A 60-year-old woman ecomplains of fatigue, back pain, and passing red urine in t
ID: 197453 • Letter: A
Question
A 60-year-old woman ecomplains of fatigue, back pain, and passing red urine in the morning but not at other times of the day Manual differential counts: WBC: 4.3 x 10L RBC: 2.02x10/ Hgb: 6.2 g/dL Hat: 17.9% MCV: 88.6 I1 MCH: 30.7 pg MCHC: 34.6 g/dL PLT: 109.6x 10/L 1. What is the significance of the cell counts, indices, and peripheral blood smear image shown? The results of the proposed additional tests were as follows Relative reticulocyte count 93 Elevated serum indirect bilirubin and LDH activity, abnormally low haptoglobin level Flow cytometric testing patient's RBCs and granulocytes lacked GPI-anchored peoteins (CD55 and CD59), whereas all control materials provided appaopeiate results Hemosiderin was detected in urine sediment with Prussian blue staining. 2. Based on all the data provided, what condition is confinmed? 3. How would the bone marrow respond? 4. What information is most diagnostic? S, In addition to the presence of hemosiderin in the urinary sediment, what other laboratory test results could be used to help confirm intravascular hemolysis?Explanation / Answer
Haptoglobins bind free hemoglobin released from erythrocytes with high affinity and thereby inhibits its oxidative activity .
In clinical tests, the level of haptoglobin [Hp] is used to screen for and monitor hemolytic anemia. In this disease, free hemoglobin is released into the circulation and Hp binds the hemoglobin. This causes a decline in Hp levels. But it is observed that in extravascular hemolysis too the Hp levels can decrease. This happens because the retinoendothelial system can also release hemoglobin in the blood sysem. Therefore , haptoglobin level is not a very reliable way to differentiate between intravascular and extravascular hemolysis.
Hemoseridine is an iron storage complex found within the cells. Haemosiderin often forms after haemorrhage. When there is bleeding, the RBCs die and the hemoglobin is released into the extracellular space. Macrophages engulf the hemoglobin to degrade it , producing hemosiderin and biliverdin. Excessive accumulation of hemosiderin might occur in the liver cells, lungs, spleen, kidneys, lymph nodes and bone marrow. Hemosiderin may deposit in diseases associated with iron overload.
The pathology which leads to the diagnosis of the disease as intravascular hemolysis is increased total bilirubin, which is mostly indirect [ unconjugated] bilirubin . This happens when the porphyrin ring of hemoglobin is converted into unconjugated bilirubin within macrophages. In intravascular hemolysis RBCs lyse in the circulation releasing hemoglobin into the plasma . The fragmented RBCs are called schistocytes.
Since the RBCs have ruptured , their shape will be changed. Therefore,the blood smear will show the changed shape of RBCs which are actually only the membrane remnants [ because they have ruptured and released their hemoglobin] , and maybe presence of erythroparasites. This will confirm the disease as intravascular hemolysis.
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