An 18-year-old man with a history of type I diabetes since age 14 presents to the clinic for further management. He notes several episodes of hypoglycemia at around 2 a.m. that awaken him from sleep since starting on his school's tennis team. He practices in the afternoon. His 8 a.m. glucose readings prior to breakfast are all greater than 200 mg/dL. His current insulin regimen is as follows: Breakfast: NPH 20 units with 5 units of regular insulin Supper: NPH 15 units with 5 units of regular insulin His average fingerstick glucose readings over the past week are as follows:Which of the following recommendations would most likely improve his glucose control?
Answer(s): B
The patient has type I diabetes, therefore oral agents are contraindicated. The glucose pattern he has is known as the Somogyi phenomenon. His increased activity has made him more insulin sensitive, especially at the time of the day that he is most at risk of hypoglycemic reactions. When NPH is given at supper time, the peak action will be ~2 a.m. Changing the timing of the NPH to bedtime, will advance the peak to ~46 a.m., a time when the patient is becoming increasingly insulin resistant (Dawn phenomenon). As his glucose is already increasing at supper, discontinuing the regular insulin at that time may avoid nocturnal hypoglycemia, but at the expense of higher glucose values. Increasing the regular insulin at breakfast will likely cause hypoglycemia prior to lunch.
A 32-year-old male is seen in the ER with a nondisplaced fracture of the ulna after a fall. Incidentally, the intern noticed that the patient is jaundiced and has a palpable spleen. He orders a CBC which shows a Hgb of 10.2 g/dL. The patient reveals that he has chronic anemia and intermittently has been prescribed iron. On further questioning, he says that he had a cholecystectomy at age 23 and that he has family members with similar symptoms. The intern reviews the peripheral smear and finds spherocytes. What would be the best way to confirm this man's diagnosis?
Answer(s): C
Hereditary spherocytosis (HS) is a familial hemolytic disorder with clinical features, ranging from an asymptomatic condition to a fulminant hemolytic anemia. The morphologic hallmark of HS is the microspherocyte, which result from membrane protein defects leading to cytoskeleton instability. Spectrin deficiency leads to loss of erythrocyte surface area, which produces spherical RBCs. Spherocytic RBCs are culled from the circulation by the spleen leading to the development of splenomegaly. Spectrin deficiency and the degree of deficiency correlate with the extent of spherocytosis, the degree of abnormality on osmotic fragility test results, and the severity of hemolysis. Hemolysis primarily is confined to the spleen and, therefore, is extravascular.Although four abnormalities in red cell membrane proteins have been identified, spectrin deficiency is the most common. Spectrin deficiency results from impaired synthesis, whereas in other instances, it is caused by quantitative or qualitative deficiencies of other proteins that integrate spectrin into the cell membrane. In the absence of these binding proteins, free spectrin is degraded, leading to spectrin deficiency. The major complications are aplastic or megaloblastic crisis, hemolytic crisis, cholecystitis and cholelithiasis, and severe neonatal hemolysis. The classic laboratory features of HS include minimal or no anemia, reticulocytosis, an increased mean corpuscular hemoglobin concentration (MCHC), spherocytes on the peripheral blood smear, hyperbilirubinemia, and abnormal results on the osmotic fragility test. The most sensitive test to help detect HS is the osmotic fragility test performed after incubating RBCs for 1824 hours under sterile conditions at 37°C. Osmoti c fragility measures RBC resistance to hemolysis when exposed to a series of increasingly dilute saline solutions. The sooner hemolysis occurs, the greater the osmotic fragility of the cells.
A 74-year-old female with a history of hypertension and hypothyroidism is admitted with easy bruising, guaiac positive stools, and anemia (Hgb 8.1 g/dL). Screening coagulation tests reveal a prolonged activated partial thromboplastin time (aPTT) with a normal prothrombin time (PT) and platelet count.What is the next step in the diagnosis of this woman's problem?
