Pedia

1. Sickle Cell Diseases & beyond
Prof.(Dr).Bharat Parmar
M.D.(Paediatrics). DHA. FAIMS.
Professor & Head of Paediatric Department
Zydus Medical College Hospital,Dahod

2. Highlights includes :
 SCD characterstics
 Etiopathogenesis
 VOC clinical hall marks of SCD
 Vaso-occlusion VOCs : end organ damage,multi-organ failure & death
 Practical life style approach to prevent VOCs
 Epidemilogy
 Clinical menifestations
 Long term comlplications
 investigations

3. Management :
 Hydroxyurea
 Newer modalities
 Crizalizumab
 Concluding remarks

4.  SCA is second commonest haemoglobinopathy in India,characterised by
presence of an abnormal heamoglobin i.e. HbS due to substitution of
glutamic acid by valine at the sixth position of β chains.
 Genetic basis : Deletion of β-globin gene on chromosome 11 is the basic
genetic defect in SCA,which may be :
 A Homozygous sickle cell disease ( SS )with complete replacement HbA
by HbS or
 B Heterozygous sickle cel trait (AS)with HbS concentration of 35-45 %
 In addition many cases have mixed hemoglobinopathies, i.e.
 HbS- thalassemia, HbS-C disease.

5.  SCD is characterised by presence of
 Sickle haemoglobin( HbS)
 Chronic haemolysis
 Vaso-occlusive crisis recurrent pain episodes
 Multiorgan dysfunction
 And early death

6. Etiopathogenesis :
 In normal oxygenated state, HbS function normally. However hypoxic state deoxygenated HbS
develops abnormal coupling of globin chains to deform the shape of RBC in to sickle form.while
this sickling is reversible in initial stages, persistent hypoxia leads to irreversible sickling of
RBCs,which are then trapped in microvasculature or spleen to produce vaso-occlusive lesions and
hemolysis, respectively.
 Suldging of deformed RBCs in small vessels further aggravate hypoxia & sickling
 Thus three factors are mainly responsible for pathogenesis of SCA
 (a) vaso-occlusive events (b) chronic hemolysis (c) local as well as generalized hypoxia due to a&
b respectively Pathophysiology of SCD gose beyond red blood cells

7. 7
Traditionally, SCD Pathology Was Thought to Be Due to
Vascular Blockages Caused By Sickle RBCs
RBC, red blood cell.
Sickle Cell Disease. National Heart Lung and Blood Institute. https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease. Accessed May 31, 2019.
Cross-section of sickle cell
A. Normal red blood cells B. Abnormal, sickled, red blood cells
(sickle cells)
Normal red RBC
RBCs flow freely
within blood vessel
Sickle cells
blocking blood flow
Sticky sickle cells
Cross-section of RBC
Normal
haemoglobin
Abnormal haemoglobin
from strands that
cause sickle shape
Adapted from Sickle Cell Disease. National Heart Lung and Blood Institute. https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease

8. 8
The pathophysiology of SCD goes beyond Red
Blood cell
1. Habara A & Steinberg MH. Exp Biol Med (Maywood) 2016;241:689–96; 2. Rees DC et al. Lancet 2010;376:2018–31; 3. Labie D & Elion J. Pathol Biol (Paris) 1999;47(1):7–12; 4. Hebbel RP et al. J Clin Invest
1980; 65(1):154–60
Polymerization of Hb in deoxygenated
conditions3,4
Pliable erythrocytes into rigid, sickle-shaped
cells,3 which were initially identified as the cause
of vaso-occlusion in the 1960s
• These morphological abnormalities are insufficient to fully explain vaso-occlusion, since the time taken for
HbS polymerization (and sickling of RBCs) is longer than the blood circulation time required for
reoxygenation5,6
• There is a vascular damage in SCD, which involves WBCs, platelets & endothelial cells4,5

9. Key drivers of vaso-occlusion1-5:
9
 Endothelial activation
 Enhanced adhesion
 Neutrophil activation
 Polymerisation
 Chronic haemolysis
The Current Perspective Acknowledges the Multifactorial
Nature of Sickle Cell Pathology
CAM, cell adhesion molecule; EC, endothelium; EDHF, endothelium-derived hyperpolarizing factor; eNOS, endothelial nitric oxide synthase; HbF, fetal haemoglobin; ISC, irreversible sickled cell; MTHFR, 5,10-methylenetetrahydrofolate reductase; N,
neutrophil; R, sickle reticulocytes; RBC, red blood cell.
1. Rees DC, Williams TN, et al. Lancet. 2010;376(9757):2018-2031. 2. Zhang D, Xu C, et al. Blood. 2016;127(7):801-809. 3. Frelinger AL, Jakubowski JA, et al. Platelets. 2013;25(1):27-35.
4. Okpala I. Curr Opin Hematol. 2006;13(1):40-44. 5. Steinberg MH. Br J Haematol. 2005;129:465-481.
R
RBC
ISC
EC
N
Neutrophils
Activation /
Inflammation
CD 64
L-selectin
Elastin
Cytokines
Endothelial
Activation
eNOS
ET-1
EDHF
CAMs
Integrins
Selectins
Polymerisation
HbF
α-thalassaemia
Cation transport
Membrane proteins
Adapted from Steinberg MH. Br J Haematol. 2005;129:465-481.
Enhanced
Adhesion
E-selectin
P-selectin
L-selectin
Chronic
Haemolysis
Heme
Toll-like receptors
Inflammation

