2. Introduction
 Sickle cell disease (SCD), an inherited disorder due to
homozygosity for the abnormal
hemoglobin, hemoglobin S (HbS).
 Hemoglobin S (HbS), results from the substitution of a
valine for glutamic acid as the sixth amino acid of the
beta globin chain, which produces a hemoglobin
tetramer (alpha2/beta S2) that is poorly soluble when
deoxygenated.

4. Characteristic Sickle Shaped RBCs

5. Major Clinical Menifestations
 Anemia
 Vaso-oclusive Crises
 Episodes of ischemic pain (i.e., painful crises)
 Ischemic malfunction or frank infarction in the
spleen,
central nervous system,
bones,
liver,
kidneys,
retina &
lungs.

6. Anemia
 Chronic Anemia
 Acute severe anemia
 There are three settings in which an acute fall in
hemoglobin concentration may be superimposed upon the
chronic anemia
1.Splenic sequestration crisis
2.Aplastic crisis
3.Hyperhemolytic crisis

7. Vaso-occlusive crisis & its effects
 Acute painful episodes
 Multi organ failure
 Effect on growth and
development
 Psychosocial effects
 Infection
 CVA
 Bone ischemia &
infarction
 Cardiac –MI
 Dermatological---Leg
ulcer
 Hepatobiliary
 Pulmonary
 Renal
 Retinopathy
 Effects on pregnancy
 Priaprism

8. Acute Chest Syndrome
The acute chest syndrome (ACS) is the most common form
of acute pulmonary disease in patients with
SCD, occurring in almost one-half of patients.
It is the most frequently reported cause of death in
adults, and is a risk factor for early mortality.

9. Definition of Acute Chest
Syndrome

Presence of a new pulmonary infiltrate, not due to
atelectasis,
 Involving at least one complete lung segment
 Chest pain
 Temperature >38.5ºC
 Tachypnea, wheezing, or cough

10. Etiology
Causes can be listed as:
1. Unknown cause
2. Pulmonary infarction
3.Fat embolism
4.Chlamydia pneumoniae infection
5.Mycoplasma pneumoniae infection
6.Viral infection
7.Mixed infections
8.Other pathogens

11. Clinical findings
Patients with ACS present with
 fever
 chest pain
 extremity pain,
 dyspnea
 nonproductive cough
Examination of the chest may reveal local tenderness
over the ribs or sternum; findings of pulmonary
consolidation may also be noted.

12. Common laboratory findings






Leukocytosis
Thrombocytopenia or thrombocytosis
Falling hemoglobin concentration
Elevations in lactate dehydrogenase
High Bilirubin levels
Chest Radiographs

13. Diagnosis of Acute Chest
Syndrome
No current laboratory or radiographic finding permits the
differentiation of ACS from other acute pulmonary
manifestations of SCD, including pneumonia and
infarction.
The finding of pulmonary infiltrate should be treated as
infectious pneumonia (assume both are present) until
proven otherwise.

14. Pulmonary infarction due to PE or ACS?
This differentiation remains problematic.
 Lack of evidence for DVT
 Abnormal ventilation-perfusion scans
 Inability to safely perform contrast studies in
these patients because of the possible
association with further sickling.

15. Investigations for ACS
1.
2.
3.
4.
5.
6.
7.
8.
Steady state Hb% & Hb electrophoresis
CBC, Retics & peripheral film
Blood Cultures
Urine microscopy & cultures
CXR
U&E
Blood group & antibody screening
ABGs & Pulse oxymetry

16. Acute Management
Clinical severity of Acute Chest Syndrome is broad.
Close monitoring of progressive pulmonary changes and
escalating severity because the clinical status of these
patients can quickly deteriorate if the underlying
pulmonary insult is not reversed.

17. Therapeutic Interventions
 The goals of therapy are
 To correct underlying factors that contribute
to deoxygenation of hemoglobin including
dehydration & Infections
 To control pain
 To support the patient’s respiratory &
haemodynamic status

18. Fluid Management

If dehydration is present, it should be corrected as
hypovolemia can contribute to increase sickling.
 Once it is corrected, euvolemia should be
maintained.
 Overhydration or rapid hydration should be avoided
 Weights should be monitored daily along with
intake/output for assessment of the fluid status and
management of the patient

19. Infections
Broad spectrum empiric coverage with
 a third generation cephalosporin (eg, cefotaxime or
ceftriaxone) for common bacterial coverage and
 a macrolide (eg, azithromycin or erythromycin) for
coverage of atypical organisms (such as mycoplasma and
chlamydia)
should be initiated immediately on admission.

20. Pain control
Opiates (Morphine, Diamorphine, Pathedine)
Ketorolac
Tramadol
Epidural Analgesia
Methylprednisolone
Poloxamer 188

21. Respiratory support
Oxygen supplementation should be provided to maintain
arterial oxygen saturation ≥ 92 percent.
Incentive spirometry, preferably supervised by a clinical
worker, should be employed at least every two hours to
prevent atelectasis from hypoventilation.

22. Patients with poor respiratory effort or rising
oxygen requirements
Use of positive pressure ventilation devices such as
nasal mask continuous positive airway pressure
(CPAP) or bilevel positive airway pressure (BiPAP)
may be useful.
Patients with respiratory failure and acute
respiratory distress syndrome
Conventional or high-frequency oscillatory mechanical
ventilation can be used.

23. Other respiratory interventions
 Inhaled nitric oxide
 Extra corporeal membrane oxygenation
 Bronchoalveolar lavage
(Bronchoscopy with bronchoalveolar lavage (BAL), usually reserved for
patients with severe or progressive infiltrates, provides both diagnostic and
therapeutic benefits. Bronchial samples can be examined for lipid content in
alveolar macrophage as evidence for pulmonary fat embolism and also sent
for culture. In intubated patients, bronchoscopy with suction and removal of
bronchial casts has been reported to improve patient ventilation)

24. Transfusion
In patients with ACS, transfusion therapy should be
considered early in the course of the disease.
 Simple Transfusion
 Exchange Transfusion

25. Simple Transfusion
The goal of simple transfusion is to increase the
hematocrit (Hct) to 30 percent or hemoglobin (Hgb) to 11
g/dL.
 To improve oxygenation
 For accentuated anemia
 For patients with clinical or radiological progression
of disease but not impending respiratory failure.
 For patients in whom exchange transfusion will be
delayed.

26. Exchange Transfusion




Neurological involvement
Lung involvement (PaO2<9kPa with FiO2>60%)
Rapidly falling haemoglobin
Priaprism

27. Complications
Neurologic events may complicate the course of
ACS, particularly when patients have severe pulmonary
disease and/or respiratory failure, including;
 Reversible posterior leukoencephalopathy syndrome
 Silent cerebral infarcts
 Acute necrotizing encephalitis