A 25-year-old man with a history of intravenous drug use has had one bout of Pneumocystis carinii (jirovecii) pneumonia which was successfully treated a year ago. Over the past week he has developed painful, progressive visual loss involving both eyes. Laboratory studies show a WBC count of 3600/microliter with differential count of 78 segs, 3 bands, 5 lymphs, and 14 monos. Which of the following infections is he most likely to have?
A Cryptosporidium parvum
B Staphylococcus aureus septicemia
C Pneumocystis carinii (jirovecii)
D Cytomegalovirus
E Mycobacterium avium-intracellulare
NEXT QUESTION - - INDEX OF QUESTIONS - - EXAM MENU
A 60-year-old woman has had fevers for 5 months. On physical examination her temperature is 38.1 C. A chest radiograph shows a diffuse reticulonodular pattern along with enlarged hilar lymph nodes. A supraclavicular lymph node biopsy shows non-caseating granulomata with fibrosis, but a Ziehl-Neelsen stain shows no acid-fast bacilli. Which of the following is the most likely diagnosis?
A Silicosis
B Scleroderma
C Mycobacterium avium-intracellulare infection
D Byssinosis
E Sarcoidosis
A 65-year-old previously healthy woman has had a non-productive cough increasing in severity over the last 10 days. She has a temperature of 38.0 C. A chest radiograph shows faint interstitial infiltrates but no areas of consolidation. A CBC reveals a WBC count of 8900/microliter with differential count of 60 segs, 3 bands, 25 lymphs, and 12 monos. A sputum gram stain reveals a few gram positive cocci, gram negative cocci, and Candida with few neutrophils. Her condition gradually improves over the next week. Which of the following infectious agents is most likely responsible for her illness:
A Mycobacterium tuberculosis
B Klebsiella pneumoniae
C Cryptococcus neoformans
D Influenza A virus
E Pneumocystis carinii (jirovecii)
A 26-year-old G3 P2 woman has an ultrasound performed at 19 weeks gestation that shows fetal hydrops. TORCH titers are done that show an elevated Toxoplasma IgG and IgM titer. Which of the following findings is most likely to be present in the fetus as a consequence of this infection?
A Cervical lymph node enlargement
B Keratitis
C Cerebral inflammation with calcification
D Pneumonia alba
E Congenital cardiac defects
A 35-year-old postpartum woman has developed a fever over the last two days. On physical examination her temperature is 38.9 C, heart rate 110/minute, respirations 35/minute, and blood pressure 70/30 mm Hg. Laboratory studies show a WBC count of 13,790/microliter. A blood culture grows Esherichia coli. These findings are most likely to be produced through which of the following mechanisms?
A Myocardial failure
B Vasodilation
C Hemorrhage
D Thrombosis with embolism
E Renal failure
A 39-year-old man had an acute febrile illness with fever, pharyngitis, lymphadenopathy, and malaise a week following a trip to a city known for its commercial sex workers. He is tested for HIV a month later and is positive. In how many years would you predict that his peripheral blood CD4 lymphocyte count will drop below 200/microliter:
A 1
B 5
C 10
D 15
E 30
A 50-year-old man has had a chronic cough for the past 7 months. On physical examination his temperature is 37.8 C. He appears cachectic. A chest radiograph showed a diffuse reticulonodular pattern with multiple small 2 to 3 mm nodules in all lobes of the lungs. A transbronchial biopsy shows foci of epithelioid macrophages and lymphocytes within the lung parenchyma. These findings are most strongly suggestive of infection with which of the following organisms?
A Staphylococcus aureus pneumonia
B Mycobacterium tuberculosis
C Influenza virus
D Pneumocystis carinii (jirovecii)
E Chlamydia trachomatis
A 30-year-old previously healthy man has had a 10% loss of body weight over the past month. Physical examination reveals oral thrush. Laboratory studies show a CD4 lymphocyte count of 152/microliter. He is further interviewed to establish the risk factor for his illness. Which of the following risks is most likely to be considered irrelevant to his illness?
A Sexual intercourse with an HIV-infected person
B Sharing a needle for drug injection from an HIV-infected person
C Transplacental spread from an HIV-infected mother
D Needlestick injury drawing blood from an HIV-infected person
E Cleaning up a spill of HIV-infected blood without gloves
A clinical study is performed on patients in the hospital who had procedures done to obtain material for microbiologic culture for bacterial organisms. It is observed that some body sites are colonized by micro-organisms which are not considered pathogens, but which are found to grow in culture from those sites. However, there a some body sites from which only pathogens are grown. Which of the following sites is most likely to yield only pathogenic bacteria on culture?
