Med D - Haemotology Flashcards

1
Q

Thrombocytopenia describes a ____ ________ ________. The normal platelet count is 150-450 x 109/L. There is a long list of causes of a low platelet count. They can be split into problems with ____________ or _____________.

A

Thrombocytopenia describes a low platelet count. The normal platelet count is 150-450 x 109/L. There is a long list of causes of a low platelet count. They can be split into problems with production or destruction.

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2
Q

Reduced platelet production can occur with:

A
  • 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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3
Q

Increased platelet destruction can occur with:

A
  • Medications (e.g., sodium valproate and methotrexate)
  • Alcohol
  • Immune thrombocytopenic purpura (ITP)
  • Thrombotic thrombocytopenic purpura (TTP)
  • Heparin-induced thrombocytopenia (HIT)
  • Haemolytic uraemic syndrome (HUS)
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4
Q

Mild thrombocytopenia may be asymptomatic and found incidentally on a full blood count.

Platelet counts below 50 x 109/L will result in easy bruising and prolonged bleeding times. It may present with:

A
  • Nosebleeds
  • Bleeding gums
  • Heavy periods
  • Easy bruising
  • Haematuria (blood in the urine)
  • Rectal bleeding
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5
Q

Platelet counts below 10 x 109/L are at high risk for spontaneous bleeding. Particularly concerning are:

A
  • Intracranial haemorrhage
  • Gastrointestinal bleeding
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5
Q

What is Immune Thrombocytopenic Purpura

A

Immune thrombocytopenic purpura (ITP) can also be called autoimmune thrombocytopenic purpura, idiopathic thrombocytopenic purpura and primary thrombocytopenic purpura. They all refer to the same condition.

ITP is a condition where antibodies are created against platelets. An immune response against platelets leads to their destruction and a low platelet count (thrombocytopenia).

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6
Q

The clotting system creates blood clots to stop bleeding. There are several ways this system can malfunction. The top differentials of abnormal or prolonged bleeding to remember are:

A
  • Thrombocytopenia
  • Von Willebrand disease
  • Haemophilia A and haemophilia B
  • Disseminated intravascular coagulation (usually secondary to sepsis)
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7
Q

Presentation of ITP

A

It characteristically presents with purpura, which are non-blanching lesions caused by bleeding under the skin.

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8
Q

Management of ITP

A

Care involves monitoring the platelet count, controlling blood pressure, and suppressing menstrual periods.

Management options include:

  • Prednisolone (steroids)
  • IV immunoglobulins
  • Thrombopoietin receptor agonists (e.g., avatrombopag)
  • Rituximab (a monoclonal antibody that targets B cells)
  • Splenectomy
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9
Q

What is Thrombotic Thrombocytopenic Purpura

A

Thrombotic thrombocytopenic purpura (TTP) is a condition where tiny thrombi develop throughout the small vessels, using up platelets. As the problem is in the small vessels, it is described as a microangiopathy. It causes:

Thrombocytopenia
Purpura
Tissue ischaemia and end-organ damage

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10
Q

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

A

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

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11
Q

Deficiency in the ADAMTS13 protein can be due to:

A
  • An inherited genetic mutation (hereditary)
  • Autoimmune disease, where antibodies are created against the protein (acquired)
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12
Q

Treatment for Thrombotic Thrombocytopenic Purpura

A

Treatment is guided by a haematologist and may involve plasma exchange, steroids and rituximab.

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13
Q

What is Heparin-Induced Thrombocytopenia

A

**Heparin-induced thrombocytopenia (HIT) **involves the development of antibodies against platelets in response to heparin (usually unfractionated heparin, but it can occur with low-molecular-weight heparin). Heparin-induced antibodies target a protein on platelets called platelet factor 4 (PF4).

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14
Q

What is Von Willebrand disease (VWD)

A

Von Willebrand disease (VWD) is the most common inherited cause of abnormal and prolonged bleeding.

In von Willebrand disease, there is a deficiency, absence or malfunctioning of a glycoprotein called von Willebrand factor (VWF). Von Willebrand factor is important in platelet adhesion and aggregation in damaged vessels.

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15
Q

How is Von Willebrand disease (VWD) inheritied

A

autosomal dominant.

16
Q

There are three types of von Willebrand disease:

A
  • **Type 1 **involves a partial deficiency of VWF and is the most common and mildest type
  • Type 2 involves the reduced function of VWF
  • Type 3 involves a complete deficiency of VWF and is the most rare and severe type
17
Q

VWD presentation

A

Patients present with a 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

A family history of heavy bleeding (e.g., menorrhagia) or von Willebrand disease is relevant.

18
Q

Diagnosis of VDW

A

Diagnosis is based on a history of abnormal bleeding, family history, bleeding assessment tools and laboratory investigations. Due to the various underlying causes and types, there is no single von Willebrand disease test.

