Haematology and oncology Flashcards
At what platelet level should you considered giving platelet transfusion ?
<10 and no bleeding
<30 with active bleeding e.g. epistaxis, melaena
<100 if severe bleeding or bleeding from critical site e.g. CNS
What is one problem with platelet transfusion that occurs more so than with other blood products?
Bacterial contamination of platelets is more common than with other blood products.
What should target platelet levels be pre-op?
for any patient - >50
For those at risk of bleeding 50-75
those at risk of bleeding from critical site >100
What conditions are contraindicatory for platelet transfusion?
Autoimmune thrombocytopenia
Heparin induced thrombocytopenia
Thrombotic thrombocytopenia purpura
chronic bone marrow failure
name 3 types of porphyria’s ?
acute intermittent porphyria
porphyria cutanea tarda
variegate porphyria
What is the common pathogenesis with the porphyrias?
abnormalities in enzymes synthesising Heme resulting in the accumulation of intermediates = porphyrins
how does porphyria cutanea tarda present?
photosensitive bullae
skin fragility on face and dorsal aspect of hands
what form is porphyria cutanea tarda (i.e. which organ?) and how is it caused?
hepatic form
can be caused by hepatocyte damage - alcohol, oestrogens
defect in uroporphyrinogen decarboxylase
how can you investigate porphyria cutanea tarda?
elevated uroporphyrinogen
pink florescence urine under wood lamp
How do you manage Porphyria cutanea tarda (PCT)?
Chloroquine
what enzyme is defective in variegate prophyria?
protoporphyrinogen oxidase
what pattern of inheritence is variegate porphyria?
autosomal dominant
How does variegate porphyrias present?
photosensitive blistering rash
abdominal and neuro symptoms
most common in south aftrican
How does a PET scan work?
flurodeoxyglucose used as a radiotracer.
tumours are active and take up this marker
images are combined with CT to give an idea of if lesions are metabolically active
At what stage of pregnancy is risk of DVT/VTE the highest?
3rd trimester
what is the cause of increased risk of VTE in pregnancy?
hypercoaguable state - increase in factors VII, VIII, X and fibrinogen
decrease in protein S
stasis in legs - uterus compressing on veins. progesterone dilates veins.
what treatment is used for DVT in pregnancy?
LMWH
warfarin contraindicated
causes of splenomegaly including massive splenomegaly….
massive spenomegaly: myelofibrosis CML visceral leishmaniasis malaria gauchers syndrome
other causes: (not massive)
- EBV, hepatitis
- malaria
- sickle cell/ thalassemia
- haemolytic anaemia
- portal hypertension
- CLL, hodgekins
- rheumatoid arthritis (feltys)
- infective endocarditis
Where are thymomas located? what age do they present?
most common tumour of anterior mediastinum
Occur during 6th and 7th decades of life
what diseases are thymomas associated with?
Myasthenia gravis (30-40%)
Dermatomyositis
Red cell aplasia
SLE, SiADH
what are the causes of death with a thymomas?
compression of airway
cardiac tamponade
what is transexamic acid?
antifibrinolytic
lysine derivative
binds plasminogen and plasmin preventing the breakdown of fibrin
used in menorrhagia
which type of central venous catheter gives a higher risk of VTE?
femoral > subclavian
which underlying conditions increase risk of VTE?
malignancy thrombophilia: e.g. Activated protein C resistance, protein C and S deficiency heart failure antiphospholipid syndrome polycythaemia nephrotic syndrome
Behcet's sickle cell disease paroxysmal nocturnal haemoglobinuria hyperviscosity syndrome homocystinuria