Sickle Cell disease Flashcards
What happens on biochemical level for sickle cell disease?
Glu to Val at position 6
What is the inheritance of sickle cell disease?
autosomal recessive single gene defect chain in haemoglobin – production of sickle cell haemoglobin (HbS)
Why is sickle cell disease dangerous?
HBs polymerizes when deoxygenated causing RBCs to deform producing sickle cells which are fragile and haemolyse and block small vessels
How common is sickle cell disease?
More than 1 in 2000 live births
Why is the obstruction of small vessels dangerous?
obstruction of small blood capillaries can cause painful crises, damage to major organs and increased vulnerability to severe infections
What are symptoms or signs of sickle cell disease?
- Parent diagnosed with sickle cell anaemia, other sickle cell disease or sickle cell trait
- Persistent pain in skeleton, chest and/or abdomen
- Dactylitis
What is possible DDx of sickle cell disease?
- Gout
- Septic arthritis
- Connective tissue diseases
- Avascular necrosis
- Perthes’ disease
- Acute abdomen
- Osteomyelitis
- Trauma
- Parvovirus B19 infection
- Iron deficiency anaemia
What investigations are used in sickle cell disease?
- DNA based assays
- Haemoglobin isoelectric focusing (Hb IEF)
- Cellulose acetate electrophoresis
- HPLC
- Haemoglobin solubility testing
- Peripheral blood smear
- FBC and reticulocyte count
- Iron studies
What confirms sickle cell diagnosis?
- DNA based assays
- Hb electrophoresis confirms diagnosis
- Blood film
What does peripheral blood smear of sickle cell disease show?
- nucleated red blood cells
- sickle-shaped cells
- Howell-Jolly bodies
What does the FBC and reticulocyte show in sickle cell disease?
some anaemia
What is the conservative chronic treatment for sickle cell?
trigger avoidance
What is the medical chronic management of sickle cell?
- Hydroxycarbamide if frequent crisis (increase HbF)
- Antibiotics and immunization to avoid hyposplemism (as then immunocompromise)
- Repeated blood trasnfusion
- Hydroxyurea
What is the surgical chronic management of sickle cell?
Bone marrow transplant is curative but controve
How do you treat sickle cell disease in crisis?
- Saturate: supportive oxygen
- Antibitocs (if needed)
- Pain relief
- Cannula (IV fluids)
How do you treat complications of sickle cell?
- Stroke: exchange blood transfusion
- Sequestration crisis: splenectomy
- Chronic cholecystitis: cholecystectomy
What are possible complications of sickle cell disease?
- Anaemia
- Opioid dependence
- Iron overload from chronic transfusions
- Liver complication and cholethiasis
Etc.
What is prognosis of sickle cell disease?
- life long morbidity and reduced life expectancy
- US average age 58
- Africa 50-90% children with ssd die before 5th bday
What measures are put in place for sickle cell disease to be manageable?
- new born screening
- genetic counselling
- pre-natal tests
- parental education can help prevent 90% if deaths from sequestrian crises
What is the genetic mutation in sickle cell disease?
Point mutation
β Globin Gene
Chr 11
How common is sickle cell trait?
20% of tropical Africa population have Sickle cell trait
What is sickling predisposed by?
- Hypoxia
- Dehydration
- Acidosis
- Infection
What are the symptoms of sickle cell trait?
- Asymptomatic*
2. Resistance to Falciparum Malaria
What are Howell Jolly Bodies?
- nuclear remnants from RBCs
- normally they are filtered out via the spleen
