Haematology Flashcards
what happens in antithrombin deficiency?
decreased inhibition of factor IIa and Xa
symptoms of DVT?
swelling, redness, warmth, pain
post-thrombotic syndrome (damage to valves)
Absence of GpIb surface glycoprotein results in?
Bernard Soulier syndrome
( only 1 b in Gp1b and in Bernard soulier)
It is a Platelet adhesion problem
clinical features of coagulation disorders?
- bleeding into deep tissues muscles and joints
2. bleeding delayed but prolonged
what questions would you ask a patient whose labs suggest iron deficiency aneamia?
Menstrual/postmenopausal bleeding Diet - vegetarian/vegan GI symptoms - dysphagia/dyspepsia/abdominal pain/change in bowel habit/hematemesis/rectal bleeding/melaena Aspirin/NSAIDs Weight loss
role of coagulation?
To generate thrombin (IIa), which will convert fibrinogen to fibrin
Why is aspirin used as anti platelet therapy?
Decreases thromboxane A2. Decreases platelet activation
what happens in factor V leiden?
Mutant factor 5. The coagulation factor is resistant to degradation by activated protein C
functions of B12?
DNA synthesis, homocysteine metabolism
Integrity of the nervous system
What is used to treat hemophilia A?
Desmopressin
below which platelet count is spontaneous bleeding common?
AND severe spontaneous bleeding?
- <40 x 10^9
2. for severe spontaneous bleeding <10 x 10^9
What is the effect of direct Xa inhibitors on PT and PTT?
Prolong both
What is the result of absence of factor XI?
bleed after trauma but not spontaneous
conditions associated with AIHA?
SLE - polyarthritis, renal impairment, facial skin rashes, hepatitis, tiredness
CLL
*positive dat test. Splenomegaly
what do lab tests show in DIC?
increase in FDPs (D-dimers) - due to activation of fibrinolysis
decrease in fibrinogen
what causes a prolonged PT and normal APTT
factor 7 deficiency
mechanism of ITP
anti-GpIIb/IIIa antibodies bind to platelets -> destruction by splenic macrophages
- blood smear will show megakaryocytes but other cell counts will be fine
- May be associated with viral illness
- decrease in platelet count
Give two possible investigations you would undertake if a disorder of primary heamostasis is suspected.
platelet count
vWF assay
clinical examination
signs of B12 deficiency?
paresthesia
Pale Yellow tinge to skin
Changes in the way you move or walk around
Reversible dementia
causes of vessel wall disorder?
- hereditary hemorrhagic telangiectasia, Ehlers-Danlos Syndrome
- Acquired - steroid therapy, aging (senile purpula), vasculitis, scurvy
Usually affect collagen synthesis
causes of thrombocytopenia (low platelet count)?
- Bone marrow failure - leukemia, B12 deficiency
- Accelerated clearance - Immune (ITP) is common, Disseminated Intravascular Coagulation (DIC)
- Pooling and destruction in enlarged spleen (e.g cirrhosis and portal hypertension
What is the result of absence of prothrombin (Factor II)?
lethal
a patients VWF is found to show reduced platelet adhesion, what type of Von
Willebrand disease does this indicate?
type 2
how does LMWH work?
enhances antithrombin- predominantly inactivates Xa
Direct Xa inhibitors decrease the formation of —
Thrombin
If a patient with iron deficiency anemia reports weight loss and intermittent abdominal pain, what investigations do you order?
- FIT for blood in stool
- Upper Gi endoscopy, duodenal biopsy, colonoscopy (GI investigations)
- Coeliac antibody testing
causes of megaloblastic aneamia?
Vitamin B12 and folate deficiency
Agents or mutations that impair DNA synthesis:
azathioprine cytotoxic chemotherapy
Folate antagonists - methotrexate
Bone marrow cancers - myelodysplastic syndrome
what is DIC?
widespread activation of clotting factors leading to deficiency
platelets also consumed -> thrombocytopenia
what are common symptoms of anemia?
Fatigue, pallor, dyspnea, tachycardia
absence of GpIIb/IIIa surface glycoprotein results in?
