USMLE-Infectious

A 36-year-old woman who lives in the suburbs of a large city comes to your office for a tuberculin skin test. She will be volunteering in her daughter's school cafeteria and the school district requires tuberculin testing. You inject a small amount of Mycobacterium tuberculosis purified protein derivative (PPD) in the skin and 2 days later she returns for a reading. You measure 12 mm of induration. She reports no history of tuberculosis exposure and no underlying medical conditions. She has never before been tested for tuberculosis. She was born in the United States, is not a healthcare worker, and has never spent time in prison. What is the best next step in her management?

A 22-year-old male student presents with an acute onset of fever, double vision, and painful swelling around his eyes. He also has significant muscle pain in his neck and jaw muscles. A week earlier, he experienced a period of abdominal pain, nausea, vomiting, and diarrhea, all of which resolved spontaneously. He has a history of intravenous drug abuse but has recently completed of a drug rehabilitation program. He is febrile. Physical examination shows "splinter" hemorrhages, periorbital edema, and chemosis. Chest is clear to auscultation. Cardiac exam reveals no murmur. Abdomen is soft and nontender with no organomegaly. His complete blood count is shown below: Hemoglobin 13.0 g/L MCV 85 fl Platelets 228,000/mm3 Leukocyte count 10,500/mm3 Neutrophils 56% Eosinophils 21% Lymphocytes 23% Based on these findings, what is the most likely diagnosis?

A 55-year-old pig farmer is brought to the emergency department (ED) after having a seizure two hours ago. During his transit to the ED, he has another seizure. On arrival, he is unconscious, pulseless, and not breathing. Resuscitation is successful and the patient is stabilized; however, he does not do well over the next several days and is eventually declared dead. His wife says that he had been healthy most of his life, except for the past few weeks, when he was complaining of headaches. Autopsy shows multiple fluid-filled cysts in the brain parenchyma. Which of the following is the most likely diagnosis of this patient?

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?

A 55-year-old man has undergone renal transplantation due to end-stage renal failure. His postoperative course was uncomplicated. He is currently taking prednisone and cyclosporine. He is afebrile and his pulse is 80/min, respirations are 14/min, and blood pressure is 130/65 mm Hg. Physical examination is unremarkable. Which of the following should be added to his current medication regimen to prevent opportunistic infections?

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 36.6C (98.0F), 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?

A 24-year-old man is found to be HIV positive. He is asymptomatic. Physical examination is unremarkable. Laboratory tests show: CD4 count 400/micro-L HIV viral load 9,000 copies/mL VDRL negative Toxoplasma serology negative PPD test 6mm induration His chest x-ray is unremarkable. What is the most appropriate next step in the management of this patient?

A very worried 25-year-old woman comes to the office, presents a positive pregnancy test, and says, "I'm six weeks pregnant. Two months ago, I received the rubella vaccine and my doctor told me to avoid getting pregnant for the next three months. I'm very concerned about the health of my unborn baby. I'd like to know all the available options to prevent any harm to my baby." What is the most appropriate next step in the management of this patient?

A 65-year-old man presents to the emergency department with a two-day history of fever, headache, altered mental status, and vomiting. His past medical history is significant for renal transplantation secondary to polycystic kidney disease, hypertension, and diabetes. He takes aspirin, insulin, nifedipine, cyclosporine, and prednisone. He has no known drug allergies. His temperature is 39.2C (102.5F), pulse is 102/min, respirations are 18/min, and blood pressure is 120/75 mm Hg. He is alert but confused. Fundoscopy does not show any abnormalities. His neck is stiff. Lungs are clear to auscultation. He has a normal S1 and S2 with a II/IV systolic ejection murmur heard best in the right infraclavicular area. Complete blood count shows a WBC count of 17,000/cm3 with neutrophilic leukocytosis. His blood is drawn and sent for culture. Lumbar puncture is performed and the results are pending. Which of the following is the most appropriate empiric antibiotic therapy for this patient?

A 30-year-old male has recently been diagnosed with HIV infection. He denies drug abuse. He is currently asymptomatic, and physical examination is unremarkable. He is in a stable heterosexual relationship. Laboratory studies show a CD4 count of 350/microL, HIV viral load of 15,000 copies/mL, negative VDRL, negative toxoplasma serology, tuberculin skin test of 7 mm induration, negative HBsAg, and positive anti-HBsAg antibodies. Hepatitis C antibodies are negative. Complete blood count, serum chemistries, and liver function tests are within normal limits. He has not received any vaccinations since being diagnosed with HIV. Which of the following vaccines is indicated in this patient?