10. Summary
• The Pathophysiology of SCD and VOCs goes beyond RBC
• Key Drivers of Vaso-occlusion:
 Endothelial activation
 Enhanced adhesion
 Neutrophil activation
 Polymerization
 Chronic hemolysis
• There is a vascular damage in SCD, which involves WBCs, platelets & endothelial cells
10

11.  Polymerization of deoxygenated HbS is primary event in pathology of SCA
 The pathogenesis of vaso-occlusion is complex
 HbS is insoluble in low oxygen tesions and polymerizes as long fibres which
result in the red cell becoming sickle shape
 Vaso-occlusion is caused by the adhesion of sickle erythrocytes and
leucocytes to endothelium which result in vascular obstruction and tissue
ischemia.
 The degree of sickle erythrocytes adhesion co-relate with vaso-occlusion &
increased severity of disease
 Activted & adherent leucocytes are the likely drivers of vaso-occlusion in
collecting venuels where as sickle erythrocytes may contribute to occlusion of
small vessels.

12.  The complex effect of SCD go beyod red blood cell Vaso-
occlusion haemolysis & anemia
 Chronic vascular damage HbS Polymerization
 Inflammation & cell activation & sickle red blood cell Sickling
& haemolysis
 VOC are the clinical hallmark of SCD
 VOC may be only the tip of iceberg when it comes to ongoing
vaso-occlision

13.  VOCs clinically visible VOC can be unpreditable extremely painful event that last
on average 10 days.
 Vaso-occlusion
 Multicellular adhesion
 Inflammation & cell activation
 Subclinical on going & often silent vaso-occlusion occur systematically during
patient life time potentially regulating in acute & chronic complication

14.  In addition platlets bind to erythrocytes, monocytes & neutrophil to form
aggregates which contribute to abnormalities of blood flow in patient of SCD.
 Although the adhesion of leucocytes to endothelium during inflammation can
involve multiple molecules the process initiated by P-selectin
 P-selectin is found in storage granules of resting endothelial cell& platlet and
rapidly transformed to the cell membrane on activation of cell during the process of
inflammation
 P-selectin that is expressed on the surface of endothelium mediates abnormal
rolling & static adhesion of sickle erythrocytes to vessels suface in vitro

15. Painful VOCs are the clinical hallmark of SCD1
15
Each VOC is
associated with
inflammation that
worsens with
recurring episodes,
leading to serious
complications and
end-organ damage
Clinical
features
include the
rapid onset of
severe pain in
one or more
joints or
extremities
VOC events lead to
hypoxia, ischemia
and tissue damage,
giving rise to the pain
experienced by SCD
patients
VOCs are the number one cause of hospitalization for SCD patients
1. Ballas SK et al. Blood 2012;120:3647–3656.

16. VOC has four distinct phases and can last for avg
9-11 days1
 ACS, acute chest syndrome; MOF, multiorgan failure
1. Republished with permission of American Society of Hematology, from Ballas SK et al. Blood 2012;120:3647–56; permission conveyed through Copyright Clearance Center, Inc.
Day
Resolving
phase
Established
phase
Initial
phase
Prodromal
phase
0
1
2
3
4
5
6
7
8
9
10
-2 -1 0 1 2 3 4 5 6 7 8 9 10
Categorical
pain
scale
1. Prodromal phase1
 Symptoms include
numbness,
paresthesia, and
aches
 May be
asymptomatic
4. Resolving
phase1
 Pain severity
decreases
2. Initial phase1
 Patients reach
peak pain severity
 Increased anxiety
3. Established phase1
 Patients maintain peak
pain severity
 Signs of joint effusion
and inflammation
Recurrent crises with no intermediate pain1
Chronic pain1
Prodromal Initial Established Resolving Initial Established Resolving
Categorical
pain
scale
Crisis day Crisis day
10
0 9
8
7
6
5
4
2
1
–1
–2 3
2
4
6
10
8
10
9
8
7
6
5
4
2
1
–1
–2 3
Prodromal Initial Established Resolving Initial Established Resolving
Categorical
pain
scale
Crisis day Crisis day
10
0 9
8
7
6
5
4
2
1
–1
–2 3
2
4
6
10
8
10
9
8
7
6
5
4
2
1 3
Common timing for onset
of complications
eg ACS, MOF, relapse, death
Predormal
Phase
Initial
Phase
Established
Phase
Resolving
Phase

