WEEK 1 - I’m feeling short of breath Flashcards
branches of the pulmonary ______ participate in gas exchange at the ________ _______ membrane
- arteries
- alveolar capillary membrane
an obstruction in the pulmonary artery would cause an immediate increase in blood pressure in which region?
right ventricle
When an obstruction causes a restriction of flow, increased pressure will occur upstream of the blockage. Should a blockage occur in the pulmonary artery, blood will pool behind the blockage (upstream) in the right ventricle, increasing the pressure in this chamber. This is called pulmonary hypertension.
what is gas exchange reduced by?
- obstruction of the pulmonary artery — reduces perfusion therefore reduces gas exchange
- fibrosis of the alveolar tissue
For gas exchange to occur, our respiratory and circulatory systems work together via 3 systematic mechanisms:
- _________, movement of air into and out of the lungs.
- __________, movement of gases between air spaces in the lungs and the bloodstream.
- __________, movement of blood in and out of the capillary beds of the lungs.
fibrosis of the alveolar tissue _______ diffusion as the alveolar surface is scarred.
For gas exchange to occur, our respiratory and circulatory systems work together via 3 systematic mechanisms:
- Ventilation, movement of air into and out of the lungs.
- Diffusion, movement of gases between air spaces in the lungs and the bloodstream.
- Perfusion, movement of blood in and out of the capillary beds of the lungs.
Fibrosis of the alveolar tissue reduces diffusion as the alveolar surface is scarred.
what covers the internal surface of the thoracic cavity?
pleura
what is the name of the physical space between the lungs and ribcage?
pleural cavity
what is the function of the serous fluid in the pleural cavity?
support lung expansion when you breathe in
what are the 2 layers of the pleural cavity?
the parietal pleura that covers the rib cage and the visceral pleura that covers the lung
which pleura is sensitive to pain, pressure and temperature and is innervated by the phrenic and intercostal nerves?
parietal
what 4 things can cause sudden onset of pleuritic chest pain and SOB?
- pulmonary embolism
- musculoskeletal chest pain
- pneumothorax
- pleurisy
what is the most common cause of chest pain in primary care?
musculoskeletal conditions
what does musculoskeletal chest pain arise from?
bones, ligaments, muscles or the costochondral junctions in the ribcage
what is a key diagnostic feature for isolated musculoskeletal chest pain?
reproducing the patient’s pain by palpation or by movement
what is usually sufficient for musculoskeletal chest pain treatment?
explanation, reassurance and treatment with NSAIDs
what is pleurisy?
inflammation of the parietal pleura
when a patient presents with pleuritic chest pain, what are some potentially life-threatening disorders that physicians should consider first?
pulmonary embolism, myocardial infarction, pneumothorax
Pericarditis and pneumonia are two other significant causes of pleuritic chest pain that should be considered before pleurisy is diagnosed.
what is one of the most common causes of pleurisy?
Viruses that have been linked as causative agents include influenza, parainfluenza, coxsackieviruses, respiratory syncytial virus, mumps, cytomegalovirus, adenovirus, Epstein-Barr and now of course corona virus.
what is a pneumothorax?
a collection of gas in the pleural space that results in a variable amount of lung collapse on the affected side
what are the types of pneumothoraxes?
SPONTANEOUS
- primary = no underlying lung disease
- secondary = lung disease present/or smoking history at least 20 PYs
TRAUMA
- iatrogenic = procedure related/barotrauma in ICU
- non-iatrogenic = RTC, trauma, fall
what are risk factors for a primary pneumothorax?
- tall
- thin
- male (5:1)
- 20-40
what are risk factors for a secondary pneumothorax?
