30 Clinical Pathology
1 An ultrasound examination of a 29-year-old primigravida performed at 18 weeks’ gestation shows a male fetus that is mildly growth retarded. Multiple congenital anomalies are present, including ventricular and atrial septal defects, horseshoe kidney, and omphalocele. Amniocentesis is performed, and the fetal cells obtained are examined using FISH analysis. Based on the findings shown in the figure, which of the following karyotypic abnormalities is most likely to be present in this fetus?
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(E) 2 A 29-year-old woman has had fatigue with dizziness for the past 5 months. On physical examination, she has an erythematous malar rash. She has no lymphadenopathy, but there is a palpable spleen tip. She is afebrile. Laboratory studies show hemoglobin, 8.9 g/dL; hematocrit, 27.8%; MCV, 103 µm3; RBC distribution width index, 22; WBC count, 8650/mm3; platelet count, 222,000/mm3; and reticulocyte count, 3.3%. The peripheral blood smear shows polychromasia, but no schistocytes. Her serum total bilirubin is 3.2 mg/dL with direct bilirubin 0.8 mg/dL, and haptoglobin is 5 mg/dL. Antinuclear antibody and anti–double-stranded DNA tests are positive. What additional laboratory test finding is she most likely to have?
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(E) 3 A 68-year-old man has had worsening dyspnea and orthopnea for the past 3 years with increased production of frothy sputum. On examination, crackles are auscultated at lung bases. A chest radiograph shows bilateral interstitial infiltrates, distinct Kerley B lines, and a prominent left heart border. Laboratory studies show Na+, 135 mmol/L; K+, 3.8 mmol/L; Cl−, 99 mmol/L; CO2, 25 mmol/L; glucose, 76 mg/dL; creatinine, 1.5 mg/dL; and urea nitrogen, 30 mg/dL. Fractional excretion of sodium is less than 1%. Plasma renin, aldosterone, and antidiuretic hormone levels all are increased. Brain-type natriuretic peptide (BNP) is 200 pg/mL (normal <100 pg/mL). What is the most likely diagnosis?
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(F) 4 A 12-year-old boy has had worsening problems with joint mobility involving his arms and legs, particularly his knees and ankles, for the past 6 years. He has been receiving therapy for this condition. His grandfather had a similar condition and died at age 25. On physical examination, he has no visible petechiae or areas of purpura. Laboratory studies show that prothrombin time is 12 seconds, and partial thromboplastin time is 52 seconds. After addition of an equivalent aliquot of normal plasma, the partial thromboplastin time is 30 seconds. Hemoglobin is 12.9 g/dL, platelet count is 238,500/mm3, and WBC count is 6620/mm3. His platelet function studies are normal. What is the most likely inheritance pattern for his condition?
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(E) 5 Genetic testing of a family is performed using Southern blot with a DNA probe spanning the region of a suspected mutation. The results are shown in the figure. Based on these findings, which of the following types of gene mutations is most likely to be present in this family?
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6 A 58-year-old man reports increasing malaise over the past 8 months. He recently developed a cough productive of yellowish sputum, and a sputum culture grew Streptococcus pneumoniae. On physical examination, he has no lymphadenopathy or hepatosplenomegaly. Laboratory studies show serum creatinine, 4 mg/dL; urea nitrogen, 38 mg/dL; total protein, 9.3 g/dL; albumin, 4.1 g/dL; and alkaline phosphatase, 297 U/L. The finding on serum protein electrophoresis is shown in the figure. Which of the following laboratory findings is most likely to be reported?
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(E) 7 A 40-year-old man has been taking daily insulin injections for the past 25 years. When he does not arrive at work, a friend visits his house and finds him on the floor in an obtunded state. He is taken to the hospital by ambulance. On admission to the hospital, he cannot be aroused. He is afebrile, with a pulse of 90/min, respirations of 17/min, and blood pressure of 90/60 mm Hg. Laboratory studies show a hemoglobin A1c concentration of 8.9%, serum glucose level of 11 mg/dL, and serum osmolality of 295 mOsm/kg. Urinalysis shows 4+ ketonuria with a specific gravity of 1.010. Which of the following statements best characterizes these findings?
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(E) 8 A 31-year-old woman has experienced menorrhagia for the past year. She has developed easy bruisability to her skin, even with minor trauma, over the past month. She has multiple contusions of varying ages seen over her torso and extremities on physical examination. She has no difficulty with movement. No neurologic deficits are noted. Prothrombin time is 12.5 seconds, and partial thromboplastin time is 27 seconds. Hemoglobin is 13.3 g/dL, hematocrit is 42.1%, MCV is 95 µm3, platelet count is 25,000/mm3, and WBC count is 7500/mm3. A bone marrow biopsy specimen shows increased numbers of megakaryocytes. What is the most likely diagnosis?
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9 In a study of immunodeficient patients, samples of patient blood are collected and analyzed by flow cytometry. The figure at the bottom of the page shows the results for one group of patients. These patients are statistically more likely to develop non-Hodgkin lymphomas. Which diagnosis is most applicable to this group of patients?
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(G) 10 An 8-year-old girl exhibits lethargy and somnolence with dizziness and weakness after a 6-hour bus ride returning from summer camp. On physical examination, her temperature is 37°C, pulse is 107/min, respiratory rate is 28/min, and blood pressure is 130/85 mm Hg. Breath sounds are audible in all lung fields with no wheezes or crackles. A chest x-ray shows no abnormalities. Arterial blood gas analysis shows pH 7.35, Po2 95 mm Hg, Pco2 37 mm Hg, and HCO3− 20 mEq/L. Pulse oximetry shows an oxygen saturation of 90%, but the spectrophotometrically measured oxyhemoglobin saturation is 60%. Her blood lactic acid is 8 mmol/L, and total creatine kinase is 445 U/L with MB fraction of 5%. She is given 100% oxygen in a hyperbaric chamber and improves in 20 minutes. She is most likely to have experienced poisoning with which of the following?