17. VOCs may be only the tip of the iceberg when it
comes to ongoing vaso-occlusion1,2
CLINICALLY VISIBLE
VOCs are unpredictable,
extremely painful events
that last, on average,
10 days1,2
VOCs
Vaso-Occlusion
Multicellular Adhesion
Inflammation and Cell
Activation and Endothelial
Damage
SUBCLINICAL
Silent, ongoing
vaso-occlusion
occurs systemically
during a patient's
lifetime, potentially
resulting in
acute and chronic
complications3
CLINICALLY VISIBLE
VOCs are extremely painful events
that last, on average, 10 days1,2
VOCs
Vaso-Occlusion
Multicellular Adhesion
Inflammation and Cell
Activation and Endothelial
Damage
SUBCLINICAL
Silent, ongoing vaso-
occlusion occurs
systemically during a
patient's lifetime,
potentially resulting in
acute and chronic
complications3
MRI, magnetic resonance imaging; T1, T1- weighted: T2, T2-weighted.
1. Ballas SK et al. Blood. 2012;120(18):3647-3656. 2. Piel FB et al. N Engl J Med. 2017;376(16):1561-1573. 3. Thein MS et al. Pathology. 2017;49(1):1-9. 4. Mankad VN, Williams JP, et al. Blood. 1990;75(1):274-283.
VOCs are
clinically visible
painful events
But more is
happening
beneath the
surface2,3

18. 2. Multicellular Adhesion2-4
Activated cells and chronic
inflammation initiate a complex
cascade of cell interactions leading
to upregulation of adhesion
mediators that drives multicellular
adhesion among endothelial cells ,
WBCs, sickled RBCs,
and platelets.
1. Inflammation and Cell
Activation1,2
The blood vessels of patients with
SCD are in a chronic state of
inflammation because of activated
endothelial cells of the blood vessel
wall
1
Multicellular adhesion promotes vaso-occlusion and VOCs -
a vicious cycle in Sickle Cell Disease1-4
 1. Conran N et al. Hemoglobin. 2009;33(1):1‐16. 2. Zhang D et al. 2016;127(7):801‐809. 3. Puri L et al. Paediatr Drugs. 2018;20(1):29‐42. 4. Kappelmayer J, Nagy B. Biomed Res Int.
2017;2017(6138145):1‐18. doi: 10.1155/2017/6138145.
18
3. Vaso-Occlusion and VOCs1-3
Ongoing silent vaso-occlusion and
VOCs are associated with an
increased risk of organ damage and
death
End-Organ Damage1,2
Multicellular adhesion drives
ongoing, silent, vaso-occlusion,
that can result in VOCs, also
known as sickle cell pain crises,
the clinical hallmark of sickle
cell disease.
2
3

19. As a result of vascular damage, activated
endothelial cells play a critical role in the
pathophysiology of VOCs by interacting with
circulating blood cells and forming
multicellular clusters.
• Circulating blood cells adhere to activated
endothelial cells and each other via
proteins called adhesion molecules,
including P-, E-, and L-selectin
Adhesion Mediators like P-Selectin drives an essential role in
pathogenesis of Vaso-occlusion and VOC1-3
19
Activated
endothelial cells
Activated platelet
Red blood cell
White blood cell
Activated
endothelial cells
Non-activated
endothelial cells
P-selectin
L-selectin
L-selectin ligand
E-selectin ligand
P-selectin ligand
As a result of vascular damage, activated
endothelial cells play a critical role in the
pathophysiology of VOCs by interacting with
circulating blood cells and forming
multicellular clusters.
Circulating blood cells adhere to activated
endothelial cells and each other via proteins
called adhesion molecules, including
P-, E-, and L-selectin
References: 1. Conran N et al. Hemoglobin. 2009;33(1):1‐16. 2. Zhang D et al. Blood. 2016;127(7):801‐809. 3. Kappelmayer J, Nagy B. Biomed Res Int. 2017;2017(6138145):1‐18. doi: 10.1155/2017/6138145.
Activated platelet
Red blood cell
White blood cell
Sickled red
blood cell
E-selectin

20. This analysis included 264 adult patients with sickle
cell anemia (HbSS) followed for a median of ~5 years
in the United States
(The Bethesda Sickle Cell Cohort Study, 2001-2007)
•VOCs were defined as patient-reported
emergency department visit or hospitalization for
pain treatment in the 12 months prior to
enrolment
One or more VOCs in a given year have been
associated with an increased risk of death at an
earlier age1
Survival in patients with HbSS genotype was shown to be lower at ~56 years of age
Reference: 1. Darbari et al. PLoS One. 2013;8(11):e79923.doi:10.1371/journal.pone.0079923.
20
VOCs were associated with death at a younger age: 66.2 years
for patients with 0 VOCs in the past year and 55.8 years for
patients with ≥1 VOCs in the past year (P=0.04)

