Sickle Cell Disease

Question 1

What is sickle cell disease?

Answer 1

A genetic condition causing sickle shaped RBCs

RBCs are fragile and more easily destroyed, leading to a haemolytic anaemia

Question 2

Genetic inheritance pattern of sickle cell disease

Answer 2

Autosomal recessive condition where there is an abnormal gene for beta-globin on chromosome 11

1 copy of the gene results in sickle cell trait

2 copies are required for sickle cell disease

Question 3

Investigations for sickle cell disease

Answer 3

Pregnant women at risk of being carriers of sickle cell genes offered testing during pregnancy

Newborn screening heelprick test at 5 days

Question 4

Management of sickle cell disease

Answer 4

Avoid dehydration and other triggers of crises

Ensure vaccines are up to date

Antibiotic prophylaxisto protect against infection, usually withpenicillin V(phenoxymethypenicillin)

Hydroxycarbamidecan be used to stimulate production offoetal haemoglobin(HbF)

Blood transfusionfor severe anaemia

Bone marrow transplantcan be curative

Question 5

Complications of sickle cell disease

Answer 5

Anaemia

Increased risk of infection

Stroke

Avascular necrosisin large joints such as the hip

Pulmonary hypertension

Painful and persistent penile erection (priapism)

Chronic kidney disease

Sickle cell crises

Acute chest syndrome

Question 6

Management of sickle cell crisis

Answer 6

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 (NSAIDs should be avoided where there is renal impairment)

Penile aspiration is used to treatpriapism

Question 7

Triggers of sickle cell crisis

Answer 7

Infection

Dehydration

Cold

Significant life events

Question 8

Presentation of sickle cell disease

Answer 8

Anaemia with clinically detectable jaundice from chronic haemolysis

Increased risk of encapsulated infections due to hyposplenism from chronic sickling, as well as microinfarction of the spleen

Childhood risk of overwhelming sepsis

Vaso-occlusive crisis

Acute chest syndrome (most serious), which can lead to acute hypoxia, need for ventilation and emergency transfusion

Haemolytic crisis, aplastic crisis (parvovirus infection), sequestration crisis

Priapism

Question 9

Long term issues in sickle cell disease

Answer 9

Stroke

Cognitive problems

Adenotonsillar hypertrophy

Cardiomegaly and heart failure from chronic anaemia

Renal dysfunction

Pigment stones

Leg ulcers