A 60-year-old Caucasian woman undergoes elective coronary artery bypass surgery and aortic valve replacement. Her postoperative course is complicated by acute renal failure, atrial fibrillation, and pulmonary edema. On the third postoperative day, extubation is attempted but not tolerated, thus warranting reintubation. On the fifth postoperative day, she develops a fever to 38.9 C (102 F). Her pulse is 110-120/min and irregular, respirations are 36/min, and blood pressure is 110/65 mmHg. Her chest x-ray shows right middle and lower lobe infiltrates. WBC count is elevated with bandemia. Gram stain of her sputum shows gram-negative rods. She is given intravenous ceftriaxone; however, she deteriorates over the next 24 hours. Which of the following is the most appropriate next step in the management of this patient?

A 42-year-old man with advanced HIV infection has a two-week history of pain and difficulty with swallowing. He was given fluconazole for these symptoms one week ago, but his pain has worsened. His current medications include tenofovir, emtricitabine, efavirenz, and trimethoprim-sulfamethoxazole. His CD4 count is 90/microl and viral load is 300,000copies/ml. Endoscopy reveals large, irregular, linear ulcers in the esophagus. A biopsy of the abnormal mucosa reveals tissue destruction and the presence of intranuclear and intracytoplasmic inclusions. Which of the following is the most appropriate pharmacotherapy for this patient?

A 26-year-old man presents to the physician's office with a two-day history of multiple symptoms, including rash on his trunk, headache, fatigue, malaise, myalgias, and high-grade fever. The rash is not associated with pain, itching, or burning. It has expanded over the last two days. He went on a camping trip in Vermont two weeks ago, and recalls a tick bite at that time. There is a single lesion on his trunk, which is erythematous with central clearing. The rest of the examination is unremarkable. What is the most appropriate next step in the management of this patient?

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?

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?

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?

A 54-year-old patient walks into a blood donation camp at a community hospital. His blood report shows an ELISA positive for HIV and HBsAg. He is notified of this finding, and a subsequent western blot test is also positive for HIV. Considering this new diagnosis of HIV, which of the following is indicated in this patient?

A 7-year-old Caucasian boy with a history of cystic fibrosis presents to the emergency department with a two-day history of high-grade fever and cough productive of purulent, green-colored sputum. He also complains of chest pain, which is worsened by breathing. His temperature is 39.6C (103.2F), pulse is 112/min, respirations are 26/min, and blood pressure is 90/60 mm Hg. Chest examination shows dullness on percussion and increased tactile fremitus in the right lung base. Chest x-ray shows a right lower lobe infiltrate. Which of the following is the most appropriate pharmacotherapy for this patient?

A 35-year-old HIV-positive male comes to the physician's office because of pain on swallowing and substernal burning for the last 3 days. Examination of the oral cavity is unremarkable. Lungs are clear to auscultation and percussion. His current medications include zidovudine, didanosine, indinavir, trimethoprim-sulfamethoxazole, and azithromycin. His last CD4 count is 40cells/microl. What is the most appropriate next step in the management of this patient?

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 39.2C (102.2F), 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?

A 36-year-old man from Ohio presents with fever, malaise, fatigue, and skin lesions on his right forearm. His fever is low-grade, without any rigors or chills. His temperature is 38.4C (101 F), pulse is 87/min, and blood pressure is 124/74mm Hg. Examination shows 1-2cm warty, heaped-up skin lesions with a violaceous hue and sharply demarcated border. Some of these lesions are crusted. Wet preparation of purulent material from skin lesions shows yeast Based on these findings, what is the most likely diagnosis?

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?

A 22-year-old man comes to the urgent care clinic with a one-week history of fever, sore throat, and malaise. He has tried several over-the-counter products with partial relief. His temperature is 38.8C (102F), pulse is 110/min, respirations are 18/min, and blood pressure is 130/70 mm Hg. Oropharyngeal examination reveals palatal petechiae with streaky hemorrhages and blotchy, red macules. The tonsils are enlarged and covered with whitish exudate. Mild jaundice is present. Enlarged lymph nodes are palpable posterior to the sternocleidomastoid muscle bilaterally. Axillary lymphadenopathy is also present. Abdominal examination reveals normal bowel sounds and mild hepatosplenomegaly. His complete blood count is shown below: Hemoglobin 14.0 g/L MCV 88fl Platelets 140,000/mm3 Leukocyte count 14,500/mm3 Neutrophils 33% Lymphocytes 66% Eosinophils 1% Which of the following is commonly associated with this patient's condition?