21. 21
Vaso-occlusion and VOCs can lead to end-organ damage,
multi-organ failure, and death1-4
BRAIN
At least 25% of patients with SCD
will experience a neurological
complication in their lifetime6
KIDNEYS
Up to 18% of all deaths in patients
with SCD have been associated with
kidney dysfunction7
REPRODUCTIVE SYSTEM
Up to 35% of men will experience
priapism, and women are at
increased risk for a VOC during
menstruation10,11
LUNGS
• 75% experience Acute Chest
Syndrome5
• 20% patients suffered from Pulmonary
hypertension12
LIVER
End-organ damage to the hepatobiliary
system is typically the result of
vaso-occlusion, with approximately 40%
of VOCs affecting the liver8,9
SCD is a multisystem disorder that affects
nearly every organ in the body (including
the heart, eyes, and bones)3
1. Ballas SK, et al. Blood. 2012;120(18):3647-3656. 2. Kanter J, et al. Blood Rev. 2013;27(6):279-287. 3. Piel FB et al. N Engl J Med. 2017;376(16):1561‐1573. 4. Brousse V, et al. DOI: https://-doi.org/10.1111/-j.1365-2141.2011.08999.x. 5. Elmariah H, et
al. Am J Hematol. 2014;89(5):530-535. 6. Thust SC, et al. Br J Radiol. 2014;87(1040):20130699. 7. Nath KA, et al. Nat Rev Nephrol. 015;11(3):161-171. 8. Shah R, et al. World J Gastrointest Pathophysiol. 2017;8(3):108-116. 9. Koskinas J, et al. Scand J
Gastroenterol. 2007;42:499-507. 10. Crane GM, et al. Anemia. 2011; 2011:297364. 11. Smith-Whitley K. Blood. 2014;124(24):3538-3542. 12. Powars DR, et al. Medicine (Baltimore). 2005;84(6):363-376;

22. VOCs can lead to many different acute and chronic complications
1. Claster S & Vichinsky EP. Br Med J 2003;327:1151–1155.
2. The Voice of the Patient FDA report 2014
The complications highlighted in green are some of those most closely linked to VOCs
“I can deal with the
pain, but what…I’m
most concerned
about is the fact that
my organs are
dying, my tissues
are dying, every
time I’m having a
sickle cell episode”2
Retinopathy
Acute chest
syndrome
Acute splenic
sequestration
Pulmonary
hypertension
Priapism and
impotence
Heart
disease
Vertebral
body collapse
Nephropathy
Liver failure Arthropathy
Leg ulcers
Chronic pain
Chronic
anaemia
Avascular
necrosis
Risk of
infection
Overt and
silent stroke
The clinical severity of SCD can be unpredictable1

23. Prevention of VOCs is preferable to management,
but options are limited
1. Bender MA, Seibel GD. Sickle Cell Disease. In: Pagon RA et al. GeneReviews; Seattle: University of Washington 1993–2017; 2. Ballas SK et al. Sci World J 2012:949535;
3. Tewari S et al. Haematologica 2015;100:1108–16; 3. Ware RE et al. Lancet 2017:390;311–23; 4. Bloch EM et al. Transfus Med Rev 2012;26:164–80
Practical approaches Blood transfusion
 Single and long-term blood
transfusion programmes can help
prevent acute and chronic
complications3
 Potential side effects include
transfusion reactions and iron
overload3
 Transfusions are often challenging
owing to the lack of availability of
safe blood4
Good hydration, especially during
exercise1
Temperature management, including
avoidance of extreme cold3
Adequate sleep2
Avoidance of emotional stress,
or use of stress-coping skills2

24. Practical lifestyle approaches can help to prevent VOCs
Good hydration, especially
during exercise1
Temperature management, including
avoidance of extreme cold3
Adequate sleep2
Avoidance of emotional stress,
or use of stress-coping skills2
 Dehydration of RBCs is an important contributor to the sickling
process2
 Maintain adequate daily fluid intake
 Be aware of risk factors for dehydration. eg exercise or air travel
 Monitor tiredness and restwhen needed
 Cold temperatures trigger vasoconstriction and reduce blood flow,
promoting deoxygenation
 In addition to temperature, other environmental factors eg wind
speed have been linked to VOCs
 Use stress-coping techniques, such as yoga
Limitations
 Dehydration, cold, stress and fatigue cannot be totally avoided in daily life
 These approaches are not disease-modifying, and have not been evaluated in clinical trials
1. Bender MA, Seibel GD. Sickle Cell Disease. In: Pagon RA et al. GeneReviews; Seattle: University of Washington 1993–2017; 2. Gallagher PG. Blood 2015;126:2775–6; 3. Tewari S et al. Haematologica 2015;100:1108–16; 4.
Jenerette CM et al. Nurs Res Pract 2011;270594

25. Role of Blood transfusion in SCD
25
Single transfusion indications1,2
ACS, transient aplastic crises,
anaemia, acute splenic
sequestration, preoperative
procedures
Long-term/chronic transfusion
indications1,2
Stroke, abnormal TCD, multi-
system organ failure
Blood transfusions play an important role in the treatment and prevention of the
acute and chronic complications of SCD. Transfusions can either be a single
procedure or as part of a long-term treatment regimen1
The aim of transfusion is to increase oxygen-carrying capacity, restore blood
volume, prevent VOC, and reduce sickle erythropoiesis
Short-term side effects 1,2
Volume overload, acute non-
haemolytic reactions
1. Howard J. ISBT Science Series 2013;8:225–228; 2. Ware RE et al. Lancet 2017:390;311–323
Long-term side effects1,2
Alloimmunization,
hyperhaemolytic transfusion
reactions, iron overload

26. Epidemiology
 SCA is most common in African & American blacks. In India it
is highly prevalent in aboriginal tribes e.g. Teli Mahar Kunbhi
etc of central India (Orissa,Chattishgh,Vidarbha) and Gujarat
i.e. Dahod, Godhra.

