Week 5/6 - D - Pulmonary oedema, A.R.D.S, Deep vein thrombosis / Pulmonary embolism, Pulmonary hypertension/Cor pulmonale Flashcards
What is the blood supply to the lungs? Do these arteries come from (branches of) the right or left ventricle)
The lungs have a dual blood supply They receive deoxygenated blood from the pulmonary arteries - pulmonary circulation (right ventricle) They receive oxygenated blood from the bronchial arteries - systemic circulation (usually branch off the thoracic aorta)
What is pulmonary oedema and what is the commonest cause of it? Does it cause an obstructive or restrictive pattern of disease?
Pulmonary oedema is the accumulation of fluid in the lungs It causes a restrictive pattern of disease Commonest cause of pulmonary odema is secondary to congestive heart failure (left ventricule failure)
Acute lung injury may also cause pulmonary edema through injury to the vasculature and parenchyma of the lung. How does acute lung injury lead to non-cardiogenic pulmonary oedema?
Acute lung injury can cause and increase in hydrostatic pressure in the lungs and cause cellular injury to the aveolar cells and the lining This can lead to an increased capillary permability leading to flooding of the alveoli - NON CARDIOGENIC PULMONARY OEDEMA
What is localised acute lung injury often due to? What is widespread acute lung injury known as?
Localised can be pneumonia Widespread inflammation of the lungs - acute respiratory distress syndrome
ACUTE RESPIRATORY DISTRESS SYNDROME What is the colloquial name for ARDS? What are the causes?
aka SHOCK LUNG Causes * Pneumonia * Gastric aspiration * Sepsis * Diffuse infection * Severe tuama
What are the clinical features of ARDS?
Cyanosis Tachycardia Tachypnoea Diffuse crackles
What is the criteria used to diagnose adult respiratory distress syndrome? (4 parts in the criteria)
BERLIN CRITERIA 1. Acute onset -within a week of known clinical insult 2. CXR shows bilateral infiltrates 3. Respiratory failure not explained by cardiogenic oedema (eg congestive heart failure) 4. Hypoxaemia (blood tests)
What is the treatment of ARDS?
Respiratory support - usually mechanical ventilation needed Treat the underlying disease Provide fluid and electrolyte balance
DEEP VEIN THROMBOSIS Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein, most commonly in the legs or pelvis Are proximal or distal DVTs more liekly to embolise?
Proximal (iliofemoral) DVTs are most likely to embolise Distal (popliteal) DVTs are least likely to embolism
What are the clinical features of a DVT and what are the differentials?
Clinical features are unilateral: Whole leg or calf depending on site * Redness (rubor) * Pain (dolor) * Warmth (calor) * Swollen (tumour) Differentials - cellulitis, Baker’s cyst rupture
What is the score that is calculated in patient’s before deciding which investigations to carry out in a patient with suspected DVT?
This would be the two-level DVT Well’s score Pretest clinical probability scoring system for DVT
What does a Well’s score of equal to or less than one mean and what is carried out? If this tests is negative what happens, if this test is positive what happenes?
Well’s score of =1 means DVT unlikley Measure D-dimer. if negaive DVT excluded. If positive proceed to USS - if positive treat as DVT
What is the D-Dimer?
* The formation of thrombus is normally followed by an immediate fibrinolytic response, resulting in generation of plasmin which causes the release of fibrin degradation products (predominantly containing D-dimer) into the circulation.
What are other possible causes of a raised D-Dimer?
Although a positive D-dimer result can indicate thrombosis, other possible causes of a raised D-dimer include liver disease, inflammation, malignancy, pregnancy, trauma, and recent surgery.
Are D-Dimer tests sensitive or specific?
* D-dimer tests have relatively high sensitivity but low specificity (false positive results are common). * Therefore, whilst a negative D-dimer may be useful in excluding DVT, a positive D-dimer is of no diagnostic value, but merely mandates further testing.
What does a Well’s score of equal to or greater than two mean and what is carried out? Which tests need to be positive for a DVT diagnosis?
