Clinical Biochemistry and Haematology - Essay Example

Clinical Biochemistry and Haematology Insert (s) Clinical Biochemistry and Haematology Case study 1 1. What is the differential diagnosis? (20 marks) Based on John’s clinical history and the presented signs and symptoms, the underlying pathology of his condition is most likely to be caused by autoimmune haemolytic anaemia. There is however a number of other likely diagnoses that should be taken into consideration before an appropriate treatment and management plan are selected (Beck, 2009, p.45). One of the differential diagnoses is Sideroblastic anaemia. Generally Sideroblastic anaemia is condition where by the bone marrow is unable to produce healthy red blood cells (erythrocytes) and thereby resulting into haematological malignancies. Sideroblstic anaemia can either ne inherited or acquired but in Johns case, an inherited disease is ruled out because he is already 64 years old and has never experienced any related disorder. Vitamin B6 and copper deficiencies are some of the likely precipitants of sideroblastic anaemia. Another probable diagnosis for John’s condition is Zieves syndrome but the condition can also be ruled out in John’s case because he has no history of prolonged alcohol abuse. John’s condition can therefore be diagnosed as autoimmune haemolytic anaemia. The diagnosis of John’s case was confirmed by the results of the Comb’s test which was carried out. For example, the test revealed some aggregation in the red blood cells and is likely to have been caused by action of antibodies against the red blood cells. 2. Explain the significance of the full blood count and biochemistry results (20 marks) The results of full blood count (FBC) are significantly important in the determination of an individual’s health status, assessment of drug treatment and dietary deficiencies as well as during the diagnosis of a number of hematologic conditions. On the other hand, blood biochemistry tests such as Comb’s test can effectively be used to check for a number of abnormalities in the body chemistry (Blann, 2007, p.56). In most haematology laboratories, full blood count and biochemistry tests are some of the widely used wide screening methods that are often applied to check for the presence of disorders such as anaemia(decreased haemoglobin or red blood cells), infections as well as a number of other common diseases that can be manifested in different parts of the blood. FBC may also be requested or performed in a number of other more specific situations such as to determine the severity of blood loss in an individual, help diagnose diseases such as anaemia and leukaemia, monitor the response to some types of drug treatment as well as to investigate the history of abnormal clotting or bleeding. Healthy individuals are generally expected to have their blood cell populations within the normal limits and therefore a doctor may order a full blood count for a person having the symptoms associated with anaemia such as weakness and jaundice to help diagnose the cause. On the other hand, platelet count can be used to determine the number of platelets in a particular volume of blood. The average platelets volume in a healthy person is 150 - 400 x 109/L and low platelet count is generally used to confirm the cause of blood clotting problems or excessive bleeding associated with diseases of bone marrow such as leukaemia. Packed Cell Volume (PVC) or haemotocrit (Hct) is a measure of the red blood cell percentage to the total blood volume in the body and as a result when there is a low haematocrit it will be an indication of anemia, loss of blood or even bone marrow failure (Schwartz, 2011, pp.163). 3. What is the origin of the abnormalities seen on the blood film? (20 marks) A number of abnormalities such as the presence of polychromasia and spherocytes were detected on John’s blood film. Polychromasia is an abnormality of red blood cells in which the erythrocytes appear greyish blue when a blood smear is examined under a microscope. This condition is normally detected through the use of stains that usually changes the colour of the affected red blood cells and is largely attributed to the presence of young immature red blood cells in a patient’s blood (James, 2009, p.277). Poluchromatic red blood cells often stain dark blue or gray and tare therefore distinguishable from the normal blood cells as shown in the figure below. Figure1: Polychromasia as seen in a blood film One of the possible origins of this blood abnormality is the presence of haemolytic anaemia in the patient leading to the destruction of mature red blood cells. When there is a reduction in the number of mature red blood cells in the blood, the brain usually signals the kidneys to produce more erythropotein hormones and a rise in the level of erythropoietin may then signal the re3lase of young and immature red blood cells into the blood thereby resulting into polychromasia. Lastly, the likelihood that polychromasia in John’s blood was caused by autoimmune haemolytic anaemia was further confirmed by the results of Coombs test that showed some aggregation in the blood cells (Blann, 2007). Spherocytes are another important abnormality that was detected in John’s blood. Unlike, polychromasia, this abnormality is characterized by red blood cells which appear to be smaller and less denser compared to their normal counterparts. The increased density is particularly caused by loss of the erythrocytes’ normal biconcave shape while the smaller sizes of spherocytes is caused by the partial loss of their cell membrane. Fugure2: Spherocytes in a blood film Generally Spherocytosis has many origins including the patient might have had a hereditary spherocytosis. In some cases the main reason might have been immune haemolytic anaemia or if the patient suffered from Zieve’s syndrome or even if he had Microangiopathic haemolytic anaemia this would have led to the patient having spherocytosis. The clinical history of John however confirms that the presence of spherocytes in his blood smear was likely to be attributed to immune haemolytic anaemia. 