Case 15 Flashcards
What is haemostasis?
Physiological process by which the body stops bleeding after blood vessel injury
What is a thrombus?
Blood clot in a blood vessel or in the heart
What is coagulation?
Process of turning blood from liquid into a gel to form a blood clot
Which protein forms mesh like network in blood clots?
Fibrin
What is fibrinolysis?
Process by which blood clots are broken down and dissolved
Describe process of fibrinolysis?
Plasmin (an enzyme) degrades fibrin
What is an embolism?
When a blood clot or other materials (eg fat) travel through blood stream and become lodged, obstructing blood flow
Three factors which increase likelihood of thrombosis?
Abnormalities of the vessel wall
Abnormalities of blood flow
Abnormalities of bloods constituents
Describe first part of process of blood clot formation (up to platelet plug formation)
1)Injury occurs - and collagen and tissue factors are exposed
2)Vascular spasm - smooth muscle walls contract rapidly to reduce blood flow through damaged vessel
3)Platelets adhere to site of injury and become activated, forming platelet plug
Explain the intrinsic clotting pathway of coagulation cascade?
Occurs inside blood vessel
1)Factor XII (12) activated by Collagen
2)Factor XI (11) activated by factor XII (12)
3)Factor IX (9) activated by Factor XI (11), Factor VIII (8) and calcium ions
4)Factor X (10) activated by Factor IX (9), Factor VIII (8) and calcium ions
Explain the extrinsic pathway of coagulation cascade?
Occurs outside blood vessel
1)Tissue factors and Factor VII (7) activate Factor X (10)
End product of both extrinsic and intrinsic pathways in coagulation?
Factor X (10)
Explain the common pathway of coagulation cascade?
After extrinsic and intrinsic pathways…
Prothrombin is converted into Thrombin by Factor X (10), Factor V (5), calcium ions and phospholipids
Explain final part of coagulation after the common pathway?
1)Soluble fibrinogen converted into insoluble Fibrin strands by thrombin
2)Fibrin strands form a mesh network which trap blood cells and form stable blood clot
3)Clotting factors and platelets reinforce clot making it stronger
What is a venous thromboembolism?
Blood clots in veins
(Eg deep vein thrombosis or pulmonary embolism)
What is deep vein thrombosis?
Blood clot in deep vein (usually legs)
What is pulmonary embolism?
Blood clot in lungs
What is haemostasis?
A process to prevent and stop bleeding when blood vessel is damaged
What are Hypercoagulable states?
A variety of conditions where blood has increased tendency to clot
(Can be genetic caused by various mutations, or acquired eg by cancer, pregnancy or by certain medications)
What are the risk factors for deep vein thrombosis?
Alteration to blood flow (eg immobilisation, pregnancy, obesity)
Vessel wall damage
Hypercoagulable states
What is haemoptysis?
Coughing up blood from respiratory tract
How can obesity increase risk of developing venous thromboembolism?
Impaired blood flow
Endothelial dysfunction
Hypercoagulability
Systemic inflammation
What are anticoagulants?
Medications which help prevent formation of blood clots
What is Warfarin and how does it work?
Oral anticoagulant (prevents blood clot formation)
Inhibits bodies ability to use Vitamin K to produce certain clotting factors
What are Heparins and how do they work?
Injected anticoagulants
Indirectly inhibit clotting by enhancing activity of antithrombin - natural anticoagulant
What are DOACs and how do they work?
Direct Oral anticoagulants
Inhibit specific clotting factors in blood
Administered orally
What are Apixaban, Edoxaban and Rivaroxiban and how do they work?
DOACs - direct oral anticoagulants
New oral anticoagulant medications (prevents blood clot formation)
Inhibit factor Xa in clotting cascade (so clots wont form)
What is Dabigatran and how does it work?
Oral anticoagulant (prevents blood clot formation)
Inhibits thrombin
Side effects of anticoagulants?
Increased risk of bleeding
Increased risk of bruising
GI side effects
Increased risk of haematoma
Increased risk of osteoporosis
Thrombocytopenia (decreased level of platelets in blood)
What is a haematoma?
Blood leaked out of a blood vessel (like a big bruise)
Often caused by trauma but can be spontaneous
When patients are taking anticoagulants what property of other drugs and supplements etc should you be cautious of?