A Floor of mouth
B Skin of hands
C Cecum
D External ear
E Alveoli
Upon return from a 6 month trip to West Africa, a 28-year-old woman develops paroxysms of chills and fever that persist for a month. On physical examination the spleen tip is palpable. A CBC shows: Hgb 10.5 g/dL, Hct 31.6%, MCV 89 fL, platelets 211,000/microliter, and WBC count 7350/microliter. Her serum haptoglobin is decreased. A direct Coombs test is negative. A urinalysis shows sp gr 1.012, pH 5.5, and 3+ blood with no protein, glucose, or ketones. Urine microscopic examination shows no RBCs or WBCs or casts. Which of the following diseases is most likely to be diagnosed in this woman by observation of her peripheral blood smear?
A Babesiosis
B Relapsing fever
C Malaria
D Trypanosomiasis
E Filariasis
An experiment is performed to analyze complement activation. It is observed that some bacterial organisms instigate complement activation via the alternate pathway. These organisms are found to have abundant lipopolysaccharide as part of their cell wall structure. Which of the following organisms is most likely to fulfill these observations?
A Staphylococcus aureus
B Treponema pallidum
C Klebsiella pneumoniae
D Mycobacterium tuberculosis
E Candida albicans
A study is performed of health care workers who have had a needlestick injury while performing their jobs. The number of health care workers who subsequently became HIV positive is compared with the number of exposures in which HIV infection was present. Which of the following is the most likely risk for seroconversion with a single exposure to HIV by a needlestick injury?
A About the same as for hepatitis C virus
B Less than 1 in 300
C About 1 in 20
D About the same as for hepatitis B virus
E Nonexistent when using latex gloves
A clinical study is performed to analyze the risk to a patient for serious infection with standard invasive diagnostic medical and surgical procedures. It is observed that the risk for infection is low when proper technique is employed, but there is some risk involving every procedure. Which of the following procedures is likely to present the most minimal risk for serious infection?
A General anesthesia for tooth extraction
B Foley catheter placement for two weeks
C Nasogastric tube insertion
D Laparotomy
E Intravenous catheter placement for a week
An experiment is conducted to assess the efficacy of disinfectants in the hospital. It is observed that some disinfectants display efficacy towards more microbial agents than others. Which of the following substances is most likely to be efficacious toward the largest number of infectious agents?
A 3% Hydrogen peroxide
B 0.5% Sodium hypochlorite
C 10% Neutral buffered formalin
D 1% Quaternary ammonium chloride
E 50% Ethanol
A 41-year-old man has noted firm reddish area on the glans of his penis for the past week. On physical examination the lesion is 0.4 cm in diameter, has surface ulceration with a firm base, but it is not particularly painful. This lesion resolves over the next week, but then a month later he develops a bilateral palmar maculopapular rash. The rash subsides in 3 weeks. Which of the following infectious agents is most likely to produce these findings?
A Treponema pallidum
B Human papillomavirus
C Hemophilus ducreyi
D Neisseria gonorrheae
E Human immunodeficiency virus
A 20-year-old commercial sex worker has lower abdominal pain of 24 hours duration. There is no previous history of similar abdominal pain. On physical examination her temperature is 38.4 C. She has a markedly tender lower abdomen on palpation. Laboratory studies show her total WBC is 29,000/microliter with 85% neutrophils, 10% lymphocytes, and 5% monocytes. At laparotomy there is a distended, fluid-filled, erythematous left fallopian tube that is about to rupture. The tube is resected. Fluid from the tube is sent for culture. Which of the following organisms is most likely to be cultured?
B Neisseria gonorrheae
C Human papillomavirus
D Candida albicans
E Staphylococcus epidermidis
A 10-year-old child has had a severe watery diarrhea for the past 2 days. She is oliguric. On physical examination she has poor skin turgor. Laboratory studies show serum sodium 155 mmol/L, potassium 4.5 mmol/L, chloride 110 mmol/L, and CO2 26 mmol/L. A stool culture yiedls an organisms which causes the persistent activation of adenylate cyclase by GTP which leads to excessive intestinal fluid loss. Which of the following organisms is most likely to produce a toxin that has this effect?