A 25-year-old HIV-positive male comes to a physician with complaints of headache and left-sided weakness of recent onset. His temperature is 38C (100.8F), blood pressure is 115/70mm Hg, respirations are 14/min, and pulse is 73/min. Neurological examination reveals decreased power, hyperreflexia, and upgoing plantars in the left upper and lower limb. Neuroimaging by CT shows multiple ring-enhancing lesions. What is the most appropriate next step in management?

A 43-year-old male presents to a physician with an ulcer on the shaft of his penis. The ulcer is non-tender, with a raised border and a smooth base. There is bilateral inguinal adenopathy. The rest of the examination is unremarkable. Dark field microscopy of a specimen from the ulcer base reveals spirochetes. Which of the following additional screening studies should be performed on this patient?

A 25-year-old female presents to her physician with a painful ulcerative lesion on her labia for the past 2 days. She also complains of dysuria. She admits to having sexual intercourse with multiple partners for the last 6 years. Tzanck preparations of one of her lesions reveal multi-nucleated giant cells. She is encouraged to undergo testing for HIV and other STDs. Which of the following is the most appropriate screening test for HIV infection?

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 39.0C (102.2F), 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?

An 18-year-old young man comes to your clinic with complaints of fatigue, malaise, fever, and sore throat for the past few days. His temperature is 38.8C (101 F), pulse is 90/min, respirations are 18/min, and blood pressure is 135/70 mm Hg. Physical examination reveals cervical lymphadenopathy, pharyngeal hyperemia, and splenomegaly. Complete blood count shows leukocytosis with predominant atypical lymphocytes. The heterophile antibody test is positive. When you ask if he has any questions, he replies with, "Well, I'm a rugby player in school, so I need to know when I can start playing again." What is the most appropriate advice for this patient?

A 25-year-old man presents to the physician's office because of a clenched fist injury ("fight bite") incurred during a gang fight. The injury occurred two days ago and he has now started to develop pain, swelling, and redness around the wound. His immunizations are up to date. His wounds are cleaned in the clinic. Plain films of hand do not show evidence of foreign body or osteomyelitis. Which of the following is the most appropriate antibiotic for his current condition?

A 30-year-old white, HIV-infected male from Ohio presents with low-grade fever, anorexia and weight loss of 3.6kg (Bib) for the past 3 weeks. His baseline PPD test was negative. His pulse is 87/min, blood pressure is 126/76 mm Hg, temperature is 38.3C (101F), and respirations are 18/min. Examination shows oropharyngeal ulcers and hepatosplenomegaly. Lab testing shows: Hematocrit 36% Platelet count 50,000/microL WBC count 3, 1 00/microL Blood culture establishes the diagnosis of histoplasmosis. What is the most appropriate next step in the management of this patient?

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 102F (39.0C), 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 102.3F (39.3C), and lung exam reveals increased tactile fremitus in the left lower lobe. What is the most likely pathogen responsible for his current condition?

A 54-year-old diabetic woman comes to the emergency department because of increasing neck and facial pain, fever, and chills. A few weeks ago, she developed an infection on the side of her neck. She thought it would go away with over-the-counter medication, but the infection has now started to drain. For the past twenty years, she has had diabetes, which is well-controlled with an oral hypoglycemic. She denies trauma, travel, and smoking. Physical examination reveals an area of erythema and induration at the base of the neck. Serosanguineous fluid is draining from a small defect in the skin near the center of the lesion. There is no crepitus. Histological analysis of the discharge reveals the presence of gram-positive, branching bacteria. The treatment for this patient is·

A 28-year-old man presents to ER with fever, chills, and generalized weakness for the past one week. He has no history of pre-existing heart disease, but he was admitted to the hospital six months ago for cellulitis of the right arm. His temperature is 40.0C (104 F), pulse is 110/min, respirations are 22/min, and blood pressure is 110/65 mmHg. Oropharynx is clear. Lungs are clear to auscultation. A holosystolic murmur is heard at the lower sternum which increases in intensity with inspiration. His blood is drawn and sent for culture. What is the most appropriate initial antibiotic therapy for this patient?

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?

A 7-year-old boy is brought to the office by his mother due to anal pruritus for the past month. His symptoms are most severe at night. Physical examination is normal, except for mild perianal erythema. Stool examination is normal. "Scotch tape test" is positive. Which of the following is the most appropriate treatment for this child's condition?