4. Explain the underlying pathology of John’s condition and comment on any likely causes for this based on his history (40 marks) Based on John’s clinical history, the underlying pathology of his condition is likely to be caused by autoimmune haemolytic anaemia. The diagnosis of John’s case was particularly confirmed by the results of the Comb’s test which revealed some aggregation in the red blood cells and is likely to have been caused by action of antibodies against the red blood cells. Immune mediated haemolytic anaemia refers to a condition whereby an individual’s immune system produces antibodies that attacks his own red blood cells. Just as was seen in John’s condition, the destruction of many red blood cells in a patient usually results in a anaemia which is normally characterized by a feeling of weakness and dizziness among other symptoms (Mehta and McIntyre, 2004, p.1786). On the other hand, because the red blood cells of the patient were being lost internally without any bleeding, John’s physical examination also revealed the presence of jaundiced sclera rather than the normal pale colour. The iron contained in the destroyed red blood cells is usually sent to the liver in the form of a yellow pigment known as bilirubin. For example, as shown in the history of the patient, there is a high level of bilirubin and this is likely to be attributed to the increased breakdown of hemoglobin. The enlarged and palpable spleen as was seen in the physical examination of John’s condition can be best explained by the fact that human spleen usually enlarges itself when it finds itself processing a large number of damaged blood cells that it normal does. Lastly, the patient’s quick response to corticosteroids and folic acid (immune suppressive medications) treatment was also another important confirmation that the pathology of the condition was associated with immune mediated haemolytic anaemia. Case study 2 1. What is your differential diagnosis of Claire’s acute condition based on the above information? What clinical investigation could be carried out to confirm the acute problem? (10) Although Claire’s clinical history indicates that she is most likely to be suffering from deep vein thrombosis (DVT), there are quite a number of other potential diagnoses of her acute condition some of which include pulmonary embolism and thrombophlebitis (Beck and Francis, 2005, p.76).Unlike deep vein thrombosis, pulmonary embolism is usually characterized by a blockage of the major lung artery or one of its branches by a blood clot, fat, air or substance that has travelled from the other parts of the body (Arnout, 2003, p.102). Despite the fact that a number of Claire’s clinical symptoms such as severe chest pains and low blood oxygen saturation were consistent with PE, the condition was ruled out by the results of ECG, chest radiograph and coagulation screen which were all normal. On the other hand, thrombophlebitis is another important differential diagnosis of Claire’s condition that is usually manifested by an inflammatory development of a thrombus inside a vein. Patients suffering from this condition may however develop phlebitis. 2. Explain the aetiology of the chest pain which Claire is suffering (10) A deep vein thrombosis is a condition in which a blood clot is formed in individual’s veins of the leg and may be subsequently transported to the other parts of the body such as the lungs through the blood stream (Chee and Watson, 2005, p.678). Although DVT usually happens in the legs, it can also develop or other areas such as the chest, arms or other parts of the body. With regard to the etiology of Claire’s condition, there are a number of probable causes some of which include her previous history of pulmonary embolism or deep thrombosis and inherited blood clotting problem. Additionally the long plane flight is also likely to have been aggravated by economy class syndrome which is normally attributed to long flights such as the one she had during her travel from Malaysia back to UK. Venous stasis which leads to DVT is mostly attributed by the prolonged immobilization, obstruction of the venous return by compression of the lower limb veins and as part of a general reduction in blood flow especially as a result of the in-flight dehydration. 3. Discuss the clinical rational for the request for D-dimer testing (30) D-dimer is a blood test that measures the concentration of d-dimer in the bloodstream of a patient. The determination of the D-dimer concentration in the body can effectively be used to rule out the presence of a number of conditions such as deep venous thrombosis (DVT), pulmonary embolism and myocardial infarction. D-dimer is mostly determined by a blood test that is done in order to help diagnose thrombosis. The main purpose o the d-dimer is to perform the test to patients that are suspected of having thrombotic disorders. The rationale is that the diagnosis, if negative will rule out the presence of thrombosis. On the other hand, if the result is positive it will indicate the presence of thrombosis but this will not eliminate other causes. The main purpose of the d-dimer test is to exclude the thrombo embolic disease in the scenarios where their probability is quite low. Furthermore the d-dimer test can be used in the diagnosis of