The IX t h Makassed Medical Congress - American University of Beirut

T h e I X t h M a k a s e d M e d i c a l C o n g r e s s
ADVANCES IN PEDIATRIC SICKLE CELL DISEASE
Miguel R. Abboud MD
Sickle cell disease is an inherited hemoglobinopathy affecting over 80,000 people in the US and
many more worldwide including the Arab world. The myriad clinical complications of sickle cell
disease have their starting point in a single amino acid substitution in the b chain of human
hemoglobin. This substitution results is in sickle hemoglobin (Hb S) that polymerizes under conditions
such as hypoxemia and acidosis. The polymerization causes perturbations in the erythrocyte
integrity which lead to hemolysis and vaso-occlusion. Recently, two clinical phenotypes of sickle
cell disease have been described. The hemolysis associated phenotype is characterized by
severe anemia, leg ulcers and pulmonary hypertension. When vaso-occlusion predominates the
clinical picture is defined by severe painful episodes, acute chests syndrome, splenic infarction,
stroke and avascular necrosis of target joints. The disease is also characterized by endothelial
dysfunction and a vasculopathy. The course of the disease is very unpredictable but for many
patients is associated with significant morbidity, decreased life expectancy and poor quality of
life. The risk of early mortality is highest in older patients with a history of severe complication such
a recurrent acute chest syndrome, renal failure and pulmonary hypertension.
Chronic transfusions are effective in preventing many complications of sickle cell disease but
this modality of therapy has significant complications such as iron overload and alloimunization.
Hydroxyurea has been show to be very effective in ameliorating certain manifestations of the
disease, such as painful crises and acute chest syndrome. This modality of therapy also and leads
to a longer life expectancy. Many patients however will have poor response to hydroxyurea and
still require other forms of therapy. Like for thalassemia the only curative modality is correction of
the genetic defect by allogeneic hematopoietic cell transplantation. This presentation will focus
on recent findings in the pathophysiology and therapy of sickle cell disease.
ITP IN CHILDREN : AN UPDATE
Françoise Mazingue MD
ITP is frequent in young children, characterised by severe isolated thrombocytopenia and
presence of auto antibodies to platelets. The risk of severe bleeding is often over estimated and
seriously impacts the way of life of the child and his family, more than the disease itself would do.
Most of ITP are post infectious (viral or post vaccination). Since a few years, ITP management
has been modified. Bone marrow examination is usually not necessary for diagnosis if clinical
examination and blood count exclude leukemia. Treatment is based on Buchanan score and
platelets count. In case of mild bleeding and platelets >10 000/mm3 one can just clinically survey,
hospitalization is not necessary.
On the other hand, in case of severe hemorrhage or life threatening bleeding, treatment will
associate IV Ig to steroids (4mg/kg, during 4 days), sometimes platelets transfusions are necessary.
In case of refractory ITP, one can have to use Vincristine and sometimes Rituximab. Chronic ITP
is lasting for more than 12 months. The diagnosis of primary chronic ITP remains one of exclusion.
There are a lot of secondary ITP. It’s necessary to establish diagnosis with accuracy to adapt
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