A 45-year-old female presents to emergency room complaining of urinary frequency, burning during urination, and weakness. Her last menstrual period was one year ago, and she is not sexually active. She is not taking any medications. Her temperature is 37.8 C (100 F), blood pressure is 120/76 mmHg, pulse is 80/min, and respirations are 14/min. Very mild costovertebral angle tenderness is present. IV ceftriaxone is started. Two days later, the patient feels much better. Antibiotic susceptibility testing returned with an uropathogen (E. coli) highly sensitive to ceftriaxone, gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole (TMP/SMX). Which of the following is the most reasonable next step in the management of this patient?

A 19-year-old man presents to your office with a one-week history of fever, fatigue, and sore throat. He denies diarrhea or rash. He has no significant past medical history. His brother died of cystic fibrosis at 14 years of age. He admits to occasional cigarette use and alcohol consumption. He has smoked marijuana several times but has never used injectable drugs. He is sexually active with one partner and uses condoms occasionally. Physical examination reveals enlarged tonsils with a whitish exudate and enlarged, slightly tender lymph nodes deep to the sternocleidomastoid muscle bilaterally. The exam is otherwise unremarkable. Which of the following is the best initial test in this patient?

A 24-year-old man from Long Island, New York, presents with fever, drenching sweats, and malaise for the past week. For the last few days, he has noted jaundice and dark-colored urine. He recalls being bitten by a tick two weeks ago. His surgical history includes splenectomy after a car accident 10 years ago. He does not use tobacco, alcohol, or illicit drugs. His temperature is 39.5C (103F), pulse is 106/min, and blood pressure is 110/70 mm Hg. Systemic examination is unremarkable, except for jaundice. Based on these findings, what is the most likely diagnosis?

A 37-year-old man comes to his primary care physician for the evaluation of slightly pruritic skin lesions around his anus. He denies fever, malaise, and anorexia. He is sexually active with multiple male partners and occasionally uses condoms. He has never been tested for HIV or other sexually transmitted diseases. He has no drug allergies. Examination shows skin-colored, verrucous, papilliform lesions around his anus. Which of the following is the most appropriate treatment for this patient?

28-year-old, HIV-infected female from Michigan is admitted with Pneumocystis jirovecii pneumonia (PCP) secondary to noncompliance with prophylaxis. She was diagnosed with HIV infection three years ago. Her C04 count on admission is 30/microl, and viral load is 300,000copies/ml. Her pneumonia is adequately treated with IV antibiotics, and she subsequently receives zidovudine, lamivudine, nelfinavir, and trimethoprim-sulfamethoxazole. What is the most appropriate drug to be added to her current regimen?

A 27-year-old, HIV-positive man comes to his physician with a two-day history of fever, profuse watery diarrhea, and abdominal cramps. He has been taking zidovudine, didanosine, and indinavir for the past eight months. His temperature is 37.9C (100.2F), pulse is 102/min, respirations are 14/min, and blood pressure is 105/70 mm Hg. He is started on fluid and electrolyte support. What is the most appropriate next step in the management of this patient?

A 65-year-old Connecticut resident calls your office after finding a 3 mm red-brown tick attached to his right leg. He just returned from a hiking trip and was about to a take a shower when he discovered the tick. Which of the following is the best advice to give this patient?

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?

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 (102.2F), 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?

A 55-year-old woman presents with a three-week history of low-grade fever, weight loss of 4.5kg (10lb), 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 38.5C (101.3F), 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?

A 55-year-old pig farmer is brought to the emergency department (ED) after having a seizure two hours ago. During his transit to the ED, he has another seizure. On arrival, he is unconscious, pulseless, and not breathing. Resuscitation is successful and the patient is stabilized; however, he does not do well over the next several days and is eventually declared dead. His wife says that he had been healthy most of his life, except for the past few weeks, when he was complaining of headaches. Autopsy shows multiple fluid-filled cysts in the brain parenchyma. Which of the following is the most likely diagnosis of this patient?