disseminated intravascular coagulation which is a blood disorder. According to Colman (2006, p.34), D-dimer analysis depends primarily on the the binding of a monoclonal antibody in relation to a particular epitope on the D-dimer fragment. Coagulation is the formation of a blood clot referred to us thrombus. The coagulation occurs when the protein of the coagulation cascade are activated. This can happen when there is a contact with a damaged blood vessel or in other cases through activation of factor VII by tissue activating factors. In both cases it will lead to development of thrombin. Thrombin is an enzyme that turns the soluble blood protein called fibrinogen into fibrin which then aggregates into proteofibrils. Thereafter another thrombin- generated enzyme, factor XIII is then cross linked between the fibrin proteofibrilis at the D fragment site. 4. How the additional information should be followed up and further tests to confirm diagnosis (10) After the revelation of additional information that Claire’s first cousin also suffered from deep vein thrombosis and another one miscarried for the second time, there are a number of tests that should be carried to confirm the diagnosis as well as determine whether the condition is hereditary. In Claires case, the new information as well as the fact that she is below 45 years old is a likely suggestion that her condition is due to her genes. According to Samama (2005, p.3418), the other important genetic risks that should also be taken into consideration include gene related abnormalities such as protein C deficiency, Antithrombin III deficiency and protein S deficiency. An individual with any of the above deficiencies is likely to have a greater risk of developing DVT if she inherited her faulty genes from both of her parents. Generally one of the new tests that should be performed to confirm the diagnosis is a genetic screening to determine possible mutations that causes Claire’s problems. The other confirmatory tests include blood tests to determine the levels of protein C and S levels. 5. Does this new information help to understand Claire’s previous pregnancy problems? Explain the pathology underlying this? (20) It will be quite resourceful for the doctor to have a prior knowledge of Claire’s family history of thrombosis to help understand her previous pregnancy problems. For example as evidenced from Claire’s cousins having miscarriage during the pregnancy, it is also likely that Claire’s past miscarriages have been caused by her underlying condition. Clotting disorders such as deep venous thrombosis often result in complications that may lead to miscarriage during pregnancy. This is particularly because DVT can cause a stillbirth or a miscarriage in the event that a blood clot is transported and lodged in the placental artery thereby reducing the supply of oxygen to the foetus (Fischbach and Dunning, 2009, p.203). In some cases, the clot may interrupt the flow of nutrients and gas exchange between the fetus and the mother leading to slow growth and late pregnancy loss. 6. What advice should be taken with regard to the following situations? (a)Taking a long-haul flights (b) the chances of her future successful pregnancies (10) With regard to taking long haul flights, I would advice Claire to avoid long international flights since such flights contribute to the formation of deep venous thrombosis in susceptible individuals like her (WHO, 2007, p.17). For example her sickness was attributed to the long flight (economy syndrome) she had during her travel from Malaysia back to UK. On the other hand, as earlier been noted, clotting disorders such as deep venous thrombosis often result in complications that may lead to miscarriage during pregnancy. Consequently to enhance her success of her future pregnancies, Claire should undergo tests to determine the levels of protein C and S levels. According to Blackburn (2007, p.23), appropriate therapies should then be taken to boost the levels of these genetic markers and improve her chances of getting a successful pregnancy. References Arnout, J. (2003). Thrombosis: fundamental and clinical aspects. Leuven: Leuven University Press. Beck, E. R. & Francis, J. L. 2005. Differential diagnosis. New York: Arco Medical. Beck, N. (2009). Diagnostic hematology. London: Springer. Blackburn, S. T. 2007. Maternal, fetal, & neonatal physiology: a clinical perspective. St. Louis, Mo, Saunders Elsevier. Blann, A. D. (2007). Routine blood results explained. Keswick: Cumbria, M&K Pub. Chee, Y.L., Watson, H.G. 2005. Air Travel and Thrombosis. Br Journal of Haemotol. 130(5), pp.671-680. Colman, R. W. 2006. Hemostasis and thrombosis: basic principles and clinical practice. Philadelphia: Lippincott Williams & Wilkins. Fischbach, F. T., & Dunning, M. B. 2009. A manual of laboratory and diagnostic tests. Philadelphia: Lippincott Williams & Wilkins. James A.H.2009. Arterioscler Thromb Vasc Biol. 29(3), pp.326-31. James A.H.2009.Hematology American Soc Hematol Educ Program 4(9,), pp.277-285. James, A. H. & Ortel, T. L. 2007. 100 questions and answers about deep vein thrombosis and pulmonary embolism. London, Class. Mehta, A.B, McIntyre, N.2004. Oxford Textbook of Clinical Hepatology. Oxford University Press. pp. 1786–1787. Samama M. 2005. An epidemiologic study of risk factors for deep vein thrombosis in medical outpatients. Archives of Internal Medicine, (160), pp.3415-3420 Schwartz, R. S. 2011. Autoimmune and intravascular hemolytic anemias In: Goldman L, Schafer AI, eds. Cecil Medicine.Elsevier; 6(4), pp.163. World Health Organization. 2007. WHO research into global hazards of travel (Wright) project: final report of phase 1. Geneva: World Health Organization. Read More