Bleeding disorders Flashcards by Alaa M.

What is Henoch-Schonlein Purpura?

IgA vasculitis that presents with a purpuric rash affecting the lower limbs and buttocks in children. Inflammation occurs in the affected organs due to IgA deposits in the blood vessels

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Henoch-Schonlein Purpura is often triggered by..

Upper airway infection or gastroenteritis

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Four classic features of HSP are..

Purpura (100%)
Joint pain (75%)
Abdominal pain (50%)
Renal involvement (50%)

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Abdominal pain in HSP can lead to..

Gastrointestinal haemorrhage, intussusception and bowel infarction

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HSP affects the kidneys in around 50% of patients, causing..

IgA nephritis. Can lead to microscopic or macroscopic haematuria and proteinuria

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T or F: If there is more than 2+ of protein on the urine dipstick the child has developed nephrotic syndrome and will have a degree of oedema

True

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Ix for HSP

FBC + blood film
Renal profile

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Tx for HSP

Analgesia for arthralgia
Nephropathy - supportive

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Criteria for diagnosing HSP

EULAR/PRINTO/PRES criteria

Palpable purpura (not petichiae) + at least one of:

Diffuse abdominal pain
Arthritis or arthralgia
IgA deposits on histology (biopsy)
Proteinuria or haematuria

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It is important that patients with HSP are monitored closely whilst the illness is active. They need close monitoring with repeated..

Urine dipstick monitoring for renal involvement
Blood pressure monitoring for hypertension

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What is Thrombocytopenia?

Low platelet count

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Reduced platelet production can occur with..

Certain viral infections (e.g., Epstein-Barr virus, cytomegalovirus and HIV)
B12 deficiency
Folic acid deficiency
Liver failure, causing reduced thrombopoietin production by the liver
Leukaemia
Myelodysplastic syndrome
Chemotherapy

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Increased platelet destruction can occur with..

Sodium valproate and methotrexate
Alcohol
Immune thrombocytopenic purpura
Thrombotic thrombocytopenic purpura
Heparin-induced thrombocytopenia
Haemolytic uraemic syndrome

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Platelet counts below 50 x 109/L will result in..

Easy bruising and prolonged bleeding times (nosebleeds, bleeding gums, heavy periods etc)

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Platelet counts below 10 x 109/L are at high risk for..

Spontaneous bleeding:

Intracranial haemorrhage
Gastrointestinal bleeding

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The top differentials of abnormal or prolonged bleeding to remember are..

Thrombocytopenia
Von Willebrand disease
Haemophilia A and haemophilia B
Disseminated intravascular coagulation (usually secondary to sepsis)

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What is ITP?

Antibodies are created against glycoprotein IIb/IIIa or Ib-V-IX complex leading to thrombocytopenia

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Characteristic of ITP

Purpura

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Mx of ITP

Prednisolone
IV immunoglobulins
Thrombopoietin receptor agonists (e.g., avatrombopag)
Rituximab
Splenectomy

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Children with ITP usually have an acute thrombocytopenia that may follow __________ or ____________. In contrast, adults tend to have a more __________ condition

Children with ITP usually have an acute thrombocytopenia that may follow infection or vaccination. In contrast, adults tend to have a more chronic condition

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Epidemiology of ITP in adults

More common in older females

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Ix for ITP in adults

Full blood count: isolated thrombocytopenia
Blood film

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Mx for ITP in adults

Oral prednisolone
IVIG if active bleeding or an urgent invasive procedure is required

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What is Evan’s syndrome?

ITP in association with autoimmune haemolytic anaemia (AIHA)

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ITP in children is an example of which type of reaction?

Type II hypersensitivity reaction

Ix for ITP in children

FBC Blood film Bone marrow examination if there is lymph node enlargement/ splenomegaly, high/ low white cells failure to resolve/respond to treatment

Mx of ITP in children

Resolves within 6 months Avoid activities that may result in trauma (e.g. team sports) If platelet is very low then: Oral/ IV corticosteroid IV immunoglobulins Platelet transfusions in an emergency (e.g. active bleeding) but only a temporary measure as they are soon destroyed by the circulating antibodies

Give examples of drugs that cause thrombocytopenia

Quinine Abciximab NSAIDs Diuretics: furosemide Antibiotics: penicillins, sulphonamides, rifampicin Anticonvulsants: carbamazepine, valproate heparin

If a patient with gestational ITP becomes dangerously thrombocytopenic, she will usually be treated with..

Steroids and a diagnosis of ITP assumed

Pregnant women found to have low platelets during a booking visit or those with a previous diagnosis of ITP may need to be tested for..

Serum antiplatelet antibodies for confirmation

Gestational thrombocytopenia does not affect the neonate, but ITP can do if..

Maternal antibodies cross the placenta

T or F: Depending on the degree of thrombocytopenia in the newborn, platelet transfusions may be indicated. Serial platelet counts can also be performed to see whether there is an inherited thrombocytopenia

True

What is Thrombotic Thrombocytopenic Purpura?

