Sickle Cell Disease - Clinical Correlation

Question 1

What is the frequency of SCD in African-American population?

Answer 1

1/400

Question 2

What is the average lifespan for those with SCD?

Answer 2

Females = 50
Males = 45

Question 3

20% of SCD patients have 80% of complications. (T/F)

Answer 3

True

Question 4

What is the most common cause of death in children with undiagnosed SCD?

Answer 4

bacterial sepsis

Question 5

What percentage of African-Americans have the sickle cell trait (AS)?

Answer 5

8-10%

Question 6

What is typical ratio of HbA:HbS in patients with sickle cell trait (AS)?

Answer 6

55-65% : 45-35%

Question 7

What is the most common and most severe genetic form of SCD?

Answer 7

SS - homozygous HbS

2/3 of SCD patients

Question 8

What percentage of African-Americans are carriers for the HbC?

Answer 8

2-3% (AC)

Question 9

What percentage of patients with SCD are heterozygous SC?

Answer 9

25% - HbS/HbC

Question 10

What is sickle beta thalassemia?

Answer 10

HbS trait + Beta thalassemia trait = SCD

- no/little HbA –> only HbS

Question 11

What causes sepsis in patients with SCD?

Answer 11

vaso-occlusion of the spleen

- inhibited bacterial clearance

Question 12

What kind of bacteria are most likely to cause sepsis in a patient with SCD?

Answer 12

encapsulated bacteria

Question 13

2/3 of deaths are within ___time)___ of first symptoms.

Answer 13

8 hours

Question 14

What is done to prevent sepsis in patients with SCD?

Answer 14

Prophylactic antibiotics

- Penicillin

Question 15

What is the most common complication of SCD throughout life?

Answer 15

Painful Vaso-occlusion Episode

Question 16

What is given to treat the pain episodes seen in patients with SCD?

Answer 16

Narcotics

• morphine, patient controlled analgesia = best
• respiratory depression and addiction are rare

Question 17

What are goals of supportive care for patients with SCD?

Answer 17

1. pain control
2. fluids
3. ensure oxygenation
4. control fever

** Transfusion not usually helpful

Question 18

What is the first diagnostic sign of SCD in an unscreened infant?

Answer 18

swollen digits

Question 19

How often does stroke develop in children with SCD?

Answer 19

10%

Question 20

How is stroke treated in patients with SCD?

Answer 20

Transfusions

• also given as profylactic agent
• 80% of blood replaced

Bone marrow transplant

Question 21

How often are recurrent strokes avoided in patients with SCD?

Answer 21

prophylactic transfusions about every month

Question 22

How can risk of stroke be detected in patients with SCD? What is done if risk is deemed high?

Answer 22

transcranial doppler

• ultrasound measuring flow velocity
• • high velocity = more occluded

prophylactic blood transfusion
- prevents 80% of strokes

Question 23

What is the most common cause of death in patients over the age of 5 (including adults) who have SCD?

Answer 23

Acute Chest Syndrome

Question 24

What is given to a patient who has Acute Chest Syndrome?

Answer 24

1. Antibiotics
   - in case it’s pneumonia
2. Oxygenation
   - increase O2-sat.
   - – prevent the progression of sickling
3. Incentive Spirometry
   - increase breath size
   - avoid shorter breaths due to chest pain
4. Transfusion acutely if more severe
   - may also be given to prevent recurrence

Question 25

What is the cause of Acute Splenic Sequestration Crisis?

Answer 25

Acute vaso-occlusion of the outlet vessels from the spleen | - blood pools in spleen

Question 26

When are patients most likely to get Acute Splenic Sequestration Crisis?

Answer 26

first 5 years of life

Question 27

What is the acute treatment for Acute Splenic Sequestration Crisis?

Answer 27

Fluid resuscitation Transfusion *treated like shock

Question 28

What is done to prevent mortality of Acute Splenic Sequestration Crisis?

Answer 28

Teaching parents splenic palpation - early detection - listen to parents

Question 29

What studies provide pertinent genetic information to counsel parents about sickle cell disease in their future children?

Answer 29

Electrophoresis of Hb 1. A 2. A2 3. F 4. S 5. C Blood count

Question 30

What genotypes produce SCD?

