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Haematology week 3 > Bleeding disorders > Flashcards

Bleeding disorders Flashcards

1
Q

What are the 2 most common compents of the normal haemstatic system to have a problem in it ?

A
  1. Primary haemostasis - formation of platelet plug
  2. Secondary haemostasis - formation of fibrin clot
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2
Q

What are the 3 things which can have a problem in them resulting in failure of platelet plug formation ? (think about the 3 things needed)

A
  1. Vascular defects
  2. Platelet disorders; reduced number (thrombocytopenia) or reduced function (most commonly due to anti-platelets e.g. aspirin, NSAID’s)
  3. Von willebrand factor; deficiency (most common) or abnormal function
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3
Q

What are the main congenital defects which cause vascular defects resulting in failure of primary haemostasis ?

A

Connective tissue disorders e.g. Marfans syndrome, Ehler danlos syndrome

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4
Q

What is the more common causes of vascular defects/abnormalities resulting in failure of primary haemostasis ?

A

Acquired abnormalities:

  • Vasculitis e.g. Henoch-scholein purpura
  • Senile purpura
  • Steroids
  • Scurvey
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5
Q

What are the signs/symptoms of marfans syndrome ?

A

Major signs:

  • Lens dislocation
  • Aortic dissection or dilatation
  • Long spidery fingers (arachnodactyly)
  • Armspan > height
  • Pectus deformity
  • Scloiosis
  • Flatfeet (pes planus)

Minor signs:

  • High arched palate
  • Joint hypermobility
  • Mitral valve prolapse

Also repeated pnemothroaces

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6
Q

What are the signs/symptoms of ehler danlos syndrome ?

A
  • Joint hypermbolity
  • Loose unstable joints that dislocate easily
  • Fatigue
  • Easy bruising (due to failure of platelet plug)
  • Joint pain & clicking
  • Stretchy skin, may break easily
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7
Q

What is the typical presentation of senile purpura ?

A
  • Affects older people
  • Chacterised by recurrent formation of bruises after mild trauma on the extensor surfaces
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8
Q

What are the characteristic features of henoch-schonlein purpura?

A
  • Purpura (none blanching purple papules due to intradermal bleeding) these bruises mainly appear on the legs or bottom (one of the main symptoms of a primary haemostasis disorder)
  • Usually occurs between ages 2-11 & affects boys > girls
  • May get some joint pain & swelling, abdo pain +/- kidney disease (haematuria, renal failure) (dont think you get thrombocytopenia which is useful to differentiate from ITP)
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9
Q

What are the main causes of thrombocytopenia ?

A

Decreased marrow production:

  • Aplastic anaemia
  • Megablastic anaemia
  • Marrow infiltration e.g. leukaemia, myeloma
  • Marrow suppression e.g. chemo, radiotherapy

Excessive platelet destruction:

  • DIC - disseminated intravscular coagulation
  • ITP - immune thrombocytopenia
  • Hypersplenism (covered in another lect.) - EBV, HIV are common causes
  • TTP - thrombocytic thrombocytopenic purpura
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10
Q

What is ITP

A

This is an autoimmune disorder which results in thrombocytopenia due to anti-platelet antibodies

It is defined as a platelet count < 100x109 in the absence of other causes or disorders assocoated with thrombocytopenia:

  • Absent systemic symptoms such as weight loss, fever, joiny pain (arthralgia), alopecia, venous thrombosis
  • No splenomegaly or hepatomegaly
  • No lymphadenopathy
  • Absence of medicines that cause thrombocytopnia e.g. heparin, alcohol etc
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11
Q

Who is most commonly affected by ITP ?

A
  • Usually children 2 weeks after an infection
  • Or mainly seen in women
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12
Q

What are the 2 main ways ITP can present?

A
  1. Acute - lasting 6-8 weeks
  2. Chronic lasting > 12 months
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13
Q

What are the signs/symptoms of ITP ?

A
  • Some children may have no symptoms at all
  • Most common symptoms are bleeding, purpura, epitaxis & menorrhagia
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14
Q

What are the investigations which should be done for someone suspected of having ITP ?

A

FBC & blood film - there should be no evidence of abnormalities other than platelets < 100x109

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15
Q

What is the treatment of ITP ?

A

Mild symptoms - no tx needed

If severe bleeding symptoms e.g. mucosal bleeding or platelets < 20x109 then tx = prednisolone

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16
Q

Describe the pathology of TTP

A
  • Abnormally large and sticky multimers of von Willebrand’s factor cause platelets to clump within vessels
  • In TTP there is a deficiency of ADAMTS13 (a metalloprotease enzyme) which breakdowns (‘cleaves’) large multimers of von Willebrand’s factor
  • Overlaps with haemolytic uraemic syndrome (HUS)
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17
Q

What are the clinical features of TTP?