A 65-year-old man presents to the emergency department with a two-day history of fever, headache, altered mental status, and vomiting. His past medical history is significant for renal transplantation secondary to polycystic kidney disease, hypertension, and diabetes. He takes aspirin, insulin, nifedipine, cyclosporine, and prednisone. He has no known drug allergies. His temperature is 39.2C (102.5F), pulse is 102/min, respirations are 18/min, and blood pressure is 120/75 mm Hg. He is alert but confused. Fundoscopy does not show any abnormalities. His neck is stiff. Lungs are clear to auscultation. He has a normal S1 and S2 with a II/IV systolic ejection murmur heard best in the right infraclavicular area. Complete blood count shows a WBC count of 17,000/cm3 with neutrophilic leukocytosis. His blood is drawn and sent for culture. Lumbar puncture is performed and the results are pending. Which of the following is the most appropriate empiric antibiotic therapy for this patient?

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?

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 37.2C (99F). Abdominal and rectal examinations are unremarkable. Which of the following is the most likely cause of this patient's symptoms?

A 34-year-old recently migrated African American male presents with severe headache and high-grade fever with chills for the last two days. He also complains of severe malaise, myalgia and vomiting. He adds that the present episode started with feeling of intense cold and chills with shivering followed by high-grade fever. He had two similar episodes in the past, when he was in Africa. His vitals are, T 38.9C (102F), RR 20/min, PR 110/min and BP100/60 mm Hg. He has pallor with mild splenomegaly but rest of his physical examination is normal. What is the most likely diagnosis in this patient?

A 22-year-old man comes to the urgent care clinic with a one-week history of fever, sore throat, and malaise. He has tried several over-the-counter products with partial relief. His temperature is 38.8C (102F), pulse is 110/min, respirations are 18/min, and blood pressure is 130/70 mm Hg. Oropharyngeal examination reveals palatal petechiae with streaky hemorrhages and blotchy, red macules. The tonsils are enlarged and covered with whitish exudate. Mild jaundice is present. Enlarged lymph nodes are palpable posterior to the sternocleidomastoid muscle bilaterally. Axillary lymphadenopathy is also present. Abdominal examination reveals normal bowel sounds and mild hepatosplenomegaly. His complete blood count is shown below: Hemoglobin 14.0 g/L MCV 88 f l Platelets 140,000/mm3 Leukocyte count 14,500/mm3 Neutrophils 33% Lymphocytes 66% Eosinophils 1% Which of the following is commonly associated with this patient's condition?

A 36-year-old man from Ohio presents with fever, malaise, fatigue, and skin lesions on his right forearm. His fever is low-grade, without any rigors or chills. His temperature is 38.4C (101 F), pulse is 87/min, and blood pressure is 124/74mm Hg. Examination shows 1-2cm warty, heaped-up skin lesions with a violaceous hue and sharply demarcated border. Some of these lesions are crusted. Wet preparation of purulent material from skin lesions shows yeast Based on these findings, what is the most likely diagnosis?

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?

A 65-year-old African-American man is hospitalized after a car accident. He has a vertebral fracture at the level of the fifth thoracic vertebra and is unable to move his lower extremities. Since his injury, he has needed a catheter for micturition. Which of the following is the most effective measure for decreasing the risk of a urinary tract infection in patients requiring bladder catheterization?

A 34-year-old male comes to the physician's office due to a severely pruritic lesions on his hands. He denies any trauma but recalls using his hands to change the sand of his children's sandbox when they went to Miami Beach three days ago. He later developed pruritic, erythematous papules over his arm. These papules progressed to serpiginous, reddish brown, elevated lesions, which are evident bilaterally on the upper extremities on exam. What is the most likely diagnosis?

A 54-year-old diabetic woman comes to the emergency department because of increasing neck and facial pain, fever, and chills. A few weeks ago, she developed an infection on the side of her neck. She thought it would go away with over-the-counter medication, but the infection has now started to drain. For the past twenty years, she has had diabetes, which is well-controlled with an oral hypoglycemic. She denies trauma, travel, and smoking. Physical examination reveals an area of erythema and induration at the base of the neck. Serosanguineous fluid is draining from a small defect in the skin near the center of the lesion. There is no crepitus. Histological analysis of the discharge reveals the presence of gram positive, branching bacteria. The treatment for this patient is·

A 72-year-old man presents to the ED during the month of January complaining of non-productive cough, fever, malaise, runny nose, and severe body aches. The symptoms came on suddenly last night. He has no other medical problems. Physical examination reveals a temperature of 38.9°C (102.0.F) and oxygen saturation of 88% on room air. His lung exam reveals diffuse crackles with occasional wheezes. Laboratory values are: Hematocrit 44% Platelets 219,000/mm3 Leukocyte count 4,100/mm3 Neutrophils 65% Lymphocytes 32% His chest x-ray reveals diffuse interstitial infiltrates bilaterally. What is the most appropriate initial therapy for this patient?

