thrombotic disease Flashcards

Question

what are the causes of PAD

Answer 1

- diabetics - smoking - obesity - infection - damage to the vessels - sedentary lifestyle - HBP - nutritional deficiencies - emboli - inflammation of blood vessels

Answer 2

- none at first - coolness of skin - infections which dont heal - poor nail and skin health - pain while walking and stops with rest - discolouration - pale

Answer 3

- angiography - doppler ultrasound - blood pressure at arms and legs - pulse palpation at ankles -Ankle-brachial index (ABI) Blood pressure in ankle and arm should be measured Systolic blood pressure in ankle / arm = 0.9 - 1 (normal) <0.9 : represents PAD 0. 71 - 0.9 : mild PAD 0. 41 - 0.7 : moderate PAD <0.4 : severe PAD

Answer 4

Change of lifestyle: regular exercise, smoking cessation, weight reduction for obese & reduce alcohol consumption Medications for hyperlipidaemia, hyperglycaemia/diabetes & hypertension Anti-platelet drugs: e.g. aspirin (75 mg daily) Naftidrofuryl oxalate (vasodilator) (100-200 mg/ 3 times a day) alleviates symptoms of intermittent claudication and improve pain-free walking distance in moderate cases Cilostazol (PDE inhibitor-vasodilation and inhibits platelet activation) is for second-line treatment where lifestyle modifications and other interventions failed Surgical procedures: angioplasty and endartectomy

Answer 5

Occurs in deep veins in lower extremities (legs) Blood flows back to heart due to muscle movement Reduced/nil movement or injuries diminishes or stops blood flow in veins So accumulation of platelets & plasma proteins leads to clotting The clot could be smaller, so it can break up easily by fibrinolysis Large clots can occlude the veins and prevent the blood flow permanently Dislodged clots can travel to heart and then lodge in lungs (called pulmonary embolism) Can cause serious complications if untreated

Answer 6

Inactivity – immobile for a long period (e.g. during/after surgeries, due to other illness or long journeys Stay at hospitals – long staying at hospitals with reduced activity Blood vessel damage – injury to the blood vessels can narrow or block the blood flow. Vasculitis, varicose vein and certain medications can also damage the blood vessels Medical conditions – can increase the clotting activity (cancer treatments – chemo & radiotherapy; heart & lung diseases; infectious diseases, e.g hepatitis Genetic conditions – thrombophilia – blood is more likely to clot; Hughes syndrome – blood is abnormally sticky Pregnancy – makes blood to clot quickly Combined contraceptive pills & hormone replacement therapy (increased oestrogen can cause blood to clot easily) Previous DVT, obesity, smoking, age (>60) and dehydration

Answer 7

Sometimes asymptomatic Pain, tenderness and swelling in one of the legs Heavy pain in the affected area Warm skin in the area of the clot Redness of the skin at the back of leg below the knee If untreated, can lead to pulmonary embolism Breathlessness Chest pain – gets worse during breathing Sudden collapse

Answer 8

- blood test for D-dimer levels - ultrasound scan - venogram

Answer 9

Anticoagulants to prevent the clots getting bigger and breaking off Heparin (low molecular weight (mostly used form) & standard unfractionated) – an anticoagulant and inhibitor of thrombin IV infusion or intermittent subcutaneous injection (Low molecular weight) IV infusion, injection or subcutaneous injection – standard heparin ``` Warfarin sodium (oral anticoagulant-tablet) – should be started same time as heparin – prevents further clotting Not recommended for pregnant women ``` Rivaroxaban (Factor Xa inhibitor) Apixaban (thrombin inhibitor) Compression stockings – to prevent formation of new clots or post-thrombotic syndrome Waking exercise, raising legs at resting Inferior vena cava filters when anticoagulants are not suitable Small mesh device – prevent large clots travelling to heart and lungs Placed into the vein using a catheter and ultrasound scan

Answer 10

Drugs to inhibit platelet function (mostly in arterial thrombosis) E.g. Aspirin, clopidogrel and dipyridamole Mainly used for the prevention of arterial thrombotic diseases (MI, stroke, etc.) Platelet activation