Tiny thrombi develop throughout the small vessels, using up platelets

In TTP, as the problem is in the small vessels, it is described as a microangiopathy. It causes..

Thrombocytopenia Purpura Tissue ischaemia and end-organ damage

Thrombi develop due to a problem with a specific protein called ADAMTS13. This protein normally..

Inactivates von Willebrand factor Reduces platelet adhesion to vessel walls Reduces clot formation

Deficiency in the ADAMTS13 protein can be due to..

An inherited genetic mutation (hereditary) Autoimmune disease, where antibodies are created against the protein (acquired)

Thrombotic thrombocytopenic purpura overlaps with..

Haemolytic uraemic syndrome (HUS)

Fluctuating neuro signs (microemboli) Microangiopathic haemolytic anaemia Thrombocytopenia Renal failure

Thrombotic thrombocytopenic purpura

Causes of TPP

Post-infection e.g. urinary, gastrointestinal Pregnancy Drugs: ciclosporin, oral contraceptive pill, penicillin, clopidogrel, aciclovir Tumours SLE/HIV

In Heparin-Induced Thrombocytopenia, heparin targets a protein on platelets called..

Platelet factor 4 (PF4)

Physiology of HIT

HIT antibodies bind to platelets and activate the clotting system, causing a hypercoagulable state and thrombosis (e.g., deep vein thrombosis). They also break down platelets and cause thrombocytopenia

Ix of HIT

HIT antibodies on a blood sample

Tx of HIT

Stopping heparin and using an alternative anticoagulant guided by a specialist (e.g., fondaparinux or argatroban)

What is DIC?

Activation and release of TF which binds with coagulation factors that then triggers the extrinsic pathway (via Factor VII) which subsequently triggers the intrinsic pathway (XII to XI to IX) of coagulation

Causes of DIC

Sepsis and trauma Obstetric complications e.g. aminiotic fluid embolism, HELLP Malignancy

↓ platelets ↓ fibrinogen ↑ PT & APTT ↑ fibrinogen degradation products schistocytes due to microangiopathic haemolytic anaemia

DIC

Prothrombin time: Prolonged APTT: Normal Bleeding time: Normal Platelet count: Normal

Warfarin administration

Prothrombin time: Normal APTT: Normal Bleeding time: Pronlonged Platelet count: Normal

Aspirin administration

Prothrombin time: Often normal (may be prolonged) APTT: Prolonged Bleeding time: Normal Platelet count: Normal

Heparin

Prothrombin time: Prolonged APTT: Prolonged Bleeding time: Prolonged Platelet count: Low

DIC

Von Willebrand disease mode of inheritance

Autosomal dominant

Von Willebrand disease can also occur secondary to..

Underlying disease (e.g., leukaemia)

Von Willebrand factor is important in..

Platelet adhesion and aggregation in damaged vessels

What are the three types of VWF?

1: partial deficiency of VWF and is the most common and mildest type 2: reduced function of VWF 3: involves a complete deficiency of VWF and is the most rare and severe type

History of unusually easy, prolonged or heavy bleeding: Bleeding gums with brushing Nosebleeds (epistaxis) Easy bruising Heavy menstrual bleeding (menorrhagia) Heavy bleeding during and after surgical operations

VWF

Ix for VWF

History of abnormal bleeding, family history, bleeding assessment tools and laboratory investigations

Mx of VWF

In response to significant bleeding: Desmopressin (stimulates the release of vWF from endothelial cells) Tranexamic acid Von Willebrand factor infusion Factor VIII plus von Willebrand factor infusion

Haemophilia mode of inheritance

X-linked recessive disorder of coagulation

Haemophilia A is due to a deficiency of factor ____ whilst in haemophilia B (Christmas disease) there is a lack of factor ____

Haemophilia A is due to a deficiency of factor VIII whilst in haemophilia B (Christmas disease) there is a lack of factor IX

Haemoarthroses Haematomas Prolonged bleeding after surgery or trauma

Haemophilia

Ix for Haemophilia

Prolonged APTT Bleeding time, thrombin time, prothrombin time normal

Tx for Haemophilia

The affected clotting factors (VIII or IX) can be given by intravenous infusion, either regularly or in response to bleeding

Up to 10-15% of patients with haemophilia A develop antibodies to..

Factor VIII treatment

____________ is the commonest cause of primary haemostatic failure

Thrombocytopenia

Multiple factor deficiencies that affect secondary haemostasis

Liver failure Vitamin K Deficiency/Warfarin therapy DIC

Factors ___________ are carboxylated by vitamin K which is essential for function

II, VII, IX & X

Where is Vit. K absorbed?

Upper intestine Requires bile salts for absorption

What causes Vit. K deficiency?

Poor dietary intake Malabsorption Obstructive jaundice Vitamin K antagonists (warfarin) Haemorrhagic disease of the newborn