27. Clinical manifestation :
 Clinical manifestation of SCA depend on whether the case is homozygous or
heterozygous.
 Presence of high fetal Hb prevents manifestation of SCD during first few months of
life.
 Homozygous sickle cell disease usually manifest beyond 4-6 months of age with :
 Chronic haemolytic anemia with moderate pallor and signs of chronic hypoxia,e.g.
extertional dysponea and growth failure signs of hemodynamic decompensation
e.g.CCF and cardiomegaly while older children may also develop gall stones due
to excess bilirubin production.

28.  Moderate splenomegaly with or without hypersplenism.
 Splenomegaly frequently regresses after 5-6 years due to
autosplenectomyafter repeated splenic infracts. Altered splenic functions
predispose these cases for serious infection,i.e. sepsis,meningitis &
osteomyelitis
 by capsular organisms,i.e.pneumococci,H.influenzae and salmonella
 Signs of microvascular ischemia and recurrent infracts e.g.
clubbing,nephropathy,chronic leg ulcers,recurrent epistaxisetc.
 Sickle cell nephropathy characterised by recurrent hematuria and
hyposthenuria i.e.loss of concentration capacity due to recurrent medullary
infracts.

29. Sickle cell crises :
 Acute crises episodes,which may be spontaneous or develop after exposure to hypoxic
events,e.g. fever,infection,dehydration,acidosis,and high altitudes.
 Main types of crises seen in SCD are as follows :
 Vaso-occlusive crises are most common and usually spontaneous with wide clinical
spectrum,e.g. sudden painful swelling of hands and feet due to ischemic necrosis of
small bones Hand-foot syndrome, acute abdominal pain ( mesenteric ischemia
),cerebro-vascular strokes, acute chest syndrome (pulmonary embolism) sudden
blindness (retinal occlusion)& priapism(venous obstructionin corpora cavernosa)
Vaso-occlusive crises precipitated by cold,hypoxia,infection&dehydration.
 Sequestration crises with massive splenomegaly with circulatory collapse due to
sudden pooling of blood in the spleen and are most common in younger children
usually after acute febrile illness.It occur in spleen,chest & liver

30. Haemolytic crises : This is haemolysis it usually accompanies a painful
crises.
Hyper-haemolytic crises : wth sudden and severe haemolytic episodes are
seen in cases with co-existing G6PD deficiency.
Aplstic crises : with sudden bone marrow depression and pancytopenia are
usually associated with parvovirus B19 infection.
Megaloblastic crises : Megaloblastic anemia following chronic haemolysis &
chronic erythroid hyperplasia leading to folate deficiency & sudden arrest of
erythropoiesis.
Hb can be drop makedly as much as 2-3 mg/dl
Supplementation of folic acid is main stay of treatment

31.  Painful abdominal crises : vaso-occlusion of mesenteric artery leads to localised area of
bowel dysfunction. There is severe abdominal pain & sign of peritoneal irritation.
Persistent bowel sound differentiate it from acute abdomen requiring surgical
exploration. It usually resolves in periods of 3 days.
 Management : Bowel rest, maintainance of hydration by IV fluids.
 Vaso-occlusive crises : This occur due to obstruction to microcirculation.
 Obstruction of capillaries of bone marrow causes ischemic necrosis & death of bone
marrow and initiate inflammatory response increasing intramedullary pressure ,clinically
there is swelling over affected bones with severe pain & tenderness seen in younger
children. Affects small bones of hand & feet causing Hand-foot syndrome or
Dactilytis.Child get aches & pain
 Management : Hydration & analgesics

32.  Avascular necrosis of bones occur secondary to vaso-occlusion of
nutrient artery femoral head,humerus & upper end of tibia can be
affected but severe disability more common secondary to femoral head
necrosis due to weight bearing.
 Neurological involvement includes paresis,hemiplegia & monoplegia.
Common age 3-10 years. It result of occlusion of major blood vessels.
About 70 to 90 % children get repeated episodes.
 Management : chronic transfusion regimen to keep HbS level below
30-35%

33.  Infection These children are at high risk of infection with
encapsulated bacteria such as streptococcus
pneumoniae,Hemophilus influenzae B,Meningococcus &
Salmonella species. They are at risk of overwhelming
infection, particularly if more then 3 years age, with
meningitis,septicemia,pneumonia.