A well’s score of greater than or equal to 2 indicates that a DVT is likely. * DO both D-Dimer and USS * If both negative exclude DVT * If USS positive and D-dimer negative - treat as DVT * If USS negative and D-dimer positive - repeat USS in 1 week
What is the 1st line treatment for a diagnosed DVT? * How long is treatment continued for? * How long is treatment continued for in cancer patients?
NOAC (apixaban or rivoroxaban) given 1st line - 3 months In cancer patients, NOAC should be given for 6 months
What can be given as an alternative therapy if NOAC (specifically apixaban or rivoroxaban) is unavailable?
If neither apixaban or rivaroxaban are suitable then either * LMWH for at least 5 days followed by dabigatran or edoxaban OR * Patient is prescribed LMWH with warfarin - stop LMWH when INR 2-3 or after 5 days use, continue warfarin for 3 months
How is calf swelling measured in DVT? (one of the components of Well’s score)
Calf swelling >3cm compared with asymptomatic leg measured 10cm below the tibial tuberosity
In patients with an unprovoked DVT, investigations should be carried out to look for an underlying cause What should these investigations be?
Patients should receive thrombophilia testing (hereditary thrombophilias and antiphospholipd antibodies - (haematology) Patients should receive tests for an underlying malignanacy - * A physical examination (guided by the person’s full history). * A chest X-ray. * Blood tests (full blood count, serum calcium, and liver function tests). * Urinalysis. CT abdo/pelvis and momogram in women if >40years
PULMONARY EMBOLISM How do pulmonary embolisms tend to arise?
Pulmonary emboli usually arise from a venous thrombosis in the pelvis or legs (proximal or distal DVT) - clots break off and pass through the veins and the right side of the heart before lodging in the pulmonary circulation Rare causes - eg septic emboli from right side endocarditis
What are the risk factors for PE? (same as for DVT)
Factors in vessel wall (eg endothelial hypoxia) Abnormal blood flow (venous stasis) Hypercoaguable blood (cancer patients, post-MI etc) - Virchow’s triad
What are the clinical features of a PE?
Symptoms * Acute breathlessness * Pleuritic chest pain * Haemoptysis * Unilateral leg swelling Signs * Hypotension and tachycardia * Raised JVP * Cyanosis
Why can a pulmonary embolism lead to hypotension? There is increased pulmonary vascular resistance reducing blood flow to the left ventricle and therefore reducing cardiac output
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What investigations are carried out in a patient with if PE is suspected?
Carry out an assessment of their general medical history, a physical examination, and, where necessary, investigations eg FBC, ABG , CXR, ECG Two level PE Well’s score can be used to assess the clinical probability of PE
What may be seen on ABG, CXR and ECG in a patient with a PE?
ABG - may show decreased PaO2 and decreased PaCO2 CXR - useful for ruling out other diagnoses eg pneumothorax, pleural effusion
- ECG - S1, QIII, TIII (deep S waves, pathological Qwaves, inverted Twaves)
- RBBB
- Right axis deviation
What score do you need in the two level PE well’s score to carry out which tests?
* For people with a Wells score of more than 4 points (PE likely), arrange hospital admission for an immediate computed tomography pulmonary angiogram (CTPA) * For people with a Wells score of 4 points or less (PE unlikely), arrange a D-dimer test. If the test is positive, arrange admission to hospital for an immediate CTPA and, where necessary, other investigations. If D-Dimer is negative, then consider alternative diagnosis
How is PE treated? Normally and if cancer (long term) When is thrombolysis considered?
PE - NOAC (apixaban or rivoroxaban) given 1st line - 3 months In cancer patients, NOAC should be given for 6 months Only consider Thrombolysis if the person is haemodynamically unstable with a massive PE
What can be given as an alternative therapy if NOAC (specifically apixaban or rivoroxaban) is unavailable?
If neither apixaban or rivaroxaban are suitable then either LMWH for at least 5 days followed by dabigatran or edoxaban OR Patient is prescribed LMWH with warfarin - stop LMWH when INR 2-3 or after 5 days use, continue warfarin for 3 months
In patients with an unprovoked PE, investigations should be carried out to look for an underlying cause What should these investigations be?
