sickle cell anaemia Flashcards
which gene is affected in sickle cell disease?
beta global on chromosome 11
inheritance is autosomal recessive
what are complications of sickle cell?
Anaemia Increased risk of infection Stroke Avascular necrosis in large joints such as the hip Pulmonary hypertension Painful and persistent penile erection (priapism) Chronic kidney disease Sickle cell crises Acute chest syndrome
how is sickle cell generally managed?
Avoid dehydration and other triggers of crises
Ensure vaccines are up to date
Antibiotic prophylaxis to protect against infection with penicillin V (phenoxymethypenicillin)
Hydroxycarbamide can be used to stimulate production of fetal haemoglobin (HbF). Fetal haemoglobin does not lead to sickling of red blood cells. This has a protective effect against sickle cell crises and acute chest syndrome.
Blood transfusion for severe anaemia
Bone marrow transplant can be curative
how does sickle cell cause anaemia?
their sickle shape makes them fragile and vulnerable to breakdown- haemolytic anaemia
which drug stimulates the production of fetal haemoglobin?
hydroxycarbamide
what is acute chest syndrome?
Acute chest syndrome (ACS) is defined as a new radiodensity on chest imaging accompanied by fever and/or respiratory symptoms
what are some triggers for sickle cell crisis?
can occur spontaneously or be triggered by stresses such as.... infection, dehydration, cold significant life events.
how is a sickle cell crisis managed?
Have a low threshold for admission to hospital
Treat any infection
Keep warm
Keep well hydrated (IV fluids may be required)
Simple analgesia such as paracetamol and ibuprofen
Penile aspiration in priapism
avoid NSAIDS if there is renal impairment
what is the main trigger for vasoclusive crisis and how can it be managed?
associated with dehydration and raised haematocrit
this leads to sickle shaped blood cells clogging the capillaries and causing distal ischaemia
symptoms include pain and fever, an example is priapism, which is trapping of blood in the penis for men. it is a urological emergency and is treated with aspiration
what is splenic sequestration crisis?
Splenic sequestration crisis is caused by red blood cells blocking blood flow within the spleen.
This causes an acutely enlarged and painful spleen.
The pooling of blood in the spleen can lead to a severe anaemia and circulatory collapse (hypovolaemic shock).
what is the management for splenic sequestration crisis?
considered a medical emergency
supportive management:
- blood transfusion
- fluid resus
- treat anaemia and shock
prevention:
- splenectomy, used in cases of recurrent crisis
what is the risk of having recurrent splenic sequestration crisis?
Recurrent crises can lead to splenic infarction and therefore susceptibility to infections.
what is the trigger for an aplastic crisis in sickle cell anaemia?
parvovirus B19, it usually resolves spontaneously within 1 week
what are causes of acute chest syndrome?
This can be due to infection (e.g. pneumonia or bronchiolitis)
non-infective causes (e.g. pulmonary vaso-occlusion or fat emboli).
what is the management of acute chest syndrome?
Antibiotics or antivirals for infections
Blood transfusions for anaemia
Incentive spirometry using a machine that encourages
effective and deep breathing
Artificial ventilation with NIV or intubation may be required