A Escherichia coli
B Salmonella enteritidis
C Vibrio cholerae
D Shigella flexneri
E Staphylococcus aureus
A 61-year-old man with a history of poorly controlled diabetes mellitus develops pain and swelling over the right side of his face over the past 2 days. On physical examination his temperature is 37.8 C. There is tenderness to palpation over the right maxillary region. A CT scan shows expansion with bony erosion around the right maxillary sinus. A gram stain of an aspirate from this site reveals broad, non-septate hyphae. Additional laboratory studies show serum glucose 278 mg/dL with 4+ ketones and 4+ glucose in urine. These findings are most likely to occur with infection by which of the following organisms?
A Coccidioides immitis
D Mucor
E Actinomyces israeli
An 18-year-old man is plowing a field on a hillside. The tractor strikes a large rock and tips over, pinning him underneath. The ground is muddy, and he is able to work his way free. He discovers a deep, penetrating puncture wound to his calf. He walks home and washes the soil off the wound site and puts a bandage over it. A week later the wound is healing, and the leg is not swollen, but he begins to experience generalized muscle spasms, with stiffness and pain in his shoulders and back. He has difficulty with eating and swallowing, with painful stiff jaw and facial muscles. Which of the following organisms is most likely responsible for these findings?
A Clostridium difficile
B Clostridium septicum
C Clostridium perfringens
D Clostridium tetani
E Clostridium botulinum
A 37-year-old man has had progressive dementia and loss of motor function over the past 2 years. A CT scan of the brain shows mild cerebral atrophy. Laboratory studies show that he is HIV positive. His HIV-1 RNA level is 5660 copies/mL. His neurologic decline is most likely to be caused by which of the following infectious agents?:
A Cryptococcus neoformans
B Cytomegalovirus
C HIV
D Toxoplasma gondii
E Mycobacterium avium-complex
A 27-year-old man with a history of injection drug usage develops a high fever. On physical examination, his temperature is 39.3 C. He has a loud heart murmur. An echocardiogram reveals 1 to 2 cm vegetations on two cusps of his aortic valve. A chest radiograph demonstrates bilateral pulmonary edema. Which of the following complications of his disease is he most likely to develop?
A Aortic stenosis
B Constrictive pericarditis
C Pulmonary infarction
D Cardiac myxoma
E Cerebral mycotic aneurysm
A budget decrease for epidemiology services by a state health department occurs because of decreasing tax revenues. As a consequence, surveillance for reportable infectious diseases becomes more difficult to perform in a timely fashion. Which of the following health care problems is most likely to occur because of reduced surveillance?
A Lack of prevention of Staphylococcus aureus food poisoning outbreaks
B An increased death rate from human immunodeficiency virus infections
C Increased development of resistant strains of Streptococcus pneumoniae
D More hospital outbreaks of pseudomembranous colitis from C. dificile
E Failure to identify promptly a beginning epidemic of Neisseria meningitis
A 41-year-old man has had a chronic cough for 3 months. Last week he experienced an episode of hemoptysis. On physical examination his temperature is 37.8 C, pulse 80/minute, respirations 17/minute, and blood pressure 130/85 mm Hg. A chest radiograph shows a cavitary 4 cm nodule in the right upper lung. There are a few adjacent smaller nodules with calcifications. Laboratory studies show WBC count 9300/microliter with hemoglobin 13.5 g/dL and platelet count 228,040/microliter. Which of the following is the most likely causative infectious agent?
A Aspergillus fumigatus
B Pseudomonas aeruginosa
C Cytomegalovirus
D Mycobacterium kansasii
E Chlamydia psittaci
A 30-year-old man has a severe headache developing over the past 4 days. He goes to the emergency department, and on examination he has nuchal rigidity. His temperature is 38.2 C. Bilateral papilledema is present. Needle tracks are noted in his left antecubital fossa. He quickly becomes obtunded and dies. At autopsy the meninges are clouded and obscure the sulci. A microscopic section of meninges shows numerous 7 micron sized yeast-like organisms with narrow-based budding and no hyphae by Gomori methenamine silver stain. Which of the following laboratory test findings was he most likely to have had prior to death?
A CD4 lymphocyte count of 100/microliter
B 4+ ketonuria
C Positive ANA with a nucleolar pattern
D Factor V Leiden mutation
E Increased carcinoembryonic antigen
A 40-year-old man has had a productive cough with yellowish sputum for the past 10 days. On examination his temperature is 38.2 C. There are crackles on auscultation of the left upper lung. A chest radiograph reveals a nodule in the left upper lobe that has a central cavity with an air-fluid level. A complete blood count shows a total WBC count of 15,700/microliter with differential count of 73 segs, 10 bands, 12 lymphs, and 5 monos. Which of the following findings is most likely to be present in his sputum specimen?
