Objectives At the end of this lecture the student should be able to  Name the common disorders of pulmonary circulation (embolism, vasculitis, alveolar haemorrhage and pulmonary hypertension).  Describe pulmonary embolism (PE) and discuss it as follows: o Definition. o Substances other than thrombus that can embolize into the pulmonary circulation. o Pathogenesis and risk factors.  Compare and contrast the clinical features of: o Small/medium pulmonary embolism. o Massive pulmonary embolism. o Multiple, recurrent pulmonary emboli.  Clinical prediction score.  List the usual laboratory and radiological investigations

Normal Pulmonary Circulation

Pulmonary Circulation disorders Diseases that might affect pulmonary vasculature may include:  Autimmune diseases ( vasculitides, anti-basement membrane antibodies)  Infection (schistosomaisis)  Congenital  Neoplastic (hemangiomas)  Pulmonary embolism  Pulmonary hypertension

Pulmonary embolism Definition:  Abrupt blockage of a pulmonary artery or one of its branches – most commonly = embolus from deep veins of the lower limbs  Pulmonary embolism + DVT = venous thromboembolism VTE Stasis Hyper coagulobility Endothelial injury

Epidemiology  ,00 patients each year  Annual incidence of VTE is 1in 1000 persons.  Incidence increases with age  Male = female (recurrent VTE commoner in males)  - US data

Causes and Risk Factors Prothrombotic factors Virchow triad Antithrombotic factors

Causes and Risk Factors Should be considered in history Hereditary factors Deficiency of natural anticoagulants (ATIII, protein C & S Resistant to inhibitors factor V Leiden Increased coagulation factors e. g VIII, XI etc Defect in fibrinolytic pathway dysfirinogenemia Acquired factors Immobilization Major surgery/ trauma Central venous catheter Obesity Malignancy Pregnancy Advanced age Medical illness e.g. SLE mixed hyperhomocysteinemia Elevated level of Lpa Low level of TFP inhibitors

Causes and Risk Factors

Clinical Presentation  Can be difficult to diagnose (no specific signs and symptoms).  There are 3 clinical syndromes associated with pulmonary embolism: 1.Small/ Medium sized emboli 2.Large (massive) emboli 3.Recurrent small embli

Clinical Presentation 1-Small/ medium pulmonary embolism: (Embolus in terminal P vessel)  Chest pain  Breathlessness  Haemoptysis O/E  Tachypnoea  Pleural rub  Crackles  Pleural effusion  May be fever  Cardiovascular examination is normal

Clinical Presentation 2-Massive pulmonary embolism (obstruction of R V outflow)  Rare  Sudden collapse  Severe chest pain  Shock (pale, sweaty)  Syncope

Clinical Presentation O/E mainly cardiac signs  Tachypnoea  Tachycardia  Hypotension  Cyanosis  Raised JVP prominent ‘a’ wave  R. ventricular heave, gallop, widely splits2  The chest is usually clear

Clinical Presentation 3-Multiple recurrent pulmonary emboli:  Increased breathlessness over weeks or months  Weakness, syncope occasional angina (exertion) O/E (pulmonary hypertension)  Right ventricular heave  Loud P2

Clinical Presentation

List of Investigations Non imaging tests: 1.Plasma D-dimers ( -ve result excludes diagnosis) 2.ECG (SI, QIII,TIII) Non invasive imaging tests: 1.Chest radiography 2.CT angiography (the BEST diagnostic test) 3.Ventilation / Perfusion scan ( -ve result excludes diagnosis) 4.Doppler ultrasonography 5.Echocardiography

List of Investigations Invasive imaging tests 1.Pulmonary angiography 2.Contrast venography  ABG: Low PCO2 Low PO2

Investigations

Diagnostic Approach 2-Clinical prediction score 3- Select appropriate test 1- Symptoms & signs suggestive of PE

Diagnostic Approach Clinical prediction score : I.Revised Geneva score II.Wells score Revised Geneva score:  low risk 0- 3  Intermediate risk  High risk >10

Diagnostic Approach Revised Geneva score Items of the Revised Geneva ScorePoints for Revised Version Age > 65 years old 1 Previous history of PE or DVT 3 Surgery or fracture within 1 month 2 Active malignancy 2. Unilateral leg pain 3 Hemoptysis 2. Heart rate (bpm) ≥ 95 5 Pain on lower-limb deep venous palpation and unilateral oedema 4

Diagnostic Approach

Differential Diagnosis  Myocardial infarction  Pericarditis  Aortic dissection  Pneumonia  Pleurisy  Chest wall pain  Congestive heart failure

Treatment Treatment goals  Stabilize the patient i.Oxygen for hypoxia ii.Analgesics for chest pain  Prevent extension of current thrombus (short term) i.Parenteral anticoagulants – heparin ii.Oral anticoagulants - warfarin

Treatment  Prevent recurrent VTE (long term) i.Continue anticoagulation (warfarin) for 6 weeks- 6month- indefinitely ii.Life style changes iii.Graduated compression stockings iv.IVC Filter  Lysis or removal of a thrombus in case of haemodynamic instability (massive PE): i.Thrombolytic therapy e. g. streptokinase ii.Pulmonary embolectomy

Prevention  Avoid prolonged immobilization  Smoking cessation  Contraception (non hormonal)  Obesity should be treated  Thromboprophylaxis in high risk patient

Other Rare Causes of Pulmonary Embolism  Fat embolism (long bone fractures, acute pancreatitis)  Air embolism (decompression sickness, iatrogenic)  Amniotic fluid embolism (postpartum)  Septic embolism (sepsis)  Tumor embolism

Summary  Pulmonary embolism is usually caused by a thrombus in the deep proximal veins of the legs that breaks off and lodges in the lungs  Patient may be a symptomatic or may present with typical symptoms including dyspnoea & chest pain. Massive pulmonary embolism may present with hypotension, shock or sudden death.  An integrated diagnostic approach involving clinical prediction rules and non invasive testing can be used to evaluate patients.  The aggressiveness of treatment is dependent on the severity of pulmonary embolism.  Prevention of DVT in hospitalized patient is crucial to preventing embolism.

References  Kumar & Clark’s Clinical Medicine 8 th edition  /