Patients should receive thrombophilia testing (hereditary thrombophilias and antiphospholipd antibodies - (haematology) Patients should receive tests for an underlying malignanacy - A physical examination (guided by the person’s full history). A chest X-ray. Blood tests (full blood count, serum calcium, and liver function tests). Urinalysis. CT abdo/pelvis and momogram in women if >40years
Inferior vena caval (IVC) filters are designed to trap fragmented thromboemboli from the deep leg veins en route to the pulmonary circulation (whilst preserving blood flow in the IVC filter) When are these given to patients?
Various filters are available and can be placed in the IVC filter on either a temporary basis for example * in people with PE who cannot have anticoagulation treatment) * or a permanent basis (for example in people with recurrent PE despite adequate anticoagulation treatment after alternative treatments have been considered).
PULMONARY HYPERTENSION The pulmonary circulation is normally a high flow, low pressure circulation What is the normal pressure and what classifies as pulmonary hypertension? What is used to measure the pulmonary arterial pressure?
* Normal mean pulmonary arterial pressure (mPAP) is 12-20mmHg * Pulmonary hypertension is defined as a mPAP >25mmHg or >30mmHg during exercise Swan-Ganz pulmonary artery catheterization is the passing of a thin tube (catheter) into the right side of the heart and the arteries leading to the lung - used to measure pulmonary arterial pressure
How can the systolic pulmonary pressure be estimated? What systolic pulmonary pressure estimate gives a possible pulmnary hypertension diagnosis?
Systolic pulmonary arterial pressure can be estimated using an echogardiogram doppler A systolic pulmonary arterial pressure >40mmHg gives a possibe Pulmonary hypertension diagnosis
Primary pulmonary hypertension (PPH) is high blood pressure in the lungs. It is also known as idiopathic pulmonary arterial hypertension. It’s a rare lung disorder in which the blood vessels in the lungs narrow (constrict) and the pressure in the pulmonary artery rises far above normal levels Which type of pulmonary hypertension occur due to left heart disease?
This would be pulmonary venous hypertension - the pulmonary veins are unable to drain into the left heart due to disease
There are many different causes of secondary pulmonary arterial hypertension and they are put into categories (this is postgraduate af) Name some causes of secondary pulmonary arterial hypertension?
Secondary arterial pulmonary hypertension Hypoxic - COPD, OSA, Pulmonary fibrosis Multiple PE - Chronic thromboembolic pulmonary hypertension (CTEPH) Vasculitis - eg systemic sclerosis, SLE, PAN Cardiac left to right shunt - ASD, VSD
What is cor pulmonale?
Cor pulmonale is right sided heart failure caused by chronic pulmonary hypertension There is right heart hypertrophy and dilatation
What are the features of cor pulmonale/pulmonary hypertension? (symptoms, signs, auscultatory noises)
Symptoms - dyspnoea, fatigue, syncope Signs * Raised JVP, * Hepatomegaly * Peripheral oedema * Right ventricular heave at left parasternal edge * Pan-systolic murmur - murmur of tricuspid regurgitation
What investigations are carried out in pulmonary hypertension?
FIND UNDERLYING CAUSE * ECG * CXR - shows cardiomeaglu * O2 sats * Echo - * systolic pulmonary pressure * Valvular disease * Right and left ventricle dimensions Pulmonary arterial catheter- Swan ganz catheter Auto, antibodies if suspected vasculitis
In patients with secondary pulmonary hypertension, it is important to treat the underlying cause of the disease What supportive treatment is given for pulmonary arterial hypertension (primary or secondary)?
A number of supportive measures such as * Oxygen therapy, * Diuretics * Prophylactic anticoagulation - warfarin Pharmacological management - pulmonary vasodilators - LECTURE SAYS FOR PRIMARY DISEASE * Individuals with PAH which is unresponsive to medical management may be referred for a lung or heart-lung transplant.
What are some of the pulmonary vasodilators used for primary disease?
* Phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil) * Endothelin 1 receptor antagonists (bosentan, ambrisentan, macitentan) * Prostacyclin agonists (iloprost, treprostinil, epoprostenol)
