Medicine 5th year, 8th lecture/part three (Dr. Sabir)


Published on

The lecture has been given on Apr. 3rd, 2011 by Dr. Sabir.

Published in: Health & Medicine
1 Comment
  • I find this content very interesting. I´m sure the medical community would be more than happy to discover this. Please, help us spreading this content by sharing it on social net on Medicine. Thanks
    Are you sure you want to  Yes  No
    Your message goes here
  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Medicine 5th year, 8th lecture/part three (Dr. Sabir)

  1. 1. Sickle Cell Anemia Dr. Sabir
  2. 2. What is Sickle Cell Anemia (SCA)? <ul><li>an inherited condition that results in a decrease in the ability of red blood cells to carry oxygen throughout the body </li></ul><ul><ul><li>Sickle red blood cells become hard and irregularly shaped (resembling a sickle) </li></ul></ul><ul><ul><li>Become clogged in the small blood vessels and therefore do not deliver oxygen to the tissues. </li></ul></ul><ul><ul><li>Lack of tissue oxygenation can cause excruciating pain, damage to body organs and even death. </li></ul></ul>
  3. 3. Pathogenesis <ul><li>Normal hemoglobin </li></ul><ul><li>2 alpha and 2 beta chains </li></ul><ul><li>form a 4 chain tetramer </li></ul><ul><li>HbS: </li></ul><ul><li>Valine substituted for glutamic acid in both beta chains (HbSS). </li></ul><ul><li>This occurs due to single point mutation at sixth position of beta globin chain which has thymine instead of adenine. </li></ul>
  4. 4. PATHOGENESIS Arterial pO 2 oxyHbS(soluble) Stiff,viscous sickle cell Venous pO 2 deoxyHbS polymerised) Membrane changes Ca 2+ influx,K + leakage Capillary venule occlusion Shortened red cell survival Microinfarction Ischemic tissue pain Ischemic organic malfn. Anemia, jaundice
  5. 5. Mechanism -HbS <ul><li>When sickle haemoglobin (HbS) gives up its oxygen to the tissues, HbS sticks together </li></ul><ul><ul><li>Forms long rods inside RBC </li></ul></ul><ul><ul><li>RBC become rigid, inflexible, and sickle-shaped </li></ul></ul><ul><ul><li>Unable to squeeze through small blood vessels, instead blocks small blood vessels </li></ul></ul><ul><ul><li>Less oxygen to tissues of body </li></ul></ul><ul><li>RBCs containing HbS have a shorter lifespan </li></ul><ul><ul><li>Normally 120 days </li></ul></ul><ul><ul><li>Chronic state of anaemia </li></ul></ul>
  6. 6. <ul><li>Sickle Cell Trait </li></ul><ul><li>Sickle haemoglobin (S) + Normal haemoglobin (A) in RBC </li></ul><ul><ul><li>Adequate amount of normal Hb (A) in red blood cells </li></ul></ul><ul><ul><ul><li>RBC remain flexible </li></ul></ul></ul><ul><ul><ul><li>Carrier </li></ul></ul></ul><ul><ul><ul><li>Do Not have the symptoms of the sickle cell disorders, with 2 exceptions </li></ul></ul></ul><ul><ul><ul><li>Pain when Less Oxygen than usual (scuba diving, activities at high altitude (12,000ft), under general anaesthesia) </li></ul></ul></ul><ul><ul><ul><li>Minute kidney problems </li></ul></ul></ul>
  7. 7. LAB DIAGNOSIS <ul><li>SICKLE TEST: Red cells with HbS take a sickle shape when mixed with a freshly prepared solution of the reducing agent sodium metabisulphite.(2%) Giving an appearance of turbidity. </li></ul><ul><li>SOLUBILITY TEST: Hb added to solution of sodium dithionite(reducing agent) in phosphate buffer.Turbidity shows presence of HbS. </li></ul><ul><li>Hb ELECTROPHORESIS </li></ul>
  8. 8. BLOOD PICTURE <ul><li>Hb : 6-9gm%, may be lower </li></ul><ul><li>Anemia: normocytic, normochromic </li></ul><ul><li>MCV,MCH: Normal </li></ul><ul><li>Stained film:Moderate anisopoikilocytosis, sickle cells, oval cells, occ target cells, Howell-Jolly bodies </li></ul><ul><li>Reticulocytosis (10-20%) </li></ul>