19
Q

VWD management

A

Von Willebrand disease does not generally require daily treatment. Management is needed in response to significant bleeding or trauma (to stop bleeding) or in preparation for operations (to prevent bleeding). Options include:

  • Desmopressin (stimulates the release of vWF from endothelial cells)
  • Tranexamic acid
  • Von Willebrand factor infusion
  • Factor VIII plus von Willebrand factor infusion
20
Q

VWD management of heavy mentrual periods

A

Options for heavy menstrual periods include:

  • Tranexamic acid
  • Mefenamic acid
  • Mirena coil
  • Combined oral contraceptive pill
  • Norethisterone

A hysterectomy (surgical removal of the uterus) may be required in severe cases of heavy menstrual bleeding.

21
Q

WHat is haemophilia A and B

A

Haemophilia A and B are severe inherited bleeding disorders. Haemophilia A is caused by a deficiency of factor VIII. Haemophilia B (also known as Christmas disease) is caused by a deficiency in factor IX.

22
Q

How are haemohpilia inherited?

A

X-linked recessive diseases

23
Q

Who do X linked recessive conditions primarly affect

A

haemophilia A and B primarily affect males because males only have one X chromosome and require only one abnormal copy to have the disease

24
Q

How can females be affected in X-linked recessive conditions?

A

For a female to be affected, they would require an affected father and a mother who is either a carrier or affected.

25
Q

Haemophilia
Most cases present in neonates or early childhood. It can present with ________ ____________, ________________ and ______ __________ in neonates

A

Most cases present in neonates or early childhood. It can present with intracranial haemorrhage, haematomas and cord bleeding in neonates

26
Q

Spontaneous bleeding into joints (____________) such as the ankle, knee or elbow can lead to joint damage and deformity. Bleeding into the muscles can cause ___________ __________

A

Spontaneous bleeding into joints (haemarthrosis) such as the ankle, knee or elbow can lead to joint damage and deformity. Bleeding into the muscles can cause compartment syndrome.

27
Q

Diagnosis of Haemophilia

A

Diagnosis is based on bleeding scores, coagulation factor assays and genetic testing

28
Q

Management of Haemophilia

A

The affected clotting factors (VIII or IX) can be given by intravenous infusion, either regularly or in response to bleeding. A complication of this treatment is the formation of **antibodies **(called inhibitors) against the treatment, resulting in it becoming ineffective.

29
Q

The mnemonic for remembering the causes of microcytic anaemia is “TAILS”:

A

T – Thalassaemia
A – Anaemia of chronic disease
I – Iron deficiency anaemia
L – Lead poisoning
S – Sideroblastic anaemia

30
Q

There are 3 As and 2 Hs for normocytic anaemia

A

A – Acute blood loss
A – Anaemia of chronic disease
A – Aplastic anaemia
H – Haemolytic anaemia
H – Hypothyroidism

31
Q

Megaloblastic anaemia is caused by:

A

B12 deficiency
Folate deficiency

32
Q

Normoblastic macrocytic anaemia is caused by:

A
  • Alcohol
  • Reticulocytosis (usually from haemolytic anaemia or blood loss)
  • Hypothyroidism
  • Liver disease
  • Drugs, such as azathioprine
33
Q

What is Reticulocytosis

A

Reticulocytosis refers to an increased concentration of reticulocytes (immature red blood cells). This happens when there is a rapid turnover of red blood cells, such as with haemolytic anaemia or blood loss.

34
Q

There are many generic symptoms of anaemia:

A
  • Tiredness
  • Shortness of breath
  • Headaches
  • Dizziness
  • Palpitations
  • Worsening of other conditions, such as angina, heart failure or peripheral arterial disease
35
Q

Symptoms specific to iron deficiency anaemia include:

A
  • Pica (dietary cravings for abnormal things, such as dirt or soil)
  • Hair loss
36
Q

Signs of specific causes of anaemia include:

A
  • Koilonychia refers to spoon-shaped nails and can indicate iron deficiency anaemia
  • Angular cheilitis can indicate iron deficiency anaemia
  • Atrophic glossitis is a smooth tongue due to atrophy of the papillae and can indicate iron deficiency anaemia
  • Brittle hair and nails can indicate iron deficiency anaemia
  • Jaundice can indicate haemolytic anaemia
  • Bone deformities can indicate thalassaemia
  • Oedema, hypertension and excoriations on the skin can indicate chronic kidney disease
37
Q

Ix for anemia

A

Blood tests depend on the suspected cause. Possible blood tests include:

  • Full blood count for haemoglobin and mean cell volume
  • Reticulocyte count (indicates red blood cell production)
  • Blood film for abnormal cells and inclusions
  • Renal profile for chronic kidney disease
  • Liver function tests for liver disease and bilirubin (raised in haemolysis)
  • Ferritin (iron)
  • B12 and folate
  • Intrinsic factor antibodies for pernicious anaemia
  • Thyroid function tests for hypothyroidism
  • Coeliac disease serology (e.g., anti-tissue transglutaminase antibodies)
  • Myeloma screening (e.g., serum protein electrophoresis)
  • Haemoglobin electrophoresis for thalassaemia and sickle cell disease
  • Direct Coombs test for autoimmune haemolytic anaemia

A colonoscopy and oesophagogastroduodenoscopy (OGD) are indicated for unexplained iron deficiency anaemia to exclude gastrointestinal cancer as a source of bleeding.

A bone marrow biopsy is indicated for unexplained anaemia or possible malignancy (e.g., leukaemia or myeloma).

38
Q
A