All of the following statements regarding Sickle Cell Anemia is true,
EXCEPT:
a) Patients require frequent blood transfusions
b) Patients usually presents before the age of 6 months
c) There is a positive correlation between HBS and polymerization
of HBS
d) Reccurent infections is the most common cause of death
Correct Answer - B
Sickle cell anemia is an autosomal recessive disorder, caused by an amino acid
substitution of valine for glutamine in the sixth position on the beta-globin chain. Onset of
the disease starts during the first year of life especially after 6 months of age, when
hemoglobin F levels falls, as a signal is sent to switch from production of gamma globin to
beta globin.
Hemoglobin S is unstable and polymerizes during hypoxemia and acidosis, leading to
sickling of red blood cells. Patients develops jaundice, pigmented gallstones,
spleenomegaly, and poorly healing ulcers over the lower tibia. Acute painful episodes can
occur due to acute vaso-occlusion by clusters of sickled red cells during infection,
dehydration, or hypoxia. Common sites of acute painful episodes include the bones and the
chest.
Ref: Current Medical Diagnosis and Treatment 2012, Chapter 13 ; Medical Assisting:
Administrative and Clinical Competencies By Lucille Keir, 6th Edition, Page 471