34. Long- term problems :
 Failure to thrive ( due to chronic disease )
 Pigment gallstones ( due to haemolysis )
 Salmonella osteomyelitis.
 A septic necrosis of hip
 Priapism ( pooling of blood within corpora cavernosa )
 Renal failure
 Congestive heart failure
 Proliferative retinopathy
 Splenomegaly in infancy, with autosplenectomy (due to splenic crises) later
 Leg ulcer

35. Heterozygous sickle cell trait :
 It is usually asymptomatic, though mild vaso-occlusive
menifestations may develop in severe hypoxic conditions.
Identification of these cases by
 high-risk & family screening is vital for genetic counselling.
 Mixed haemoglobinopathies usually have milder presentation
except
 HbS-β thalassemia which clinically indistinguishable with SS
disease.

36. Investigations :
 Peripheral smear : showing characteristic sickled RBCswith
poikilocytosis,target cells,nucleated RBCs,& Howell-Jolly bodies ( signs of
splenic dysfunction ).
 Sickling test– a simple screening test to demonstrate sickling in suspected
cases.
 Hb solutibility test involves adding measured amount of Hb in to a
concentrated reducing solution. Turbid precipitate indicate presence of
HbS.
 Hb electrophoresis is confirmatory, which reveals concentration of various
Hb

37.  Hb electrophoresis in sickle cell syndrome :
 HbA % HbS % HbA2 HbF% HbC %
 Sickle cell disease 0 85-95 2-3 5-15 -
 SA trait 55-60 40-45 2-3 - -
 S- Thalassemia 0-20 60-80 3-5 10-20 -
 S-C disease 0 45-50 - - 45-50
 All values in % of total Hb

38.  Other investigations may reveal non-specific evidences
 of haemolytic disease, i.e. moderate anemia
 High reticulocyte count
 Hypercellular marrow with erythroid hyperplasia
 And hyperbilirubinemia
 Antenatal diagnosis is possible at 12 weeks, by DNA-PCR
studies on fetal fibroblst

39. Management :
 Prevention & early treatment of precipitating events, e.g.
fever,infections,dehydration,acidosis,and hypoxia due to any cause
including high altitude.
 Supportive treatment in acute crises,wth fluids/electrolyte
correction,alkali therapy to prevent acidosis and blood transfusion.
Simple analgesics, e.g. paracetamol and cold fomentation may be
used to reduce pain in vaso-occlusive crises.
 Treatment of chronic anemia : Repeated tranfusions are generally
not required,except in severe cases or during crises. Folic acid
supplement are necessary in all cases due to increased
erythropoetic activity.

40.  Prevention of infection ( due to splenic dysfunction )with
Pneumococcal, meningococcal and H influenzae B vaccines.
 Children more then 2 years should receive penicillin prophylaxis
from 3-4 months of age as current pneumococcal vaccines may be
given only after 2 years.
 Surgery : Transfusion are performed preoperatively for major
surgery to reduce the HbS fraction < 30%
 Anaesthetic care is taken to keep patient warm, well oxygenated,
and hydrated pain free and acidosis avoided

41. Hydroxyuera :
 Hydroxyurea is myelosuppressive agent to stimulate HbF production
 Some what prevent hypoxia
 To reduce hospitalization due to vaso-occlusive crises and need for blood
transfusion by 50%
 It is relatively safe and well tolerated in children above 2 years of age
except potential but reversible risk of bone marrow suppression.
 Typical starting dose is 15-20 mg/kg/day OD which may be increased by 5
mg/kg every 8 weeks to maximum of 35 mg/kg/day
 It should be temporarily discontinued if absolute neutrophil count fall
<2000/mm3 or platelet count fall < 80000/mm3

42. Hydroxyurea is the mainstay for SCD Management
Republished with permission of the Amercian Society of Hematology, from Ware RE. Blood
2010;115:5300–11; permission conveyed through Copyright Clearance Center, Inc.
HbF, fetal haemoglobin; MoA, mechanism of action; NO, nitric oxide
1. Ware RE. Blood 2010;115:5300–11
1 Induces production of HbF, thus reducing
HbS polymerization
2 Reduces neutrophil and reticulocytecounts
3 Decreases neutrophil andreticulocyte
adhesiveness, improving blood flow
4 Reduces RBC haemolysis
5 Causes release of NO, a vasodilator
1
3
4
Bone
marrow Megakaryocyte
2
Erythroid
progenitor Hydroxyurea
Endothelial
5 cell
Nitric oxide
Blood vessel
Neutrophil
Reticulocyte
Erythrocyte
Myeloid
precursor
Hydroxyurea
HU, hydroxyurea
2. Charache S, Terrin ML. N Engl J Med. 1995;332:1317-1322.
• Hydroxyurea (HU) therapy can
improve the clinical course of
SCD in some adults with 3+
crises per year2
• Lower annual rates of
crises vs placebo (median
2.5 for hydroxyurea vs 4.5 for
placebo, per year, p < 0.001)
• Longer median time to
first crisis (3 mo for
hydroxyruea vs 1.5 mo for
placebo, p = 0.01) and
second crisis vs placebo
(8.8 mo vs 4.6 mo, p < 0.01)
Maximal tolerated doses of
hydroxyurea may not be
necessary to achieve a
therapeutic effect2

