Haematology for MRCP Part 1

A 20-year-old man with known sickle cell disease presents with fever, pleuritic chest pain and breathlessness during a painful crisis. Oxygen saturation is 89%, and a chest radiograph shows new bilateral infiltrates. What is the most appropriate management?

1. Urgent treatment of the acute chest syndrome correct Correct. The acute chest syndrome needs urgent oxygen, antibiotics, pain relief and often a transfusion that swaps out the sickle blood.
2. Treat the precipitating cause Such as infection or dehydration. Here, fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis points elsewhere.
3. Vaccination and penicillin prophylaxis For the spleen not working properly. But fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis does not point to it.
4. Prompt analgesia, hydration and oxygen for a painful crisis The core of treating an acute crisis. It does not fit fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.
5. Transfusion or exchange transfusion in selected cases For severe complications. That does not match fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.

The point: Sickle cell disease is an inherited blood disorder passed on in an autosomal recessive way (a child needs a faulty gene copy from both parents). A single gene change makes an abnormal form of haemoglobin called haemoglobin S. When oxygen levels drop, haemoglobin S sticks together (polymerises) and bends red cells into a sickle shape. These sickle cells break down early (haemolyse) and block small blood vessels (occlude them). It shows up as a long-term anaemia from ongoing red cell breakdown and repeated painful episodes from blocked vessels (vaso-occlusive crises), brought on by cold, dehydration, infection and low oxygen. The acute chest syndrome (fever, chest pain, low oxygen and new patches on the chest x-ray) is a leading cause of death and needs urgent oxygen, pain relief, antibiotics and often a transfusion that swaps out the sickle blood (exchange transfusion). Other crises are the aplastic crisis (a common virus called parvovirus B19 causes a sudden fall in haemoglobin with a low count of new red cells, called reticulocytes) and splenic sequestration, where blood suddenly pools in the spleen. Repeated small blockages damage the spleen so it stops working properly (functional hyposplenism), which raises the risk of infection from certain bacteria that have a protective outer coat, so vaccination and long-term penicillin are given to prevent this. Long-term care includes hydroxycarbamide, a drug that raises a protective type of haemoglobin (fetal haemoglobin) and cuts down how often crises happen, transfusion in some cases, and regular screening for the long-term organ damage of stroke, high blood pressure in the lungs (pulmonary hypertension), eye damage (retinopathy) and kidney disease. An acute painful crisis is treated with prompt pain relief (often strong opioids), fluids, oxygen and treating whatever triggered it.

Source: British Society for Haematology — sickle cell disease guidelines British Society for Haematology · tier 2, specialty society or college

A 20-year-old man with known sickle cell disease presents with fever, pleuritic chest pain and breathlessness during a painful crisis. Oxygen saturation is 89%, and a chest radiograph shows new bilateral infiltrates. What is the most appropriate definitive treatment?

1. Vaccination and penicillin prophylaxis For the spleen not working properly. That does not match fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.
2. Prompt analgesia, hydration and oxygen for a painful crisis The core of treating an acute crisis. But fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis does not point to it.
3. Transfusion or exchange transfusion in selected cases For severe complications. It does not fit fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.
4. Treat the precipitating cause Such as infection or dehydration. Here, fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis points elsewhere.
5. Hydroxycarbamide to reduce crises correct Correct. Hydroxycarbamide raises the protective fetal haemoglobin and cuts down future crises.

The point: Sickle cell disease is an inherited blood disorder passed on in an autosomal recessive way (a child needs a faulty gene copy from both parents). A single gene change makes an abnormal form of haemoglobin called haemoglobin S. When oxygen levels drop, haemoglobin S sticks together (polymerises) and bends red cells into a sickle shape. These sickle cells break down early (haemolyse) and block small blood vessels (occlude them). It shows up as a long-term anaemia from ongoing red cell breakdown and repeated painful episodes from blocked vessels (vaso-occlusive crises), brought on by cold, dehydration, infection and low oxygen. The acute chest syndrome (fever, chest pain, low oxygen and new patches on the chest x-ray) is a leading cause of death and needs urgent oxygen, pain relief, antibiotics and often a transfusion that swaps out the sickle blood (exchange transfusion). Other crises are the aplastic crisis (a common virus called parvovirus B19 causes a sudden fall in haemoglobin with a low count of new red cells, called reticulocytes) and splenic sequestration, where blood suddenly pools in the spleen. Repeated small blockages damage the spleen so it stops working properly (functional hyposplenism), which raises the risk of infection from certain bacteria that have a protective outer coat, so vaccination and long-term penicillin are given to prevent this. Long-term care includes hydroxycarbamide, a drug that raises a protective type of haemoglobin (fetal haemoglobin) and cuts down how often crises happen, transfusion in some cases, and regular screening for the long-term organ damage of stroke, high blood pressure in the lungs (pulmonary hypertension), eye damage (retinopathy) and kidney disease. An acute painful crisis is treated with prompt pain relief (often strong opioids), fluids, oxygen and treating whatever triggered it.

Source: British Society for Haematology — sickle cell disease guidelines British Society for Haematology · tier 2, specialty society or college

A 20-year-old man with known sickle cell disease presents with fever, pleuritic chest pain and breathlessness during a painful crisis. Oxygen saturation is 89%, and a chest radiograph shows new bilateral infiltrates. What is the most likely complication?

1. Aplastic crisis from parvovirus B19 A sudden fall in haemoglobin. It does not fit fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.
2. Splenic sequestration Blood suddenly pooling in the spleen. Here, fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis points elsewhere.
3. Stroke From blocked blood vessels in the brain. But fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis does not point to it.
4. Chronic organ damage High blood pressure in the lungs, eye damage and kidney disease. That does not match fever, chest pain, low oxygen and new chest x-ray patches during a sickle crisis.
5. Acute chest syndrome correct Correct. This presentation is the acute chest syndrome, a leading cause of death.

The point: Sickle cell disease is an inherited blood disorder passed on in an autosomal recessive way (a child needs a faulty gene copy from both parents). A single gene change makes an abnormal form of haemoglobin called haemoglobin S. When oxygen levels drop, haemoglobin S sticks together (polymerises) and bends red cells into a sickle shape. These sickle cells break down early (haemolyse) and block small blood vessels (occlude them). It shows up as a long-term anaemia from ongoing red cell breakdown and repeated painful episodes from blocked vessels (vaso-occlusive crises), brought on by cold, dehydration, infection and low oxygen. The acute chest syndrome (fever, chest pain, low oxygen and new patches on the chest x-ray) is a leading cause of death and needs urgent oxygen, pain relief, antibiotics and often a transfusion that swaps out the sickle blood (exchange transfusion). Other crises are the aplastic crisis (a common virus called parvovirus B19 causes a sudden fall in haemoglobin with a low count of new red cells, called reticulocytes) and splenic sequestration, where blood suddenly pools in the spleen. Repeated small blockages damage the spleen so it stops working properly (functional hyposplenism), which raises the risk of infection from certain bacteria that have a protective outer coat, so vaccination and long-term penicillin are given to prevent this. Long-term care includes hydroxycarbamide, a drug that raises a protective type of haemoglobin (fetal haemoglobin) and cuts down how often crises happen, transfusion in some cases, and regular screening for the long-term organ damage of stroke, high blood pressure in the lungs (pulmonary hypertension), eye damage (retinopathy) and kidney disease. An acute painful crisis is treated with prompt pain relief (often strong opioids), fluids, oxygen and treating whatever triggered it.

Source: British Society for Haematology — sickle cell disease guidelines British Society for Haematology · tier 2, specialty society or college