CSIM lungs Flashcards
three reasons you see a diffusely abnormal CXR?
- impaired gas transfer
- reduced lung volume
- restrictive ventilatory function (stiffened or shrunken lungs)
ratio of FEV1 : FVC in an obstructive picture?
FEV1 < FVC
< 70% is diagnostic
in obstructive disease why is there gas trapping and what symptom does this cause?
bronchiole collapse on expiration
difficult to exhale completely
when is bronchiolitis seen in adults?
transplants
rheumatoid disease
idiopathic
chemical exposure
Lung biopsy - focal bronchiolar fibrosis and fibroblast proliferation
most likely diagnosis?
bronchiolitis
define bronchioles
branches of a bronchus that are smaller than 2mm and have NO cartilage
what is hypersensitivity pneumonitis?
AKA extrinsic allergic alveolitis - inflammation of the alveolar due to inhaled dust particles
define pneumoconiosis and give examples
lung disease from mineral dust
it can be fibrogenic or non-fibrogenic
silicosis
coal works pneumoconiosis
asbestosis
those are all FIBROGENIC
who is at risk of silicosis
working with:
concrete
sand blasting
artificial stone
why is sand not dangerous?
silica only dangerous when an unnatural force is applied to it to make it smaller
characteristic finding on biopsy in silicosis?
dense fibrosis with bi-refringent particles
characteristic finding on biopsy in coal miners pneumoconiosis
Dust accumulation around terminal bronchioles with fibrosis
light exposure to asbestos is associated with what?
pleural disease (mesothelioma, pleural plaques /fibrosis )
need heavy exposure to affect lungs
what is the radiological marker of asbestos exposure?
pleural plaques - these will be asymptomatic
whos at risk of siderosis and what is it?
welders - this is a non-fibrogenic pneumoconiosis
what do pleural plaques look like on CXR?
holly leaves (they dont really)
most common complication of pleural plaques?
benign diffuse pleural thickening -> fluid accumulation -> breathlessness
two things that can help differentiate ILD from asbestosis?
IDL :
dont get plaques
can get clubbing ( never clubbing in asbestosis)
when does malignant mesothelioma present?
~30 yrs post exposure
why is there a reduced lung volume in malignant mesothelioma ?
diffuse pleural thickening
what are TLCO and KCO?
they are both measurements of the transfer factor of CO
they are used to assess the integrity of the gas–exchanging part of the lung
TLCO = transfer factor for the lung for carbon monoxide i.e. Total diffusing capacity for the lung KCO = transfer coefficent i.e. Diffusing capacity of the lung per unit volume, standardised for alveolar volume (VA)
what systemic symptom is there in extrinsic allergic alveolitis?
shivers after exposure due to immunological response
4 causes of L tracheal deviation?
- right tension PT
- L lobar collapse
- goitre
- right pleural effusion
5 causes of unilaeral pleural effusion
lung cancer mesothelioma TB pneumonia asbestosis
how does asbestosis cause pleural effusion?
diffuse pleural irritation causes the blood vessels to be leaking
how is a pleural tap made safer?
US guidence
what tests are done on pleural fluid?
bio chem: protein, glucose, pH, LDH (lactate dehydrogenase)
culture and sensitivity
TB test
sensitivity and specificity in cytological exam of pleural fluid?
looking for cancer cells:
if present then definitely cancer
not always present in cancer
i.e. specific not sensitive
differences on CT between benign and malignant pleural disease
malignant mesothelioma: lumpy and affects the whole way round the lung including mediastinum
benign: just thicker but still smooth
what screening would you do for mesothelioma in people who are a high risk?
none because there is no treatment :(
commonest cause of new onset breathlessness before 32?
asthma
some occupations that increase risk of astma
farming
painting
plastics
cleaning
what type of allergen react with specific IgE antibodies?
high molecular weight allergens e.g. flour
when does occupational asthma occur?
normally within a year of new work after a latent interval of symptomatic exposure
when in the day is occupational asthma worst?
at work and evening / nighttime
how much asthma is occupational
1/6 cases
on going exposure to occupational allergens can lead to what?
progressive and permanent asthma
what immunological investigations can be done to help diagnose asthma?
