Transcript What is Sickle Cell Disease?

What is Sickle Cell Disease?
What is Sickle Cell Disease?
• An inherited disease of red blood cells
(erythocyctes)
• Affects a protein inside the red blood cells
called hemoglobin.
• Sickle-shaped red cells interrupt blood flow
by blocking small blood vessels
• Tissue that has no blood flow is damaged
and causes pain
What is Sickle Cell Disease?
A person with sickle cell
disease has one different
substance in the way it
makes hemoglogin. This
substance is the amino
acid valine in one spot
where there should be
glutamic acid.
This one change causes
the chemical to form long
strings when it lets loose
of its' oxygen. This
causes the red cell to
become deformed into a
"sickle" shape.
Sickle Cell Hemoglobin
Beta S
Beta S
Hemoglobin SC
Beta S
Beta C
Diagnosis
The most widely used blood test for sickle cell disease and
trait is the hemoglobin electrophoresis. A blood sample is
placed in an electric field on filter paper and the different
hemoglobins travel at different speeds to the negative
pole. Click here to see the test for four blood samples:
HbAA -Normal, Hb AS - Trait, Hb SS - Disease, Hb SC
Hb AA
Start
Hb A
Hb S
Hb C
HB AS
HB SS
Hb SC
Diagnosis Sickledex
The presence of sickle hemoglobin can be rapidly
determined by a five minute solubility test (Sickledex).
This test is only helpful by excluding sickle cell disease
when negative in a patient older than six months of age
without severe anemia or a very high fetal hemoglobin
level. It is impossible to separate sickle cell disease from
trait with this test.The test is positive if 10 percent Hb S is
present, making it impossible to separate sickle cell trait
from individuals with disease
Diagnosis - Blood Smear
Sickle red cells
Normal vs. Sickle
Hemoglobin
Normal
• Disc-Shaped
• Soft (like a bag of jelly)
• Easily flow through
small blood vessels
• Lives for 120 days
Sickle
• Sickle-Shaped
• Hard (like a piece of
wood)
• Often get stuck in small
blood vessels
• Lives for 20 days or
less
Normal Shape to Sickle
Long rods of
hemoglobin form
deforming the
red cell
Microscope view
of long rods in a
sickle red blood
cell
Normal Shape to Sickle
Normal vs. Sickle red cells
If no oxygen, then pain
and damage occurs
Sickle red cells are stickier
Sticky red cells block blood flow, then
pain and damage occurs
Worldwide Distribution
Hemoglobin S
Hemoglobin D
Hemoglobin C
Worldwide Distribution
Hemoglobin S
Sickle Cell Disease is found in
Africans, Turks, Greeks, Saudi
Arabians, Egyptians, Iranians,
Italians, Latin Americans and
Asiatic Indians.
Sickle cell disease is present in one out of four hundred African
Americans in the United States. It is the most common genetic
disease in this country. All new born babies should be tested at birth
for sickle cell disease, so prevention can be started right away. A
simple blood test can be done from the baby's blood.
Trait vs.. Disease
Sickle cell trait is present in one out of ten African
Americans. About half of the hemoglobin in the red cell is
sickle and the cell will exhibit sickling when under severe
conditions of low oxygenation. Hematuria or blood in the
urine is the most common problem. There are case reports of
people with sickle cell trait having more severe sickle related
problems when placed under severe conditions such as
extreme pressure and low oxygen conditions. Those with trait
should be advised of the risks of extreme physical activity,
severe pressure changes, deep sea diving, and the possibility
of hematuria.
Trait vs.. Disease
Pedigree
A pedigree is a map of the types of hemoglobin in
the family tree. This helps to identify those with
the trait and those with disease. In this pedigree,
both parents have sickle trait, 1 in 4 children will
have Sickle cell disease, one half will have trait
and 1 in4 will have normal hemoglobin
Pedigree
AA
AS
AS
AS
AS
SS
There are two genes for hemoglobin, one of which is inherited
from each parent. If one normal gene and one
abnormal gene is passed on by each parent, only half of the
hemoglobin produced will be abnormal and the individual
will be a carrier of the abnormal gene. This is commonly
referred to as having the trait of the disease.
Pedigree
AA
AS
AS
AS
AS
SS
If an individual inherits an abnormal gene from each parent, 80100 percent of the abnormal hemoglobin will be manufactured
and the disease will result. There is a 1 in 4 chance of this
happening
Managing Sickle Cell
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•
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Fluids
Antibiotics
Rest
Pain Medication
Prevention of infections
Healthy lifestyle
Complications From Sickle
Cell Disease
• Sickle cells become trapped and destroyed
in the spleen causing Splenic Sequestion
• Shortage of red blood cells or anemia
• Pain episodes
• Stroke or Brain Damage
• Kidney failure
• Pneumonia or Chest Syndrome
• Increased Infections
Spleen Function
• Acts a filter against foreign organisms that infect
the bloodstream.