A 1+ acid fast bacilli
B Viral inclusions
C Atypical squamous cells
D Hemosiderin-laden macrophages
E 4+ gram positive cocci
A 78-year-old woman has a 5 year history of Alzheimer's disease. She develops a fever and cough productive of copious amounts of yellowish sputum over the past day. Her vital signs on admission include temperature 38.1 C, pulse 105/minute, respirations 26/minute, and blood pressure 110/75 mm Hg. She has dullness to percussion at the right lung base. She dies after only two days in hospital. The microscopic findings from the right lower lobe at autopsy include numerous neutrophils within the alveolar spaces, with minimal destruction of alveolar walls. Which of the following is the most likely infectious cause for her pulmonary disease?
A Influenza A virus
B Streptococcus pneumoniae
C Mycobacterium tuberculosis
Universal precautions are mandated as part of Occupational Safety and Health Administration (OSHA) regulations for all health care work places in the U.S. Which of the following is the best form of implementation for OSHA precautions in the health care setting?
A Only specimens from patients known to have an infectious disease should be labelled as infectious
B All needles used for venipuncture should be recapped or broken prior to disposal to prevent spread of infection
C All patients must be tested for hepatitis B and HIV on admission to a health care facility
D Any blood spill should be cleaned up promptly
E Health care workers should wash their hands upon arrival at work
A 55-year-old man has had a non-productive cough with fever for 5 months. He has experienced a 6 kg weight loss during that time. His temperature is 37.7 C. A chest radiograph reveals upper lobe cavitary lesions and hilar lymphadenopathy. These findings are most consistent with infection by which of the following organisms?
B Parainfluenza
C Hemophilus influenzae
D Pseudomonas aeruginosa
E Nocardia asteroides
During a trip for a business meeting at a city located in a tropical region, several adult males eat lunch at a cafe along the street. From 1 to 3 days later, they all develop a watery diarrhea. On physical examination there are no remarkable findings. Stool samples reveal no neutrophils and no red blood cells. They recover completely within 4 days. Which of the following organisms is most likely to produce their disease?
A Salmonella typhi
B Escherichia coli
C Staphylococcus aureus
E Vibrio cholerae
A 30-year-old man has had dysuria for the past 4 days. On physical examination he is afebrile, but there is a purulent urethral discharge. A gram stain of this exudate reveals gram negative diplococci. Without treatment, which of the following complications is he most likely to have?
A Squamous cell carcinoma
B Suppurative lymphadenitis
C Meningitis
D Hemorrhagic cystitis
E Urethral stricture
A 19-year-old student has noted fever for one week with sore throat, mild diarrhea, headache, and generalized aching. His examining physician notes pharyngitis, generalized lymphadenopathy, and a very mild diffuse erythematous rash. A history of unprotected sexual intercourse with male and female partners over several months is obtained. If his HIV test is positive, then which of the following is the most likely interpretation of these findings?
A He has clinical AIDS at this time
B He has acute retroviral illness
C The test is probably a false positive
D He will not develop clinical AIDS if treated with zidovudine
E He should not worry about transmitting HIV to others
A 22-year-old primigravida has not felt any fetal movement for the past 3 days. Her fetus is stillborn a day later at 28 weeks gestation. The fetus at the time of birth is noted to be hydropic. At autopsy the fetus is found to have marked hepatosplenomegaly and periventricular leukomalacia with necrosis and calcification. Microscopically, in the renal tubules are epithelial cells that are large and have intranuclear inclusions. Which of the following congenital infections is most likely to cause these findings?
A Cytomegalovirus
C Toxoplasmsa gondii
D Rubella
A 65-year-old man has a stroke leaves him incapacitated and in hospital. A week later he develops a fever and cough. He becomes septic. A chest x-ray shows bilateral patchy infiltrates and a right lower lobe 5 cm nodule that has an air-fluid level. Which of the following organisms is most likely to be cultured from his blood?
D Aspergillus fumigatus
E Histoplasma capsulatum
A 34-year-old woman has a 17 mm diameter area of reddish induration noted on her forearm 3 days after a PPD test was placed. Which of the following microscopic findings is most likely to be present in this area?
A Intranuclear inclusions
B Langhans giant cells
C Gummatous necrosis
D Abscess formation
E Decubitus ulcer
A 47-year-old man has noted dysuria for a week. He then develops a high fever along with shaking chills. A physical exam reveals a temperature of 38.3 CC and flank tenderness on the right. A urinalysis reveals numerous WBCs and WBC casts. He has a CBC that shows: Hgb 13.9 g/dL, Hct 42.1%, MCV 90 fL, platelet count 299,000/microliter, and WBC count 13,890/microliter with differential count of 78 segs, 9 bands, 10 lymphs, and 3 monos. Which of the following organisms is most likely to be cultured from his urine?
