SICKLE CELL ANEMIA

M.Murat Güçlü 224

EFE DEMİR 256

9 – B

What is Sickle Cell Anemia (SCA)? First described in Chicago in 1910

by James Herrick as an inherited condition that results in a decrease in the ability of red blood cells to carry oxygen throughout the body Sickle red blood cells become hard and irregularly shaped (resembling a

sickle) Become clogged in the small blood vessels and therefore do not deliver

oxygen to the tissues. Lack of tissue oxygenation can cause excruciating pain, damage to body

organs and even death.

Mechanism Red blood cells (RBC)

Contain a special protein called haemoglobin (Hb)

Hb is the component that carries oxygen from the lungs to all

parts of the body

Most people have only hemoglobin type – Hb A within RBC

(normal genotype: Hb AA)

Sickle Cell: HbS

S similar to A, but one structural change

Other types: HbC, HbD, and HbE

Mechanism -HbS When sickle haemoglobin (HbS) gives up its oxygen to

the tissues, HbS sticks together › Forms long rods form inside RBC › RBC become rigid, inflexible, and sickle-shaped› Unable to squeeze through small blood vessels, instead

blocks small blood vessels› Less oxygen to tissues of body

RBCs containing HbS have a shorter lifespan› Normally 120 days› Chronic state of anaemia

Normal and Sickled Red Blood Cells in Blood Vessels Figure B shows abnormal, sickled red

blood cells clumping and blocking the blood flow in a blood vessel. The inset image shows a cross-section of a sickled red blood cell with abnormal strands of hemoglobin

Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

TRAIT

Sickle haemoglobin (S) + Normal haemoglobin (A) in RBC Adequate amount of normal Hb (A) in red blood cells

RBC remain flexible Carrier Do Not have the symptoms of the sickle cell disorders, with

2 exceptions

1. Pain when Less Oxygen than usual (scuba diving, activities at high altitude (12,000ft), under general anaesthesia)

2. Minute kidney problems

Three common types of Sickle Cell Disorders

1.) Sickle Cell Anemia Sickle haemoglobin (HbS) + Sickle haemoglobin

(HbS)

Most Severe – No HbA

2. Hemoglobin S-C disease Sickle haemoglobin (HbS) + (HbC)

3. Hemoglobin S-Beta thalassemia Beta thalassaemia gene reduces the amount of HbA

that can be made Sickle haemoglobin (HbS) + reduced HbA Milder form of Sickle Cell Disorder than sickle cell

anemia

Medical Complications

1. pain episodes

2. strokes

3. increased infections

4. leg ulcers

5. bone damage

6. yellow eyes or jaundice

7. early gallstones

8. lung blockage

9. kidney damage and

loss of body water in urine

10. painful erections in men (priapism)

11. blood blockage in the spleen or liver (sequestration)

12. eye damage

13. low red blood cell counts (anemia)

14. delayed growth

REFERENCES http://www.sicklecellsociety.org/ : Another Great Site information, Counselling and Caring for those with Sickle Cell Disorders and their

families: UK based

http://www.sicklecelldisease.org/: Sickle Cell Disease Association of America

The Human Genome Project Sickle Cell Education Site at http://www.massinteraction.org/html/genome/

http://www.ascaa.org/ American Sickle Cell Anemia Association ASCAA was founded in 1971 and is the oldest sickle cell research, education, and

social services organization in the United States.

http://www.ncd.gov/

http://www.painfoundation.org/