A

All have MAHA (microangiopathic haemolytic anaemia) & thrombocytopenia

Additional features:

  • AKI
  • Fluctuating CNS signs (e.g. seizures, hemiparesis, decreased conciousness, decreased vision)
  • Fever
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18
Q

What are the causes of TTP?

A
  • post-infection e.g. urinary, gastrointestinal (bloody diarrhoea)
  • pregnancy
  • drugs: ciclosporin, oral contraceptive pill, penicillin, clopidogrel, aciclovir
  • tumours
  • SLE
  • HIV
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19
Q

What is the management of TTP?

A

It is an emergency get help

  • 1st line = urgent plasma exchage
  • 2nd line = steroids
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20
Q

How is TTP diagnosed?

A

Same as for HUS

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21
Q

What is HUS and its causes ?

A

It is generally seen in young children and is usually secondary to:

  • classically Shiga toxin-producing Escherichia coli (STEC) 0157:H7 (‘verotoxigenic’, ‘enterohaemorrhagic’). This is the most common cause in children, accounting for over 90% of cases
  • pneumococcal infection
  • HIV
  • Rare: SLE, drugs, cancer
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22
Q

What are the clinical features of HUS?

A

Triad of:

  1. AKI (usually worse AKI than in TTP)
  2. Microangiopathic haemolytic anaemia (MAHA)
  3. Thrombocytopenia
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23
Q

How is HUS investigated ?

A
  • FBC showing - anaemia, thrombocytopaenia, fragmented blood film (schistocytes)
  • Clotting tests are normal
  • U&E: acute kidney injury
  • stool culture
24
Q

What is the treatment of HUS ?

A
  • 1st line treatment is supportive e.g. Fluids, blood transfusion and dialysis if required (there is no role for antibiotics, despite the preceding diarrhoeal illness in many patients)
  • The indications for plasma exchange in HUS are complicated. As a general rule plasma exchange is reserved for severe cases of HUS not associated with diarrhoea
25
Q

What are the causes of poor platelet function ?

A
  1. Mainly drugs (anti-platelets) e.g. aspirin, NSAID’s (also has a similar function to aspirin)
  2. Renal failure - due to build up of toxins inhibiting platelet function

==> look out for symptoms of renal failure or people on drugs e.g. aspirin or NSAID’s who present with symptoms of primary haemostasis dysfunction

26
Q

What is the inheritance of VWF deficiency ?

A
  • Autosomal dominant
  • Look out for a strong fam history of bleeding - history of increased menorrhagia & bleeding post e.g. dental extraction
27
Q

What are the symptoms of VWF deficiency ?

A

They are the symptoms of a primary haemoastic problem & are generally mild in severity:

  • Bruising
  • Epitaxis
  • Menorrhagia
  • Increased bleeding post commonly tooth extraction (but also post-op bleeding increased)
28
Q

What are the investigations used to diagnose VWF deficiency ?

A
  • PT - normal
  • APTT - prologned (due to VWF role with protecting VIII, therefore VIII is decreased causing prolongation)
  • VWF antigen decreased
29
Q

What are the 2 main ways in which fibrin clot failure can arise ?

A
  1. Multiple clotting factor deficiencies e.g. DIC (note DIC causes decreased platelets & clotting factor def. hence mentioned in both primary & secondary haemostatic disorders)
  2. Single clotting factor deficiencies e.g. haemophilia
30
Q

What are the main causes of multiple clotting factor deficiencies ?

A
  1. Liver failure
  2. Vit K def./warfarin therapy
  3. Complex coagulopathy - DIC
31
Q

What 2 tests will both be prolonged in multiple clotting factor deficiences ?

A

PT & APTT

32
Q

Where are all the clotting factors synthesised ?

A

In hepatocytes in the liver (hence in liver failure you can get decreased clotting factor sythesis)

33
Q

What clotting factors function depends on Vit K?

A

Factors II, VII, IX & X - they depend on Vit K carboxylating them

Note - the same factors are inhibited by warfarin

34
Q

Describe where we get vit K from ?

A

We get vit K from our diet primarily from green leafy veg e.g. burssle sporuts, broccoli, kale & intestinal synthesis by bacteria

35
Q

Where is vit K absorbed & what is required for its absorption ?

A

Absorbed in the uppper intestine, requires bile salts for its absorption

36
Q

What type of vitamin is vit K ? (or what is the solubility of it)

A

It is a fat soluble vitamin

37
Q

What are the causes of vit K deficiency ?

