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Select the ONE answer that is BEST in each case.
A 4-month-old infant is anemic with a hemoglobin level of 9.5 g/dL and MCV 77 fL. The baby looks well, the height and weight growth parameters are normal, and she is breastfeeding well. Which of the following is the most likely cause for her anemia?
Iron deficiency is the most common cause of anemia in infancy. Sixty percent of body iron concentration at birth is contained in circulating Hb. Milk is a poor source of iron, so the most common cause of iron deficiency in infancy is prolonged breast or bottle feeding. Cereals are high in iron content.
Which of the following is the most likely effect of increased levels of red blood cell 2,3 diphosphoglycerate (2,3-DPG)?
The 2,3-bisphosphoglycerate (2,3-BPG) binds to the central cavity of the heme molecule and changes the configuration in favor of oxygen release. The other common factors that affect oxygen affinity are temperature and pH. The oxygen affinity of Hb is easily characterized by P50; the oxygen tension at which Hb is half-saturated.
A 63-year-old man is involved in a motor vehicle accident and is brought to the hospital. On examination, his blood pressure is 90/60 mm Hg, pulse 110/min, and his abdomen is distended and rigid. He has internal injuries and bleeding on an abdominal CT scan, and requires emergent blood transfusion on his way to the operating room. His blood group is AB. Which of the following statements is not correct?
Group AB has neither anti-A nor anti-B antibodies, as both A and B antigens are on the red cells. Persons with type AB blood are considered “universal recipients.” It is a rare blood group (only 2–3% of population); if large amounts of blood are required in an AB individual, any type of blood (A, AB, B, O) can be used as long as the plasma is removed from the donor blood (in other words packed RBCs are used).
A 60-year-old man notices right-sided chest pain after sneezing. The pain is made worse with breathing, but he reports no fever, sputum, or cough. Recently, he has been experiencing back discomfort and easy fatigue on exertion. On examination, the heart sounds are normal and lungs are clear. The left 6th rib is tender on palpation. X-rays of his chest are shown in Fig. 5–3 a and b. Which of the following is the most likely diagnosis?
There is lytic destruction of the 6th rib with a pathologic fracture and an extrapleural mass. The most common manifestation of multiple myeloma is multiple, “punched-out” lesions in the flat and tubular bones. Some may appear as discrete lytic lesions and remain as solitary lesions.
A 36-year-old woman with sickle cell disease presents with increasing pain in her right hip. She has no fever, chills, back or other bone pain, and there is no history of any trauma. On examination, her temperature is 37.3C, range of motion in the right hip is reduced, she walks with a limp, and the right leg is shorter than the left. Movements of the hip and walking on it are painful. X-rays of the hip are shown in Fig. Which of the following is the most likely diagnosis?
The diagnosis is AVN of the femoral head. Bone complications occur frequently in patients with sickle cell anemia. Infarcted areas of bone and bone marrow can become sites of infection (osteomyelitis) with Staphylococcus aureus or salmonella, but the lack of fever and clinical signs in this patient suggest AVN. Infarction of the femoral head nutrient artery leads to AVN and chronic joint pain. The humeral head is also at risk of AVN. Septic arthritis is a less common complication.
A 30-year-old woman presents with increasing fatigue, but no other symptoms. On examination the conjunctivae are pale, her sclera are icteric, blood pressure 110/70 mm Hg, pulse 110/min, lungs clear, and heart sounds normal. Castell’s sign is negative and no spleen is palpable. Her hemoglobin is 6 g/dL, and the rest of the laboratory workup is shown in Table 5–1. Which of the following is the most likely diagnosis?
Autoimmune hemolytic anemia is the most likely diagnosis. Spherocytosis is seen as well in burn victims, in microangiopathic hemolysis, and in congenital spherocytosis.