  9. 10. Screening <ul><li>Haemoglobin Electrophoresis </li></ul><ul><ul><li>Simple Blood test </li></ul></ul><ul><ul><li>Routine screening in high risk groups </li></ul></ul><ul><ul><ul><ul><li>During pregnancy </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Before anaesthesia </li></ul></ul></ul></ul><ul><li>Prenatal Testing </li></ul><ul><ul><li>Amniocentesis </li></ul></ul><ul><ul><ul><li>16 and 18 weeks of the pregnancy </li></ul></ul></ul><ul><ul><ul><li>small risk of causing a miscarriage (1 in 100) </li></ul></ul></ul><ul><ul><li>Chorionic villus sampling (CVS) </li></ul></ul><ul><ul><ul><li>9th or 10th week of pregnancy </li></ul></ul></ul><ul><ul><ul><li>very small amount of material from the developing placenta </li></ul></ul></ul><ul><ul><ul><li>slightly higher chance of miscarriage </li></ul></ul></ul>
  10. 11. Early Symptoms and Complications <ul><li>Typically appear during infant's first year </li></ul><ul><ul><ul><li>1 st symptom: dactylitis and fever (6 mo-2 yrs) </li></ul></ul></ul><ul><ul><ul><li>Pain in the chest, abdomen, limbs and joints </li></ul></ul></ul><ul><ul><ul><li>Enlargement of the heart, liver and spleen nosebleeds </li></ul></ul></ul><ul><ul><ul><li>Frequent upper respiratory infections </li></ul></ul></ul><ul><ul><ul><li>Chronic anemia as children grow older </li></ul></ul></ul><ul><li>Over time Sickle Cell sufferers can experience damage to organs such as liver, kidney, lungs, heart and spleen </li></ul><ul><li>Can result in death </li></ul>
  11. 12. Medical Complications <ul><li>pain episodes </li></ul><ul><li>strokes </li></ul><ul><li>increased infections </li></ul><ul><li>leg ulcers </li></ul><ul><li>bone damage </li></ul><ul><li>jaundice </li></ul><ul><li>early gallstones </li></ul><ul><li>lung blockage </li></ul><ul><li>kidney damage and </li></ul><ul><li>loss of body water in urine </li></ul><ul><li>painful erections (priapism) </li></ul><ul><li>blood blockage in the spleen or liver (sequestration) </li></ul><ul><li>eye damage </li></ul><ul><li>low red blood cell counts (anemia) </li></ul><ul><li>delayed growth </li></ul>
  12. 13. Serious Complications: PAIN Recurrent Pain Episodes or Sickling Crises <ul><li>Occur at any age but appear to be particularly frequent during late adolescence and early adult life </li></ul><ul><ul><li>Unpredictable </li></ul></ul><ul><ul><li>Red Blood Cells get stuck in the small veins and prevent normal blood flow </li></ul></ul><ul><ul><li>Characterized by severe pain in the back, chest, abdomen, extremities, and head </li></ul></ul><ul><ul><li>Highly disruptive to life </li></ul></ul><ul><ul><li>Most common reasons for individuals to seek health care </li></ul></ul>
  13. 14. <ul><li>Fever </li></ul><ul><li>Chest pain </li></ul><ul><li>Shortness of Breath </li></ul><ul><li>Increasing tiredness </li></ul><ul><li>Abdominal swelling </li></ul><ul><li>Unusual headache </li></ul>Danger Signs of a Crisis <ul><li>Any sudden weakness or </li></ul><ul><li>loss of feeling </li></ul><ul><li>Pain that will not go away </li></ul><ul><li>with home treatment </li></ul><ul><li>Priapism (painful erection </li></ul><ul><li>that will not go down) </li></ul><ul><li>Sudden vision change </li></ul>SEEK URGENT HOSPITAL TREATMENT IF IN CRISIS
  14. 15. Crises <ul><li>During a crisis </li></ul><ul><ul><li>severe pain in the fingers, toes, </li></ul></ul><ul><ul><li>arms, joints,legs, back, abdomen, and bones. </li></ul></ul><ul><li>Decrease in oxygen to the chest and lungs </li></ul><ul><ul><li>May lead to acute chest syndrome </li></ul></ul><ul><ul><ul><li>Damage to the lungs </li></ul></ul></ul><ul><ul><ul><ul><li>Severe pain and fever </li></ul></ul></ul></ul><ul><ul><ul><ul><li>airways narrowing, further reducing O 2 </li></ul></ul></ul></ul><ul><ul><ul><li>Leads to an increased risk of potentially </li></ul></ul></ul><ul><ul><ul><li>fatal infections </li></ul></ul></ul>