A 49-year-old man presents with a three-week history of fever, weight loss, and anorexia. He also reports muscle aches. He has no cough or shortness of breath. He has a thirty pack-year history of cigarette smoking. His temperature is 38.9C (102 F), blood pressure is 120/76mm Hg, pulse is 90/min, and respirations are 16/min. Lungs are clear to auscultation. The rest of the physical examination is unremarkable. Blood cultures reveal Streptococcus bovis. Echocardiogram reveals vegetations on the mitral valve. Other than antibiotic treatment, what further step is recommended in this patient?

A 32-year-old man from Arkansas presents to physician with a two-day history of fever, headache, malaise, and myalgias. His family says that he seems slightly confused. He recalls having a tick bite two weeks ago after walking through the woods. His temperature is 39C (102F), pulse is 90/min, and blood pressure is 125/80 mm Hg. Neck is supple and there is no lymphadenopathy noted. Oropharynx is clear. Chest auscultation is unremarkable. Abdomen is soft and non-tender. There is no rash evident. Neurologic examination is nonfocal. Laboratory testing shows: Complete blood count: Hemoglobin 14.0 g/L MCV 88 fL Platelets 78,000/mm3 Leukocyte count 2,500/mm3 Neutrophils 56% Eosinophils 1%Lymphocytes 33% Monocytes 10% Liver studies: Total protein, serum 6.5 g/dL Total bilirubin 1.0 mg/dL Direct bilirubin 0.8 mg/dL Alkaline phosphatase 110 U/L Aspartate aminotransferase (SGOT) 98 U/L Alanine aminotransferase (SGPT) 105 U/L What is the most appropriate next step in the management of this patient?

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?

A 23-year-old man is brought to the emergency room because of confusion and hallucinations. While in ER, he has an episode of generalized tonic-clonic seizures. His past medical history is significant for illicit drug use. His temperature is 40.0C (104.0F), pulse is 95/min, and blood pressure is 120/80 mm Hg. He is confused and disoriented. Fundoscopy is with in normal limits. There is no neck stiffness. The neurological examination shows upgoing plantar reflexes bilaterally. Lumbar puncture is performed and CSF analysis shows the following: Glucose 35mg/dl Protein 80mg/dl WBC count 150/cm3 Neutrophils 10% Lymphocytes 90% Gram stain Negative CT scan of the brain without contrast is normal. Which of the following is the most appropriate next step in the management of this patient?

A 22-year-old woman presents to the emergency department after she is bitten on her right arm by her neighbor's dog. She provoked the dog while it was eating. The dog is not immunized against rabies, but does not show any signs of rabies. Her right forearm shows a deep bite wound. Her last tetanus booster was 3 years ago. Her wound is cleaned with soap, water, and povidone-iodine solution. What is the most appropriate next step in the management of this patient?

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?

A 25-year-old male comes to the clinic because of a painless ulcer on his penis. He denies fever or urethral discharge, but admits to recent sexual activity with a prostitute. He describes severe rash and face swelling with penicillin. Physical examination reveals a shallow, non-tender ulcer. There is no lymphadenopathy. Dark field microscopy reveals spirochetes. Which of the following is the most appropriate treatment for this patient?

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 102F (39.0C), 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 102.3F (39.3C), and lung exam reveals increased tactile fremitus in the left lower lobe. What is the most likely pathogen responsible for his current condition?

65-year-old female who lives in nursing home and is bed ridden due to severe right hemiparesis is brought to the ER because of altered mental status and decreased oral intake. Her past medical history includes hypertension, diabetes, hyperlipidemia, and myocardial infarction. She has a chronic indwelling Foley catheter to avoid contamination of a sacral decubitus ulcer. She is febrile in the ER. Examination shows dry mucus membranes and clear lungs. She is disoriented. The decubitus ulcer has good granulation tissue and does not appear infected. Labs show: Hemoglobin 12.0 g/L Leukocyte count 12 500/mm3 Blood urea nitrogen (BUN) 28 mg/dL Serum creatinine 0.8 mg/dL Serum bicarbonate 24 mg/dL Urinalysis: Specific gravity 1.036 Protein 1+ pH 8.5 Blood negative Glucose 1+ Ketones negative Leukocyte esterase positive WBC 50-100/hpf Bacteria few Which of the following is the most likely cause of her altered mental status?