affects feeding, sleeping or growth
tracheomalacia
may be caused by external compression (vessels, tumour)
associated with genetic conditions
barking cough, recurrent croup, breathless at exertion and stridor/wheeze
resolves naturally may require physio or antibiotics when unwell
trachea-oesophageal fistula
abnormal connection between trachea and oesophagus
choking, colour change, unable to pass nasogastric tube
surgical repair required
why does respiratory distress syndrome occur ad how is it treated?
occurs because of surfactant deficiency
antenatal steroids, surfactant replacement and appropriate ventilation & nutrition
what is meant by remodelling?
alteration or airway structure allowing external influence which leads to abnormalities
