Pulmonary Embolism in MRCP

Pulmonary Embolism in MRCP

I saw a case of suspected Pulmonary Embolism today, therefore, we will talk about PE today in our MRCP blog today.

I think that Pulmonary Embolism is important not just because you are sitting for MRCP Part 1 and 2 but also as a clinician in everyday practise because it is often missed and not treated.

As defined in Wikipedia, Pulmonary embolism (PE) is blockage of the pulmonary artery (or one of its branches) by a blood clot, fat, air, amniotic fluid, injected talc or clumped tumor cells. By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs.



However, when we talk about venous thromboembolism, always remember that there are three aspects you must always remember when blood clots inside a vessel. It can be due to either alterations in blood flow, factors in the vessel wall and factors affecting the properties of the blood--- these three factors are well known as Virchow's triad.

Remember that PE usually occurs due to embolism from a blood clot from the lower limb and predisposing factors for deep vein thrombosis is the most popular questions asked in MRCP.

It is easy to remember that there are two major risk factors predispose you to have thrombosis, either inherited or acquired, always suspect inherited causes if young patients present with thromboembolic events and there is presence of family history. Just remember that some inherited causes like Protein C,S, anti-thrombin deficiency and Factor-V Leiden mutation.

But put more emphasis on acquired causes because they are the more important and commoner causes for thromboembolic events, remember the mnemonics below,

EMBOLISM
E- Extra causes- inherited causes
M-Malignancy
B- Baby ( Pregnancy)
O- Oral Contraceptive pill
L- Large- obesity ( maybe lead you to immbolity)
I- Immune disease-Antiphospholipid
S-Surgery
M- Mobility ( immobilization)


Patients with PE usually present with SOB, haemoptysis, chest pain and even sudden death.

There are various investigations can be done to diagnose PE, however, remember you may find Westermark sign ( localised pulmonary oligaemia) in CXR and classical ECG finding ( S1QIIITIII) . Although you seldom see these in clinical practice, I do not understand why these questions are alwyas asked in your MRCP.


However, in 1995 Wells et al suggested a scoring system to diagnose PE and if you are sitting for MRCP PACES, learn this criteria hard!!


The treatment is easy, use heparin and give them warfarin for at least 6 months.

ECG in MRCP(3)

ECG in MRCP(3)

I have covered common MRCP questions about ECG in my previous 2 posts, today, we are going to talk about heart block, there are two main type of heart block, AV ( atrio-ventricular) block and intraventricular block. We will talk about AV block today. As you might remember as a medical student, there are three subtypes of AV block, namely first, second and third degree heart block.

First degree heart block
It is easy to pick up in your ECG, normal PR interval is 0.12-0.20s, if PR interval is more than 0.2s, it is considered as first degree heart block.

Note: Always remember that shortened PR interval occurs in WPW syndrome!

Second degree heart block

There are two types of second degree heart block,

a) Classical “Wenckebach” ( Mobitz type 1) where the PR interval gets longer (by shorter increments) until a nonconducted P wave occurs. The RR interval of the pause is less than the two preceding RR intervals, and the RR interval after the pause is greater than the RR interval before the pause.




b) Mobitz type 2- For this heart block, AV block the PR intervals are constant until a nonconducted P wave occurs. ( as below ECG)

Third degree heart block

Easy to remember, complete AV dissociation