SECTION 11 BL0OO Upper Gastrointestinal Bleeding A 30-year-old man,a middle-managenent executive,consults his physician in a state of panic because for the last 2 weeks his stools have been internittently hlack. Although he had considered himself healthy,he in fact has heen aware of daily epigastric discomfort and pain over the last 2 years.His distress occurred at first late in the afternoon and more recently also in the niddle of the night,awakening him from sleep.le has been relieving the pain by eating food or by taking Tums, tablets of calcium carbonate,but he has taken no other medicatfons.In the past week.the patient has also noticed that he becomes short of breath (dyspneic)whem he clihs a flight of stairs.The patient has been under considerable stress at work, he drinks very few alcoholic beverages,but he is a heavy cigarette smoker. The physician notes that the patient is exceptionally pale:the pallor is nost obvious in the conjunctivae and the nail heds.Except for a resting heart rate of 100 beats/min (a slightly high value)and doubtful tenderness on palpation of the epigastrium.the patient's physical examination is unremarkable.Stool obtained by rectal examination is indeed black.and a guaiac test,perforned on the stool to check for blood,is positive. 1.An immediate concern is whether the patient's pallor,dyspnea,and marginally elevated heart rate are related to the presence of blood in the stool.To assess this possibility.what laboratory studies would you order imediately? 2.The patient's hematocrit was 21$hemoglobin was 6 g/dl,and the red blood cell count was 4 nillion/4L.What can you deduce from these values? 3.Hypochromic microcytic anemia is commonplace in patients with chronic blood loss and reflects depletion of the iron stores needed for hemoglobin symthesis.If the patient had lost blood in a single brief event (e.g..had he vonited a substantial anount of blood).the hematocrit would have fallen.but the red blood cells and
SECTION II BLOOD Upper Gastrointestinal Bleeding A 30-year-old man, a middle-management executive, consults his physician in a state of panic because for the last 2 weeks his stools have been intermittently black. Although he had considered himself healthy, he in fact has been aware of daily epigastric discomfort and pain over the last 2 years. His distress occurred at first late in the afternoon and more recently also in the middle of the night, awakening him from sleep. He has been relieving the pain by eating food or by taking Tums, tablets of calcium carbonate, but he has taken no other medications. In the past week, the patient has also noticed that he becomes short of breath (dyspneic) when he climbs a flight of stairs. The patient has been under considerable stress at work, he drinks very few alcoholic beverages, but he is a heavy cigarette smoker. The physician notes that the patient is exceptionally pale; the pallor is most obvious in the conjunctivae and the nail beds. Except for a resting heart rate of 100 beats/min (a slightly high value) and doubtful tenderness on palpation of the epigastrium, the patient's physical examination is unremarkable. Stool obtained by rectal examination is indeed black, and a guaiac test, performed on the stool to check for blood, is positive. 1. An immediate concern is whether the patient's pallor, dyspnea, and marginally elevated heart rate are related to the presence of blood in the stool. To assess this possibility, what laboratory studies would you order immediately? 2. The patient's hematocrit was 21 %, hemoglobin was 6 g/dL, and the red blood cell count was 4 million/µL. What can you deduce from these values? 3. Hypochromic microcytic anemia is commonplace in patients with chronic blood loss and reflects depletion of the iron stores needed for hemoglobin synthesis. If the patient had lost blood in a single brief event (e.g., had he vomited a substantial amount of blood), the hematocrit would have fallen, but the red blood cells and
henoglobin level would have been reduced in proportion.Because hypochromic microcytic anemia can occur in conditions other than blood loss,several tests could be ordered to confirm the original diagnosis.Which tests might be ineluded? 4.The patient was examined by a gastroenterologist,who pointed out that black stools usually result from bleeding high in the gastrointestinal tract:if the bleeding were from lower in the gastrointestinal tract,the hemoglobin would not have been degraded to a black derivative.The physician postulated that the patient had bled from the peptic ulcer and confirmed this finding by direct visualixation of the lesion through a flexible gastroscope.Although tempted to perform a transfusion.the physician instead prescribed medication to treat the ulcer.and ferrous sulfate.to be taken by mouth,to treat the anenia.What was the rationale for this maneuver? 5.How is the efficacy of therapy assessed? ANSVER 1.A complete blood coumt including hematocrit (the proportionate volume of red blood cells in a given volume of blood.measured after blood is centrifuged in a standardized way).hemoglobin levels,red and white blood cell counts,platelet count,and examination of a stained blood smear. 