• Filters out old red bloods cells from the
bloodstream and recycles them.
Minor role:
Manufactures red blood cells only
toward the end of fetal life and
after birth the function is taken
over by the bone marrow.
Acts as a blood reservoir
Spleen Location
• Soft, purplish-red
organ that lies
under the
diaphragm on the
left side of the
abdominal cavity.
• The spleen is like
a filter inside to
recycle old blood
cells and clear
bacteria
Spleen Stick
• A tongue
depressor can be
used to measure
and track spleen
size
• Place the tip on the
left nipple and
make a mark
where the spleen
tip is felt
Spleen Stick
• On one side of the
stick write the
child’s name,
sickle cell type,
and average
hemoglobin level
• One the back put
dates above the
line where the
spleen tip was
1/1/98
What is Splenic Sequestion
• Sudden trapping of
blood within the spleen
• Usually occurs in infants
under 2 years of age
• May be associated with
fever, pain, and
respiratory symptoms.
• Circulatory collapse and
death can occur in less
than thirty minutes.
Treatments For Splenic
Sequestion
• Intravenous fluids
• Blood transfusion as necessary
• Spleen removal or splenectomy
Hand Foot Syndrome Dactylitis
Sickle dactylitis is one of
the first complications in
sickle cell syndromes with
the highest incidence
between ages six months
and two years.
The sickle red cells cause
painful swelling of the
hands and feet. This is
treated with fluids and
pain medication. It usually
will go away in a few days
without any problems.
Kidney
Kidney damage starts very early
and progresses throughout life
causing complications in many
individuals with sickle syndromes.
The kidneys may not filter normally,
passing protein and/or excessive
amounts of water.
Bone Pain
More prolonged and constant
pain can be seen with bone
infarction, sickle arthritis, and
aseptic necrosis of the femur or
humerus. With chronic pain,
non-steroidal anti-inflammatory
medications should be used.
TENS units, relaxation
techniques, occupational and
physical therapy approaches
may be useful in reducing pain
and maintaining a good
lifestyle.
Eye Problems
Sickle cells can cause
damage to the blood
vessels in the eye,
especially in SC
disease. New weaker
blood vessels may form
and break open and
bleed. Early treatment
with laser therapy can
prevent such bleeds.
Strokes
Strokes are a blockage of blood flow to a part of the brain
caused by the sickle cells. The symptoms include one sided
weakness, numb feelings, seizures, slurred speech or facial
weakness. Treatment is with chronic transfusion to
maintain the Hb S level at less than 30% to prevent recurrences
or even prevent the first stroke.
Present evidence suggests that the need for transfusion may
be life-long and complications such as alloimmunization, iron
overload, and exposure to infectious disease may be common
complications. Bone marrow transplantation may, in the future,
offer these children the best chances for a more normal life.
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Anemia - Jaundice
Anemia or a low red blood cell count,
is lifelong, starting in the first year of
life. The average red cell life is
reduced from a normal of 120 days
down to an average of 10 to 20 days
in sickle cell anemia. This produces
anemia, a high reticulocyte count,
and a bone marrow factory that is
producing 3 to 4 times more red cells
than normal. Other problems related
to the anemia are yellow eyes or
jaundice (elevated indirect
bilirubin),which later in childhood
and early adult life can cause
gallstones
Acute Chest Syndrome
Pneumonias or infections
in the lung, and acute
chest syndrome, caused
by sickling red cells
blocking blood vessels in
the lung, are the most
common complications.
Infections are treated
with antibiotics and
acute chest is treated
with blood transfusions
It’s hard to tell the two
apart so both treatments
are used
Priapism
Priapism is the painful erection
of the penis caused by sickling
red cells.
This complication usually has
an onset at age 5 to 35. It often
occurs as a severe episode
requiring hospitalization
following multiple episodes of
short duration termed
stuttering. Onset in the early
morninga waking the patient is
common. Treatment includes
pain relief, hydration, exchange
transfusion, and surgical shunt
procedures .
Leg Ulcers
Leg ulcers are seen in 10 to
15% of older children and
adults with sickle cell
anemia. They may start as
a simple insect bite or cut
that will not heal. They are
likely caused by poor
circulation to the skin.
Treatment includes saline
wet-to-dry dressings, Unna
boots ,and special wound
dressings. Leg elevation
and use of elastic stockings
are very important to
speed healing.