General haematology Flashcards
What are the 3 major groupings of anaemia?
What are the investigations to order if suspecting haemolysis?
Positive direct antiglobulin test
What are the 2 major groups of haemolytic anaemia?
What are the causes of pancytopaenia?
What are the causes of thrombocytopaenia?
What do the different coagulation tests look at and what causes their derangement?
What are the main causes of DIC?
What are the features that may indicate toxicity when on Dabigatran?
- Renal failure
- Elevated APTT
- Elevated thrombin time
- Spontaneous bruising/bleeding
How is Dabigatran toxicity treated?
- Idarucizumab (Praxbind) IV 5gm bolus
- Prothrombinex 50IU/kg
- FFP
- Tranexamic acid
- RRT, removes about 60% in 2hrs (particularly if concomitant renal failure)
What are the blood products that a typical Jehovas Witness wouldn’t allow?
- FFP
- Cryoprecipitate
- Platelelets
- PRBC’s
- Prothrombinex
- Albumin
- FEIBA
Some branches may allow some products
May or may not allow auto-transfusion and cell saver
What are the clinical features of Upper limb effort thrombosis?
AKA Paget-Schroetter syndrome
AKA Venous thoracic outlet syndrome
Clinical
- Usually presents in younger people after recent significant upper limb activity
- Acute upper extremity swelling
- Urschels sign (chest wall vein dilatation)
- Palpable venous cord
Risk Factors
- Athletic muscular men
- Younger age including adolescents
- Strenuous upper extremity activity
- Repetetive overarm hyperabduction
- Thrombophilia
- Thoracic outlet abnormalities
- Malignancy
- Recent indwelling vascular device
Complications
- Phlegmasia cerulea dolens
- Thoracic outlet obstruction
- Brachial plexus compression
- Acute PE
Treatment
- Subcut enoxaparin 1mg/kg BD
- Thrombolysis/thrombectomy
What are the potential complications of sickle cell syndrome?
- Acute chest syndrome
- Splenic sequestration
- Acute aplastic crisis
- Vaso-occlusive crisis (ie priapism)
- Renal failure
- Retinopathy
- Sepis (ie salmonella sp)
- Ischaemic stroke and ICH
What are the principles of management of a sickle cell acute chest syndrome?
- IV rehydration
- Adequate analgesia
- Treat hpoxia
- Cover with antibioitcs for sepsis
- Screen for other causes ie MI
What is the cause and differential diagnosis of MAHA?
Microangiopathic haemolytic anaemia
- aka Coombs negative haemolytic anaemia
- aka non-immune haemolysis
- A negative Coombs test with Schistocytes on peripheral blood smear is pathognomonic
Envenomation
- Australian snakes (brown)
Infections
- HUS, endocarditis, HIV, Malaria
Systemic
- Severe hypertension
- Eclampsia/HELLP syndrome
Iatrogenic
- Mechanical valve replacement
Haematological
- DIC acute or chronic
- Pre and post stem cell transplant
- Systemic malignancies
Autoimmune HIT-like syndromes
What are the risk factors for childhood leukaemia? What are good prognostic indicators?
Risks
- Family history
- Radiation exposure
- Immunosuppression
- Alkylating agents
- Trisomy 21
- Neurofibromatosis
- Bloom syndrome
- Ataxia telangiectasia
Good prognostic indicators
- Age 1-10
- WCC <50 at presentation
- No testicular involvement at presentation
- Don’t have trisomy 21
- No CNS disease
- No steroid exposure prior to diagnosis (ie since symptoms started)
Which coagulation study is prolonged in all 3 forms of haemophilia?
PTT
- Partial thromboplastin time
Prothrombin time (PR) and platelet count are normal in all 3
A = VIII (8)
B= IX (9) AKA Christmas Disease
C= XI (11)
Which coagulation tests does Dabigatran prolong?
APTT and TT
If both are normal then patient is not therapeutically anticoagulated from Dabigatran ingestion
What coagulation tests does Apixaban and Rivaroxaban affect?
PT, INR and APTT
However these may also be normal, if these tests are normal it in no way precludes the person from being therapeutically anticoagulated
Need an anti-factor Xa level
What is the dosing for Andexanet Alfa in severe DOAC bleeding?
800mg bolus over 30mins
THEN
8mg/min for 2hrs
Total 1760mg IV
What is the thrombotic complication of Covid vaccination and how is it treated?
Vaccine induced (or associated) thrombotic thrombocytopaenia (VITT or VATT)
- AKA TTS, AKA VIPIT (vaccine induced prothrombotic immune thrombocytopaenia)
- Causes acute thrombotic complications ie splanchnic thrombus formation, cerebral venous sinus thrombosis etc
- Related to Heparin-induced thrombocytopaenia
Tests
- D-Dimer markedly elevated (5x or more), -ve essentially rules it out
- Fibrinogen low, platelets low (<150), elevated white blood cells
- Anti-PF-4 antibodies are the confirmatory test
Treatment
- Non-heparin anticoagulation (NOAC’s, fondaparinux)
- Can consider IVIG to counter antibodies
What is the definition and treatment for ITP?
Definition
- Immune mediated low platelet count <100 with an otherwise well child with NAD FBE/FIlm
- RIsk of spontaneous severe bleeding ie SAH is <1%
Treatment Categories
- Based on clinical not platelet count
Low RIsk
- Petechiae/purpura, not significant bleeding (can still have minor gum or <5mins epistaxis)
- Conservative with FBE/film in 1 week + review + education
Medium risk
- >5min epistaxis or more severe external bleeding ie haematuria, significant menorrhagia etc
- Platelet transfusion
- 2mg/kg Pred to max 60mg
- IVIG1gm/kg
- TXA for epistaxis
High risk/Life threatening
- Major internal/external haemorrhage, ICH is life threatening
- Arbitrary differentiation as treatment the same
- 1gm/kg vIVIG
- Methylpred pulses 30mg/kg IV
- Platelets 20ml/kg +/- more
- IV TXA 15mg/kg
- Urgent haem consult
What is the typical discharge advice for ITP?
