Hematology Final Exam

A 9-year-old boy is brought to the emergency room by his mother because he has been bleeding continuously from the site of a tooth extraction two days ago. His grandfather had a “blood condition” but she does not think that it was ever diagnosed. On examination there is ongoing oozing from the site of left maxillary first molar.

Laboratory studies:

• Platelet count: 200,000/mm^3
• Partial thromboplastin time: 52 seconds, complete correction with normal plasma
• Prothrombin time: 13 seconds

Which is the first step in coagulation that would be abnormal?

A physician is investigating a patient with menorrhagia resistant to treatment. He requests a laboratory test in which alpha granules from activated platelets are applied to a solution enriched with inactivated platelets from the patient. Ristocetin is then applied the solution and the granules bind to a platelet receptor. Activation of a normal receptor induces a conformational change that allows platelets to aggregate and increases light transmission or “scatter” through the solution.

The receptor being tested is

A 13-year-old girl is brought to the physician for recurrent epistaxis. He mother reports no trauma or head injuries. The patient denies drug use. Vital signs are all within normal limits. On physical examination the doctor notices bruises on her arms and legs. Laboratory studies show:

• Platelet count: 95,000/mm3
• Prothrombin Time: 12 seconds
• Partial thromboplastin time: 31 seconds
• Bleeding time:  15 minutes (N= 2-7 minutes)

The physician notices massive platelets on peripheral blood smear. When a Ristocetin assay is done no platelet aggregation is observed. Which of the following is the most likely cause of the patient’s current condition?

A previously healthy 43-year-old woman presents to her physician because of 3 day history of fever and fatigue. She also endorses tingling in her left hand and headaches during this same time. During physical exam the doctor notices pallor, scleral icterus, and petechia on the legs, arms, and back. A mental exam is performed and the patient has problems recalling how she got to the hospital and her birthday. Laboratory studies reveal:

• Hemoglobin: 9.3 g/dL
• Platelets: 27,300/mm^3
• Bleeding Time: 14 minutes (N = 2-7 minutes)
• Prothrombin Time: 13 seconds
• Partial Thromboplastin Time: 37 seconds
• Serum
  • Creatinine: 1.9 mg/dL
  • Total Bilirubin: 2.5 mg/dL

A peripheral blood smear is performed and shows RBC fragments. Which of the following is the most likely underlying cause of the patient’s current condition?

A 79-year-old woman comes to her physician for a follow-up examination. Last week she was diagnosed with bacterial sinusitis and was treated with a drug that binds to the 23S rRNA of the bacterial 50s ribosomal subunit, inhibiting translocation. 5 years ago, she was diagnosed with atrial fibrillation that is being treated with warfarin and metoprolol. The physician notices that compared to one month ago there is a slight increase in INR. Which of the following best explains this observation?

An investigator is studying the role of different chemicals and substances during the inflammatory process and hemostasis. Alpha granules from activated platelets are applied to a solution containing inactivated platelets. Ristocetin is then applied the solution and the granules bind to a receptor of interest. When binding occurs, this induces a conformational change. Which of the following receptors is responsible for the observation seen by this investigator?

A 21-year-old woman presents to her physician because she has had severe pain in her right leg over the past 3-4 days. The leg pain becomes worse when walking and is relieved with rest. She has had no shortness of breath. Review of systems reveals that she and her husband have not been able to have a baby despite trying for two years. She has been pregnant three times, but miscarried each pregnancy in the second trimester. Family history: her mother had rheumatoid arthritis and her maternal aunt has multiple sclerosis.

Vital signs are normal.

On examination, her right calf is diffusely erythematous, swollen, and tender. On duplex ultrasonography, the right popliteal vein is not compressible. Laboratory studies show an elevated serum level of D-dimer.

In view of this history, the patient should be further evaluated for which cause of thrombophilia?