- COPD 60% cases
- cigarette or cannabis smoker 20PYs
- marfans/homocystinuria
- familial — Birt-Hogg-Dube syndrome (Auto Dom) mutation in folliculin gene
- asthma
what is the classic presentation of a primary spontaneous pneumothorax?
pleuritic chest pain and dyspnoea at rest — the symptoms do not correlate closely with the size of the pneumothorax — in many cases the symptoms are mild and approximately half of patients will present after more than 2 days of symptoms
why are symptoms of a secondary spontaneous pneumothorax more severe?
because lung function may already have been compromised by the underlying pathological process
secondary spontaneous pneumothorax symptoms vary depending on what? what is the primary complaint?
symptoms will vary depending on the cause e.g. fever, weight loss, night sweats but the primary complaint is that of breathlessness which is often out of proportion to the size of the pneumothorax radiologically.
in a secondary spontaneous pneumothorax, unlike symptoms, what are the examination findings affected by?
the size of the pneumothorax — therefore a small pneumothorax can be impossible to identify on clinical examination
the lungs tend to ________ and the chest wall tends to _______
- collapse
- expand
the tendency for elastic recoil to ______ lungs and chest wall to ______ means pleural pressure will be _____ compared to alveolar pressure
- collapse
- expand
- negative
when no muscles act on the chest wall, “equilibrium” will be achieved when the force generated by the pressure gradient across the _______ wall (_________ pressure) is equal and opposite to __________ _______
what is this point?
- alveolar (trans-pleural pressure: Ppl — Palv)
- elastic recoil
this point is functional residual capacity
when do the lungs sit at functional residual capacity?
at the end of every normal expiration, when respiratory muscles are relaxed
at FRC, what does alveolar pressure equal?
atm pressure therefore no airflow
for inspiration, what must alveolar pressure be less than?
atm pressure
for expiration , what must alveolar pressure be greater than?
atm pressure
what happens in a simple pneumothorax? what does a chest drain do?
- pleural pressure equals atm pressure
- no force to counter elastic recoil
- lung collapses
- normal lung expansion cannot take place
- the lung will stay collapsed until the puncture is sealed
- a chest drain, acting as a one way valve allows air to escape from the pleural space, during expiration, and the lung will reinflate
what happens in a tension pneumothorax?
- injury creates a tear in the tissue that acts as a one way valves
- on inspiration, air is drawn into the pleural space
- on expiration the air in the pleural space is trapped and compressed
- pleural pressure can quickly exceed central venous pressure and obstruction cardiac filling leading to a life-threatening fall in cardiac output
NEEDLE ASPIRATION is a life saver
what is an embolism?
obstruction of a blood vessel by a blood clot or foreign substance
what % of leg thrombi embolise?
20% — more above the knee than below
where may a large clot get stuck in the lungs?
bifurcation of the main pulmonary arteries —> haemodynamic compromise
where might smaller clots get stuck? result?
more distally in the lungs —> infarction —> pleuritic pain
what are more uncommon or rare causes of pulmonary embolisms?
- fat (fracture of long bones)
- amniotic fluid (post-partum)
- air (from disconnected CVL)
- tumour embolus
- infected vegetations (tricuspid endocarditis)
- foreign materials (iv drug users)
mainly blood clots
what are the types of pulmonary embolisms?
ACUTE thromboembolic PE
- massive PE
- sub-massive PE
- non-massive/low risk PE
CHRONIC thromboembolic PE
- repeated small emboli —> occlusion
- progressive SOB, pulmonary hypertension, right heart failure
what are risk factors for venous thromboembolism?
note cigarette smoking not in list
what are symptoms of PE?
ranges from none to sudden death
- acute/sub-acute SOB
- pleuritic chest pain
- haemoptysis (usually small)
- dizziness
- syncope
- restlessness/anxiety
what are the 3 cardinal signs of PE?
- dyspnoea
- tachypnoea
- pleuritic pain
what are other signs of PE?
- tachycardia
- cyanosis
- pyrexia — due to an infarct of the lung that can cause a fever
- signs of DVT or scar from recent surgery
- loud/widely split P2 sound of heart
- pleural rub
- raised JVP with pressure on right heart
- hypotension
what score assesses the clinical possibility of a PE?
Wells Score — add up total
5+ = PE likely — straight to CT to look for blood clot
what would you do in a patient with a Wells score of below 5?
means PE less likely -> do a D-dimer assay
what would bloods look like in someone who has had a small-medium PE?
- pH 7.56 — slight alkalosis
- pCO2 3.9 kPa — dropped — as hyperventilating to compensate for the area of the lung not being perfumed with blood
- pO2 11.4 kPa — normal. might be higher if hyperventilating
what would bloods look like in someone who has had a massive PE?
