(Exam) Part 2 WUKONG 7.2 (455-509) 255-509

147) A 65-year-old woman comes to the office for a health maintenance visit. She has been your patient for the last 15 years. When you ask how she has been, she replies with, "Well, I'm very health-conscious now. I read all the health magazines regularly, and exercise for 30 minutes daily. I eat a lot of garlic to control my cholesterol, and drink cranberry juice to keep my kidneys strong. I don't smoke, but I drink alcohol during social events. I've been compliant with regular screening colonoscopies, mammograms, and pap smears. Doc, since my mother died from ovarian cancer, do you think I can have an abdominal ultrasound every 6 months, plus any additional necessary tests,

148) A 22-year-old African-American man presents to the ER with fever, jaundice, abdominal pain, and dark urine. His heart rate is 100/min and blood pressure is 100/60 mmHg. Peripheral blood smear reveals bite cells and red blood cell inclusions seen after crystal violet staining. The patient most likely suffers from which of the following conditions?

149) A 34-year-old male is brought to the emergency department with altered mental status. His girlfriend reports that he has had fever and cough for the past two days. His past medical history is significant for abdominal trauma two years ago that required splenectomy and left-sided nephrectomy. On physical examination, his temperature is 39° C (102.2°F), blood pressure is 80/50 mm Hg, pulse is 110/min, and respirations are 32/min. Gram-positive cocci are cultured from his blood. Which of the following is most likely impaired in this patient?

150) A 43-year-old man presents to your office with low energy and increased fatigability. He also complains of daytime sleepiness and occasional headaches. He drinks two to three glasses of wine daily but does not smoke. He sleeps in a separate room from his wife because she finds his constant snoring annoying. On physical examination, his blood pressure is 160/100 mmHg and his heart rate is 80/min. His BMI is 31.5 kg/m2. His abdomen is soft and non-tender. The liver span is 10 cm and the spleen is not palpable. Laboratory findings are: Hematocrit 60%, WBC count 9,000/mm3, Platelets 190,000/mm3. Which of the following is most likely responsible for this patient's increased hematocrit?

151) A 6-year-old African-American child is brought in by his father for complaints of easy fatigability and pallor. These symptoms occurred after the son was treated with "some medication" for a recent diarrhea. Physical examination is normal except for pallor and multiple petechiae. Laboratory values are as follows: Hb 8.0 g/dL, WBC 12,000/cmm, Platelets 50,000/cmm, Blood glucose 118 mg/dL, Serum Na 135 mEq/L, Serum K 5.3 mEq/L, Chloride 110 mEq/L, Bicarbonate 18 mEq/L, BUN 38 mg/dL, Serum creatinine 2.5 mg/dL, Total bilirubin 3 mg/dL, Direct bilirubin 0.5 mg/dL, PT 12 seconds, APTT 30 seconds, LDH 900 IU/L, Reticulocyte count 6%. A peripheral blood smear reveals giant platelets and multiple schistocytes. What is the most likely underlying pathophysiology for this boy's pallor?

153) A 79-year-old woman presents to your office complaining of an intermittent skin rash over the last several months. She denies fever, headache, and recent weight loss. Her past medical history is significant for diet-controlled diabetes and right knee osteoarthritis treated with acetaminophen. Physical examination reveals several dark purple ecchymotic areas over the dorsum of both arms. Her abdomen is soft and non-tender. The liver span is 8 cm and the spleen is not palpable. Laboratory studies reveal: Hematocrit 47%, WBC count 5,800/mm3, Platelet count 220,000/mm3, Serum creatinine 0.8 mg/dL\, Fibrinogen 350 mg/dL, Prothrombin time 10 sec, INR 1.0, Partial thromboplastin time 25 sec. Which of the following is the most likely cause of this patient's complaint?

154) A 42-year-old woman is evaluated for chronic abdominal pain and fatigue. Her pain is epigastric, crampy, and sometimes awakens her from sleep. She denies any recent weight loss, nausea, or vomiting. Her diet consists mainly of fruits and vegetables. She also complains of a "strange appetite" for paper and ice that she has never had before. Upper gastrointestinal endoscopy reveals an ulcer located on the anterior wall of the duodenal bulb. Her unusual appetite is most directly related to:

155) A 22-year-old female presents to the emergency room with a nosebleed. A quick review of her records reveals that she presented with the same problem yesterday, at which time the bleeding was stopped with prolonged local pressure. On review of systems, the patient also reports easy bruising for the past several months. On physical examination, her heart and lungs appear normal. The liver span is 8 cm and the spleen is not palpable. There are scattered ecchymoses over her arms and legs. Laboratory findings include the following: Hematocrit 45%, Platelet count 9,000/mm3, Leukocyte count 5,500/mm3, Neutrophils 56%, Eosinophils 1%, Lymphocytes 33%, Monocytes 10%, Fibrinogen 250 mg/dL, Prothrombin time 13 sec. Which of the following is the most likely cause of this patient's condition?

