CIS - Sickle Cell

Question 1

name the beta globin amino acid substitution and the chromosome involved in sickle cell disease

Answer 1

• beta globin gene on chromosome 11
• single amino acid substitution: glutamic acid –> valine
• autosomal recessive

Question 2

explain the pathophysiology of acute splenic sequestration in sickle cell disease

Answer 2

vaso-occlusion in the spleen due to aggregation of sickle cells

• -> splenic pooling of RBCs (marked fall in Hb)
• -> elevating reticulocyte count
• -> rapidly enlarging spleen
• -> hypovolemic shock

Question 3

explain the pathophysiology of acute chest syndrome in sickle cell disease

Answer 3

infection occurs with mycoplasma or step. pneumoniae

• -> infarction occurs due to in-situ thrombosis (clotting of blood)
• -> embolic phenomena (purple-ish coloring of the skin) due to fat embolism

Question 4

list the organisms that functional asplenia/autosplenectomy in children with sickle cell disease are particularly susceptible to acquiring (7)

Answer 4

Steptococcus pneumoniae
Neisseria meningitidis
Klebsiella pneumoniae
Haemophilus influenzae
Salmonella typhi
Cryptococcus neoformans
Pseudomonas aeruginosa