- pH 7.68 = even more alkalotic
- pCO2 = 3.2 kPa
- pO2 = 6.2 kPa
what might a CXR look like with a PE?
- maybe normal
- linear shadow, small effusion
- peripheral wedge
- paucity of vessels (increase in shadowing)
what might an ECG look like with a PE? massive?
- sinus tachycardia
- massive:
- ST/T wave changes V1-V3, right axis deviation
- S1,Q3,T3 pattern (=right heart strain)
what is gold standard imaging for PE?
CT pulmonary angiogram — 1st line investigation
for PE, when would you also do an echo?
- inpatient : for high risk, large PE, evidence of right heart strain
what would you also do if there are concerns about PE being a high risk or large clot?
troponin
when would a ventilation perfusion scan be done for PE?
- effective for those without pre-existing lung disease — less radiation eg. pregnant
they are cost effective but can be difficult to interpret
what score is used for risk stratification for PE?
Pesi score
describe high risk PE
- haemodynamic instability — low BP, high HR, syncope
PE
what is immediate management for PE?
- for pleurisy : hi-flow oxygen + IV fluids + analgesia
- enoxaparin (clexane) 1.5mg/kg OD : given while being investigated
for PE, who is given thrombolysis?
tPA — tissue plasminogen activator
only for ‘high risk’ PE if severe haemodynamic compromise
what happens in an acute massive PE?
catastrophic drop in CO, collapse/hypotension, cyanosis, tachypnoea, hypoxaemia
ultimately cardiogenic shock and death
what is longer term management for PE?
- DOAC (factor Xa inhibitors) — apixaban, rivaroxaban, edoxaban
- warfarin — patient choice, monitor therapeutic index, VTE on anticoag
what treatment can be used (rarely) for patients with recurrent VTE despite anticoagulation?
IVC filter
what are the main risk factors for PE?
DVT.
Previous DVT or PE.
Active cancer.
Recent surgery.
Lower limb trauma.
Significant immobility, for example, due to hospitalisation.
Pregnancy and, in particular, for 6 weeks’ postpartum.
Other risk factors include use of combined oral contraception or hormone replacement therapy, known thrombophilias, long-distance travel, obesity, and increasing age (older than 60 years of age).
following PE treatment, what is a complication that can result and is associated with considerable morbidity and mortality?
chronic thromboembolic pulmonary hypertension
summarise signs and symptoms of PE
Dyspnoea, chest pain, cough, haemoptysis, features of DVT (including leg pain and swelling [usually unilateral], lower abdominal pain, redness, increased temperature, and venous distension), dizziness, and syncope.
Tachypnoea or tachycardia, hypoxia, pyrexia, elevated jugular venous pressure, gallop rhythm, pleural rub, hypotension, and shock.
CO2 vs O2 levels in blood leading an area of LOW V/Q
- high CO2 content
- low O2 content
CO2 vs O2 levels in blood leading an area of HIGH V/Q
- low CO2 content
- normal O2 content
where are V and Q greater in the lung?
greater at the base than the apex
overall V/Q ratio in the lung is higher where?
higher at apex than base
in respiratory disease, what can hypoxia association with resp disease result in?
hypoxic pulmonary vasoconstriction
pulmonary emboli block pulmonary arteries, upstream of what?
the capillary beds
in embolised areas, lung tissue is _____ but not ______
- local infarct can damage lung tissue
- but some protection due to perfusion by the _____ circulation
- ventilated
- perused
- bronchial
why might perfusion go up in in-embolise areas?
due to a redistribution of cardiac output
obstruction of pulmonary circulation by the infarct leads to what?
an increase in pulmonary resistance and right-side cardiac work
what does hypoxaemia result from in PE?
- ventilation perfusion mismatch
- reduced CO
- R-L shunt (increased right heart pressures may open foramen ovale)
small PE often produces few symptoms, most notably what?
dyspnoea on exertion
large PE causes high pulmonary ________ and acute ____-side heart failure which can result in _______ or _______. this can proceed to _______ or _________
- resistance
- right
- hypotension
- syncope
- circulatory shock
- death
what is a very late sign in young people of severe and life threatening respiratory distress?
hypotension
what does percussion sound like in pneumothorax/effusion
- hyper-resonant in pneumothorax
- dullness in percussion with consolidation in the lungs or effusion
when is the NEWS2 score recommended?
