Resp Flashcards
how do lungs stick to thorax?
intrapleural fluid cohesiveness - water molecules in intrapleural fluid are attacted to eachother so reist being pulled apart
negative intrapleural pressure - transmural pressure gradient so lungs forced to expand outwards while chest squezes inwards
inspiration?
which muscles?
ACTIVE process
muscles = diaphragm (major inspiratory muscle) + external intercostal muscles (bucket handle)
expiration?
normal expiration is a passive process
pneumothorax?
complication?
s/s?
air in pleural space
complication = lung collapse due to abolished transmural pressure gradient
symptoms = SOB + chest pain
signs = hyperresonant percussion + decreased/absent breath sounds
pulmonary surfactant?
secreted by?
mixture of proteins that reduces alveolar surface tension preventing aveolar collapse
secreted by type II alveoli
pulmoary distress syndrome of the newborn?
premature babies = not enough surfactant
pre and postganglionic fibres of airways?
parasympathetic stimulation?
pre = brainstem
post = walls of bronchi and bronchioles
stimulation of cholingeric fibres = bronchial smooth muscle contraction (M3 muscarinic ACh receptors on ASM cells) + increased mucous secretion (M3 on goblet cells)
stimulation of noncholinergic fibres = bronchial smooth muscle relaxion (NO and VIP)
sympathetic stimulation airway?
No innervation to ASM so instead mediated by hormones
B2-adrenoceptors activated by adrenaline from adrenal gland = ASM relaxation + decreased mucous secretion + increased mucocilliary clearance
a1-adrenoceptors = vascular smooth muscle contraction
excitation contraction coupling in smooth muscle
Ca2+ in smooth muscle
relaxation of smooth muscle
activity of myosin light chain kinase and myosin phosphatase
asthma?
Ax?
recurrent reversible obstuction to airways
Ax = allergens, exercise (cold dry air), respiratory infections (e.g. viral), smoke, dust, pollutants
status asthmaticus?
MEDICAL EMERGENCY - acute severe asthma
s/s asthma?
chronic asthma changes
s/s = tight chest, wheezing, difficulty breathing, cough
chronic changes = SM hyperplasia/hypertrophy, oedema, increased mucous secretion, epithelial damage (exposing sensory nerve endings), sub-epithelial fibrosis
phases of asthma attack?
early phase = type 1 hypersensitivity reaction (mast cells)
late phase = type IV hypersensitivity reaction (TH2, eosinophils)
FEV1?
forced expiratory volume (litres) in 1 second
asthma immune reaction
non-atopic individual?
TH2 response involving IgE
non-atopic = TH1 response involving IgG and macrophages
learn pathway
TH2 cells also release IL-5 which activates eosinophils
IL-4 and IL-13 cause mast cells to express IgE receptors
activated mast cell?
releases?
mast cell activaed via binding of antigen to IgE receptors
releases:
- chemokines - LTB4, PAF, PGD2 (attract eosinophils)
- spasmogens - histamine + leukotrienes LTC4, LTD4 (ASM contraction)
muscles of respiration?
FVC?
forced vital capacity - maximum volume that can be foricbly expelled from lungs following mximal inspiration
FEV1/FVC ratio?
normally >70%
obstructive lung disease (asthma/COPD) = <70%
restrictive = >70%
autonomic NS airways?
parasymp = bronchoconstriction
sympathetic = bronchodilation
when is peak flow used?
obstructive lung disease - asthma or COPD
restrictive airway disease?
FEV1/FVC ratio?
pulmonry fibrosis
pulomary oedema
lung collapse
pneumonia
absence of surfactant
restrictive = >70%
emphysema?
hyperinflation of lungs
different effects of O2 on pulmonary vs systemic arterioles?
binding of one O2 to Hb?
increases affinity of Hb for O2 (co-operativity)
Bohr effect?
shift of sigmoid curve to the right
foetal Hb?
benefit?
has higher affinity for O2 compared to HbA
this is because it interacts less with 2,3-biphosphoglycerate
allows O2 transfer from mother to foetus even if Po2 is low
myoglobin found?
purpose?
significance?
in skeletal and cardiac muscles - only one haem group per myoglobin molecule
provides short term storage of O2 for anaerobic conditions
prescence of myoglobin in blood indicates muscle damage
influenza clinical presentation?
fever - high, asrupt onset
malaise
myalgia
headache
cough
prostration - unable to leave bed
Ax flu?
flu-like illnesses?
not to be confused with….
influenza A + B
flu-like illnesses caused by: parainfluenza viruses
do not get confused with haemopilus influenzae - it is a bacterium and not a primary cause of flu (may be a secondary invader)
flu complications?
primary influenzal pneumonia
- high mortality!
- seen in young adults
secondary bacterial pneumonia (haemophilus)
- elderly, co-morbs
flu Tx?
symptomatic
- bed rest
- fluids
- paracetamol
antivirals
- oseltamivir
- zanamivir
epidemiology flu
winter epidemics (antigenic drift - minor mutations in surface proteins)
pandemics - rare, influenza A (antigenic shift)
(can be from animal reservoir/mixing vessel)
CO2 transport in blood?
solution - 10%
bicarbonate - 60%
carbamino compounds - 30%
carbon dioxide solubility?