Other substances with anticoagulant effects which make clotting more difficult - eg aspirin, herbal supplements, cranberry juice
How does blood move back from lower limbs to heart?
-When moving, muscle contraction compresses veins, pushing blood upwards towards heart
-One way valves in veins
-Respiration causes low pressure in thorax, blood moves along pressure gradient, back toward heart
What is venous insufficiency?
Veins have difficulty returning blood from legs to heart
Valves in veins are often weakened
Blood pooling in lower limbs occurs
What does prothrombin time (PT) test measure?
Measures time taken for blood to clot after extrinsic pathway factors added
What does Activated partial thromboplastin time (aPTT) test measure?
Measures time taken for blood to clot after intrinsic pathway factors added
What does international normalised ratio (INR) measure?
Standardised measure of clotting time
Used to monitor patients on anti coagulation treatment
What does thrombin time test measure?
Measures time taken for fibrinogen in blood to be converted into fibrin
What is fibrinogen assay?
Measures conc of fibrinogen in blood
What is D dimer protein?
A small protein fragment that is produced when a blood clot is dissolved in the body
What is D Dimer test and what is it used for?
Measures levels of D dimer proteins
Used to rule out DVT and PE
(Elevated D dimer indicate a blood clot is present in the body)
What is a Wells score?
A score used by clinicians to assess likelihood a patient has deep vein thrombosis or pulmonary embolism based on clinical features and risk factors
Examples of things which give points for Wells test (increase likelihood of DVT and PE)?
Active cancer, calf swelling, pitting oedema (skin indents on palpation), immobilisation, tachycardia, history of DVT or PE, coughing up blood
What is Computed Tomography Pulmonary Angiography?
Imaging technique to view pulmonary arteries
Dye is injected into arm vein and a series of CT scans taken as dye travels through pulmonary arteries
Abnormalities detected
What is a V/Q scan?
1) Ventilation (V) Scan
Patient inhales radioactive gas
Distribution of gas visualised using gamma camera
Shows areas of decreased ventilation
2) Perfusion (Q) Scan Radioactive tracer injected into arm Distribution of tracer in lungs is visualised using gamma camera Shows areas of decreased perfusion
The V and Q scans are compared to see any discrepancies between airflow and blood flow
What is an Ultrasound Doppler Scan?
Ultrasound test used to evaluate blood flow in blood vessels
Doppler ultrasound measures speed and direction of blood flow
It uses Doppler effect - the frequency of sound waves changes when they reflect off moving objects (eg moving red blood cells)
Biological factors which affect eating behaviours?
Age, Puberty onset, previous eating disorder, medical conditions, parents weight, family history of eating disorders or obesity, weight fluctuation.
Psychological factors which affect eating behaviours?
Body image, Interalisation of ideas, mental health, impulsivity, perfectionism, self-esteem, adverse psychological experiences, beliefs and attitudes
Sociocultural factors which affect eating behaviours?
Gender identity, social media, ethnicity/race, education, employment, relationship status, neighbourhood, weight stigma
Behavioural factors which affect eating behaviours?
Type of food eaten, if breakfast is eaten, physical activity level, smoking, weight control behaviours, intuitive eating (eating when hungry), emotional eating, sleep quality
What is restricting anorexia?
Intense fear of gaining weight and distorted body image
Extreme calorie restriction and sometimes excessive exercise
What is binge eating anorexia?
A combination of anorexia and binge eating disorder
Periods of binge eating (or purges) followed by restrictive eating and compensatory behaviours (eg self induced vomiting, use of laxitives or dieuretics, excessive exercise)
What is Bulimia?
Episodes of binge eating followed by compensatory behaviours to prevent weight gain
(Eg fasting, induced vomiting, misuse of laxatives or dieuretics)
What is binge eating disorder?
Episodes of excessive eating without feeling control
No compensatory behaviours
Often struggle with weight
Describe the motivational interviewing technique to use when discussing weight loss with patients?
O - Open ended questions
A - Affirmations (expressing empathy and appreciation for their efforts and strengths)
R - Reflective listening (summarising and paraphrasing patients statements)
S - Summarising (highlighting what patient has said and action points)