Glanzmann’s thrombasthenia
2 A’s, 3’s in Glanzmann’s = GpIIb/IIIa
It is a platelet aggregation problem
what are some causes of DIC?
- sepsis
- major tissue damage
- inflammation
Patient with Rheumatoid Arthritis, low hb, slightly low MCV, reticulocytes on low end
Low serum iron. Low transferrin. High ferritin. Normal transferrin saturation. High ESR. blood film shows microcytic hypochromic rbcs. Elevated platelet count. What is the diagnosis?
aneamia of chronic disease
warfarin is a substrate for cytochrome p450
name some p450 inhibitors that would cause increased plasma levels of warfarin -> bleeding on warfarin
name some p450 inducers
inhibitors:
- fluconazole
- erithromycin/clarithromycin
- ciprofloxacin
- omeprazole
- some anti-HIV drugs, especially protease inhibitors
- grapefruit juice
inducers
- st. johns wort
- Rifampicin (anitbiotic used to treat TB)
- Antiepileptics - carbamazepine, phenytoin, phenobarbitone, primidone
- griseofulvin (antifungal)
treatment for hereditary spherocytosis?
Folic acid to help make new red blood cells
Splenectomy if severe to increase rbc life span
other causes of normocytic aneamia?
Recent blood loss:
- Gastrointestinal haemorrhage, trauma
Failure of production of RBCs:
- Early stages of iron deficiency
- Bone marrow failure or suppression (e.g. chemotherapy)
- Bone marrow infiltration (e.g. leukaemia)
Pooling of RBCs in spleen:
Hypersplenism, e.g. liver cirrhosis
Splenic sequestration in sickle cell anaemia
state causes of Folic acid deficiency
- diet - alcoholics, poverty
- malabsorption - coeliac disease, jejunal resection
- increased demand - hemolytic aneamia, pregnancy
treat with oral supplements
increase of which coagulant proteins can result in thrombosis?
- prothrombin mutation/ Factor II
- Factor 5 leiden
- Factor 8 mutation
4 side effects of Warfarin?
- bleeding
- skin necrosis
- purple toe syndrome
- teratogenic - chondrodysplasia punctata
A patient with a disorder of primary haemostasis shows no evidence of petetchiae. What cause of the symptoms might this allow you to rule out?
thrombocytopenia
causes of macrocytic aneamia?
Lack of vitamin B12 or folic acid: megaloblastic anaemia
Use of drugs interfering with DNA synthesis
Liver disease and ethanol toxicity
Haemolytic anaemia (reticulocytes increased)
what is virchows triad?
SHE
- stasis of blood flow - surgery, long haul flights, pregnancy
- hypercoagulability - dominant in venous thrombosis
- endothlial damage - dominant in arterial thrombosis
differentiate between purpura and petechiae
purpura dont blanch when pressure is applied
pupura are larger
what deficiencies can result in thrombosis?
of anticoagulant proteins
- antithrombin deficiency
- protein C or S deficiency
State Important deactivators of coagulation. Deficiency Of them lead to what
- Antithrombin lll
- Protein C and protein S(cofactor)
- Tissue factor pathway inhibitor
Hypercoagulation
what neurological disorders can present with B12 and folate deficiencies?
Folate = neural tube defect B12 = Dementia and SACD
state 3 situations that require use of anticoagulants as prophylaxis
- following surgery
- during hospital admission
- during pregnancy
findings in hereditary spherocytosis?
signs of hemolytic anemia
Spherocytes on blood film - small, spherical, no central pallor
Splenomegaly
Which type of heparin medication requires monitoring?
UFH - results in prolongation of APTT
What is the main function of Plasmin?
- Degrade clots to FdPs and D-dimers
signs and symptoms of iron deficiency aneamia?
Symptoms - fatigue, conjunctival pallor, pica, spoon nails
Labs show Low ferritin and serum iron. High transferrin/TIBC. Low transferrin saturation
Hb electrophoresis shows no increase in HbA2 (ruling out b- thalassemia)
Blood film shows small hypochromic cells