156) A 66-year-old female comes for removal of a lipoma from her elbow. She wants the swelling out because it looks ugly when she wears sleeveless tops. Her only complaints are general malaise and fatigue for the past 8 months, which she attributes to her "being alone all the time." Her vital signs are within normal limits. Physical examination reveals mild pallor and both cervical and supraclavicular lymphadenopathy. Her preoperative blood count reveals the following: Hemoglobin 10.0 g/dL, Hematocrit 32%, Platelets 126,000/cmm, WBC 31,600/cmm. Leukocyte distribution: Segmented neutrophils 18%, Lymphocytes 77%, Bands 4%, Monocytes 1%. The pathologist reports the presence of "leukocytes that have undergone partial breakdown during preparation of a stained smear or tissue section, because of their greater fragility." Lymph node biopsy confirms the diagnosis. What is the correct statement about the above patient?

157) A 17-year-old male presents to clinic for routine check-up. He is a long distance runner and has beenachieving outstanding results recently. He is very proud of his athletic achievements, remarking that his effort "pays off." He does not smoke or consume alcohol. His family history is significant for diabetes mellitus in his mother and skin cancer in his father. Chest examination is normal. His liver span is 8 cm and his spleen is not palpable. His current laboratory findings include: Hematocrit 59%, WBC count 7,500/mm3, Platelet count 170,000/mm3, ESR 15 mm/hr. Which of the following is the most likely explanation for the high hematocrit in this patient?

158) A 65-year-old Caucasian male had undergone cardiac catheterization followed by aortic valve replacement for severe aortic stenosis and coronary artery bypass grafting for three-vessel disease. His postoperative course was complicated by atrial fibrillation and a urinary tract infection. His other medical problems include hypertension, diabetes, and hypercholesterolemia. He is also receiving heparin, ciprofloxacin, and amiodarone. On postoperative day five, he developed prolonged bleeding from the venipuncture site. His labs show: Hb 11.5 g/dL, MCV88 fl, Platelet count 50,000/cmm, Leukocyte count 7,500/cmm, Segmented neutrophils 68%, Bands 1%, Eosinophils 1%, Lymphocytes 24%, Monocytes 6%, Prothrombin time 12 sec (INR=1.0), Partial thromboplastin time 65 sec. His preoperative labs were unremarkable. What is the most likely cause of these findings in this patient?

159) A 62-year-old woman presents complaining of recurrent cough productive of yellow sputum. She was seen several weeks ago for similar complaints and was effectively treated with a course of azithromycin. Today she expresses frustration that she seems to keep getting sick with the same infection. On review of systems, the patient also reports recent-onset back pain for which she has been taking acetaminophen. Her past medical history is otherwise insignificant. She has never smoked cigarettes, and drinks alcohol only on rare social occasions. Physical examination reveals conjunctival pallor, a few scattered rales in the lungs bilaterally, and tenderness over the lumbar vertebrae. Laboratory analyses reveal: Hemoglobin 8.4 g/dL, Leukocyte count 5,500/mm3, Blood urea nitrogen 34 mg/dL, Creatinine 2.0 mg/dL, Calcium 10.9 mg/dL, Albumin 3.8 g/dL, Total protein 9.5 g/dL. This patient is at increased risk for recurrent infections because of which of the following abnormalities?

160) A 47-year-old man presents to your office complaining of occasional daytime headaches, dizziness and nausea. He has no significant past medical history. He works as a traffic controller in an underground parking lot. He does not smoke cigarettes, and consumes alcohol only on weekends. He is sexually active in a monogamous relationship with his wife and uses condoms for contraception. His cardiac exam is unremarkable. His abdomen is soft and non-tender. The liver span is 8 cm and the spleen is not palpable. Laboratory findings are: Hematocrit 59%, WBC count 7,000/mm3, Platelets 200,000/mm3. Which of the following is most likely responsible for this patient's increased hematocrit?

161) A 57-year-old Caucasian female is diagnosed with deep venous thrombosis of the right leg that was confirmed with Doppler ultrasonography. She was diagnosed with pneumonia and empyema one week earlier, and treated with chest tube, antibiotics and bed rest. On her 6th day of anticoagulation therapy, she develops right hemiparesis and slight motor aphasia. The laboratory findings are: Red blood cells 4.3 million/mm3, Hemoglobin 14.00 g/dL, White blood cells 7,000/cmm, Platelets 50,000/cmm, APTT 60 sec (N < 25-40 sec), Fibrin degradation products negative. The emergency head CT scan does not reveal blood in the subarachnoid space or brain parenchyma. Which of the following is the most probable cause of this patient's condition?