RAST: specific IgE
skin prick test
what is the airway responsiveness test and when is it used?
inhale bronchoconstrictor (histamine) and see how much the airway narrows asthmatics narrow more
4 types of investigation in diagnosing occupational asthma
immunological
serial PEF
serial airway responsiveness test
inhalation challenge (inhale allergen)
diagnosis on Hx alone is unreliable
who’s duty to report occupational hazards?
the employer
what is a RAST test and how is that different to a skin prick test?
Radioallergosorbent test - blood test for specific IgE antibodies to determine the substance to which a person is allergic to
skin prick test looks at how the skin reacts to different substances
define chronic bronchitis
Chronic or recurrent excessive mucus secretion in the bronchial tree due to irritation
productive cough lasting longer than 3 months on two consecutive years
define emphysema
An increase beyond the normal in the size of the air spaces distal to the terminal bronchiole accompanied by destruction of their walls and without obvious fibrosis
basically destruction of the alveolar walls increases the size of the air spaces
which drug given in COPD can be considered a disease modifying drug and why?
regular tiotropium leads to reduced hospitalizations due to exacerbations
treatment pathway for COPD
smoking cessation
flu jab
SABA
LAMA
ICS / LABA
pulmonary rehab
how can anxiety in COPD be addressed?
CBT
define cor pulmonale
right side HF caused by lung disease
cor pulmonale pathophys. ?
in emphysema all parts of the lung are hypoxic so there is vasoconstriction over the whole lung (an attempt to get blood to parts that ARE well ventilated)
this means the heart is effectively pumping against a ‘closed door’
how is V/Q matching suppose to work?
vasoconstriction in areas of the lung that have poor ventilation means that more blood gets to the better ventilated parts
who is LTOT indicated in?
PaO2 < 7.3 when stable OR PaO2 <8 AND ONE OF - secondary polycaethemia - peripheral oedema - pulmonary hypertension - nocturnal hypoxaemia
define hypoventilation?
abnormal breathing leads to insufficient ventilation causing hypercapnia
how does COPD cause hypoventilation?
increased dead space in the lungs: breaking down the alveolar walls
reduced perfusion:
- due to compression (due to overinflated lungs) of capillaries
- destruction of pulmonary vasculature
define type 2 resp failure
low O2
high CO2
ACIDOTIC
Mx for type 2 resp failure?
O2 aiming for 88-92% (chemoreceptor for CO2 does not stimulate patient to breath so keep them a little bit hypoxic)
steroids, NEBs and maybe abx
consider non invasive ventilation (reduced mortality by 50%)
what is obstructive sleep apnoea?
upper airway narrowing provoked by sleep -> sleep fragmentation -> significant daytime symptoms
pathophys of OSA?
dilator muscles (mainly pharyngeal dilator) fail to maintain airway patency so repeated arousal is needed to reactivate dilator.
some narrowing is normal, it can be excessive when:
- sedatives e.g. alcohol
- NM disorder effecting the pharyngeal muscle
- mass overloading
prevalence of OSA in the UK?
0.5 -1 %
why is OSA more common in men?
fat distribution
clinical features of OSA?
from most common to least:
snoring with periods of apnoea excessive sleepiness / poor concentration loss of libido nocturia unrefreshing sleep nocturnal sweating
exam findings in OSA?
pink (polycythaemia)
obese
associated with acromegaly
large neck circumference
what score can be used to assess tiredness and whats an abnormal score?
Epworth
<9 is abnormal
how does OSA lead to HF?
cor pulmonale due to hypoxia
how does cpap work?
delivers constant pressure to splint airway open
pro and cons of cpap?
highly effective poorly tolerated (dedicated cpap nurse for education)
who must patients inform about OSA?
DVLA ( only allowed to drive after 3 months of compliance with treatment)
best investigation for assessing OSA?
polysomnogram
3 investigations in OSA?
ABG
pulmonary function test
CXR
also always do a neuro-exam
in ILD, what is the interstitium?
the cells between the basement membrane of the alveolar and other alveolar and between the alveolar and capillaries
if ILD is suspected, what questions do you need to ask yourself before tx?
is there an underlying cause?
?sarcoidosis
?acute/ chronic hypersensitivity pneumonitis
what are the possible underlying causes of ILD?
connective tissue disease
drugs
organic dust
inorganic dust
define pneumonia
inflammation of the alveolar
two most common connective tissue diseases associated with ILD?