  15. 16. <ul><li>Infections </li></ul><ul><li>Thirst and dehydration caused by not drinking enough( even if thirst is not felt ) </li></ul><ul><li>Over-exertion </li></ul><ul><li>Over-excitement </li></ul><ul><li>Cold weather and cold drinks and swimming </li></ul><ul><li>Bangs, bumps, bruises and strains </li></ul><ul><li>Stress triggers pain in adults, but does not seem to do so in children. </li></ul>Triggers of Pain
  16. 17. Alleviating Pain <ul><li>Warmth: increases blood flow </li></ul><ul><li>Massaging and rubbing </li></ul><ul><li>Heat from hot water bottles and deep heat creams </li></ul><ul><li>Bandaging to support the painful region </li></ul><ul><li>Resting the body </li></ul><ul><li>Getting the sufferer to relax </li></ul><ul><ul><li>deep breathing exercises </li></ul></ul><ul><ul><li>distracting the attention </li></ul></ul><ul><li>Pain-killing medicines (analgesics): paracetamol, codeine non-steroidal anti-inflammatory, morphine if necessary </li></ul>
  17. 18. <ul><li>Taking folic acid daily to help make new red cells </li></ul><ul><li>Daily penicillin until age six to prevent serious infection </li></ul><ul><li>Drinking plenty of water daily (8-10 glasses for adults) </li></ul><ul><li>Avoiding too hot or too cold temperatures </li></ul><ul><li>Avoiding over exertion and stress </li></ul><ul><li>Getting plenty of rest </li></ul><ul><li>Getting regular check-ups from knowledgeable health care providers </li></ul>Daily Preventive Measures
  18. 19. Treating Complications <ul><li>Pain-killing drugs and oral and intravenous fluids </li></ul><ul><ul><li>To reduce pain and prevent complications. </li></ul></ul><ul><li>Transfusions </li></ul><ul><ul><li>Correct anemia </li></ul></ul><ul><ul><li>Treat spleen enlargement in children before the condition becomes life-threatening </li></ul></ul><ul><ul><li>Regular transfusion therapy also can help prevent recurring strokes in children at high risk of crippling nervous system complications. </li></ul></ul>
  19. 20. <ul><li>Hydroxyurea </li></ul><ul><ul><li>The first effective drug treatment for adults with severe sickle cell anemia reported in early 1995 </li></ul></ul><ul><ul><li>Daily doses of the anticancer drug, hydroxyurea, reduced the frequency of painful crises, acute chest syndrome, needed fewer blood transfusions </li></ul></ul><ul><ul><li>Increases production of fetal hemoglobin in the blood </li></ul></ul><ul><ul><ul><li>Fetal hemoglobin seems to prevent sickling of red cells </li></ul></ul></ul><ul><ul><ul><li>cells containing fetal hemoglobin tend to survive longer in the bloodstream </li></ul></ul></ul>Developing Treatments
  20. 21. <ul><li>Bone marrow transplantation </li></ul><ul><ul><li>Shown to provide a cure for severely affected children with sickle cell disease </li></ul></ul><ul><ul><li>Only about 18 percent of children with sickle cell anemia are likely to have a matched sibling. </li></ul></ul>Developing Treatments
  21. 22. <ul><li>The Ultimate Cure? </li></ul><ul><li>Gene Therapy </li></ul><ul><li>Correcting the “defective gene” and inserting it into the bone marrow </li></ul><ul><li>Turning off the defective gene and simultaneously reactivating another gene that turns on production of fetal hemoglobin. </li></ul><ul><li>No real cure for Sickle Cell Anemia at this time. </li></ul><ul><li>“ In the past 30 years, the life expectancy of people with sickle cell anemia has increased. Many patients with sickle cell anemia now live into their mid-forties and beyond.” </li></ul>