Week 3 - Problem of the Week - I.T.P, Haemophilia, Liver disease, P.E and D.V.T - Well's score and treatment Flashcards
Station 1 Platelets found wanting A medical student has cut himself, peeling the vegetables for a special romantic St. Valentine’s Day meal for his partner and himself. “No problem,” he thought, “I’m a second year medical student. I’ve done First Aid.” BUT….. he couldn’t stop the bleeding. He has been investigated and he has thrombocytopenia i.e. a low platelet count. a) How is it that his platelet count is so low?
His low platelet count could be due to a reduced number of platelets: * Reduced production of platelets in which there is a problem with the bone marrow * An increased destruction of the platelets ie hypersplenism or immune/idiopathic thrombocytopenia purpura or dic
What are different causes of hypersplenism? How does immune thrombocytopenic purpura (ITP) usually present?
Hyperplensim - presents usually due to causes of splenomegaly eg thalassemia, liver cirrhosis (portal hypertension causes splenomegaly), Felty’s syndrome, autoimmune haemolytic anaemias ITP - usually presents as a primary haemostatic diosrder - bleeding into the skin, bleeding from mucosal surfaces - gums, menorrhagia, retina, bleeding excessively from cuts
b) Why are platelets so important? How does their function work?
When there is a small bleed, platelets form the plug to stop the bleed The bleed damages the endothelium exposing the sub-endothelial collagen and glycoprotein Ib and vWF help bind the platelets to the sub-endothelial collagen Platelets then release granules eg ADP or TXA2 to call more platelets which aggregate via GPIIbIIIA
c) How are platelets normally formed in the body? How long is the platelet life? How many are produced per second?
Platelets come from the bone marrow budding off from the very large megakaryocytes – a bit of cytoplasm buds off from the megakaryocyte which is the platelet – lasts 7-10 days in the blood 1 million platelets are produced per second
e) What other abnormalities of his blood haemostatic system could give rise to similar clinical symptoms and signs? Likely that the boy had immune thrombocytopenic purpura
VWD - von willebrand disease - deficiency of vWF prevents the platelet adhesion to the site of endothelial damage resulting in increased injruy Vessel wall defects - eg senile purpura Steroid reduce collagen resulting in less platelet adhesion and also scurvy Connective tissue disorders Marfans or Ehlers danlos HSP- henoch schlonein purpura - purpura on buttocs and extensors - self limiting
f) With his symptoms, how would he initially have been investigated?
Full blood count and look at film See if it is an isolated platelet disorder Film to check to see if there are large platelets being produced - could show that there was increased destruction if marrow was stressing to produce more rather than marrow failure PT and APTT will rule out secondary causes and measure calcium levels
What is the treatment of immune thrombocytopenic purpura? * 1st line * 2nd line * 3rd line In ITP, antiplatelet autoantibodies attack the platelets and are removed by the spleen hence thrombocytopenia What happens to the splenic size in this condition?
1st line of many autoimmune conditions is usually steroids - prednisolone and IV immunoglobulin (IV IgG) 2nd line Splenectomy - cures most cases 3rd line Immunosupression if splenectomy fails Splenic size usually does not increase with this condition
What is emerging as a new emerging treatment for ITP that is an alternative to the splenecomty?
This would be eltrombopag - new oral thrombopoietin-receptor agonist that stimulates thombpoiesis
Station 2 Bleeding Again Another young man was supposed to be preparing a special romantic St. Valentine’s Day meal for his partner and himself and once again he had to take himself off to bed because his knee became swollen and was incredibly painful. He has haemophilia. The crazy thing is that he cut his finger with the vegetable knife earlier and that did stop bleeding on. a) What is haemophilia? b) How does it occur?
Hameophilia is an X-linked recessive disorder that is passed down in families It impairs the bodies ability to clot in response to bleeding and has a secondary haemostasis characterisitic bleeding type - where the bleeding is usually into muscles, skin and joints
c) In what way does having haemophilia affect haemostasis? D) Why did he not have prolonged bleeding following a superficial cut with a vegetable knife?
Hameophilia affects the intrinsic pathway of secondary haemostasis as it can either effect factors VIII or IX which go on to activate factors V/X in the common pathway of coagulation He did not have a prolonged bleeding following a superficial cut as primary haemostasis will plug this clot - he has no issue with his platelets, collagen or vWF
e) In what way would his clinical symptoms and signs be different from those of his friend with thrombocytopenia? Why does his knee keep on being affected by the haemophilia??
Clinical symptoms would be different as secondary haemostasis is affected - therefore bleeding into skin, muscles and joints mainly (rather than mucosal membranes and from cuts) His knee continues to be affectected because once a joint experiences a bleed once, this inflames the synovium causing neovascularisation of the joint and these small weak vessels are likely to keep on bleeding - target joint now
What are the three most common joints to be affected?
The ankle then the knee then the elbows Haemophilia usually affects the weight bearing joints first
(g) What blood tests would be useful in identifying the abnormality in the blood clotting system in haemophilia? What is the treatment of hemophilia A or B?
Diagnose by measuring coagulation times Increased APTT would show a single clotting factor deficiency on the intrinsic pathway The measure factor VIII or IX assays to identify if Haemophilia A or B respectively Haemophilia A - may be able to use desmopressin Usually recombinant factor VIII and IX concentrates are used nowadays
In addition to haemophilia I also have chronic liver disease from Hepatitis C infection from contaminated blood product therapy. h) What additional problems would this cause to my blood clotting system? Likely to have hep C because we used to used to use blood to get factors, but this increased rate of Hep C transmission and now recombinant factors are used –
He is likely to have both an increased APTT and PT due to the liver disease affecting all clotting factors produced May also have a low platelet count if the liver disease has caused portal hypertension causing hyperpslenism
Station 3 Too much of the Good life! A 28 year old barman presents to A&E, he is concerned about a major bruise over his arm and chest wall that has developed after being involved in a fight at work. On examination he has blood shot eyes as well as the bruising over his chest wall. He is also noted to have an enlarged liver. On further questioning, he admits to an alcohol intake of 60-70 units per week. a) What are you expecting to see on coag tests?
Expect to see a raised APTT and PT time as likely his liver is failing to produce clotting factors due to the liver failure Also may have low platelets
What is a high probability of DVT on Well’s score? If the patient has a high probability what is performed? If the Well’s score is unlikely of DVT what is performed? How would you rule out DVT in both likely and unlikely Well’s scores?
DVT likely if the Well’s score is >/= 2 If the Well’s score is 1or less then DVT unlikely If likely then do D-dimers and USS and DVT excluded if both are negative - if USS positive treat as DVT If unlikely - D-dimer only - DVT excluded if negative
What is a high probability of PE on Well’s score? If the patient has a high probability what is performed? If the Well’s score is unlikely of PE what is performed? How would you rule out DVT in both likely and unlikely Well’s scores?
PE is likely if Well’s score is greater than 4 PE is unlikely if Well’s score is less than 4 If PE likely then CTPA is carried out (CT pulmonary angiogram) If PE is unlikely then measure D-Dimers (sometimes CXR) (if D-dimer +, then CTPA)
