AKT Blood Flashcards
Hereditary haemorrhagic telangiectasia and collagen abnormalities such as Ehlers-Danlos syndrome are classified as what type of bleeding disorders?
These are inherited disorders of the blood vessels. Problems with connective tissue can result in friable blood vessels.
What three acquired conditions can lead to friable blood vessels?
Aging
Scurvy
Steroid treatment (Cushing’s)
This type of hereditary bleeding disorder is autosomal dominant, and is characterised by dilated microvascular swellings in the skin, mucous membranes, and internal organs. Results in nose bleeds, GI bleeds, and possibly shunting between the arteries and veins
Hereditary hemorraghic telangectasia (aka Osler-Weber-Rendu syndrome)
Bleeding symptoms tend to occur when platelet levels drop below _______
10
Platelet disorders tend to cause problems with __________ bleeding (skin, nose GI tract, GU tract, menorraghia)
superficial
What are some common causes of platelet disorders?
Bone marrow disorders
ITP
Drug-related
DIC
This self-limiting bleeding condition can follow an infection in children. It tends to be more chronic in adults, but can be treated with Prednisolone or IV immunglobulins
Immune thrombocytopenic purpura
What two substances allow platelets to stick to exposed collagen?
VWF and glycoprotein 1b
Which glycoprotein (along with fibrinogen) binds multiple platelets together?
2b/3a
What substances are released by activated platelets that lead to further platelet activation, as well as adhesion and aggregation?
Thromboxane and ADP
ADP binds to which receptor on platelets?
P2Y12 receptor
What is the role of cycloxygenase (enzyme found within platelets?)
It converts arachadonic acid into thromboxane A2 (substance which promotes further activation of platelets)
Which drug blocks the P2Y12 receptor on platelets?
Clopidogrel
Which glycoprotein is deficient in Glanzmann’s thrombocytopenia?
Gp 2b/3a
Which glycoprotein is deficient in Bernard-Soulier syndrome?
Gp 1b (remember “1Bernard”)
Which are the two most important clotting factors in hemophilia?
8 and 9
What is the most common inherited blood clotting abnormality?
Von Willebrand’s disease
Characteristic clinical sign of haemophilia?
Spontaneous bleeding into joints and muscle
Pattern of inheritance in haemophilia?
X linked recessive (affects males only, females are carriers)
If a man with haemophilia has children with a genetically normal woman, what will the inheritance pattern be for their children?
All daughters of affected men become carriers. The sons are normal.
If a genetically normal man has children with a woman who carries a gene for haemophilia, what will the inheritance pattern be for their children?
Carrier mums have 50% haemophiliac sons and 50% carrier daughters
aPTT is often used in hospitals to measure the efficacy of which drug?
Heparin (mainly testing instrinsic pathway)
PT test measures the efficacy of which drug?
Warfarin (mainly testing the extrinsic pathway)
What does INR measure?
The ratio of the patient’s PT time/normal PT time
What would blood results (lab testing) show in haemophilia?
aPTT would be prolonged
What is the treatment for haemophilia?
Infusions of recombinant factor 8 or 9 every 2-3 days
Inheritance pattern in VonWillebrand’s disease?
Autosomal dominant
Which clotting factor does Von Willebrand’s factor carry through the blood?
Factor 8
How does von willebrand’s disease present?
Deficiency in VWF is a disorder mainly affecting platelets, so it tends to present more like a thrombocytopenia with superficial bleeding. More common in females
Blood results in von willebrand disease?
Prolonged aPTT (remember low factor 8) Normal PT Normal or low platelet numbers Defective platelet function Prolonged bleeding time
Which drug increases the synthesis and release of von willebrand factor?
Desmopressin (ADH analouge)
What is Tranexamic acid used for?
Anti-fibrinolytic most often used by surgeons for patients who won’t stop bleeding post-op. Can also be used to treat von willebrand’s disease
What is the MCC of acquired coagulation disorders?
Liver disease (cirrhosis)
In which life-threatening condition does both bleeding and coagulation tend to occur?
DIC
List the vitamin K dependant clotting factors (and proteins)
2, 7, 9, and 10, as well as Proteins S and C
1972 was the diSCo era
In what conditions might people have a deficiency of Vitamin K?
Fat malabsorption
Biliary obstruction
Hemorrhagic disease of the newborn
What substance is used to treat impaired clotting in liver disease?
Vitamin K
Which drug acts as a vitamin K antagonist?
Warfarin
Which clotting factors does Warfarin inhibit?
2, 7, and 10 (and to a lesser extent, 9)
What type of bacterial infection is a common cause of DIC?
Gram negative septicaemia (eg meningococcal infections)
Which two types of cancers are associated with DIC?
Acute myelogenous leukemias or adenocarcinomas (mucin-secreting)
What initial step in the development of DIC leads to the breakdown of balance between coagulation and fibrinolysis?
The release of Tissue Factor (III) which initiates the extrinsic coagulation cascade
What is the most characteristic finding of DIC on peripheral blood films?
Red cell fragments
Blood results in DIC?
Prolonged PT and aPTT Low fibrinogen Low platelets Raised D-dimer Raised fibrin degradation products
A unilateral, painful, hot, swelling in the leg could potentially be due to a
DVT. It’s also important to remember that sometimes DVT’s can have no symptoms or signs
How can you differentiate cellulitis from DVT just by visual inspection?
Cellulitis normally has a well demarcated line separating healthy skin from infected skin
What is Virchow’s triad?
