Sickle cell disease Flashcards
How is sickle cell disease inherited?
autosomal recessive; two abnormal Hgb genes
What is the mutated version of the Hgb gene?
Hemoglobin S
What is the normal version of the Hgb gene?
Hemoglobin A
What is the cause of the mutated HbS gene?
glutamic acid is replaced with valine
How do sickle cells affect blood flow?
- vaso- occlusion
- decreased oxygen delivery to tissues
What type of hemoglobin do newborns have?
fetal hemoglobin (HcF)
When do symptoms of sickle cell disease present?
5 months of age after HbF decreases and HbS levels increase
What are the symptoms of sickle cell disease?
- pain
- anemia
- growth delays
- stroke
- infections due to blocked spleen
What are acute complications of sickle cell disease?
- vaso- occlusive crisis
- fever
- acute chest syndrome
- anemia
What are the chronic complications of sickle cell disease?
infection prophylaxis
hydroxyurea
What is the most common complication of vaso-occlusive crisis?
impeded blood flow –> pain
What can a vaso-occlusive crisis be caused by?
infection
emotional stress
exposure to cold, wind, or high-altitude
Where and how does pain usually present?
lower back, chest, legs/arms ina symmetric pattern
What are treatments for vaso-occlusive crisis?
- IV fluids
- NSAIDs
- opioid analgesics
How soon should treatment begin for a vaso-occlusive crisis?
30 min of triage- 60 min of registration
What is used for mild-moderate pain?
anti-inflammatory meds (NSAIDs or acetaminophen)
What is used for severe pain?
Oral opioid analgesics
What routes of opioid analgesic should NOT be used?
IM
transdermal
What kind of infections are patients with SCD at higher risk for?
encapsulated organisms caused by functional asplenia
When is a fever treated as a medical emergency?
any fever (orla >/= 38.3) in a child with SCD
What bugs need to be covered for fever in SCD?
s. pneumonia
GM - enteric organisms
possibly mycoplasma pneumonia
What agents are used to treat fever is SCD?
3rd gen cephalosporins (ceftriaxone)
+/- macrolide (mycoplasma pneumoniae)
+/- vancomycin (acutely ill)
What is the cause of acute chest syndrome?
vaso-occlusion of pulmonary vasculature
How is acute chest syndrome diagnosed?
new pulmonary infiltrate on chest x ray
AND ONE OF THE FOLLOWING
Fever/ tachypnea/ chest pain/ dyspnea/ hypoxia
What is the treatment for acute chest syndrome?
- supplemental oxygen
- bronchodilators
- empiric ABX (cephalosporin and macrolide)
Why should opioids and IV fluids be used with caution in acute chest syndrome?
concern for analgesia-induced hypoventilation and pulmonary edema
When are blood transfusions recommended?
life-threatening complications:
symptomatic severe acute chest syndrome
multisystem organ failure
medium or high-risk surgical procedures
When should blood transfusions NOT be used?
asymptomatic anemia
uncomplicated pain crisis
What agent is used for infection prophylaxis to decrease the incidence of pneumococcal disease?
Penicillin
Erythromycin (allergy)
What vaccines should children get to prevent infection?
- PCV 13 (newborns)
- meningococcal conjugate vaccine (2 months and older)
- annual influenza vaccine
Why is Hydroxyurea used in SCD?
increases FHb, reduces hospitalization end-organ damage, and stroke
What role does Hydroxyurea have in SCD?
prevent pharmacologic agent for pediatric patients with recurrent vaso-occlusive episodes
How long of a trial of the maximum tolerated dose is required before discontinuing treatment?
6 months
How long can hydroxyurea be taken if they have clinical response?
indefinitely
What are common adverse effects of Hydroxyurea?
- myelosuppression (mild)
- skin/ nail changes
- GI disturbances
- hair loss/ thinning
- leg ulcers
What are the serious adverse effects of Hydroxyurea?
- growth delays
- infertility
- possible secondary leukemias or other cancers
At what age should Hydroxyurea begin OFFERED if asymptomatic?
9 y/o
What does the therapy of Hydroxyurea effectiveness depend on
adherence to the dosage regimen