- Emergency: for initial assessment, serial monitoring, and assessment for triage
- Ward: for initial inpatient assessment and serial monitoring
- May not be reliable in patients with spinal cord injury due to functional disturbance of autonomic responses.
no sign of infection clinically can remove what in aiding the diagnosis in breathlessness?
pleurisy
if the size of a pneumothorax is greater than 2cm, and the patient is symptomatic with hypoxia, what is the first treatment strategy?
pleural aspiration
summarise management of spontaneous pneumothorax
what 4 things would you expect to find in examination with a right sided tension pneumothorax?
- hyper resonant on the right
- normal breath sounds on the left
- reduced breath sounds on the right
- tracheal deviation to the left
immediate management for pneumothorax
most airlines do not allow you to fly within ______ of a pneumothorax.
6 weeks
what conditions cause haemoptysis?
- Pulmonary embolism
- Lung cancer
- Pleurisy
- Pneumonia
- Tuberculosis
- Bronchiectasis
what 7 features comprise the 2 level Wells score?
- immobilisation for more than 3 days or surgery within 4 weeks
- an alternative diagnosis is less likely than PE
- malignancy within 6 months of palliative
- clinical signs/symptoms of DVT
- HR > 100
- previous DVT/PE
- haemoptysis
what is the definitive test to diagnose PE?
CTPA = CT pulmonary angiogram
look at one med for PE ECG
ok
what is the commonest chest x ray feature in Pulmonary embolism?
a normal CXR
watch anaphylaxis video
ok
in what circumstances would you not perform a CTPA?
- Intravenous contrast is excreted by the kidneys and a rare side effect is renal damage. If the renal function is significantly impaired then IV contrast is contraindicated.
- If there is a history of contrast allergy.
- In pregnant women the radiation exposure to the breasts is very high as lactating breasts are very radiosensitive and this would increase your long term risk of breast cancer.
In these circumstances you would look for venous thromboembolism in the lower limbs by performing a Doppler ultrasound of the legs and/or perform a ventilation/perfusion scan which has less radiation exposure.
The diagnosis is a Pulmonary embolism with high probability. Whilst awaiting the CTPA the patient is started on subcutaneous ____________ (enoxaparin or clexane). Once a PE is confirmed then the subcutaneous treatment is switched to an ______ anticoagulant. There are a number of ____ anticoagulants that can be prescribed hence why all of them are selected in the question above.
Warfarin requires ____ monitoring and bridging with subcutaneous _________ for a number of days and also needs regular outpatient monitoring of ____ and thus it is used infrequently due to prolonging hospital stay and need for monitoring. Newer anticoagulants such as __________ and ___________ do not need you to continue the subcutaneous _____________ and do not need any outpatient monitoring and are preferred.
Answer: Diagnosis
The diagnosis is a Pulmonary embolism with high probability. Whilst awaiting the CTPA the patient is started on subcutaneous anticoagulation (enoxaparin or clexane). Once a PE is confirmed then the subcutaneous treatment is switched to an oral anticoagulant. There are a number of oral anticoagulants that can be prescribed hence why all of them are selected in the question above.
Warfarin requires INR monitoring and bridging with subcutaneous enoxaparin for a number of days and also needs regular outpatient monitoring of INR and thus it is used infrequently due to prolonging hospital stay and need for monitoring. Newer anticoagulants such as rivoroxaban and apixaban do not need you to continue the subcutaneous enoxaparin and do not need any outpatient monitoring and are preferred
what are the most common reactions of anticoagulation?
bleeding, bruising, nausea and anaemia
anticoagulation works by……
preventing further blood clots
what are the pharmacological treatment options for confirmed PE based on guidelines?
- Offer apixaban or rivaroxaban first line
- If these are not suitable, heparin (LMWH) for at least 5 days followed by dabigatran or edoxaban, or LMWH concurrently with a VKA (warfarin) till therapeutic anticoagulation is achieved
Take into account comorbidities, contraindications and the person’s preferences when choosing anticoagulation treatment
What are the contraindications to Rivaroxaban?
- pregnancy
- cirrhosis with coagulopathy
Bronchial breathing and crackles are heard in what?
pneumonia
do assessments
ok