43. Many patients still experience recurrent VOCs while receiving HU, and many others are
unwilling to use HU
43
• while efficacious, still many pts continue to experience VOCs
• Physician concerns around safety – “cancer drug”, “causes infertility”
• Inconvenient for physicians because of frequent early dose adjustments and monitoring
• Inconvenient for patients -Size of the Capsule – 500mg
Hydroxyurea use is associated with many
challenges
*Ritho J et al, Am J Hematology 2011 Oct;86(10):888-90. Charache et al. NEJM 1995; Lanzkron et al. Am J Hematol. 2006; Brandow et al. Exp Rev Hematol. 2010

44.  Role of hydroxyurea :
 Blood markers : Hb , % FHb , MCV , Leucocyte count increased
 Clinical : Pain crises , hospitalizations , Blood transfusion ,acute chest
syndrome decreased
 Prevention of end organ damage spleen,brain kidney not evaluated
 Mortality decreased
 Short term effects : Leucopenia , Thrombocytopenia, Anaemia
 Long term

45. Vaso-occlusive crises ;
 Hospitalization
 Check CBC, Retic count, blood groups LFT RFT CRP Blood culture
 Xray chest if respiratory symtoms ECG if chest pain
 Srong analgesia usually IV opiates
 IV fluids 50% above usual formula
 Oxygen ( by CPAP if necessary e.g. acute chest syndrome
 Bed rest keep warm
 Monitor closely saturation pulse BP RR Pain Nausea
 IV antibotics if infection present or suspected

46.  Transfusion if necessary ( multiple may be needed )
 Exchange transfusion if indicated ( this decreases the
proportion of of sickle cells )
 In severe painful crises, neurological damages,sequestration,
sickle chest syndrome, priapism

47. Newer modalities :
 Bone marrow transplantation
 Stem cell transplantation
 Humanized Monoclonal antibody i.e. Crizalinzumab
 Other HbF stimulating agents : Butyrate & 5-azacytidine
 HbF reducing agents, e.g. DDAVP & Calcium channel blokers
 Membrane –stabilizing agents e.g. Zinc
 Hb solubility increasing agents e.g. urea,cynate
 Recombitant humam erythopoietin
 Genetic counselling, carrier detection, and antenatal diagnosis is essential
in all cases to prevent further morbidity in family

48. Crizalinzumab :
 Crizalinzumab is the first & an only taegated monoclonal antibody
that works by inhibiting P- selectin mediated multicellular adhesion
in SCD
 Crizalinzumab 2.5 mg/kg ( low dose ) & 5 mg/kg ( high dose )
 Loading dose 2 weeks apart
 Maintainace dose every 4 weeks
 Each dose administered intravenously over period of 30 minutes.
 It is humanised monoclonal antibody that binds to P-selectin &
block its interaction with P-selectin glycoprotein ligand

49. 49
 P-selectin is expressed on platelets
and endothelial cells1,2
 E-selectin is rapidly induced by
inflammatory cytokines2
 L-selectin is expressed on all
granulocytes and monocytes and
on most lymphocytes2
 Selectins participate in the
adhesion, rolling, and capture of
blood cells2
Role of Selectins in Multicellular Adhesion
NETs, neutrophil extracellular traps; TLR, toll-like receptors.
1. Mcever RP. Cardiovasc Res. 2015;107(3):331-339. 2. Ley K. Trends Mol Med. 2003;9(6):263-268. 2.. 3. Zhang D, Chen G, et al. Blood. 2016;127(7):801-809.
Microbiota-derived signals
“Aged”
NETs
Blood flow
TLRs/Myd88
“Nascent”
Rolling
Adhesion
?
Adapted from Zhang D, Chen G, et al. Blood. 2016;127(7):801-809.

50. P-selectin: a cell adhesion molecule
50
Normal erythrocytes do not adhere to endothelial cells strongly or in substantial quantities,
because they are not known to bear selectin ligands or to bind to P-selectin1,2

51. Up regulation of P-selectin is a major contributor to the
development of VOCs
Activated P-selectin binds leucocyte PSGL-1 receptor and PSGL-1-like receptor
on sickled cells
51
1. Manwani D & Frenette PS. Blood 2013;122:3892–3898
Cell–cell interactions should be multicellular and result in the formation of a vaso-occlusive
clot, leading to pain, haemolytic anaemia, organ injury and early mortality1
Activated P-selectin binds leucocyte PSGL-1 receptor and PSGL-1-like receptor on sickled cells

52. 52
• Humanized monoclonal antibody
• Binds P-selectin and blocks its interaction with its ligands including P-selectin
glycoprotein ligand​
Mechanism of action - Crizanlizumab
Data on file: Clinical Investigator’s Brochure for SelG1, Edition 6.0
Kd, equilibrium dissociation constant (low value = high affinity); VOC, vaso-occlusivecrisis
Hinge
CH2
CH3
Variable light chain
Human kappa light
chain constant region
Variable heavy chain
Human germline
framework regions
Complementarity-
determining regions
(murine origin)
Modified human IgG2 heavy
chain constant region
Two x 218 amino
acid light chains
Two x 448 amino
acid heavy chains
High affinity for
human P-selectin
Kd = 5.9 ± 2 nM
Molecular weight
~148kDa

