Pulmonary embolism
Medical Emergency - Pulmonary embolism is a big cause of sudden death. When it happens, you gotta sort it!
Definition
A clot in the lung.
Epidemiology
15% of people with a DVT will have one. Also more common in any people immobile, or who have just had surgery.
Pathophysiology
A venous thombus (clot), often from a DVT, pass into the blood circulation around the lungs, preventing blood flow to the lungs. Obviously this is bad, since you need blood in the lungs to get oxygen in your blood. Oxygen in the blood is very useful thing to have.
Risk Factors
- Malignancy
- Recent Surgery, especially major stuff like hip replacement.
- Immobility
- The oral contraceptive.
- Previous thromboembolic events, such as a DVT, stroke or thrombophilia.
- Recent travel, especially flying, or sitting in a coach for two days.
Clinical Features
- Sudden shortness of breath
- Severe pleural (sharp, inspiratory) chest pain.
- Haemoptysis (coughing up blood)
- Syncope - brief loss of consciousness.
- Pleural rub - if you hear a pleural rub, or see it written in an exam, think PE or pneumonia.
Also hypotension, tachycardia, gallop rhythm, raised JVP, right ventricular heave, tachypnoea (fast breathing) and cyanosis.
Also worth looking for a DVT in their leg.
Investigations
- Blood tests - FBC, U+Es, CLS
- ECG - usually normal, or sinus tachycardia.
- Chest Xray - Wedge shaped area of infarction.
- ABG - PaO2 down, PaCO2 down, pH up.
- D-dimer blood test - rules out PE; if its not raised, it can't be a PE. Raised by any clotting though, so doesn't confirm diagnosis.
- CTPA - diagnostic
Management
- ABC
- 100% oxygen
- Morphine 10mg IV with antiemetic, if patient in a lot of pain.
- Surgery may be necessary.
- Start heparin.
- If the BP is lower than 90 systolic, treat shock with colloid.
- Start warfarin.
- Confirm diagnosis.
Prognosis
Big ones can be a big cause of sudden death. The smaller they are, the better the prognosis, but mortality can be 20%.