Answer(s): E
A 1:1 mixing study is done when the PT or PTT is prolonged. The patient's plasma is mixed with normal plasma and the abnormal test is repeated. If the mixing of normal plasma corrects the abnormal test (PT or PTT), then a factor deficiency is suggested; otherwise, an inhibitor is suspected. Similarly, an incubated mixing study is done 1 hour (and occasionally 2 hours) after mixing of the patient plasma with normal plasma. It is used to differentiate a lupus anticoagulant from factor inhibitors.
A 23-year-old African-American presents with acute-onset pain in the abdomen, back, and legs. On physical examination, his pulse is 115 bpm, respiratory rate is 20, blood pressure is 100/70 mmHg, and temperature is 101°F. There is scleral icterus, a s ystolic ejection murmur at the right upper sternal border, bilateral rhonchi, a right upper quadrant abdominal scar from a cholecystectomy, and a diffusely tender abdomen without rebound. A neurologic examination is normal. A peripheral blood smear is shown in Figure.Among the initial orders for this patient should be which of the following?
This patient has sickle cell anemia. This is evident from sickle cells forms on the peripheral blood smear in Figure 1-13. Pain medication is an important initial concern. It is often difficult to determine whether a patient in sickle cell crisis has an ongoing infection. Infections can precipitate sickle cell crisis. With respect to community-acquired pneumonia, the diagnosis is difficult. A patient with sickle cell crisis can have fever as a result of the sickle crisis. They can have an increased respiratory rate, physical examination, and CXR findings which suggest pneumonia as a result of pulmonary infarctions. A white blood count can be elevated due to marrow stimulation. In the presence of the acute chest syndrome, characterized by chest pain, hypoxia, and CXR infiltrates, antibiotics would be indicated. Without further information, it is hard to decide to empirically start broad-spectrum antibiotics for community-acquired pneumonia. Transfusions should generally be avoided in patients with sickle cell anemia who are not symptomatic due to the anemia. Since patients in sickle cell crisis have intravascular hemolysis, their reticulocyte counts are usually high and they can replace their blood quickly. Repeated small transfusions will lead to autoantibodies that will make further transfusions difficult. Arterial blood gas determination should not be the first step, given the above information. A CT scan of the abdomen is not indicated given the nonspecific nature of the patient's abdominal findings. Parvovirus B19 can cause aplastic crisis in patients with hemoglobinopathies, including sickle cell disease. A tip to this diagnosis is the decreased reticulocyte count in a patient who normally would have a high reticulocyte count. Given the information listed above, there is no indication for broad- spectrum antibiotics. Splenectomy is not a reasonable alternative at this point. Patients with sickle cell disease have autosplenectomy by the time they are adults. A bone marrow biopsy maybe indicated because of the low platelet count, but not initially. GnCSF is not indicated because the patient does not have neutropenia.Patients with sickle cell disease typically have isosthenuria.This is due to repeated infarction of the renal papilli. This causes destruction and interference with the counter current mechanism that causes urine concentration. As a result, patients with sickle cell anemia have the inability to concentrate their urine. This results in fluid and electrolyte abnormalities. Patients in sickle cell crisis are usually fluid depleted. This and the sickled blood cells cause hyperviscosity and microinfarctions. There is no evidence that the patient has diabetes insipidus, which usually has a urine specific gravity less than 1.005. Patients with UTIs do not have isosthenuria due to RBCs and WBCs that increase the urine specific gravity. Sickle cell patients may have zinc deficiency, but this is not a cause of isosthenuria.
A 23-year-old African-American presents with acute-onset pain in the abdomen, back, and legs. On physical examination, his pulse is 115 bpm, respiratory rate is 20, blood pressure is 100/70 mmHg, and temperature is 101°F. There is scleral icterus, a s ystolic ejection murmur at the right upper sternal border, bilateral rhonchi, a right upper quadrant abdominal scar from a cholecystectomy, and a diffusely tender abdomen without rebound. A neurologic examination is normal. A peripheral blood smear is shown in Figure.A CBC with differential and platelets later shows the Hgb to be 6.4, white blood count is 2100 with 85% polymorphonuclear forms, platelet count is 100, and the reticulocyte countis 0.5. Which of the following would be an appropriate next test?
Answer(s): A
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