RA (low percecntage but high burden due to amount of RA) systemic sclerosis (high percentage but low burden as it's rare)
common drugs that cause ILD?
methotrexate (DMARD for RA) amiodarone (for arrhythmias) nitrofurantoin (for UTIs) bleomycin (for cancer) radiotherapy
inorganic dust that cause ILD?
asbestos, coal ( technically organic), silica
organic dust that causes ILD?
farmer’s lung
pigeon fancier’s lung
mould in the house
Raynaud’s phenomenon is typical of what?
connective tissue disease
what questions to ask to rule out CT disease in ILD?
cold/ pale hands
dry eyes / mouth
muscle pain
joint pain
reflux is common in what cause of ILD?
systemic sclerosis
sound of lungs in ILD?
velcro crackles at base of lungs
what do squeaks on inspiration suggest?
hypersensitivity pneumonitis
Ix in suspected ILD?
CXR
CT
appearance of ILD on CXR?
shaggy boarders to the lungs where there has been thickening of the interlobular membranes
what imaging is best in ILD and why?
CT: 1 mm helical scan prone and supine, on insiration and expiration
CXR is very non-specific
in ILD how can you tell fluid from interstitial disease on CT?
do the scan PRONE and SUPINE, if the suspicious area disappears when the patient is turned over then it’s just fluid
why do an expiratory CT scan in ILD?
in ILD: on expiration the bronchioles will snap shut too early and this will lead to a mosaic pattern (air trapping)
define usual interstitial pneumonia
this is the histological hallmark of IPF:
normal healthy alveolar next to destroyed lung
this is also seen on CT
what is it that restricts the lung function on ILD?
band of fibrosis inhibits elastic quality of lung
when is ILD usually diagnosed?
72 yrs
classical presentation of ILD?
progressive breathlessness and dry cough
what is the typical prognosis of ILD?
poor but very varable
blood tests in ILD?
Autoantibodies
- RhF/anti-CCP,
- extractable nuclear antigens (anti-Ro/La/Jo-1)
- Anti-dsDNA,
- ANCA
Angiotensin converting enzyme (ACE)/calcium (sarcoid)
Precipitating antibodies (hypersensitivity pneumonitis)
what is sarcoidosis?
Chronic, multi-system granulomatous disease
of unknown aetiology
diagnosis of sarcoidosis?
diagnosed by characteristic features:
- bilateral lymphadenopathy on the neck
rarely biopsied
what are the three component to pulmonary function tests?
spirometry: FEV1 , FVC
lung volumes: TLC, RV
transfer factor: TLCO, KCO
what is the disadvantage of the transfer factor test?
have to be able to hold breath for 10s , lots of patients cant do that
draw out flow-vol. loops for normal lungs, large airway obstuctioin and small airway obstruction
normal - upside down V
large airway disease- looks like a BURGER
small diffuse airway disease - looks like a church and steeple
on a flow-vol graph:
what is the point where the line crosses the x axis?
what is the top of the curve?
FVC
Peak expiratary flow
how can spirometry be normal in asthma patients?
asthma is a variable and reversible disease
what will TLC and RV look like in an obstructive picture?
TLC -raised due to chronic hyper inflation
RV - raised due to gas trapping
RV in restrictive picture
falls / same
what things decrease the TLCO
Ventilation Perfusion Mismatch - common in many lung diseases
Reduction in the area of alveolar-capillary membrane - e.g. emphysema
Increased thickness of alveolar-capillary membrane - e.g. pulmonary fibrosis
Pulmonary Blood flow - e.g. pulmonary hypertension
Haemoglobin concentration - e.g. anaemia leads to a decrease in TLCO
in a healthy person with one lung what will the KLO and TLCO be?
KLO - 100%
TLCO - 50%
TCLO and KCO in asthma?
both normal
TLCO and KCO in COPD?
both decreased
TLCO and KCO in ILD?
both decreased
in extra-thoracic restrictive conditions e.g. obesity what will the KCO and TLCO be?
TLCO - decreased
KCO - can be increased due to lung working even harder to keep up
what imaging is most useful in ILD?
high resolution CT - more detail in each picture but less frequently taken (every 10mm ish)
what 5 conditions can asbestos cause?
- pleural plaques - asymptomatic
- pleural fibrosis - benign breathlessness
- mesothelioma
- lung cancer
- asbestosis (pulmonary fibrosis caused by asbestos)
which conditions require heavy exposure to asbestos?
lung cancer and asbestosis