A 50-year-old woman presents to the clinic complaining bleeding from her gums when she brushes her teeth. The week before, she developed a large ecchymosis on her leg after a minor bump into a table edge. She has active celiac sprue with only a partial response to gluten-free diet. She still has moderate steatorrhea. Laboratory testing shows:

• Partial thromboplastin time: 36 seconds
• Prothrombin time: 17 seconds
• Platelet count 300,000/mm^3
• Hematocrit: 34%
• WBC count: 4600/mm^3

The cofactor deficiency causing these findings is necessary for the carboxylation of glutamate residues of

A 79-year-old woman comes to her physician for a follow-up examination. Last week she was diagnosed with bacterial sinusitis and was treated with a drug that binds to the 23S rRNA of the bacterial 50s ribosomal subunit, inhibiting translocation. 5 years ago, she was diagnosed with atrial fibrillation that is now being treated with warfarin and metoprolol. Laboratory testing shows that compared to one month ago there is a small increase in her INR.

Which of the following best explains this observation?

A 1-year-old boy is brought to his primary care physician by his mother because he has developed jaundice. She first noticed this a few weeks after he was discharged from the hospital after he was born. Jaundice has occurred intermittently since. The boy’s father underwent splenectomy when he was a teenager.  Physical examination reveals jaundice and splenomegaly.

Laboratory studies:

• Hemoglobin: 9.2 g/dL
• Mean corpuscular volume: 80 micrometers
• Mean corpuscular hemoglobin concentration 38 (N=32-34 g/dL)
• WBC count: 7100/mm^3
• Platelet count: 249,000/mm^3
• Red cell distribution width: 17% (N= 13-15)
• Reticulocyte count: 11%
• Coombs test: Negative
• ESR: 10 mm/h

Peripheral blood smear reveals red blood cell cells seen in the image.

The cause of the patient’s symptoms is most likely a defect in

A 37-year-old woman visits her physician because of complaints of fatigue and ‘pains in her stomach’. She also notes that sometimes when she wakes up in the morning her urine is brown. Past history reveals an upper respiratory infection 2 weeks ago and hepatic vein thrombosis 3 years ago for which she received anticoagulation for 1 year. Physical examination is unremarkable.

Laboratory values show:

• Hemoglobin: 6.1 g/dL
• WBC count: 2,300/mm^3
• Platelet count: 75,000/mm^3
• PBS: No qualitative abnormalities
• Reticulocyte count: elevated
• Serum:
  • Total bilirubin: 7.0 mg/dL
  • Lactate dehydrogenase: 680 U/L
  • Haptoglobin: 20 mg/dL (N= 41-165 mg/dL)
  • Coombs test negative

The cause of this patient’s current condition is most likely due to

A 26-year-old man presents to the emergency department because his skin and eyes have become yellow over the past 6 days. He also complains of sharp back pain. He has experienced this before but it usually corrects on its own. He notices that his urine appears darker than normal and is foamy. He immigrated from Sicily 3 years ago. After a positive interferon-gamma release test at work 2 weeks ago, he has been started on isoniazid.

Temperature is 98.7 degrees Fahrenheit, pulse is 81/min, and blood pressure is 120/80. Auscultation of lung fields is negative.

Laboratory studies:

• Hematocrit: 27%
• Leukocyte count: 8500/mm^3
• Platelet count: 300,000/mm^
• Serum bilirubin
  • Total: 5 mg/dL
  • Direct: 0.4 mg/dL
• Haptoglobin: 11 mg/dL (N= 41-165 mg/dL)
• Coombs test: negative

The most likely cause of the patient’s anemia is a decreased production of

A scientist is studying hematopoiesis in developing fetuses. She notices that during different periods of development hematopoiesis occurs in different organs. She notes that hematopoietic cells populate body organs from an initial site. Which of the following organs is the first site of hematopoiesis?

In hemorrhagic diseases, the drug ristocetin is used to test for the function of a platelet membrane receptor. If there is a defect in the receptor, platelets will not aggregate and there is no increase in light transmission through the platelet-enriched plasma.

The receptor in question is

In pathologic conditions of hypoxia, the body makes it easier to release oxygen from hemoglobin in the affected tissues. There are also conditions in which it is advantageous to make attachment of oxygen to hemoglobin easier, at the expense of decreased release in tissues. Which of the following conditions make release of oxygen in the tissues more difficult?