P 495 TO 512 *Q 1 TO 50*

.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?

.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?

.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?

.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?

.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?

.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?

.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?

.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?

.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?

.44) A 20-year-old man is brought to the emergency department by his mother because of a one-day history of fever, headache, and altered mental status. He has no history of medical illness. Herpes simplex encephalitis is suspected after cerebral spinal fluid analysis shows lymphocytic pleocytosis, elevated protein level, and normal glucose level; in addition, CT scan shows contrast enhancement in the temporoparietal area. High-dose intravenous acyclovir therapy is started. Two days after the beginning of the therapy, the neurologic status improves, but the patient develops oliguria. Laboratory studies show: Serum sodium 140 mEq/L, Serum potassium 4.5 mEq/L, Serum creatinine 2.8 mg/dl, BUN 25 mg/dl. Which of the following is the most likely cause of renal damage in this patient?

.45) A 65-year-old male has been having a non-productive, hacking cough for over a week. He takes an over-the-counter medication containing guaifenesin and diphenhydramine in an effort to improve his symptoms. The next day, he complains of lower abdominal discomfort and difficulty voiding. Which of the following most likely accounts for this patient's new complaint?

.46) A 12-year-old girl is brought to the clinic due to a 2-month history of headaches. Her headaches last 1-2 hours and have no fixed time of occurrence. She denies nausea, vomiting, chills or fevers. She has no other medical problems and takes no medication. Her family history is significant for hypertension and diabetes. Her blood pressure is 156/90 mm Hg, pulse is 80/min, and respirations are 14/min. Examination shows an alert child in no distress. There is a soft to-and-fro bruit heard at the right costovertebral angle. Which of the following is the most likely cause of her hypertension?

.47) A 59-year-old man comes to the physician because of dysuria, urinary urgency, and frequency. He also complains of hematuria, nocturia, decreased force of stream, and a feeling of incomplete voiding. These symptoms have been present for more than a month. For the past few days he has been experiencing dull, non-radiating suprapubic pain. He has also been having low-grade fever and malaise for the past couple of days. He has been taking analgesics for osteoarthritis of his right knee for more than 10 years. He has a 40-pack-years history of cigarette smoking and does not use alcohol or drugs. Rectal examination shows a smooth, firm enlargement of the prostate without induration or asymmetry. Neurological examination shows no abnormalities. Urinalysis shows hematuria with isomorphic red blood cells. Laboratory studies show a serum creatinine of 1.5 mg/dl, and a PSA of 2 ng/ml. Which of the following is the most likely explanation for this patient's symptoms?

48) An 80-year-old female is brought from a nursing home with a two day history of poor oral intake and lethargy. Her past medical history is significant for hypertension, diabetes mellitus, coronary artery disease with coronary stenting two years ago and Alzheimer's disease. She was hospitalized six months ago with pneumonia. Her current medications are aspirin, lisinopril, metoprolol, hydrochlorothia zide, metformin and memantine. Her blood pressure is 95/60 mmHg and heart rate is 90/min. Physical examination reveals fine crackles at the right lung base. Her mucous membranes are dry. Her laboratory findings are significant for WBC of 15,000/mm3, creatinine of 2.1 and BUN of 61 mg/dl. Her creatinine was 0.9 mg/dl during the last admission. Which of the following is the best explanation for the abnormal laboratory findings in this patient?

49) A 60-year-old man comes to the physician because of worsening fatigue and nausea. He had a carotid angiogram for the evaluation of symptomatic carotid artery stenosis 15 days ago, and was discharged home three days after the procedure. His medical problems are hypercholesterolemia, coronary artery disease, intermittent claudication, hypertension for 18 years, and diabetes mellitus for 15 years. Physical examination shows painless, reddish-blue mottling of the skin of the extremities. Laboratory studies show: Hb 10.5 g/dl, WBC 10,000/cmm with 12% eosinophils, BUN 46 mg/dl, Serum creatinine 3.0 mg/dl, Serum C3 level Decreased. Urinalysis:pH Normal,Esterase Negative, Nitrite Negative, Protein 1+, WBC Many eosinophils, RBC 1-2/HPF. Which of the following is the most likely cause of this patient's findings?

50) A 40-year-old man comes to the physician because of a two-week history of fatigue, lower extremity edema and dark urine. He has no history of serious illnesses. He takes no medications. He does not use tobacco, alcohol, or drugs. His blood pressure is 130/80 mm Hg and pulse is 80/min. Physical examination shows symmetric pitting edema of lower extremities. Laboratory studies show a serum creatinine level of 1.1 mg/dl. Urinalysis shows 4+ proteinuria and microhematuria. Light microscopy of the specimen obtained from kidney biopsy shows dense deposits within glomerular basement membrane that stain for C3, not immunoglobulins. Which of the following is the most likely pathophysiologic mechanism that explains this patient's condition?