162) A 25-year-old African American woman presents with a photo distributed skin rash and arthralgias. She is found to have low-range proteinuria and abnormal urinary sediment. Renal biopsy findings are consistent with focal proliferative glomerulonephritis. Her complete blood count shows: Erythrocyte count 3.2 mln/mm3, Platelets 60,000/mm3, Leukocyte count 2,500/mm3. Which of the following is the most likely cause of these hematologic findings?

163) A 45-year-old Asian man presents to your office complaining of easy fatigability. He denies abdominal pain, distention, nausea, vomiting, or significant weight loss. His past medical history includes a gastrectomy for a non-healing gastric ulcer. He is not currently taking any medications. He quit smoking several years ago and does not use alcohol or illicit drugs. His vital signs are within normal limits. Physical examination reveals a shiny tongue and pale palmar creases. No lymphadenopathy, hepatomegaly, or splenomegaly is present. His blood hemoglobin level is 7.5 mg/dL and W8C count is 3,800/mm3. Stool tests for occult blood are repeatedly negative. This patient's condition involves which of the following pathophysiologic mechanisms?

164) A 23-year-old African American man is treated with an antibiotic for an uncomplicated urinary tract infection. Several days later, he presents to your office saying that his initial symptoms have improved but his urine now appears dark. He has no significant past medical history and does not use tobacco, alcohol, or illicit drugs. His temperature is 36.8°C (98.2°F), pulse is 88/min, respirations are 14/min, and blood pressure is 130/76 mmHg. Physical examination is within normal limits. The urine sample stains positive with Prussian blue and the sediment microscopy is unrevealing. What is the mechanism behind the cell damage responsible for this patient's current complaint?

165) A 6-year-old Caucasian boy is hospitalized for acute sinusitis that was accompanied with intensive nasal bleeding. Past medical history is significant for recurrent pulmonary infections and several hospitalizations for parenteral antibiotic therapy. The sweat chloride test is positive. The blood tests reveal a prothrombin time (PT) of 20 seconds. Which of the following coagulation factors is most likely to be deficient in this patient?

166) A 27-year-old man presents to the emergency department with unremitting nose bleeding. He reports having a similar bleeding episode one year ago that was stopped in the ER. He works as a computer programmer and has a sedentary lifestyle. He drinks alcohol on social occasions but does not smoke or use illicit substances. On physical examination, there are several ruby-colored papules on his lips that blanch partially with pressure. Digital clubbing is also present. His abdomen is soft and non-tender. The liver span is 8 cm and the spleen is not palpable. Laboratory findings are: Hematocrit 60%, WBC count 8,000/mm3, Platelets 180,000/mm3. Which of the following is most likely responsible for this patient's increased hematocrit?

167) A 14-year-old boy is brought by his mother because she noticed a change in his voice. He has been having frequent nosebleeds for the last month, and feels that his "left nose" is always congested. There is no history of trauma. He admits to using marijuana, in the absence of his mother. He is otherwise well, and does not take any medications. He actively participates in the school basketball tournaments. Physical examination reveals an intact nasal septum with a visible mass at the back of the left nostril. CT scan reveals an erosion of the adjacent bone. What is the most likely reason of this patient's nosebleeds?

168) A 34-year-old male who recently emigrated from Asia comes to the clinic and complains of a two-month history of exertional shortness of breath and easy fatigability. He has been taking isoniazid and rifampin for his tuberculosis, which was diagnosed four months ago. Due to his religious beliefs, he completely turned into a vegetarian for the last year. Physical examination reveals severe pallor. Peripheral smear shows macrocytosis with hypersegmented polymorphonuclear neutrophils. His WBC and platelet counts are within normal limits. This patient's most likely problem is due to which of the following?

169) A 72-year-old woman complains of fatigue, dyspepsia, and shortness of breath. Her daughter tells you that her mother also has some slight memory loss and occasionally complains of numbness in her legs. The laboratory tests you ordered show a hemoglobin of 10.2 g/dL and an MCV of 110. The most likely cause is:

170) A 23-year-old male comes to ER with five day history of diarrhea and abdominal pain. Initially, the diarrhea was watery occurring five-six times per day but yesterday he noticed blood in the stool which prompted his visit to ER. He describes his abdominal pain as colicky and severe. He also complains of nausea and decreased appetite but he has had no vomiting. His past medical history is insignificant and never had similar symptoms. He is not sexually active and he denies any illicit drug use. He has no history of recent travel. His father had colon cancer and his uncle died of liver cirrhosis. His temperature is 36.6°C (98.0°F), blood pressure is 123/82 mmHg and heart rate is 102/min. On examination, he has prominent periumbilical and right lower quadrant tenderness but no guarding or rebound. Rectal examination reveals brownish stool mixed with blood. Which of the following is the most likely diagnosis?