A
  • Poor dietary intake
  • Malabsorption
  • Obstructive jaundice e.g. gallstone in common bile duct
  • Vit K antagonists
  • Haemorrhagic disease of the newborn
38
Q

What are the signs/symptoms of liver failure ?

A
  • Nausea & vomiting
  • RUQ pain
  • Jaundice
  • Fatigue & weight loss
  • Strong alcohol history, hepatitis
39
Q

What are the signs/symptoms of malabsorption?

A
  • Diarrhoea
  • Decreased weight
  • Lethargy
  • Steatorrhoea
40
Q

What are some of the causes of GI malabsorption (which can inturn lead to vit K def.)?

A
  1. Decreased bile - primary biliary cirrhosis, ileal ressection, biliary obstruction
  2. Pancreatic insufficiency e.g. caused by pancreatic cancer, CF
41
Q

What is haemorrhagic disease of the newborn & why is it very uncommon now ?

A
  • It is where there is bleeding in one or multiple areas e.g. umbilical stump, mucous membranes, GI tract, areas where struck by needle etc
  • It is so uncommon because babies now given Vit K at birth
42
Q

What is DIC?

A
  • A condition which arises due to excessive & inappropriate activation of the coagulation system (primary, secondary & fibrinolysis)
  • Causing formation of microvascular thrombus formation (in the small vessels)
  • The thrombi formation may lead to vascular obstruction/ischaemia & multi-organ failure
  • The formation of the microvascular thrombi resulting in depletion of platelets & clotting factors
43
Q

What does the consumption of platelets & clotting factors in DIC result in ?

A
  • Bruising, purpura & generalised bleeding - bleeding from at least 3 unrelated sites is very suggestive
  • Hypotension, oliguria & tachycardia - signs of circulatory collapse
44
Q

What are the causes of DIC ?

A
  • Major trauma/burns
  • organ destruction
  • Sepsis/severe infection
  • Hypovolaemic shock
  • Obstetric emergencies e.g. placental abruption
  • Malignancy
45
Q

How is DIC diagnosed ?

A
  • FBC - decreased platelets
  • PT - prolonged
  • APTT - prolonged (PT is usually prolonged first, APTT may not yet be prolonged because VIII has the shortest hald life ==> PT affected first)
  • Fibrinogen - decreased massively
  • D-dimer - increased (as all the clots forming will be getting broken down)
46
Q

What is the treatment of DIC?

A
  • Treat the underlying cause
  • Replacement therapy - platelet transfusions, FFP for replacement of coag factors + fibrinogen replacement by giving cryoprecipitate when fibrinogen levels are low
47
Q

How is vit K def. diagnosed?

A
  • PT & APTT prolonged
  • Test for high levels of des-gamma-carboxyprothrombin (DCP) this is high in vit K def.
48
Q

How is vit K def treated ?

A

IV vit K + if acute haemorrhage give factor concentrate (2, 7, 9 & 10)

49
Q

What is haemophilia /

A

An x-linked recessive condition which results in abnormally prolonged bleeding

50
Q

What is the 2 types of haemophilia & the clotting factor def. they cause & state which is more common ?

A
  1. Haemophilia A - due to factor VIII def. (5x’s more common)
  2. Haemophilia B - due to factor IX def.

Note - both behave clinically the same

51
Q

What is the typical presentation of haemophilia ?

A
  • There is no problem with primary haemostasis
  • Often presents with prolonged bleeding after dental extraction, surgery & invasive procedures
  • HIstory of spontaneous bleeding into joints (haemarthrosis) esp into knees, ankles & elbows - this is very, very suggestive
  • Soft tissue bleeding - bruising esp in toddlers
52
Q

What is the typical presentation of haemophilia ?

A
  • There is no problem with primary haemostasis
  • Often presents with prolonged bleeding after dental extraction, surgery & invasive procedures
  • HIstory of spontaneous bleeding into joints (haemarthrosis) esp into knees, ankles & elbows - this is very, very suggestive
  • Soft tissue bleeding - bruising esp in toddlers
53
Q

What can the recurrent haemarthrosis result in, in haemophilia?

A

Arthropathy & joint deformity

54
Q

What are the investigations done to diagnose haemophilia?

A
  • PT - normal
  • APTT - prolonged
  • Factor VIII & IX assay (as talking about A&B here) - VIII decreased in A, XI decreased in type B
55
Q

What is the treatment of haemophilia ?

A
  • Avoid NSAID’s & IM injections
  • For minor bleeding - pressure & elevation + desmopressin
  • Major bleeds e.g. haemarthrosis or lifethreatening - give factor concentrate VIII or IX

Haematology week 3 (9 decks)

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