1. iBSc: Question 9 By Alan McLeod

2. Getting the best marks Read the whole question – a latter section may give you a clue about an earlier one. To see how many points you need look at the marks allocated – for example a 3 point question is generally looking for 3 salient points If giving a list answer put the best answers first – examiners will not usually mark answers too far down a list Always write something – it may get you part of a mark and is anonymised so no one will think you are stupid! If you genuinely have no clue then re-write the question to see if this sparks some ideas. If not then move on and come back at the end. And remember – always write something. Good luck!

3. Question 9 Mrs Kennedy (78) has been in hospital for 2 weeks after fracturing her left neck of femur. Q9.1 Describe the blood supply of the femoral head (3)

4. Question 9 The fracture is intracapsular and was repaired 10 days ago by a surgical procedure Q9.2 Why is the intracapsular site important in terms of outcome? (2) Q9.3 What procedure was most likely used (1)

5. Question 9 On day 14, Mrs Kennedy develops sudden onset chest pain and shortness of breath. Q9.4 List three likely diagnoses (3)

6. Question 9 A pulmonary embolus is diagnosed by ventilation perfusion scan. Q9.5 Describe the main three vessels that traverse the lung and the function of each (3) Q9.6 Which of these is obstructed by PE (1)

7. Question 9 A DVT (deep vein thrombosis) is found in her left femoral vein. Q9.7 List the common components of a thrombus (3) Q9.8 List two of her risk factors for DVT (2)

8. Question 9 She is started immediately on low molecular weight heparin and warfarin Q9.9 How do these two drugs affect clotting (6) Q9.10 Why is heparin started as well as warfarin? (1)

9. The Answers View these on ‘note view’ rather than on full screen – additional notes are provided for some slides

10. Fractured Neck of Femur Blood supply to head - In order of importance Capsular supply –From Med + Lat circumflex –From Deep femoral Nutrient artery –From deep femoral Ligamentum teres –From Medial epiphyseal

11. Fractured Neck of Femur

13. Chest Pain Differentials I Infectious / inflammatory Pneumonia, pleurisy, Costochonditis G Genetic / ideopathic E Endocrine T Trauma Fractured rib, pulled muscle, pneumothorax V Vascular Myocardial infarction, angina, aortic dissection, PE I Iatrogenic / ingested Surgical scar N Neoplastic Bony mets O Organs / other Oesophagus (spasm, reflux), heart (pericarditis) Lung, Aorta, bones, muscle, cartilege, anxiety

14. Vessels in the Lung Pulmonary Artery –Deoxygenated blood –From Right Ventricle –Oxygenated in lungs –Affected in PE Bronchial Artery –Oxygenated blood –From systemic supply –Supplies tissues of lung Pulmonary vein –Oxygenated blood –From lungs –To Left atrium

15. Thrombosis The three main factors leading to thrombus are Virchow’s Triad Flow changes Endothelial damage Composition changes of blood Usual components of thrombus Platelets Fibrin Red blood cells Several types of thrombus with varying quantities of these.

16. Thrombus Formation Platelet activation Fibrinogen  fibrin Fibrin assembles into long fibrils Platelets + Fibils = Clot RBCs join later

17. DVT Major DVT risk factors: Active cancer Paresis, paralysis or recent plaster cast of lower extremity Recently bedridden for more than 3 days Major surgery within 4 weeks. Lesser risks include: Oral contraceptive Long flights or car journeys Smoking Obesity Family history Heart failure Pacemaker

18. Vitamin K Reductase Vitamin K and Warfarin Factors 2,7,9 & 10 must be gamma carboxylated Vitamin K is a vital cofactor Warfarin inhibits enzyme –Prevents Vitamin K recycling Vitamin K Reductase Oxidised Vitamin K Reduced Vitamin K Factors 2,7,9 & 10 Gamma carboxylated Vitamin K Warfarin --

19. ATIII and LMW Heparin IIa LMW Heparin Xa Factor Xa Xa * * * Note the change in ATII conformation No substrate binding No substrate binding needed

20. ATIII and Unfractionated Heparin IIa ATIII Heparin Factor IIa (Thrombin) Xa Factor Xa Xa * * * Note the change in ATII conformation

21. ATIII and Heparin - Summary Antithrombin III deactivates clotting factors IIa (thrombin) & Xa It does NOT need heparin to do this BUT heparin makes it go FASTER LMWH only works on Xa Longer molecules in unfractionated heparin work on IIa (thrombin) as well

22. Heparin and Warfarin Heparin Effective within hours Subcutaneous (LMWH) or IV infusion (unfractionated) Not good for home use Started early to give immediate cover Warfarin Effective within days Oral Good for home use Regular INR checks needed Started early to build up to therapeutic levels before discharge.

23. The End The slides here should allow you to mark your own work – remember 1 mark per answer up to the maximum for the question. Multiply by 4 to get percentage points. I assume a 60% pass mark. Sorry but I am unable to give further advice on answers due to time constraints.