Thrombocytopenia

Question 1

What can cause reduced platelet production? (7)

Answer 1

• 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

Question 2

What can increase platelet destruction? (6)

Answer 2

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

Question 3

Give 2 examples of medications that destroy platelets

Answer 3

Sodium valproate
Methotrexate

Question 4

If platelet count is below 50 x 109/L what symptoms may be seen? (6)

Answer 4

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

Question 5

What symptoms are you concerned of when platelets are below 10 x 109/L? (2)

Answer 5

Intracranial haemorrhage
GI bleeding

Question 6

What conditions can cause abnormal or prolonged bleeding? (4)

Answer 6

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

Question 7

What is immune thrombocytopenic purpura?

Answer 7

• 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).

Question 8

What is the characteristic sign of immune thrombocytopenic purpura?

Answer 8

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

Question 9

What is involved in the management of immune thrombocytopenic purpura? (7)

Answer 9

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

Controlling bp
Suppressing menstrual periods

Question 10

What is the action of rituximab?

Answer 10

monoclonal antibody that targets the CD20 proteins on the surface of B cells.
• By attacking B cells and reducing their numbers, it reduces the production of the antibodies that are responsible for autoimmune disease.

Question 11

What is thrombotic thrombocytopenic purpura?

Answer 11

condition where tiny thrombi develop throughout the small vessels, using up platelets.

Question 12

What are the features of thrombotic thrombocytopenic purpura? (3)

Answer 12

○ Thrombocytopenia
○ Purpura
○ Tissue ischaemia and end-organ damage

Question 13

What protein is affected in thrombotic thrombocytopenic purpura?

Answer 13

ADAMTS13

Question 14

What is the normal function of ADAMTS13? (3)

Answer 14

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

Question 15

What is involved in the management of thrombotic thrombocytopenic purpura? (3)

Answer 15

Plasma exchange
Steroids
Rituximab

Question 16

What is heparin-induced thrombocytopenia?

Answer 16

development of antibodies against platelets in response to heparin (usually unfractionated heparin, but it can occur with low-molecular-weight heparin).

Question 17

What do heparin-induced antibodies target?

Answer 17

protein on platelets called platelet factor 4 (PF4).

Question 18

When does heparin-induced thrombocytopenia present?

Answer 18

5-10 days after starting heparin treatment

Question 19

What counterintuitive situation occurs in heparin-induced thrombocytopenia?

Answer 19

Low platelet count
And hypercoaguable state causing blood clots

Question 20

How is heparin-induced thrombocytopenia diagnosed?

Answer 20

testing for HIT antibodies on a blood sample.

Question 21

What is the management of heparin induced thrombocytopenia?

Answer 21

Stopping heparin and using alternative anticoagulants