171) A 55-year-old Asian man with mitral stenosis secondary to rheumatic heart disease undergoes dental surgery for caries. Postoperatively, he does well and is discharged home. Two weeks later, he presents with fever, chills, fatigue, and feels "sick." Four out of four blood culture bottles are positive for gram-positive cocci. An echocardiogram is performed and shows mitral valve vegetations. Which of the following is the most likely causative organism of this patient's condition?

172) A 16-year-old Asian boy presents with a two-day history of fever, malaise, and painful enlargement of his parotid glands. He has no significant past medical history. He was born in India, and has not received any childhood vaccinations. He recently returned from a one-week vacation in India. His vital signs are stable, except for a mild fever. Examination shows bilateral parotid enlargement. The rest of the examination is unremarkable. Which of the following organs is most likely to be affected by this patient's illness?

173) A 29-year-old man returns home to Colorado after a diving trip to Honduras in Central America. He was gone for 6 days. The day he returns, he starts to develop diarrhea, abdominal cramping, and nausea. There is no mucus and blood in the stool. He has no other medical problems and does not take medications. He does not use tobacco, alcohol or drugs. His temperature is 37.2°C (98.9°F), blood pressure is 120/74 mm Hg, pulse is 80/min, and respirations are 15/min. There is no lymphadenopathy. Chest is clear to auscultation. Abdomen is soft and non-tender. There is no organomegaly. Bowel sounds are increased. Stool is negative for leukocytes and fecal occult blood. Which of the following is the most likely pathogen responsible for his symptoms?

1) A 31-year-old, HIV-infected man from New York presents to the ER with anorexia, malaise, night sweats, fever, and weight loss of 6.8kg (15 lb) over the past one month. He also has a cough productive of yellow sputum. He was diagnosed with HIV two years ago. When last checked two months ago, his CD4 count was 220/microL. He is not taking any medications. His temperature is 39.2°C (102.2°F), pulse is 96/min, and blood pressure is 120/80 mm Hg. Physical examination reveals rales in his right upper chest. Laboratory studies show: Hematocrit 30%, WBC count 3,400/microL, Neutrophils 86%, Bands 2%, Lymphocytes 4%, Monocytes 8%. PPD test shows 3 mm induration. Chest x-ray reveals a right upper lobe cavitation. Sputum examination shows partially acid-fast, filamentous, branching rods. Based on these findings, which of the following organism is the most likely cause of this patient's pulmonary disease?

2) A 45-year-old man comes to the office and complains of intermittent, bloody diarrhea and abdominal pain for the past month. During this time period, he has lost six pounds. He was diagnosed with HIV infection in the past, but has refused antiretroviral therapy. Laboratory results show a CD4 count of 50cells/μL. The stool examination is negative. Colonoscopy with biopsy shows multiple colonic ulcerations and mucosal erosions. The biopsy shows large cells containing eosinophilic intranuclear and basophilic intracytoplasmic inclusions. What is the most likely cause of this patient's diarrhea?

3) A 73-year-old diabetic man presents with low-grade fever, facial pain over his right maxilla, and bloody nasal discharge for the last three days. For the last day, he has had diplopia. He was diagnosed with diabetes mellitus 10 years ago. For the last year, he has been on insulin. His most recent hemoglobinA1C was 12.0. His temperature is 39.0°C (102.2°F), pulse is 88/min, and blood pressure is 130/76mm Hg. Examination shows right-sided nasal congestion and necrosis of the right nasal turbinate with tenderness over the right maxillary sinus. There is chemosis and proptosis of his right eye. CT scan shows opacification of the right maxillary sinus. Which of the following is the most likely causative organism?

4) A 43-year-old HIV-positive male presents to your office with several exophytic purple skin masses on his lower abdomen. Physical examination reveals tender hepatomegaly and an abdominal CT scan shows nodular, contrast-enhanced intrahepatic lesions of variable size. Liver biopsy is attempted but severe hemorrhage results. Which of the following is the most likely cause of this patient's condition?

6) A 75-year-old female nursing home resident complains of cough and fever. Her past medical history is significant for hypertension, myocardial infarction (experienced two years ago), and a traumatic right foot amputation. Her current medications are atenolol, hydrochlorothiazide, and aspirin. Her temperature is 39.4°C (103°F), pulse is 110/min, respirations are 22/min, and blood pressure is 110/76 mmHg. Crackles are present at right lung base. Chest x-ray reveals a right lower lobe infiltrate. Which of the following pathogens is the most likely cause of this patient's condition?

