1. Sickle Cell Acute Chest Syndrome
Jenny Kim MD
Medical Director, Comprehensive Sickle Cell Program
Rady Children’s Hospital San Diego
Clinical Professor of Pediatrics
UCSD School of Medicine

2. Disclosures
NONE

3. Objectives: Acute Chest Syndrome
How common is ACS and who gets it?
What is ACS?
What causes ACS?
How do I know if a person has ACS?
How is ACS treated?

4. Pulmonary complications of SCD
Acute chest syndrome
Asthma
Pulmonary hypertension
Blood clots/PE
Obstructive sleep apnea
Pulmonary fibrosis
Chronic dyspnea
PFT changes
Am J Respir Crit Care Med. 2001; 164(11):2016
Postgrad Med J. 2003; 79(933): 384
Br J Haematol. 2005;129(4): 449

5. How common is ACS?
Cooperative Study of Sickle Cell Disease (CSSCD) study period PURPOSE to describe natural history of SCD
4000 pts with SCD observed prospectively for >/=2 yrs
ACS incidence 29%
Occurs in up to 45% of SCD pts- recurrent in up to 80%
Castro et al. Blood, 1994;84(2):643
N Engl J Med 2000;342:
N Engl J Med 2004;350:
N Engl J Med 1994;330:
Blood 1997;89:

6. How common is ACS?
In adults, ACS develops 1-3 days after admission for VOC
In children, ACS is admitting diagnosis
Adults
Children
Incidence
lower
higher
Severity
greater
less
Mortality 9% 1%
Rate of death per ACS episode
4.3%
1.1%
National Acute Chest Syndrome Study Group
N Engl J Med. 2000;342(25): 1855

7. Who gets ACS?
2nd most common cause of hospitalization for pts with SCD
Almost half developed ACS during hospitalization for something else
Increased ACS risk in children with asthma or tobacco exposure

8. Sean Fox, Pediatric EM Morsels 7/26/13
Who gets ACS?
Increased ACS incidence in sickle cell pts with:
HIGHER baseline hgb levels
LOWER fetal hgb levels
HIGHER baseline WBC
Sean Fox, Pediatric EM Morsels 7/26/13

9. Mortality due to ACS Most common cause of death in pts with SCD
One-fourth of SCD-related deaths due to ACS
Death rate in pts with ACS: 1.8% in children, 4.3% in adults
Adults with higher ACS rate -> higher mortality rate from all causes

10. What causes ACS?
National Acute Chest Syndrome Study Group (NACSSG) evaluated 671 episodes of ACS in 538 patients
Infection
Asthma
Vaso-occlusive pain episode
Smoke exposure
Postoperative complication
Chronic hypoxemia
Vichinsky et al. N Engl J Med. 2000;3432(25): 1855
Kokoska et al. L Pediatr Surg. 2004;39(6): 848

11. Vichinsky et al. N Engl J Med. 2000;3432(25): 1855
Infections
Unknown cause in 30-46%
Pulmonary infarction 16%
Fat embolism +/- infection 9%
Chlamydia pneumoniae infx 7%
Mycoplasma pneumoniae infx 7%
Viral infections 6%
Mixed infections 4%
Other pathogens 1%
A.D.A.M.
Vichinsky et al. N Engl J Med. 2000;3432(25): 1855

12. Vaso-occlusive pain episode
Hypoventilation due to sedation from opioid pain meds
Hypoventilation due to pain in chest, ribs, abdomen, back
Pulmonary infarction

13. Post-operative complication
Abdominal surgeries
—> Cholecystectomy
—> Splenectomy
Chest wall surgery: port placement
Pain - splinting, opioid sedation, hypoventilation
Atelectasis
Infection

14. Asthma Asthma increases risk for ACS in pts with SCD
Pts with SCD and asthma 2-4x more likely to develop ACS with longer inpt stays and more frequent VOC painful episodes
Bronchodilators help open reactive airways during ACS
Smoke exposure increase hospitalization rates
Pediatr Pulmonol. 2004;38(3): 229
Blood. 2006;108(9): 2923
Int J Environ Res Public Health. 2016;13(11) Epub 2016 Nov 12

15. Chronic hypoxemia
Children with SCD increased risk for nighttime hypoxemia
Nighttime hypoxemia associated with increased sickling and vaso-occlusive events and ACS
Obstructive sleep apnea
Oxygen by nasal cannula or bipap

16. Diagnosis of ACS New infiltrate on CXR Chest pain Fever
and one of the following sxs:
Chest pain
Fever
Increased work of breathing
Cough
Hypoxia

17. Acute management Hydration - not too little, not too much
Optimal pain control to minimize hypoventilation
Supplemental oxygen to keep sats >92-95%
Incentive spirometry
Bronchodilators
Steroids?

18. Acute management
Labs: CBC, retic, type/cross, blood cx, liver and renal chemistries
Antibiotics to cover for community acquired pneumonia and mycoplasma/chlamydia pneumoniae - ceftriaxone and azithromycin
Simple vs exchange blood transfusion

19. Long term management Monitor PFTs Preventative asthma management
Outpatient pulmonary referral
Supplemental oxygen for nighttime hypoxia
Chronic transfusion therapy
Hydroxyurea
Stem cell transplant

20. Summary
ACS is the 2nd most common cause of hospitalization in pt with SCD and most common cause of death.
ACS is caused by increased sickling of RBCs in the pulmonary blood vessels causing vaso-occlusion and injury to the lungs.
The trigger for ACS is often not identified. In kids, it is often infection and VOC events, and pts often already hospitalized for something else.

21. Summary
Diagnosis of ACS includes new infiltrate on CXR and either chest pain, fever, respiratory distress, hypoxia.
Acute treatment includes gentle hydration, oxygen for hypoxia, pain control, incentive spirometry, bronchodilator, antibiotics to cover community acquired pneumonia and mycoplasma/chlamydia pneumoniae, and blood transfusion.
Recurrence in up to 80% so long term management directed toward preventing recurrence: vaccines, asthma management, monitoring PFTs, pulmonary referral, hydroxyurea, stem cell transplant