Haematology Flashcards
What is the normal range for Hb in females?
11.5 - 14.5 g/dl
What is the normal range for MCV?
77-95 fl
What is the normal range for haematocrit?
0.37 - 0.47
What is the normal range for WCC?
4 - 11 x 10(9)/L
What is the normal range for platelets?
140-400 x 10(9)/L
Why is reticulocyte count relevant in anaemia?
Absence of an appropriate reticulocytosis in the setting of anaemia suggests impaired RBC production
What is APTT?
Activated Partial Thromboplastin Time
What does APTT measure?
Intrinsic pathway - factors XII, XI, IX, VIII
What causes a prolonged APTT?
Factor deficiency
Heparin treatment
What does prothrombin time measure?
Extrinsic pathway
What else is a long prothrombin time called?
High INR
What are the causes of prolonged prothrombin time?
Vitamin K deficiency
Anticoagulation with warfarin
Factor deficiency
What are D dimers?
Fibrinogen-fibrin degradation products
What is polycythaemia?
Increase in total mass of red blood cells in body
What is erythrocytosis?
Increase in concentration of red blood cells
What is primary polycythaemia?
Polycythaemia rubra vera - myeloproliferative
What causes secondary polycythaemia?
Driven by erythropoietin production
When is secondary polycythaemia physiologically appropriate?
High altitude Chronic cor pulmonale Cyanotic congenital heart disease Hypo ventilation Abnormal Hbs
When is secondary polycythaemia physiologically inappropriate?
Renal: RCC, haemangioma, post-transplant, polycystic
Hepatocellular carcinoma
Others - cerebellar haemangioma, uterine tumours, Cushing’s syndrome, EPO abuse, androgen abuse
What are the causes of microcytic anaemia?
Iron deficiency Anaemia of chronic disease Haemoglobinopathy Vit A or B6 deficiency Sideroblastic anaemia
What are the causes of folate deficiency?
Poor diet
Increased needs
Malabsorption - coeliac disease, jejunal resection
What type of anaemia do vit B12 and folate deficiency cause?
Macrocytic
What drugs cause increased MCV?
Sulfasalazine Alcohol Methotrexate Valproate Cholestyramine Some cytotoxic drugs
What are the different types of haemolysis?
Hereditary or acquired
Immune or non-immune
Extravascular or intravascular
What are the causes of AIHA (autoimmune haemolytic anaemia)?
Primary CLL Drugs SLE EBV
What are the causes of non-immune haemolytic anaemia?
Hypersplenism
Prosthetic heart valves
Sepsis
Malaria
What are the causes of mechanical haemolysis?
Cardiac haemolysis
AV malformations
Microangiopathic haemolytic anaemia eg TTP, DIC, malignancy, vasculitis, pre-eclampsia, renal vascular disorders
What are the causes of normocytic anaemia?
All of previous causes
Blood loss
Anaemia of chronic disease
Starvation or anorexia nervosa
What is the normal range for Hb in males?
12.5 - 15.5 g/dl
What does a raised reticulocyte count in anaemia suggest?
.
Active marrow response … Not necessarily haemolysis
What should you do if a platelet count comes back low?
Repeat and send full clotting screen
What drugs should be avoided in thrombocytopenia?
Aspirin
NSAIDs
What drugs can cause neutropenia?
Antipsychotics Antidepressants Anti-inflammatory Antithyroid Chemotherapy
What is the treatment for ITP?
Steroids
How do you reverse warfarin?
5mg IV vitamin K
How do you immediately reverse warfarin?
Prothrombin complex and vitamin K
What is the dose of FFP?
10 - 15ml/kg
What is virchow’s triad?
Hypercoagulability
Vascular damage
Stasis
What factors contribute to the Wells score?
Active cancer Immobilisation > 3 days Localised tenderness along DV Entire leg swollen Calf swelling > 3cm Pitting oedema Collateral superficial veins Likely alternative diagnosis
What wells score indicates the need for imaging?
Moderate or high (>1) in patients with other inter current illness
What score is a high wells score?
3 or more
When is testing D dimers a sensitive test?
To exclude DVT in non-hospitalised patients with a low risk score
Why are D dimers not used for patients in hospital?
They are raised in any inter current ilness and so not recommended - not specific
When is the probability of PE high?
A + B…
A) clinical features (SOB, tachypnoea, pleuritic chest pain, haemoptysis, syncope)
B) absence of another reasonable clinical explanation or presence of a major risk factor
What types of malignancy are major risk factors for PE?
Abdominal or pelvic
Advanced or metastatic
What is the first line imaging technique for suspected PE?
CTPA
Including intermediate or high probability in pregnancy
What other imaging techniques are used for suspected PE?
VQ scan
Echo
Leg USS
Pulmonary angiogram
When is thrombolysis indicated for PE?
Massive life-threatening PE
Haemodynamic compromise
Significant right ventricular dysfunction
How do you use heparin when commencing warfarin?
Continue heparin for minimum of 4 days until INR>2 for 2 consecutive days
What is the target INR for PE and DVT?
- 5
3. 5 if recurrent VTE whilst on warfarin
What is the relationship of proximal DVT and PE?
50% of patients with proximal DVT have asymptomatic pulmonary embolism at the time of diagnosis
What proportion of patients with PE have a DVT at the time of diagnosis?
40-50%
How long should warfarin be continued after proximal DVT or PE?
At least 3 months
When should dalteparin be used in medical patients?
Reduce mobility with one of: A) severe cardiac failure B) acute respiratory failur C) active cancer or inflammatory disease D) acute infection/inflammation plus >75y, chronic heart or resp failure, previous VTE, obesity, COCP, varicose veins
What are the contraindications to Dalteparin?
Known bleeding disorder or platelets
What are the contraindications to TED stockings?
Dermatitis Gangrene, leg ulcers Symptomatic PVD Cellulitis Peripheral neuropathy Massive oedema of legs or pulmonary oedema from CCF
Over how long should red cells be transfused?
Within 4 hr of removal from fridge
Ideally over 2-3 hours
How is the use by date of blood products relevant in practice?
Transfusion must be STARTED by midnight on day of use by
How are red cells stored?
Fridge
2-6 degrees