Inhibits platelet activation induced by ADP
Clopidogrel is an ADP-receptor blocker, and inhibits platelet activation induced by ADP. This results in a prolongation of bleeding time that is greater than that produced by acetylsalicylic acid (ASA). The effects last for 4–10 days after discontinuation. Clopidogrel is a prodrug that relies on an active metabolite for its effect, and is marginally more effective than ASA for certain conditions like stroke and acute coronary syndrome. The effect on bleeding time is additive to that of ASA.
Depletes platelet arachidonic acid
Fish oils cause a slight prolongation of the bleeding time. The mechanism is twofold: they reduce platelet arachidonic acid, and as well they compete with arachidonic acid for cyclooxygenase. Other foods that may affect platelet function include garlic, onions, and black tree fungus (found in Chinese cuisine).
A 23-year-old man has recurrent episodes of mild back and chest pain, whenever he is ill. His physical examination is normal. The hemoglobin level is 9 g/dL, MCV 85 fL, and platelets 250,000/mL. His blood film shows characteristic red cell morphologic changes that have hemoglobin units polymerizing in long chains under hypoxic stress as the underlying mechanism.
A number of factors influence the rate and degree of HbS aggregation, including concentration of HbS in the cell, cellular dehydration, and the length of time in deoxyconformation
A 32-year-old man has a mild anemia diagnosed on routine testing. He has no symptoms and feels fine. His clinical examination is normal, and a blood film reveals some target cells with some red cells having intraerythrocytic crystals.
The patients with homozygous HbC disease have mild hemolysis, splenomegaly, target cells, and HbC crystals. Unlike sickle cell disease, the prognosis is favorable.
A 4-month-old baby has developed feeding problems and diarrhea. Laboratory evaluation reveals severe anemia with hemoglobin of 7 g/dL. The blood film shows hypochromic microcytic cells and target cells. In this disorder, decreased beta-chain production leads to excess alpha-chain production and destruction of red cell precursors.
In beta-thalassemia, there is excess production of alpha-chains, which precipitate and destroy red cell precursors.
A 4-year-old boy has a chronic microcytic anemia, but no other symptoms. His physical examination is normal except for splenomegaly. His condition is due to decreased alpha-chain production, which leads to four beta-chain tetramer formation (HbH).
HbH (four beta-chains) most commonly results from the compound heterozygous state for alpha-plus-thalassemia and either deletion or nondeletion alpha-plus-thalassemia. However, the phenotypic expression of the disease is quite variable.
A 27-year-old woman complains of constant back pain. She recently had an episode of severe chest and back pain that required narcotic medications, blood transfusions, and lots of fluids to treat. On examination, she is afebrile, with midthoracic tenderness on palpation. X-rays of the spine reveal periosteal reaction of the eighth thoracic vertebra She has a chronic blood disorder where bone infarction can occur that may be difficult to distinguish from osteomyelitis.
If the bone infarction occurs in proximity to a joint, an effusion can develop. The underlying pathology is a vaso-occlusive phenomenon. Bone infarction can appear like osteomyelitis (radiographically and clinically), which is problematic since patients with sickle cell disease are also at increased risk of osteomyelitis.
A 24-year-old pregnant woman is found to be anemic.
The megaloblastic anemia of pregnancy is the most common of all folate-deficient states. Dilutional anemia and iron deficiency also occur in pregnancy. In pregnancy, a low Hb concentration may simply be due to a disproportionate increase in plasma volume, rather than a true anemia. The exact hormonal mechanism is unknown. Folate levels fall during pregnancy; therefore, frank deficiency is most common in the third trimester.
A 32-year-old woman has had a previous child with beta-thalassemia. She has just been confirmed as being 6 weeks pregnant. She is worried that the current pregnancy may also be affected. Which of the following methods is most likely to establish an accurate prenatal diagnosis?
Chorionic villus sampling in the first trimester with deoxyribonucleic acid (DNA)- based diagnosis has a high degree of accuracy. Cord blood electrophoresis is suitable for screening high-risk infants at birth.