20 times more soluble than oxygen
most Co2 trasported in blood as?
how is this formed?
bicarbonate
formed in blood by:-
carbamino compounds?
combines with Hb to produce carbamino-haemoglobin
the haldane effect?
removing O2 from Hb increases ability of Hb to pick up CO2
(the bohr effect and haldane affect work in conjunction)
i.e. O2 liberation and uptake of CO2 at tissues
bohr effect purpose?
facilitates removal of O2 from Hb at tissues by shifting dissociation curve to the right
CO2 dissociation curve
SOB - loss of elstic recoil (emphysema), dynamic airway compression
Lung volume - increased RV due to hyperinflation, increased FRC
Blood oxygenation - emphysema reduces surface area for gas exchange as it destroys alveoli (patient may have low PO2)
densities on CXR
USS densities?
when is AP used rather than PA?
disadantages of this?
when patient cannot stand i.e. very unwell or bed bound
heart shadow magnified so heart size cannot be assessed accurately
scapulae partially obscure lungs
can be difficult to achieve adequate inspiration
how to determine CXR inspiration and rotation
if CXR adequately inspired - anterior ends of at least 6 ribs should be visible
if CXR correctly centred - medial ends of clavicls should be equidistant from spinal processes of throaic vertebrae
mediastinal borders CXR
mediastinal lymph node locations + names
…
lung lobes radiograph
…
…
right superior lobe (above right horizontal fissure)
60 y/o smoker
2 stone weight loss
haemoptysis + cough
what is the abnormality?
right lower lobe collapse
where is the abnormality?
left lower lobe collapse
60 y/o smoker
afrebrile
haemoptysis + cough
what is the abnormality?
left upper lobe collapse
60 y/o smoker
febrile
haemoptysis + cough
what is the abnormality?
left upper lobe consolidation
large left pleural effusion
….
dilated bronchi
thickened bronchial walls
bilateral hilar enlargement
(probs sarcoid)
features suggestive of cardiac pain?
referred pain!!
central, crushing, heavy, tight band
usually left sided (can be epigastric)
often radiates: left arm, neck, jaw/teeth
lung pain?
contain no pain receptors
do contain J receptors = cough
pleurisy is if pathology reaches the pleura
pleuritic pain = sharp, worse on inspiration
GI chest pain?
oseophageal spasm
trapped wind
reflux oesophagitis
MSK pain chest?
usualy worse on moveent
reproducible (touch)
which systems could be respondible for chest pain?
(and so should be covered in history)
cardiac
resp
GI
MSK
breathlessness questions
“what do you mean by breathless?”
cant breathe in or out?
doing what?
orthopnoea?
paroxysmal nocturnal dyspnoea?
associated symptoms - wheeze, stridor, cough?
acute Ax breathlessness?
subacute?
chronic?
acute - PE, pneumothorax, pulmonary oedema
subacute - pneumonia, pulmonary oedema, pleural effusion, asthma/COPD
chronic - COPD, pulmonary fibrosis, PE
acute dry cough?
most common Ax?
<8 weeks
almost always viral
Ax dry cough?
viral
sinsister: lung cancer, mesothelioma, pulmonary metastases
pulmonayr fibrosis
sarcoidosis
pneumonitis (EAA)
chronic dry cough Ax?
GORD
ACE-I
upper airway disease
smoking
allergens
massive vs non-massive haemoptysis?
massive >500ml in 24 hours
non-massive <500ml in 24 hours
Ax haemoptysis?
big four: infection, carcinoma, PE, bronchiectasis
others: cardiac, AVM, anticoagulation
PMH resp?
ask about…
childhood infection
PE
TB
drug history resp?
ILD - nitrofurantoin, methotrexate, amiodarone, ACEI, bleomycin, B-blockers
airways - B-blokers, contrast, ACEI, penicillamine
vascular - phenytoin (PE), dexfenfluramine
social history resp?
occupation/hobbies - asbestos, coal mining, farming, pigeons/birds
tobacco!!!!!!
cannabis
foreign travel
pets
CO2 flap Ax?
what actually is it?
other s/s?
due to hypercapnic encephalopathy
irregular flapping of hand when wrist hyperectended (asterixis)
S/s: confusion + peripheral vasodilation
what are these?
Ax finger clubbing?
bronchial carcinoma
fibrosing alveolitis
lung suppuration (bronchiectasis, lung abscess, empyema)
cyonatic congenital heart disease
infective endocarditis
malabsorption states (UC, Crohn’s, liver cirrhosis)
congenital
Idiopathic
horner’s syndrome s/s?
Ax?
small pupils
ptosis
enopthalmos
unilateral loss of sweating
due to disruption of cervical chain
Ax: pancoast tumour, cervical lymphadenopathy, carotid dissection
sarcoidosis/TB eyes?
chronically raised CO2 eyes?
sarcoid/TB = uveitis
chronically raised pCO2 = dilated retinal veins/papilloedema
lymph nodes in the neck?
cor pulmonale s/s?
what is it?
cyanosis
raised JVP
pitting oedema
parasternal heave
loud P2
right heart failure due to chronic lung disease
superior vena cava obstruction s/s?
distention of axillary, subclavian and jugular veins
oedema of face, neck and upper chest
whats this?
s/s?
pectus excavatum
s/s: pulmonary artery flow murmur, right lower lobe CXR changes mimicking pulmonary infiltrate, diminished lung sounds
tracheal deviation direction?
towards collapse
towards consolidation
away from effusion
crepitation lungs Ax?
(sign that air is leaking out of the lungs)
surgical emphysema
chest wall trauma
iatrogenic (chest drains)
ruptured oesophagus
