1 / 23

iBSc: Question 9

iBSc: Question 9. By Alan McLeod. 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

bevis
Download Presentation

iBSc: Question 9

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

  12. Fractured Neck of Femur

  13. Chest Pain Differentials

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

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

  20. ATIII and Unfractionated Heparin Heparin IIa IIa * Factor IIa (Thrombin) ATIII Xa IIa Xa Xa Factor 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.

More Related