C Schistosoma hematobium
E Klebsiella pneumoniae
A 70-year-old man has been receiving chemotherapy for lung cancer for the past 2 months. He has developed a painful vesicular skin eruption in a dermatomal distribution on the left side of his chest during the past week. Which of the following infectious agents is most likely to cause these findings?
A Histoplasma capsulatum
B Cryptosporidium parvum
C Herpes zoster virus
D Schistosoma hematobium
E Cryptococcus neoformans
A 4-year-old girl has never received any immunizations. She has developed a fever for the past 3 days. She complains of a sore throat. On examination, there is a firmly adherent dirty gray membrane covering the tonsils. On removal of a portion of the membrane for gram stain and culture, there is marked bleeding. Microscopic examination of this membrane with tissue gram stain shows pleomorphic gram positive rods. She has an irregular heart rate. She recovers within the next two weeks. Which of the following infections is she most likely to have had?
A Bordatella pertussis
B Hemophilus influenzae
C Mumps
D Rubeola
E Corynebacterium diptheriae
A 24-year-old man has had increasing malaise for 3 weeks. He now notes a yellowish hue to his skin and sclerae. On physical examination his temperature is 37.5 C. He has right upper quadrant tenderness. Laboratory studies show his serum AST is 520 U/L and ALT 590 U/L with total bilirubin 5.8 mg/dL. His hepatitis B surface antigen test is positive. Which of the following pathologic processes is most likely to be present in his liver?
A Apoptosis
B Granuloma formation
C Coagulative necrosis
E Fatty metamorphosis
Children in winter:
Admitted to hospital
Long to breath easy.
A Adenovirus
D Parainfluenza virus
E Respiratory syncytial virus
A 30-year-old HIV-infected man has had a profuse diarrhea, with up to 12 loose watery stools per day, for the past 4 days. On physical examination he is afebrile. He has poor skin turgor. Laboratory studies show a CD4 count of 125/microliter. Which of the following infections is he most likely to have?
B Cryptosporidium
E Pseudomonas aeruginosa
A 20-year-old healthy woman is sexually active. She has noted multiple painful genital and perineal lesions that have occurred sporadically over the past 6 months. On physical examination there are epithelial vesicles ranging in size from 0.1 to 0.3 cm noted on the left labium. Which of the following infectious agents is she most likely to have?
D Herpes simplex virus
A 26-year-old woman is in the 2nd trimester of her first pregnancy. She noted a slight erythematous rash of her cheeks a week ago, but this rash has now subsided. She has noted decreased fetal movement during the past day. An ultrasound scan shows fetal hydrops. The fetus is stillborn at 29 weeks gestation. Autopsy reveals marked hydrops. Microscopic examination of the liver shows dark pink intranuclear inclusions within erythropoietic precursors. Which of the following infectious agents is most likely to have caused these findings?
A Parvovirus
B Rubeola
C Rubella
E Herpes simplex virus
A 42-year-old woman has a positive PPD and receives a screening chest radiograph that shows a discrete 2 cm right lower lobe nodule. A wedge resection of the nodule is performed at thoracotomy. Microscopic examination of the lesion reveals extensive central caseous necrosis with a rim of epithelioid macrophages, lymphocytes, fibroblasts, and collagen. Which of the following organisms is most likely to produce these findings?
C Schistosoma mansoni
A 29-year-old woman has a 10 year history of HIV infection. She has had a non-productive cough of 2 weeks' duration. In the past two days she has had a severe headache with increasing stiffness of the neck, then obtundation. On examination she has a temperature of 38.4 C. A lumbar puncture reveals an increased CSF pressure but microscopic examination shows only a few WBCs. Which of the following infectious agents is most likely to cause her illness?
An autopsy study is conducted to determine patterns of organ involvement with infectious agents. It is observed that one infectious agent appears extensively in macrophages, primarily in lymph node, spleen, and liver, leading to enlargement of those organs. It is best diagnosed from a blood culture or bone marrow sample. Which of the following organisms is most likely to produce these findings?
A Mycobacterium avium-complex (MAC)
B Human papillomavirus (HPV)
C Cytomegalovirus (CMV)
E Human immunodeficiency virus (HIV)
FIRST QUESTION - - INDEX OF QUESTIONS - - EXAM MENU