Answer 11

Drug class: Anti-platelet drug (a NSAID) Mechanism: Irreversibly binds to cyclooxygenase (COX) enzyme in platelets, inactivating COX and preventing the production of thromboxane A2, which activates platelets and increases aggregation. Role: Secondary prevention of CV events (dose vary) Counseling and cautions: Avoid if patient has history of hypersensitivity to aspirin and other NSAIDs Use with caution (or avoid) in patients with history of peptic ulceration Use with caution if patient has asthma Use with caution if using concomitantly with drugs that increase bleeding risk Use with caution in elderly with other medications or conditions

Answer 12

Drug class: Anti-platelet drug Mechanism: Pro-drug of an active metabolite irreversibly binds to ADP receptor (P2Y12) on platelets, which prevents ADP–mediated activation of platelets and aggregation. Role: Secondary prevention of CV events (dose vary) \ Counseling and cautions: Use with caution in patients at increased risk of bleeding or taking concomitantly with drugs that increase bleeding risk Discontinue use 7 days before elective surgery if anti-platelet effect is not desirable Caution if history of hypersensitivity to thienopyridines (i.e. antiplatelet drug, prasugrel)

Answer 13

Drug class: Anti-platelet drug Mechanism: Inhibiting phosphodiesterase (PDE), it prevents the hydrolysis of cAMP and cGMP and thus increase their levels to inhibit platelet activation. Role: Secondary prevention of CV events (dose vary) Counseling and cautions: Use with caution in patients taking it concomitantly with drugs that increase bleeding risk May exacerbate migraine Use with caution in case of certain CV conditions i.e. worsening angina or recent MI

Answer 14

A group of sulphated glycosaminoglycans (long unbranched polysaccharides with repeating disaccharides + amino sugar) Highly, negatively charged biomolecule in the body Commercial preparations are normally extracted from beef lungs or porcine intestine Unfractionated/standard heparin is a mix of polymers with varying lengths of side chains UF heparin activates antithrombin III and thereby inactivates thrombin, factor Xa and others Low molecular weight heparins are fractionated form and only contain small side chains (e.g. dalteparin & enoxaparin) LMW heparin inhibits mainly factor Xa via ATIII LMW heparin (e.g. dalteparin, enoxaparin & tinzaparin) or synthetic pentasaccharide (e.g. fondaparinux) are associated with less side effects compared to the UF heparin Heparin should be given as IV or subcutaneous injections Provides acute effects and half life is 40-90 minutes Effects can be terminated by stopping the infusion INR for clotting should be tested regularly Common side effects Haemorrhage – if bleeding occurs stop heparin and give protamine sulfate which inactivates heparin Thrombocytopenia – decrease platelet numbers Hyperkalaemia Osteoporosis (in prolonged use >6 months)

Answer 15

Hirudin – an anti-coagulant peptide (65 aa) present in leech saliva A potent natural inhibitor of thrombin Binds to thrombin surface directly and inhibit its activity Recombinant hirudins are commonly used E.g. Lepirudin used in patients with heparin-induced thrombocytopenia but require anti-coagulation therapy E.g. Bivalirudin used by cardiologists for patients undergoing PCI Mainly used in unstable angina or NSTEMI

Answer 16

Drug class: Anti-coagulant Mechanism: Prevents blood clot formation by inhibiting vitamin K reductase and depleting levels of the reduced form of vitamin K, a co-factor for the production of vitamin K-dependent clotting factors II (pro-thrombin), VII, IX and X Indication and dose: Prophylaxis and treatment of venous thrombosis and pulmonary embolism, Prophylaxis after insertion of prosthetic heart valves, transient ischaemic attacks or atrial fibrillation Counseling and cautions: Monitoring is essential Use with caution in patients taking it concomitantly with drugs that increase bleeding risk, history of GI bleeding or peptic ulcers, surgery etc. Check for possible interactions with other medicines Advise on possible interactions with food (i.e. cranberry juice)