53. Mechanism of action - Crizanlizumab
53
• In the chronic pro-inflammatory state in SCD, P-selectin
is upregulated and over-expressed
• P-selectin is a key player in the multicellular adesion
involved in vaso-occlusion and crises.
• Blocking P-selectin function may prevent vaso-occlusion
and improve blood flow2–4
• Humanized antibody that binds P-selectin with high
affinity and specificity, blocking its ability to bind to its
receptors1
• Long-term administration of a
P-selectin-blocking agent has the potential to improve
blood flow and avert acute VOCs in patients with SCD4
1. Ataga KI et al. N Engl J Med 2017;376:429–439; 2. Embury SH et al. Blood 2004;104:3378–3385; 3. Matsui NM et al. Blood
2001;98:1955–1962; 4. Kutlar A et al. Am J Hematol 2012;87:536–539

54. Immunization against vaccine-preventable
infections recommended
Pneumococcus Meningococcus and Haemophilus
influenzae type b
Influenza
Under 2 years Routine Routine Annual
Age 2–5 years
(fully vaccinated)
Single dose PPV Booster dose given as the
Hib/MenC vaccine
Annual
Age 2–5 years
(unvaccinated or
partially vaccinated)
Two doses of PCV
given 2 months apart,
followed 2 months later
by PPV
Two doses of the Hib/MenC
vaccine given 2 months apart
Annual
Age >5 years
(fully vaccinated)
Single dose PPV Two doses of the Hib/MenC
given 2 months apart
Annual
Age >5 years
(unvaccinated)
Single dose PPV Two doses of the Hib/MenC
vaccine given 2 months apart
Annual
Reinforcing
immunization
PPV every 5 years MenC vaccine every 5 years, Hib
vaccine not currently recommended
Annual
54
Hib, Haemophilus influenzae type b; MenC, meningococcus group C; PCV, pneumococcal conjugate vaccine; PPV, pneumococcal
polysaccharide vaccine
Booth C et al. Int J Infect Dis 2010;14:e2–e12
Recommended immunization schedule for SCD

55. Role of P-selectin &
Mechanism of action of crizanlizumab

56. Significant reduction in VOC with crizanlizumab
5 mg/kg (p=0.010)
56
2.98
2.01
1.63
Placebo Crizanlizumab
2.5 mg/kg
Crizanlizumab
5 mg/kg
-45.3%
Annual rate VOC leading to healthcare visit
Standard median
p** = 0.010
HL* = -1.01
(-2.00, 0.00)
p** = 0.180
HL* = -0.69
(-1.84, 0.02)
Crizanlizumab 5 mg/kg
• Statistically significant and
clinically meaningful reduction of
VOC leading to healthcare visit
• Confirmed by supplementary
analyses with varying populations
and management of dropouts
Crizanlizumab 2.5 mg/kg
• 32.6% reduction of VOC leading
to healthcare visit
• Not statistically significant
• Suggests dose response
Ataga KI et al. N Eng Jour Med. 2017

57. Efficacy conclusions:
57
• 45% reduction in the number of VOCs per year
• Patients with 5+ VOCs experienced 63% reduction
• More than 1/3rd (36%) of the patients had no VOC in 1 year
• 42% reduction in days hospitalized per year
• Delayed time to first VOC (3x longer)
Ataga KI et al. N Eng Jour Med. 2017

58. Safety conclusions:
58
• Majority of adverse drug reactions were mild to moderate
• Nausea, arthralgia, back-pain and pyrexia in >10% of patients
• No increase in risk of infection
• Rates of infection were similar to placebo
• Blood count results, and Blood chemistry findings were
similar to those of placebo
• Only 2 patients discontinued treatment due to adverse
reactions (vs 3 patients on placebo arm)
• 3% IRR (infusion related reaction)
Ataga KI et al. N Eng Jour Med. 2017

59. Dosage and Administration
59
Administer Crizanlizumab 5 mg/kg by
intravenous infusion over a period of
30 minutes at
Week 0, Week 2, and every 4 weeks
thereafter
Crizanlizumab may be given with or
without hydroxyurea.
• Do not mix or co-administer with other
drugs through the same IV line.
• Do not administer as IV push or bolus.
India Package Insert dated 4 Dec 19 based on US PI

60. 60
• VOCs may be only the tip of the iceberg when it comes to ongoing vaso-occlusion
• Multicellular adhesion promotes vaso-occlusion and VOCs - a vicious cycle in Sickle Cell Disease
• Vaso-occlusion and VOCs can lead to end-organ damage, multi-organ failure, and death
• VOCs have been associated with an increased risk of death at an earlier age
• VOCs can be managed using hydration, supplemental oxygen, appropriate analgesia and non-medical
techniques
• SCD patients may avoid seeking healthcare assistance during a VOC because of stigma around opioid use,
poor provider knowledge, the structure of their healthcare system, and expense
• There are forms of management therapy/preventive treatment, including blood transfusion and hydroxyurea,
but there is an unmet need for additional preventative therapies
Concluding Remarks
60