7) A 45-year-old man presents to the emergency room with a two-day history of fever, dyspnea, abdominal pain, and diarrhea. He has no chest pain, but complains of dry cough. His past medical history is significant for bone marrow transplantation for acute myeloid leukemia (AML) three months ago. His temperature is 39°C (102.2°F), blood pressure is 122/80 mm Hg, pulse is 98/min, and respirations are 22/min. Exam of the oropharynx reveals thrush. Lungs exam demonstrates bilateral diffuse rales. Heart sounds are regular. Nonspecific abdominal tenderness is present. The chest radiograph shows multifocal, diffuse patchy infiltrates. Which of the following is the most likely cause of this patient's current condition?

8) A 55-year-old woman presents with a three-week history of low-grade fever, weight loss of 4.5kg (10 lb), and malaise. She is known to have mitral valve prolapse, but is otherwise healthy. She underwent a tooth extraction one month ago. She denies alcohol, tobacco, and illicit drug use. Her temperature is 38.5°C (101.3°F), pulse is 90/min, respirations are 18/min, and blood pressure is 145/76 mm Hg. Her chest is clear to auscultation and percussion. Cardiac examination reveals a III/IV holosystolic murmur at the apex that radiates to the axilla. Chest x-ray is normal. Urinalysis is unremarkable. Blood cultures are drawn and empiric antibiotics are started. Echocardiogram shows mitral regurgitation with vegetation on the mitral valve. Which of the following organisms is the most likely cause of this patient's condition?

9) A 50-year-old man presents to the office with fatigue, malaise, and disabling joint pain in his fingers, wrists, shoulder, hips, knees, and ankles. His pain is severe and associated with a mild degree of morning stiffness for 10-15 minutes. He occasionally takes acetaminophen and ibuprofen for this pain. He has a 10-pack-year smoking history. He does not drink alcohol. Family history includes an uncle who died of liver cancer. On examination, there is grayish skin pigmentation, most prominent on the exposed parts. Abdominal examination is significant for liver enlargement 2 cm below the costal margin. Laboratory studies reveal the following: Hemoglobin 13.0 g/L, Leukocyte count 5,500/mm3, Serum creatinine 0.8 mg/dl, Blood glucose 218mg/dl, Aspartate aminotransferase (SGOT) 128 U/L, Alanine aminotransferase (SGPT) 155 U/L, Alkaline phosphatase 120 U/L , Serum iron 450 mol/L (50-170g/dL), Transferrin saturation of iron 62% (22-47%), Serum Ferritin 3000ng/L (15-200 ng/ml, males). X-ray of the joints shows narrowing of joint spaces and diffuses demineralization. This patient's condition makes him more vulnerable to which of the following infections?

10) A 19-year-old white male presents with nausea, vomiting, and abdominal cramps. He has had four episodes of vomiting over the last two hours. He has not had diarrhea or fever. Four hours ago, he ate a salad from a local restaurant. His pulse is 82/min, blood pressure is 120/80 mm Hg, and temperature is 37.2°C (99°F). Abdominal and rectal examinations are unremarkable. Which of the following is the most likely cause of this patient's symptoms?

11) A 72-year-old male presents with a two-day history of intense pain in his right ear, along with ear discharge. The pain is so severe that he is unable to sleep. It radiates to his temporomandibular joint and is aggravated by chewing. His disease has worsened despite the use of topical antibiotics. He takes metformin and enalapril. On physical examination, granulation tissue is noted in the lower part of his external auditory canal. Cranial nerves are intact. Oropharynx is clear without exudate. Which of the following is the most likely causative organism of this patient's ear condition?

12) A 26-year-old male presents to your office with periodic flank pain. He also noticed that his urine was red during the last several days. He is known to be HIV-positive. One month ago, he presented with thrush. At that time, he was found to have a CD4 count of 100, and was started on anti-retroviral therapy. His current CD4 count is 250. Physical examination reveals no oral cavity lesions. The lungs are clear on auscultation. The serum creatinine level is 2.2 mg/dl. Urinalysis shows hematuria and needle-shaped crystals in the sediment. Which of the following is the most likely cause of this patient's current condition?

13) A 12-year-old boy is brought to the emergency department because of severe pain near his left knee. He has sickle cell disease, and has been hospitalized previously for sickle cell crisis. Vital signs are notable for mild fever. Examination of the left lower extremity reveals a normal knee joint with marked tenderness and swelling over the proximal tibia. Labs show leukocytosis and elevated ESR. He is subsequently diagnosed with osteomyelitis. Which of the following organisms is the most likely cause of his condition?

14) A 67-year-old man presents to his primary care provider in January with fever and a productive cough. The patient had been seen ten days earlier with complaints of fever to 102°F (39.0°C), myalgias, rhinorrhea, and dry cough. At that time, his lung exam revealed occasional crackles. He was given a medication and told to follow up if his symptoms worsened. The symptoms did remit over the first five days, but he began to feel worse again two days ago. He smokes a half-pack of cigarettes per day and drinks alcohol several times a week. On exam today, his temperature is 102.3°F (39.3°C), and lung exam reveals increased tactile fremitus in the left lower lobe. What is the most likely pathogen responsible for his current condition?