Risk factors for DVT: Circulatory stasis, vascular injury, and hypercoagulable state
“VIrCHow”
What elements of a patient’s history correlate with circulatory stasis?
Long haul flights or car journeys, extended bed rest, major surgery, particularly lower limb orthopedic, and pregnancy
A swollen arm in a patient with a pacemaker could indicate
A DVT in the subclavian vein
List four types of vascular injury associated with DVT’s
Trauma including surgery, foreign body (cannulae, pacemaker wires), sepsis, and previous DVT
What types of things contribute to a hypercoagulable state?
Oestrogens, smoking, active cancer, inherited and acquired thrombophilias
What is the most common form of acquired thrombophilia?
anti-phospholipid syndrome
Epidemiology of anti-phospholipid syndrome?
70% female
Can coincide with SLE infection (10-15% of cases)
Possible sequela of anti-phospholipid syndrome?
Miscarriage, stillbirth, pre-eclampsia
What types of conditions cause dysfunctional fibrinogen (making it more prone to clotting)?
Severe liver disease (commonest)
Autoimmune disease
Multiple myeloma
Certain cancers (eg cervical cancer)
Most common inherited thrombophilia?
Leiden’s Factor V. Mainly people of European ancestry. Only 10% of people with mutation have thromboses, so are not typically treated with anticoagulants
What is the function of Protein C and Protein S?
They are natural anticoagulants in the blood. Protein C breaks down clotting factors V and 8. Protein S assists protein C in binding to the surface of platelets.
What is the Well’s score used to estimate?
Determines the probability of a person having a DVT or a PE
What is the order of investigations you would use for a suspected DVT or PE?
- Well’s score
- D-dimer test
- If D-dimer test is positive, then you would order a Doppler ultrasound
(mnemonic: “Whoop-D-Do”)
D-dimer is a breakdown product of
fibrin. It’s only present when the coagulation system has been activated
Is the D-dimer test more sensitive, or more specific?
Sensitive. A negative test can be used to rule out DVT/PE if low probability. Lots of other things can cause elevated d-dimer
A DVT in which veins carries a very high risk of PE?
Ilio-femoral veins
what is the treatment for calf-only DVTs?
Symptomatic (painkillers and compression stockings). Repeat ultrasound in 7 days
what is the treatment for iliofemoral DVTs?
Anticoagulant with Warfarin or DOAC (Rivaroxaban or Dabigatran). 3-6 months for first event, lifelong for second event.
What is the difference in clinical presentation between a small, peripheral PE and a large, central PE?
Small peripheral PE: pleuritic pain, breathless, haemoptysis
Large, central PE: chest pain, breathless, HYPOXIA
What is the investigation of choice when suspecting a PE?
CT pulmonary angiogram
What type of imaging can be used if PE is suspected in patients for whom CTPA is contraindicated?
Ventilation/perfusion scan (nuclear medicine)
Treatment for PE?
Initially: Heparin (particularly LMWH such as Enoxaparin), then switch to Warfarin or DOAC.
What type of additional testing should be considered in PE or DVT patient with first degree relative who has also had a VTE?
Thrombophilia testing
When are thrombolytics indicated for a patient with a PE?
ONLY if the patient is in shock with extremely low BP
What are the treatments for a patient with a massive PE?
IV fluids to restore CO
Surgical embolectomy
Catheter fragmentation
What is the number 1 cause of preventable hospital deaths?
VTE
Methods of VTE prevention?
- Subcutaneous Heparin or low dose Rivaroxaban after major joint surgery
- Venous compression stockings
- Early mobilisation
- Good hydration
Bone marrow failure is characterised by what three cellular features?
Anaemia, neutropenia, and thrombocytopenia
High turnover of cells in leukemia can result in a build up of uric acid in the blood, which can result in
gout
The hallmark of acute leukemia is when more than ______ of the cells in the bone marrow are BLAST cells
20%
What is the most common malignancy of childhood?
ALL
“Bulky disease” (enlarged mediastinal lymph nodes + splenomegaly) is a feature of which type of leukemia?
ALL
Markers for B cell ALL are
CD 19, CD 21 (1921)
What is the mneumonic for remembering B cell ALL?
B cell
Big (spleen)
Bones (marrow)
1921
Which type of leukemia features thoracic lymphadenopathy (shows up as mediastinal widening on CXR)?
T cell ALL
What are the features to remember about T Cell ALL?
Teenage boys
Thoracic LAO
Markers CD5 and CD6
What are the genetic markers associated with T Cell ALL?
CD 5 and CD6
Auer rods in the peripheral blood film are diagnostic of which type of leukemia?
AML
Which type of leukemia is associated with severe coagulopathy/ DIC?
Acute PROmyelotic leukemia
Smudge cells on blood film suggests what type of leukemia?
CLL
What are the two most common causes of splenomegaly in adults?
Myelofibrosis and CML
Which type of leukemia is very responsive (up to 90% curable) with a single treatment of chemotherapy?
Hairy cell leukemia (similar to CLL)
What type of leukemia presents with anaemia, fever, splenomegaly, and the blood film shows “filamentous cells?”
Hairy cell leukemia
Which type of leukemia is associated with the BCR:ABL oncogene?
CML
Basophilia on the blood film is virtually diagnostic of which type of leukemia?
CML
Reed-sternberg cells (with “Owl Eye” appearance) on blood films suggest what type of malignancy?
Hodgkin’s lymphoma