2.The red blood cell count is only slightly below normal.but the henstocrit and the concentration of hemoglobin are sharply reduced.These findings are typical of hypochromic microcytic anemia,that is,amemia in which the number of red blood cells is reduced,and,on average,the henoglobin content of individual red blood cells is also reduced. 3.(a)Examination of a stained blood smear.This would comfirm the diagnosis, because the red blood cells would be excessively pale,and their size and shape, normlly monotonous,nay vary widely.(b)Measurement of the concentrations of serum iron and of its carrier protein,transferrin (iron-binding globulin).In this case, serun iron was drastically redaced.and the concentration of iron-binding globulin
hemoglobin level would have been reduced in proportion. Because hypochromic microcytic anemia can occur in conditions other than blood loss, several tests could be ordered to confirm the original diagnosis. Which tests might be included? 4. The patient was examined by a gastroenterologist, who pointed out that black stools usually result from bleeding high in the gastrointestinal tract; if the bleeding were from lower in the gastrointestinal tract, the hemoglobin would not have been degraded to a black derivative. The physician postulated that the patient had bled from the peptic ulcer and confirmed this finding by direct visualization of the lesion through a flexible gastroscope. Although tempted to perform a transfusion, the physician instead prescribed medication to treat the ulcer, and ferrous sulfate, to be taken by mouth, to treat the anemia. What was the rationale for this maneuver? 5. How is the efficacy of therapy assessed? ANSWER 1. A complete blood count including hematocrit (the proportionate volume of red blood cells in a given volume of blood, measured after blood is centrifuged in a standardized way), hemoglobin levels, red and white blood cell counts, platelet count, and examination of a stained blood smear. 2. The red blood cell count is only slightly below normal, but the hematocrit and the concentration of hemoglobin are sharply reduced. These findings are typical of hypochromic microcytic anemia, that is, anemia in which the number of red blood cells is reduced, and, on average, the hemoglobin content of individual red blood cells is also reduced. 3. (a) Examination of a stained blood smear. This would confirm the diagnosis, because the red blood cells would be excessively pale, and their size and shape, normally monotonous, may vary widely. (b) Measurement of the concentrations of serum iron and of its carrier protein, transferrin (iron-binding globulin). In this case, serum iron was drastically reduced, and the concentration of iron-binding globulin
was elevated.These findings help to distinguish iron deficiency anemia froa certain other anemias,such as those caused by hereditary disorders of henoglobin synthesis and strueture.(c)Measurement of serum ferritin,which is diminished in patients with low iroe stores even before the falling hematocrit.(d)Exanination of bone marrow by using stains that detect iron.In this patient,no iron could be detected, as if the loss of iron were not acute but of long standing. 4.Ferrous sulfate is readily absorbed from the lumen of the duodenun The iron, attached to plasm transferrin,is carried to erythrocyte precursors in marrow. where it is internalized,separated from the carrier protein,and used for synthesis of heme. 5.If bleeding continues.this may he difficult to do.If appropriate therapy of peptic ulcer is successful,administration of iron may be followed within days by a rise in the mumber of reticulocytes in peripheral blood as newly formed erythrocytes enter the blood strean Within about 2 weeks the red blood cell count, hemoglohin levels,and hematocrit all rise
was elevated. These findings help to distinguish iron deficiency anemia from certain other anemias, such as those caused by hereditary disorders of hemoglobin synthesis and structure. (c) Measurement of serum ferritin, which is diminished in patients with low iron stores even before the falling hematocrit. (d) Examination of bone marrow by using stains that detect iron. In this patient, no iron could be detected, as if the loss of iron were not acute but of long standing. 4. Ferrous sulfate is readily absorbed from the lumen of the duodenum. The iron, attached to plasma transferrin, is carried to erythrocyte precursors in marrow, where it is internalized, separated from the carrier protein, and used for synthesis of heme. 5. If bleeding continues, this may be difficult to do. If appropriate therapy of peptic ulcer is successful, administration of iron may be followed within days by a rise in the number of reticulocytes in peripheral blood as newly formed erythrocytes enter the blood stream. Within about 2 weeks the red blood cell count, hemoglobin levels, and hematocrit all rise