Answer 30

1. SS 2. SC 3. S+beta thalassemia

Question 31

What topics can be covered in genetic counseling about SCD?

Answer 31

Diagnosis via amniocentesis Preimplantation genetics Harvesting placental cord blood - safest possible transplant to cure affected sibling

Question 32

What is included in the typical therapy for patients with SCD?

Answer 32

Mainly supportive 1. hydration 2. pain Rx 3. oxygenation 4. RBC transfusions

Question 33

What is the only effective drug that modifies SCD?

Answer 33

Hydroxurea

Question 34

What are the effects of hydroxyurea in patients with SCD?

Answer 34

Pathogenesis --> increases HbF Symptoms - decreases pain episodes and acute chest syndrome by 50% - decreases mortality

Question 35

What is the only possibility of curing SCD?

Answer 35

Bone Marrow Transplant | - requires HLA-identical sibling

Question 36

What percent of families have an HLA identical donor for bone marrow transplant for SCD?

Answer 36

14%

Question 37

What is the mortality rate of bone marrow transplant for treatment of SCD?

Answer 37

~5% | * reduced with use of placental cord blood

Question 38

Who are the candidates for transplant in the US?

Answer 38

1. CVA (stroke) 2. high risk for CVA (transcranial doppler) 3. Frequent debilitating painful episodes 4. Recurrent and severe acute chest syndrome

Question 39

A 7 year old boy with homozygous sickle cell anemia was fine until this morning when he could not get out of the bathtub himself. His mother noticed weakness of his left arm and leg and that his face looked funny. You should: a. See the child in clinic the next day b. Have the mother observe the child for 2 hours for improvement c. Bring the child in for hydroxyurea d. Do a RBC exchange transfusion

Answer 39

d. Do a RBC transfusion The child is likely having a stroke. This is a medical emergency, so RBC transfusion should be done urgently to prevent further damage. Hydroxyurea can help prevent strokes but is NOT acute management.

Question 40

The mother of a 4 year old with sickle cell disease wants information concerning possible bone arrow transplantation. The child has had no serious complications. There are 2 half siblings. You should: a. Do HLA testing on the half siblings and patient HLA test the siblings, parents, and patient. b. Tell her a bone marrow transplant is impossible c. Ask whether she is planning to become pregnant again.

Answer 40

c. Ask whether she is planning to become pregnant again. Half siblings are very unlikely to be appropriate donors. Future newborns, if born to the same parents, have 25% chance of being best donor: an HLA identical sibling's umbilical cord blood (assuming the sibling doe not have sickle cell disease).

Question 41

A 37 year old man with SS disease was well until this morning when he developed fever of 102 and began to have some difficulty breathing. - Temp = 101.8 - RR = 65 - PR = 150 - O2 sat. = 84% What do you do?

Answer 41

(Acute Chest Syndrome) Decreasing oxygen saturation indicates patient needs supportive care: - supplemental oxygen - antibiotics - incentive spirometry Also needs preventive care - RBC transfusion to try to prevent further pulmonary damage

Question 42

A 32 year old woman with hemoglobin SC disease comes to the ER complaining of severe and diffuse pain in both lower extremities. She has a history of possibly abusing narcotics in the past. You find no abnormalities on exam except that she appears uncomfortable. What do you do?

Answer 42

Even with the concern about narcotic abuse, you need to initially provide narcotics for severe pain. You cannot chance leaving real pain untreated. It is better to give appropriate pain medication and then observe the patient and more accurately assess how to proceed with additional pain medication.

Question 43

A 37 year old woman with sickle cell anemia presents to you in the ER with excruciating chest and abdominal pain. You give 10 mg of morphine IV and she has minimal relief after 15 minutes. Do you: a. Wait 15 min to reach peak morphine effect b. Wait because of concern of decreased respiratory effort due to morphine c. Give acetaminophen d. Give more morphine e. Give ibuprofen

Answer 43

d. Give more morphine This is a difficult situation, the reality is that you do what is basic for a physician - relieve pain. If the first dose was appropriate, carefully but surely proved more while carefully assessing the patient. We more often see inadequate pain relief causing problems as opposed to morphine induced respiratory depression.