Sickle Cell Anaemia

Question 1

what is sickle cell disease

Answer 1

• caused by hereditary hemoglobinopathy, which includes sickle cell anaemia.
• mutations in the hemoglobin beta chain lead to formation of hemoglobin S, which polymerizes when deoxygenated.

Question 2

symptoms of sickle cell

Answer 2

• vascular occlusive events ( vasoocclusive pain crisis, stroke, acute chest syndrome
• severe anemia

Question 3

what are the sickle cell genotypes

Answer 3

HbSS and HbSB0thal have the most severe clinical presentations and have almost identical clinical manifestations

Question 4

mutations in sickle cell disease

Question 5

what is sickle cell anaemia

Answer 5

most severe clinical presentation of sickle cell disease
- genotypes are homozygous HbSS and compound heterozygous HbSB0thal

Question 6

pathophysiology of sickle cell

Answer 6

HbS polymerizes when deoxygenated causing deformation of erythrocytes (sickling).
- sickle cells lack elasticity and adhere to vascular endothelium, disrupting microcirculation and causing vascular occlusion and tissue infarction.

Question 7

clinical features of sickle cell trait

Answer 7

asymptomatic
painless gross hematuria due to renal papillary necrosis: often the only symptom
sickle cell disease occurs from this due to severe oxygen deficiency

Question 8

clinical traits of sickle cell disease

Answer 8

30% develop symptoms in the first year of life
manifests after 3-6 months of age as the production of HbF decreases and HbS levels increase

Question 9

what are acute manifestations of sickle cell

Answer 9

vasoocclusive crises ; the most common acute complication
recurrent episodes of severe throbbing or sharp pain
affects the limbs, chest and back and lasts for 7 days

Question 10

infections associated with sickle cell

Answer 10

pneumonia
meningitis
sepsis
osteomyelitis

Question 11

Screening for sickle cell disease

Answer 11

• prenatal screening: both parents either have the disease or are carriers
• neonatal screening: all infants at birth ( HPLC, hemoglobiin electrophoresis)
• older infant/ adult screening : children that have emigrated from countries without neonatal screening, those that perform high intensity exercise, clinical suspicion

Question 12

sickling tests and solubilit tests

Answer 12

both should not be used to screen patients for sickle cell disease as they can’t distinguish between sickle cell trait and the actual disease
- they also cant detect other abnormal hemoglobinopathies

Question 13

issues with certain screening of sickle cell

Answer 13

As adult hemoglobin levels may be very low or absent in extremely premature infants, premature neonates with sickle cell trait may have a false-positive screening result for sickle cell disease.

Question 14

long term management in infants and children

Answer 14

• immunizations ( pneumococcal vaccines and meningococcal vaccines)
• antibiotic prevention against pneumococcal diseases until 5 years
• daily prophylactic penicillin: recommended from early infancy (1-2 months ) until 5 years of age for children with HbSS
• erythromycin is used in children with penicillin allergy
• hydroxyurea therapy
• annual transcranial dopper to screen for stroke risk from 2 months till 16 months
• regular monitoring for other common complications of sickle cell disease

Question 15

long term management in adults

Answer 15

• immunizations
• hydroxyurea therapy
• reproduction counselling and contraception
• regular monitoring for complications of sickle cell disease

Question 16

prevention of vas occlusive crises and anaemia

Answer 16

• first-line agent: hydroxyurea
  reduces the incidence of acute painful episodes and improves survival