1. A Case of Anaemia Lent term year 1

2. The case 21 year old Afro-Caribbean man Admitted with abdominal pain and priapism

3. Priapus: son of Aphrodite

4. Why does this occur?

5. Sickle Cell Disease Sickle cell disease is a common haemolytic disorder in black races. It is due to the presence of HbS, caused by a single base mutation from adenine to thymine on Chromosome 11. This produces a substitution of valine for glutamine at the 6 th codon of the  -globin chain.

6. Haemoglobin Normal adult Hb (HbA) consists of 2  and 2  polypeptide globin chains. These fold in a quaternary structure to enfold a haem group. Hb S is less soluble than Hb A and, when deoxygenated, undergoes polymerisation, leading to the formation of sickle shaped cells.

9. What is the cause of his symptoms?

10. Symptoms in Sickle cell disease: Vascular occlusion due to sickle cells lodging in capillaries. This can occur in any part of the body, causing a “sickle crisis”. Typically these can cause bone pain, pleuritic pain, cerebral infarcts, priapism and hepatic pain with fever. Long term complications can occur, including susceptibility to strp. Pneumoniae infection, chronic leg ulcers, aseptic necrosis of bone, blindness and chronic renal disease. Gallstones occur from pigment due to persistent haemolysis.

11. Sickle cells block the capillaries

12. Also: A normal blood cell lives for around 120 days Sickle cells do not live as long, and break up more easily (Haemolysis) This leads to a chronic state of anaemia

13. What investigations would you arrange?

14. Investigations A full blood count: Hb 6-8g/dl with high reticulocyte count. Blood film: Sickling of rbcs induced by sodium metabisulphite. Sickledex is a commercial test where sodium dithionite gives a turbid appearance to HbS, wheras normal Hb remains clear. Hb electrophoresis. No HbA, 80-95% Hb SS, 2-20% HbF

16. Sickle cell testing

17. electrophoresis

18. What is the immediate treatment?

19. treatment Maintain hydration with IV fluids, oxygen via face mask analgesia, usually with opiates. Consider underlying cause, such as sepsis. Priapism may be treated with normal saline washouts of corpora cavernosa and direct injection with  adrenergic agent, such as methoxamine or phenylephrine (unlicenced).

20. What about other causes of anaemia??

21. Classification of anaemia: 1.Haemoglobinopathies 2.Haemolytic- blood cells breaking up 3.Aplastic- blood cells not being made 4.Blood loss 5.Nutrient deficiency

22. Haemoglobinopathies: remember normal adult Hb has 2 α and 2β chains Sickle cell Disease HbS: both β chains abnormal Sickle cell “trait” heterozygous form. OK unless stressed in oxygen requirements e.g scuba diving, GA Sickle SC disease Thalassaemia

23. Underproduction of one or more of the globin chains α Thal: underproduction of α chains Β Thal: underproduction of β chains May have traits (heterozygous)- usually healthy May have Hb SThal See http://www.europeanhbregistry.org.uk/information /thalassaemia.html http://www.europeanhbregistry.org.uk/information /thalassaemia.html

24. Haemolytic Disease: congenital Sickle cell Spherocytosis: autosomal dominant G6PD deficiency (fava beans)

25. Haemolytic disease: acquired Haemolytic disease of newborn (Rhesus disease) Drug-induced e.g penicillin, quinine Autoimmune Infection e.g malaria Alloimmune: blood transfusion reactions

26. Aplastic anaemia: failure of bone marrow Congenital: Fanconi’s anaemia Acquired: autoimmmune viral e.g. parvovirus in fetus drugs e.g. chloramphenicol chemotherapy radiation Make diagnosis by examining the bone marrow

27. Blood loss (acute or chronic) Many diseases cause chronic blood loss: peptic ulceration menorrhagia worm infestation carcinoma of colon (esp. caecum)

28. Nutrient deficiency Iron- may be linked to chronic blood loss or malabsorption as well as diet Most common B12- may be linked to malabsorption e.g coeliac disease, pernicious anaemia (auto- immune disease with antibodies to intrinsic factor) Folate- poor diet, drugs e.g Trimethoprim, malabsorption e.g coeliac, Crohn’s

29. Sources of iron: red meat, eggs, chocolate, wine, cereals. Bioavailability may be affected by other foods

30. B12: meat products especially liver. Also shellfish

31. Folic acid: fruit & veg