15) A 33-year-old man presents with low-grade fever, abdominal cramps, and diarrhea for the past six hours. He has had eight episodes of loose, watery stool containing blood and mucus over this time period. Last night, he ate shrimp and crab meat at a local restaurant. His current pulse is 85/min, blood pressure is 110/80 mm Hg, and temperature is 37.7°C (99.9°F). There are no significant findings on abdominal or rectal examinations. Stool examination shows numerous red blood cells and leukocytes. Which of the following is the most likely causative organism of this patient's condition?

16) A 46-year-old farmer comes to the physician because of pain and swelling of his right heel. He accidentally stepped on a rusty nail while working 2 weeks ago. Although he applied over the-counter antibiotic cream locally and took acetaminophen orally, he continued to have pain at the site of the injury. He has no other medical problems and takes no medication. He has no known drug allergies. He smokes 2-3 cigarettes a day and drinks alcohol occasionally. His temperature is 38.3°C (101°F), blood pressure is 140/90 mm Hg, pulse is 84/min and respirations are 14/min. On examination, the right heel is swollen, red, and warm and tender to touch. A small puncture wound is visible. Laboratory reports show mild leukocytosis. X-ray of the right foot shows features suggestive of osteomyelitis. The most likely cause of the patient's symptoms is infection with which of the following?

17) A 31-year-old, HIV-infected man from New York presents to the ER with anorexia, malaise, night sweats, fever, and weight loss of 6.8kg (151b) over the past one month. He also has a cough productive of yellow sputum. He was diagnosed with HIV two years ago. When last checked two months ago, his CD4 count was 220/microL. He is not taking any medications. His temperature is 39.2°C (102.2°F), pulse is 96/min, and blood pressure is 120/80mm Hg. Physical examination reveals rales in his right upper chest. Laboratory studies show: Hematocrit 30%, WBC count 3,400/microL, Neutrophils 86%, Bands 2%, Lymphocytes 4%, Monocytes 8%. PPD test shows 3 mm induration. Chest x-ray reveals a right upper lobe cavitation. Sputum examination shows partially acid-fast, filamentous, branching rods. Based on these findings, which of the following organism is the most likely cause of this patient's pulmonary disease?

18) A 26-year-old man comes to his physician with a two-week history of fatigue, fever, muscle aches, and arthralgias. He denies any weight loss. His temperature is 37.7°C (99.9°F), blood pressure is 115/75 mm Hg, respirations are 14/min, and pulse is 75/min. Physical examination is unremarkable, except for splenomegaly. Laboratory studies show: Hemoglobin 13 gm/dL, WBC count 12,000/microL, Neutrophils 22%, Lymphocytes 70%, Monocytes 5%, Basophils 1%, Eosinophils 2%, Platelet count 220,000/microL. Peripheral blood smear shows large basophilic lymphocytes with a vacuolated appearance. Heterophile antibody test is negative. What is the most likely cause of this patient's symptoms?

19) A 27-year-old man presents with symptoms of fever, chills, malaise, and joint discomfort in his hands and knees. He looks unwell, his temperature is 39.4°C, blood pressure 115/70 mm Hg, pulse 110/min, head and neck is normal, and his jugular venous pressure (JVP) has a prominent c-v wave. There is also a 3/6 pan-systolic murmur heard at the right sternal border that increases with respiration. His lungs are clear, abdomen is soft, and hand joints are normal. He has multiple puncture sites on his forearms from injection drug use. Which of the following is the most likely causative organism?

20) A 73-year-old man from a nursing home develops headache, fever, cough, sore throat, malaise, and severe myalgia during a community outbreak affecting numerous other residents at the home. The symptoms gradually resolve after 3 days, and he starts feeling better but then there is a reappearance of his fever, with cough and yellow sputum production. On examination, his temperature is 38.5°C, pulse 100/min, respiration 24/min, oxygen saturation 88% and crackles in the right lower lung base, bronchial breath sounds and dullness on percussion. CXR reveals a new infiltrate in the right lower lobe. Which of the following is the most likely causative organism?

21) A 56-year-old man is having intermittent fevers and malaise for the past 2 weeks. He has no other localizing symptoms. Two months ago, he had valve replacement surgery for a bicuspid aortic valve. A mechanical valve was inserted and his postoperative course was uncomplicated. On examination, his temperature is 38°C, blood pressure 124/80 mm Hg, pulse 72/min, and head and neck are normal. There is a 3/6 systolic ejection murmur, the second heart sound is mechanical, and a 2/6 early diastolic murmur is heard. The lungs are clear and the skin examination is normal. Three sets of blood cultures are drawn and an urgent echocardiogram is ordered. Which of the following is the most likely causative organism?

