sickle cell disease

Question 1

sickle cell disease soundbite

Answer 1

Autosomal recessive disorder which is an intrinsic defect causing a hemoglobinopathy that because of sickling can cause occluded capillaries and extravascular hemolysis of sickled RBCs

(they sickle and de-sickle as they go through the circulation - this causes membrane damage and the spleen will remove these)

Question 2

difference between sickle cell disease and sickle cell trait? what do you do intraoperatively for sickle cell trait and for sickle cell disease.

Answer 2

you have two of the sickle cell recessive genes in sickle cell disease, with around 90% HbS
- in sickle cell trait you have only one of the recessive sickle cell genes - and around 40% of HgS (need about 50% hgS) except in the renal medulla. can test for sickle cell trait with metabisulfite - this will cause the cells to sickle no matter the concentration

Intraoperatively for sickle cell trait - nothing
sickle cell trait
Sickle cell disease, - make sure not dehydrated, fluids, keep oxygen high, keep patient warm, and keep pain under control (Fentanyl)

Question 3

what vaccines are needed for sickle cell disease and why?

Answer 3

autosplenectomy is why you need these specific diseases - because the spleen helps protect against encapsulated organisms,
meningitis nisseria, streptococcus pneumonia, influenza
most common cause of death in children with sickle cell disease (pathoma)

another organism increased risk of infection is salmonella paratypi osteomyelitis

the organisms are streptococcus pneumonia, neisseria meningitis, haemophilus influenza type b

Question 4

what increases chance of sickling? intraoperative things to do

Answer 4

hypoxemia, dehydration, acidosis

Sickle cell disease, - make sure not dehydrated, fluids, keep oxygen high - good vent/perfusion/extra 02, keep patient warm, and keep pain under control (Fentanyl), steroids

Question 5

How does hydroxyurea work?

Answer 5

increases HgF (we don’t know why), if hgS is less than 50% then no sickling

sidepoint:
HgF has a higher affinity for oxygen than our hemoglobin for developing fetus and is present for around 6 months after birth

Question 6

irreversible sickling

Answer 6

vase-occlusion
examples:
Dactylics - swollen hands and feet due to vaso-occlusive infarct of bones - is the common presenting sign in infants

Acute chest syndrome, vast-occlusion in pulmonary microcirculation. presents with chest pain, shortness of breath, and lung infiltrates often precipitated by pneumonia - most common cause of death in adults with sickle cell disease (pathoma)

pain crisis - caused by vaso-occlusion
renal papillary necrosis - gross hematuria and proteinuria - probably more than need to know for boards

Question 7

what are the treatments for sickle cell disease

Answer 7

hydroxurea (card on the details of this) and stem cell transplant/bone marrow transplant