Flashcards in Haematology Deck (47)
If a patient is bleeding or bruising spontaneously what are the three process that could be disrupted?
Congenital - Osler Weber Rendu syndrome, connective tissue disorders
Acquired - Infection, HSP, steriods, scurvy
Diseased marrow production - Aplastic anaemia, megaloblastic anaemia, malignancy, marrow suppression
Excess destruction - ITP, SLE, CLL, drugs, DIC, thrombotic thrombocytopenic purpura, sequestration
Poorly functioning - myeloproliferative disorders, NSAIDs, increased urea
Congenital - Haemophilia, von Willebrands
Acquired - anticoagulants, liver disease, DIC, vitamin K deficiency
When would you suspect a patient had ITP?
Immune thrombocytopenia causes low platelets and increased bleeding.
Most common in children (acutely 2 weeks after an infection) and women (chronically).
Causes bleeding and purpura (over dependent pressure areas) and increased epistaxis and menorrhagia.
Splenomegaly is not present
How do you treat ITP?
No treatment needed if mild
If symptomatic or platelets 30.
If relapsing splenectomy cures >80%
Can use immunosuppression if needed
What is Haemophillia A?
Factor VIII deficiency
X link recessive
Usually presents with pain after trauma or surgery as bleed into joints and muscles
Diagnosed by high APTT (INR will be normal) and low factor VIII assay.
How do you manage bleeding in a patient with Haemophilia A?
Factor VIII deficiency
Minor bleeding - pressure and elevation. Desmopressin raises factor VIII levels
Major bleeds (haemarthrosis) - increase factor VIII levels to over 50% of normal
Life threatening bleeds - need factor VII levels of over 100%, use recombinant factor VIII
What is Haemophilia B?
Christmas disease - factor IX deficiency
X link recessive
Behaves similar to Haemophilia A
What does von Willebrand factor do?
1. brings platelets into contact with exposed subendothelium
2. makes platelets bind to one another
3. bind factor VIII to stop destruction in circulation
What are the 4 most common forms of von Willebrand's disease?
Type I - autosomal dominant deficiency of vWF
Type II - abnormal vWF
Type III - undetectable vWF, autosomal recessive with gene deletions
Type Normandy - impaired vWF binding, causes an autosomal recessive mimic of haemophilia A
What signs and symptoms suggest von Willebrand disease?
Bruising, epistaxis, menorrhagia, - mild in type I and II
APTT increased, bleeding time increased, factor VIIIc decreased,
INR and platelets are normal
Which clotting factors are vitamin K dependent?
II, VII, IX, X
What are the differences between APPT, and PT?
Prothrombin time - tests extrinsic pathway
Tests for abnormalities in factor I, II, V, VII, X
Prolonged by warfarin, vitamin K deficiency, liver disease and DIC
Activated partial thromboplastin time - tests intrinsic pathway
Tests for abnormalities in I, II, V, VIII, IX, X, XI, XII
Prolonged by heparin treatment, haemophilia, DIC, liver disease
What are the differentials for a macrocytic anaemia?
B12 or Folate deficiency
Drugs - phenytoin, methotrexate,
What are the causes of B12 deficiency?
Stomach (lack of intrinsic factor): pernicious anaemia, post gastrectomy
Terminal ileum: ileal resection, Crohn's, bacterial overgrowth, tropical sprue, tapeworms,
Congenital abnormalities in metabolism
What are the symptoms of vitamin B deficiency?
Symptoms of anaemia
Lemon tinge to skin (due to pallor and increased bilirubin)
Irritability, depression, psychosis and dementia
Subacute combined degeneration of the spinal cord:
Joint position and vibration sensation lost
Extensor plantar responses
Absent knee and ankle jerks
Glove and stocking sensation loss
What is subacute combined degenernation of the spinal cord?
Symmetrical posterior dorsal column loss and symmetrical cortico-spinal tract loss - all caused by vit B deficiency
What is pernicious anaemia?
Autoimmune atrophic gastritis - leading to lack of intrinsic factor and therefore vit B12 deficiency
What are the different types of amyloidosis?
AL amyloid (primary) - due to clonal proliferation of plasma cells, results in production of amyloidgenic monoclonal immunoglobulins.
Deposition is seen in:
Kidneys (nephrotic syndrome), heart (restrictive cardiomyopathy, arrhythmias, angina), nerves (peripheral and autonomic neuropathy), gut (macroglossia, malabsoprtion, perforation, haemorrhage, obstruction, hepatomegaly), vascular (periorbital purpura)
AA amyloid (secondary) - occurs in chronic inflammation. The amyloid is built up from serum amyloid A (acute phase protein)
Deposition in kidneys, liver, and spleen. Cardiac involvement is rare.
Familial amyloidosis - autosomal dominant disorder.
What stain would diagnosis amyloid?
Congo red stain with red-green birefringence
How do you treat vitamin B deficiency?
hydroxyocobalamin 1mg on alternate days for 2 weeks and then 1mg every 3 months for life - if due to malabsorption
What is special about Hodgkins lymphoma?
The Reed-Sternberg cells in them, they are cells with mirror image nuclei
It has more systemic features, patients get fevers, night sweats, puritis, lethargy
What is lymphoma?
Disorder charcterised by malignant proliferation of the lymphocytes, leading to lymphadenopathy - usually rubbery and non tender
How is lymphoma staged?
Ann Arbor staging - CXR, CT and bone marrow biopsy
I confined to lymph node region
II involvement of two or more nodal areas on he same side of the diaphragm
III involvement of nodes on both side of the diaphragm
IV spread beyond the lymph nodes (liver or bone marrow)
A - no systemic symptoms other than puritis
B - weight loss >10% in last 6 months, unexplained fever >38, drenching night sweats
What is the treatment for Hodgkin's lymphoma?
What is the treatment for high grade non hodgkin's lymphoma?
R - CHOP
Rituximab, Cyclophasphamide, Hydroxydaunorubin, Prednisolone
Explain the genetic basis of sickle cell:
Autosomal recessive resulting in the abnormal production of the B chains of haemoglobin.
There is an amino acid substitution at position 6 Glu - Val, so that HbS is produced rather than HbA.
The HbS polymerizes when deoxygenated causing the RBCs to deform, leading to sickle cells - fragile , haemolyse and block small vessels
HbSS = sickle cell aneamia
HbAS = sickle cell trait, no symptoms, protected from malaria, may have venoocculsive episodes in hypoxic enviroments ie pressurised aircraft
HbSC or HbS/B thal = can have symptomatic sickling
What would you see in blood tests of a sickle cell patient?
Increased reticulocytes (increased production)
Increased billirubin (due to increased haemolysis)
How do patients with sickle cell present acutely?
Triggered by the cold, dehydration, infection or hypoxia
The occulsions can occur anyway but commonly in bone marrow, mesentery (presents with acute abdomen), CNS (leading to stroke, seizures)
Caused by parvovirus
Avascular necrosis of the femoral head
pooling of blood in the spleen leading to severe anaemia and shock.
Acute chest syndrome
pulmonary infiltrates (usually fat emboli from bone marrow)
pain, fever, tachypnoea, wheeze, cough
What are the long term complications of sickle cell?
Reduced growth and development
Pulmonary hypertension due to repeated episodes of hypoxia leading to fibrosis
Reduced immunity due to splenic atrophy
How do you manage a sickle cell crisis?
Cross match blood if pyrexial or chest signs
Antibiotics if fever, chest signs or unwell