22) A 25-year-old woman is admitted with fever and hypotension. She has a 3-day history of feeling feverish. She has no history of chronic disease, but she uses tampons for heavy menses. She is acutely ill and, on physical examination, found to have a diffuse erythematous rash extending to palms and soles. She is confused. Initial blood tests are as follows: White blood cell count: 22,000/μL, Na+: 125 mEq/L, K+: 3.0 mEq/L, Ca++: 8.0 mEq/mL, Activated partial thromboplastin time (PTT): 65 (normal 21 to 36), Prothrombin time (PT): 12s (normal < 15s), Aspartate aminotransferase: 240 U/L (normal < 40), Creatinine: 3.0 mg/dL, Antinuclear antibodies: negative, Anti-DNA antibodies: negative, Serologic tests for RMSF, leptospirosis, measles: negative. Which of the following best describes the pathophysiology of the disease process?

23) A 21-year-old woman visits her physician because of 3 weeks of a flu-like‖ illness. She reports symptoms of malaise, fever, fatigue, and a sore throat. There is no weight loss or night sweats, and she has not traveled out of country. Her past medical history is not significant and she is not taking any medications. Physical examination is normal except for enlarged cervical lymph nodes. Laboratory data show hemoglobin 13.2 g/dL; hematocrit 42%; platelets 380,000/mL; WBC 8500/mL, with 35% segmented neutrophils, 1% eosinophils, and 64% lymphocytes, of which 36% were atypical. A heterophil antibody (sheep cell agglutination) test is negative. Which of the following is the most likely causative organism?

24) A 4-year-old boy is sent to the emergency room because of clinical suspicion of meningitis. He has been ill for 2 days with fever and lethargy. On examination, he is febrile, the neck is stiff, and papilledema is present. There is no rash, the lungs are clear, and heart sounds normal. Which of the following is the most likely causative organism?

25) A 24-year-old woman presents with chills and rigors. She looks unwell, and her temperature is 39.4°C, blood pressure 100/60 mm Hg, pulse 110/min, and oxygen saturation 95%. There is a 3/6 pansystolic murmur at the right sternal border, which increases with inspiration. Her arms have multiple tattoos and needle marks from injection drug use. Blood cultures (2/2 sets) are positive for S. aureus, and she is started on appropriate antibiotics. Her renal function is mildly impaired and her urinalysis is positive for protein, and microscopy reveals red cell casts. Which of the following mechanisms is the most likely explanation for her renal abnormalities?

26) A recent outbreak of severe diarrhea is currently being investigated. Several adolescents developed bloody diarrhea, and one remains hospitalized with acute renal failure. A preliminary investigation has determined that all the affected ate at the same restaurant. The food they consumed was most likely to be which of the following?

27) A 23-year-old woman presents with a painless chronic vulvar ulcer. She recently arrived to study in the United States from Southern India. The lesion began as a papule and then ulcerated. It has persisted for several months. Currently, physical examination reveals a painless elevated area of beefy red, friable granulation tissue. She has been sexually active for several years. Which of the following is the most likely causative organism?

28) An 18-year-old man develops fever, neck stiffness, and headache. On examination, his blood pressure is 105/80 mm Hg, pulse 100/min, temperature 38.7°C, and neck flexion is very painful. The ears, throat, and sinuses are normal; there are no focal neurologic signs, and the remaining examination is normal. His is the second case of meningitis in his university dormitory building. Which of the following is the most likely causative organism?

29) A 19-year-old woman was traveling in a rural area of South America. She returned 3 weeks ago and, over the past few days, has gradually developed lower abdominal pain and diarrhea. Now the symptoms are much worse with 10 stools a day consisting mostly of mucus and blood. She is afebrile, the abdomen is tender in left lower quadrant, and the remaining examination is normal. Her stool is mostly comprised of blood and mucus. Which of the following is the most likely causative organism?

30) An 18-year-old man develops fever, neck stiff- ness, and headache. On examination, his blood pressure is 110/80 mm Hg, pulse 100/min, temperature 38.7°C, and neck flexion is very painful. The ears, throat, and sinuses are normal; there are no focal neurologic signs; and the remaining examination is normal. There are no reported similar cases in the community. Which of the following is the most likely causative organism?

31) A previously well 28-year-old female has developed gradual onset of fever and malaise over 2–3 weeks. She also complains of arthralgias and myalgias. Repeated measurement of her temperature reveals a low grade fever between 38°C and 39°C. Physical examination reveals an oval retinal hemorrhage with a clear, pale center; a pansystolic cardiac murmur heard best at the apex; and small, tender nodules on her fingertips. Which of the following is the most likely causative organism?