A 27-year-old female presents with easy fatigue and light-headedness. She also has a dry cough and fever for the past few days. On examination, she is pale, her lungs are clear, and the rest is normal. A chest x-ray (CXR) shows patchy bilateral infiltrates; the hemoglobin is 8.4 g/dL, reticulocyte count of 6%, and many spherocytes on the peripheral blood film. Which of the following is the most likely significance of the spherocytosis on the blood film?
Spherocytes are seen on the blood film in patients with moderate to severe hemolytic anemia. This patient has autoimmune hemolytic anemia due to cold agglutinins related the pneumonia. Spherocytosis is not associated with G6PD deficiency, trauma, or leukemia. The typical changes in G6PD deficiency include the presence of Heinz bodies. The cell morphology is not usually changed unless hemolysis is very severe. In hereditary spherocytosis, the Coombs’ test is negative.
A 25-year-old woman is pregnant for the first time. At prenatal assessment, she is found to have blood group A and Rh(D)-negative. Her husband is tested and he is Rh(D)-positive. Which of the following is the most appropriate initial test to determine her risk for hemolytic disease of the newborn (erythroblastosis fetalis) due to Rh incompatibility?
Testing the mother for the presence of Rh(D) antibodies (alloimmunization) is done by indirect Coombs’ test of the maternal serum with known Rh(D) positive cells. Prevention of Rh immunization by the administration of Rh antibody (via Rh immune globulin) has been an effective preventive measure for this disorder. This condition is usually associated with a positive Coombs’ test using the baby’s RBCs and a positive indirect Coombs’ test using the mother’s serum. ABO hemolytic disease of the newborn is clinically mild because the antigens are not fully expressed in utero.
A 63-year-old man presents with fatigue, shortness of breath on exertion, and easy bruising. He has no prior history of bleeding disorders, and is not taking any medications. On examination, his conjunctivae are pale, he has palpable spleen, and there are multiple bruises and petechiae on his legs. A CBC reveals a hemoglobin of 8.3 g/dL, WBC of 2300/mL, and platelets of 30,000/mL. A blood film also shows multiple lymphocytes with prominent cytoplasmic projections. A bone marrow biopsy also shows similar cells in the marrow and marrow fibrosis. Which of the following is the most likely diagnosis?
This patient has hairy cell leukemia, which is a rare form of adult of leukemia (2–3%). The disease is characterized by “hairy” cells in blood and bone marrow, splenomegaly, and pancytopenia. The lymphocytes have characteristic cytoplasmic projections, which give the disease its name. Treatment with the purine analogue, such as cladribine, produces complete remission in hairy cell leukemia. Recombinant alphainterferon is not as effective.
A 22-year-old long-distance runner is found to be mildly anemic. He is asymptomatic; his stool is negative for occult blood, and the ferritin level is 200 ng/mL. Which intervention is most likely to result in return of the hemoglobin to normal?
Supportive footwear will decrease the likelihood of “march” hemolysis, but this rarely causes anemia. Similarly, although 20% of longdistance runners have GI blood loss, this is rarely of a magnitude to explain anemia. Most elite athletes have increases in both plasma volume and red cell mass, but the increase in plasma volume is greater, resulting in a dilutional-type anemia. This is physiologically beneficial (increased O2 transport with increased blood fluidity), so there is no reason to cease exercising to correct the Hb.
A 49-year-old man presents with jaundice, nausea, and vomiting. He has a history of chronic alcoholism, and is currently drinking over one bottle of red wine a day. On physical examination, he is jaundiced and pale with a large tender liver. Laboratory data include hemoglobin of 9 g/dL, WBC of 4200/mL, and platelet count of 80,000/mL. His liver enzymes and bilirubin are also elevated. Ultrasound of the abdomen reveals liver enlargement with no bile duct obstruction, a normal size spleen, and no ascites. Which of the following is the most likely toxic effect of alcohol on the bone marrow?
Alcohol is directly toxic to dividing and maturing cells, but may also affect neutrophil function. The hematologic effects of alcohol may be direct or indirect, via diet, infection, liver disease, and GI disease. The resulting hematologic abnormalities may be profound.
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