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(F) 11 A 31-year-old, G3, P2 woman is in the second trimester. Her prior pregnancies ended with delivery of normal term infants who are still living. She has an ultrasound examination because of lack of fetal movement by 18 weeks. The fetal ultrasound examination shows microcephaly with periventricular leukomalacia and calcifications. Her HIV test is positive; her serologic test for syphilis is negative. TORCH titers are performed on maternal blood:
| IgG | IgM | |
|---|---|---|
| CMV | 1.2 (normal <0.9) | 0.7 (normal <0.9) |
| HSV type 1 | 1.2 (normal <0.9) | 0.6 (normal <0.9) |
| HSV type 2 | 0.6 (normal <0.9) | 0.5 (normal <0.9) |
| Rubella | 15 (normal <10) | 0.4 (normal <0.9) |
| Toxoplasma | 11 (normal <9) | 3.3 (normal <0.9) |
Which of the following is the most likely risk factor for this fetal infection?
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(F) 12 A 25-year-old man is involved in a rollover accident in which he is ejected from the vehicle. He sustains a compound fracture of the right humerus and undergoes open reduction with internal fixation of the humeral fracture. Three days later, he has marked swelling of the right arm and palpable crepitus. A Gram stain of exudate from the wound site has the appearance shown in the figure. What organism is the most likely causative agent for this patient’s infection?
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(E) 13 A 75-year-old woman has had a constant, dull pain in her back that has persisted for more than a month. She is in no acute distress. On physical examination, there are no abnormal findings. Laboratory findings include serum Na+, 141 mmol/L; K+, 4.4 mmol/L; Cl−, 103 mmol/L; CO2, 28 mmol/L; glucose, 101 mg/dL; creatinine, 0.9 mg/dL; urea nitrogen, 17 mg/dL; total protein, 6.8 g/dL; albumin, 4.2 g/dL; total bilirubin, 0.8 mg/dL; AST, 25 U/L; ALT, 29 U/L; calcium, 10.8 mg/dL; phosphorus, 2.3 mg/dL; and alkaline phosphatase, 228 U/L. Parathormone-related peptide is increased. What is the most likely diagnosis?
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(F) 14 A 17-year-old girl has had frequent nosebleeds since childhood. Her gums bleed easily, even with routine tooth brushing. She has experienced menorrhagia since menarche at age 14. On physical examination, there are no abnormal findings. Laboratory studies show hemoglobin, 14.1 g/dL; hematocrit, 42.5%; MCV, 90 µm3; platelet count, 277,400/mm3; and WBC count, 5920/mm3. Her platelets fail to aggregate in response to ADP, collagen, epinephrine, and thrombin. The ristocetin agglutination test result is normal. There is a deficiency of glycoprotein IIb/IIIa. Prothrombin time is 12 seconds, and partial thromboplastin time is 28 seconds. What is the most likely diagnosis?
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(E) 15 A 41-year-old woman has had increasing lethargy and weakness over the past 3 years. She complains of being cold most of the time and wears a sweater in the summer. One year ago, she had menorrhagia, but now she has oligomenorrhea. She has difficulty concentrating, and her memory is poor. She has chronic constipation. On physical examination, her temperature is 35.5°C, pulse is 54/min, respirations are 13/min, and blood pressure is 110/70 mm Hg. She has alopecia, and her skin appears coarse and dry. Her face, hands, and feet appear puffy, with a doughlike consistency to the skin. Laboratory findings show hemoglobin, 13.8 g/dL; hematocrit, 41.5%; AST, 26 U/L; ALT, 21 U/L; total bilirubin, 1 mg/dL; Na+, 140 mmol/L; K+, 4.1 mmol/L; Cl−, 99 mmol/L; CO2, 25 mmol/L; glucose, 73 mg/dL; and creatinine, 1.1 mg/dL. Which of the following serologic test findings is most likely to be positive?
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(F) 16 A 68-year-old man has had increasing dyspnea with cough productive of frothy sputum for the past 5 months. On physical examination, he is afebrile, and his blood pressure is 165/100 mm Hg. There is dullness to percussion at lung bases. He has pitting edema of the ankles. A chest radiograph shows blunting of costophrenic recesses bilaterally and cardiomegaly with prominent right and left heart borders. A right thoracentesis is performed, and 300 mL of straw-colored fluid is removed. Laboratory studies on this fluid show total protein of 2.2 g/dL (serum is 6.5 g/dL), glucose of 45 mg/dL (serum is 75 mg/dL), lactate dehydrogenase of 200 U/L (serum is 420 U/L), pH 7.2, and cell count of 100/mm3 mononuclear leukocytes, and no red blood cells. What condition does he most likely have?
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17 A 30-year-old man has had pain and burning on urination for the past week. On physical examination, he is febrile and has a pulse of 92/min, respirations of 18/min, and blood pressure of 80/45 mm Hg. Digital rectal examination indicates that he has an enlarged, tender prostate. There is costovertebral angle tenderness on the right. Scattered ecchymoses are present over the trunk and extremities. Laboratory studies show a blood culture positive for Klebsiella pneumoniae. The appearance of the RBCs in a peripheral blood smear is shown in the figure. These findings are most indicative of what condition?
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