32) A 70-year-old patient with long-standing type 2 diabetes mellitus presents with complaints of pain in the left ear with purulent drainage. On physical examination, the patient is afebrile. The pinna of the left ear is tender, and the external auditory canal is swollen and edematous. The white blood cell count is normal. Which of the following organisms is most likely to grow from the purulent drainage?

33) Three hours after a church social, eight people develop severe diarrhea. Other symptoms included nausea, vomiting, and abdominal cramps. Food served included chicken salad and cream-filled pastries. All affected individuals had the chicken salad. Which of the fol- lowing is the most likely causative organism?

34) A 9-year-old boy has a severe sore throat with fever and dysphagia. On examination, there are grayish-white papulovesicular lesions on an erythematous base that ulcerate. They are located on the soft palate, anterior pillars of the tonsils and uvula. There are no lesions on the gingiva, tongue, or lips. A clinical diagnosis of herpangina is made. Which of the following is the most likely causative organism?

35) A 10-year-old boy presents with fever, headache, photophobia, and neck discomfort in the middle of summer. He is alert and oriented, but has neck pain with flexion and extension of the head. His fundi are normal, and there are no focal neurologic findings or skin changes. A lumbar puncture reveals normal protein and glucose with a cell count of 240/mL (90% lymphocytes). Which of the following is the most likely causative organism?

36) A 60-year-old man presents with fever and malaise 6 weeks after mitral valve replacement. On examination, his temperature is 38°C, blood pressure 130/80 mm Hg, pulse 80/min, and a loud pansystolic murmur at the apex, which radiates to the axilla. He has no skin or neurologic findings. Which of the following is the most likely causative organism?

37) A previously healthy 25-year-old music teacher develops fever and a rash over her face and chest. The rash is itchy and, on examination, involves multiple papules and vesicles in varying stages of development. One week later, she complains of cough and is found to have an infiltrate on x-ray. Which of the following is the most likely etiology of the infection?

38) A 19-year-old male has a history of athlete’s foot but is otherwise healthy when he develops sudden onset of fever and pain in the right foot and leg. On physical examination, the foot and leg are fiery red with a welldefined indurated margin that appears to be rapidly advancing. There is tender inguinal lymphadenopathy. The most likely organism to cause this infection is which of the following?

39) A 60-year-old woman comes to the physician because of a 3-month history of worsening fatigue and back pain. She has had diabetes mellitus for the past three years, and hypertension for the past ten years. Laboratory studies show: Hb 9.0 mg/dL, Serum calcium 11.2 mg/dL, Serum phosphorus 3.5 mg/dL, BUN 38 mg/dL, Serum creatinine 2.0 mg/dL. Which of the following is the most likely cause of this patient's renal failure?

40) A 70-year-old man comes to the physician due to a 4-6 month history of "almost continuous urinary dribbling." This symptom is present both day and night, and is progressively getting worse. He denies dysuria and hematuria. He has a 20-year history of diabetes mellitus-type 2, hypertension, alcoholic hepatitis and coronary artery disease. He had a gastric emptying study done a few weeks ago because of continuous nausea and early satiety. He had laser photocoagulation of both eyes for diabetic retinopathy. He has smoked one pack of cigarettes daily for 50 years, and drinks 4 to 6 beers daily. He takes NPH insulin, regular insulin, metformin, aspirin, metoprolol, lisinopril and metoclopramide. His vital signs are stable. Physical examination shows a well-appearing man. Pertinent physical findings are a normal sized prostate, decreased sensation in both legs below the knees, and absent Achilles tendon and knee reflexes bilaterally. Fecal occult blood test is negative. Postvoid residual volume is 550 ml. Urinalysis shows: Specific gravity 1.020, Blood trace, Glucose positive, Ketones negative, Protein moderate, Leukocyte esterase negative, Nitrites negative, WBC 1-2/hpf, RBC 3-4/hpf. Which of the following is the most likely cause of this patient's incontinence?

41) A 46-year-old man complains of right flank discomfort. He describes decreased urination over the last week with occasional episodes of high urine output and weakness. He is otherwise healthy. There is no family history of renal disease. On physical examination, his blood pressure is 140/90 mmHg and his heart rate is 80/min. The serum creatinine level is 2.1 mg/dl. Urinalysis shows few red blood cells, white blood cells, trace protein, and no casts. Which of the following is the most likely cause of his complaints?

42) A 17-year-old man comes to the emergency department and complains of intensive left flank pain that radiates to the groin. He refers to his symptom as "stone passage," which he has experienced "for so many times since childhood." His uncle has the same problem. Urinalysis shows hexagonal crystals. The urinary cyanide nitroprusside test is positive. Which of the following is the most likely cause of this patient's condition?