Thomboembolic disease Flashcards
What is a pulmonary emboli
Blockage of a pulmonary artery by a blood clot, fat, tumour or air
What is pulmonary infarction
If blood flow and oxygen to lungs is compromised, the lung tissue may die
Most likely place for DVT
Ileo-femoral, popliteal is most unlikely
Clinical presentation of DVT
Whole leg or calf becomes swollen, hot, tender, red
Differential diagnosis of DVT
Baker’s cyst - Popliteal synovial rupture
Superficial thrombophlebitis
Calf cellulitis
Investigating DVT
Ultrasound doppler leg scan - Not invasive, exclude popliteal cyst and pelvic mass
CT scan
Types of pulmonary emboli and their presentation
Large - CV shock, low BP, cyanosis and sudden death
Medium - Pleuritic pain, haemoptysis, dyspnoea
Small - Progressive dyspnoea, pulmonary hypertension, right heart failure
Risk factors for DVT and PE
Thrombophilia, contraceptive pills, hormone replacement therapy, pregnancy, pelvic obstruction (uterus, ovary, lymph nodes), trauma, surgery, immobility - bed rest, long flights, pulmonary hypertension, obesity
Presenting complaint about DVT
Dyspnoea, pleuritic chest pain, haemoptysis, leg pain/oedema, collapse/sudden death
Investigating PE
ECG with acute right heart strain pattern
D-dimers raised - Increased fibrin degradation products indicative of significant blood clot (thrombus) formation and breakdown in the body, doesn’t tell location
Ventilation/Perfusion mismatch - Isotope lung scan
Prevention of DVT
Early post-op mobilisation
TED compression stockings
Calf muscle exercise
A subcutaneous low dose of low molecular weight heparin perioperatively - Dalteparin/Fragmin
Novel Oral Anticoagulant (NOAC) medication -
Dabigatran - Direct thrombin inhibitor
Rivaroxaban/Apixaban - Direct inhibitor of activated factor Xa
When should Heparin be stopped for treating PE
Oral Warfarin takes 3 days, antagonises vitamin K dependant prothrombin. Continue Warfarin for 3-6 months with INR aim 2.5-3.5
After 3-5 days, stop Heparin when INR > 2. Can use NOAC instead of LMWH.
When is tenecteplase used
Large life threatening PE, low BP and severe hypoxaemia. Tenecteplase is an enzyme that helps in thrombolysis - tissue plasminogen activation (tPA)
Duration of treatment for PE
Unprovoked - 6 months Provoked/temporary risk factor - 3 months Low risk distal DVT - 3 months High risk proximal DVT - 6 months Recurrent DVT - Life long
How can Warfarin be reversed
Vitamin K1
How can Heparin be reverese
Protamine sulphate
Reversal agent for NOAC
Non-available
Normal mean pulmonary arterial pressure
12-20 mmHg
How can pulmonary hypertension be measured
Right heart catheter
What is cor pulmonale
Alteration in structure and function of right ventricle caused by a primary disorder of the respiratory system.
Ex: Secondary to COPD
Clinical signs of pulmonary hypertension and right heart failure
Central cyanosis if hypoxic, dependant oedema, raised JVP with V waves, right ventricular heave at parasternal edge, tricuspid regurgitation murmur, enlarged liver
What is dependant oedema
Oedema that is influenced by gravity, in an ambulant patient this might be ankles or legs. In bed bound, might be sacral oedema
Treatment of pulmonary hypertension
Prophylactic Warfarin (anticoagulant)
Oxygen if hypoxic
Primary vasodilators -
Ca2= channel blockers - Oral Nifedipine, Diltiazem
What is chronic thromboembolism pulmonary hypertension (CTEPH)
Chronic blood clots in the lungs, with mean arterial pressure > 25mmHg
Treatment of CTEPH
Riociguat - Soluble guanylate cyclase stimulator
Pulmonary endarterectomy - Surgical removal of blood clot
Balloon angioplasty
A pattern of disease in pulmonary oedema
Restrictive
What is acute respiratory distress syndrome (ARDS)
Widespread inflammation in the lungs due to sepsis, pneumonia or trauma
Pathogenesis of ARDS
Injury causes infiltration of inflammatory cells. Cytokines are released causing oxygen free radicles and causing injury to cell membrane
Histological feature of ARDS
Hyaline membrane - Fibrinous exudate lining alveolar walls
Mechanisms of pulmonary hypertension
Hypoxia (vascular constriction), increased flow through pulmonary circulation (congenital heart disease), blockage (PE) or loss (emphysema) of pulmonary vascular bed, back pressure from left sided heart failure
Common cause of right ventricular hypertrophy
Pulmonary hypertension
What is plexiform lesion
Histopathological hallmark of pulmonary arterial hypertension. Consists of obliterative endothelial cells proliferation and vascular smooth muscle cell hypertrophy
