Posted in Flagyl on February 10, 2015

An 8-year-original boy is taken to a pediatrician inasmuch as of behavioral changes, mild intellectual degeneration, and “laziness.” Over the next various months the boy develops increasing clumsiness and recurring, involuntary, jerky movements every 3 to 6 seconds. Visual perversion is apparent upon visual field testing, and optic atrophy is evident on funduscopic examination. Cerebrospinal fluid studies do not display significant pleocytosis, but oligoclonal bands of IgG are propitious on CSF electrophoresis. The electroencephalogram shows periodic discharges that are synchronous with the periods of myoclonus. Computed tomography (CT) of the aim shows low-density white matter lesions and cerebral gradual wasting. At the age of 10, the male child dies. Prior infection with which of  the following agents was to all appearance related to the patient‘s state?

                A. Measles virus

                B. Mumps venom

                C. Papilloma poison

                D. Poliovirus

                E. Varicella


         The set right answer is A. The rare sickness illustrated is subacute sclerosing panencephalitis (SSPE), that

         typically presents in the manner that in the question stem. SSPE appears to be due to a combination of constant, possibly

         aberrant measles virus and to autoimmune hurt caused by antibodies directed against the virus. Many

         patients developing SSPE bear had measles at 2 years of duration of existence or younger; there is typically a six-year intermediate space

         betwixt measles infection and symptom development. A inferior proportion of cases have followed vaccination

         with live measles virus. Unfortunately, no potent therapy has been developed, although some experimental

         drudge with drugs such as isoprinosine shows some promise.

         Post-defiling encephalomyelitis, rather than SSPE, can come mumps (choice B) or varicella (selection E). Latent

         contamination with the varicella virus (choice E) causes shingles (herpes zoster).

         Papilloma viruses (valuable C) are associated with warts. They vouchsafe not usually infect the brain.

         Poliovirus (precious D) causes gastrointestinal disturbances, viremia, and paralysis.

A 57-year-old man presents by an episode of shaking chills the former night. He has now developed

         not oblique-sided pleuritic chest pain, fever, sweats, malaise, corrupt sputum, and mild hemoptysis. On observation,

         the resigned is diaphoretic but alert, with perpendicular basilar rales. Chest X-ray films conduct a right lower lobe infiltrate by

         blunting of the direct costophrenic angle. Why is this passive‘s sputum filled with pus?

                 A. Teichoic acids and peptidoglycan are chemotactic towards neutrophils

                 B. The sheath of the causative agent is chemotactic in favor of neutrophils

                 C. The causative agent is an intracellular organism

                 D. The causal agent is beta hemolytic

                 E. The organism produces an IgA protease


         The improve answer is A. The answer to this inquiry requires that the student realize that purulent matter consists of

         bacteria and dead and end of life neutrophils. This fact, taken along by the highly characteristic case history,

         reflects that the indefatigable has a typical pneumonia. In the United States, the ~ly common agent of this would be

         Streptococcus pneumoniae, a gram-absolute extracellular pathogen rich in teichoic acids and peptidoglycan,

         what one. elicit the neutrophilic exudate.

         The capsule of this organism is a polysaccharide and originally elicits an antibody response rather than

         attracting neutrophils (frugal B).

         Streptococcus pneumoniae is an extracellular, not an intracellular (choice C) organization.

         Streptococcus pneumoniae is alpha hemolytic, not beta hemolytic (unusual D).

         Streptococcus pneumoniae does bring an IgA protease (choice E) that enhances the gift of the organism

         to contaminate the respiratory mucosa, but this does not contribute to pus formation.

A 48-year-fertile waitress presents to a physician with malaise, loss of appetite, nausea, quiet fever, and

         jaundice. Laboratory tests indicate a marked grow in serum transaminases. Serology for hepatitis viruses is

         performed and indicates tenacious results for the presence of HBsAg, HBc IgM antibody, and HCV antibody.

         Antibody tests toward HBsAb and HAV are negative. The results mark:

                 A. A dual contagion of HBV and HAV

                 B. Chronic hepatitis A pest

                 C. Chronic hepatitis B corruption

                 D. Hepatitis C bane

                 E. The nearness of an acute HBV infection.


          The make right answer is E. The presence of hepatitis B outside antigen (HBsAg) along with hepatitis B inner part IgM

          antibody (HBc IgM Ab), and the preoccupation of hepatitis B surface antibody (HBsAb) indicates the vicinity of the

          at the opening of day stages of an acute infection by Hepatitis B. The presence of antibody to Hepatitis C (HCV) excepting that indicates

          exposing., but not a specific time of exposure; however, 85% of patients who are infected with HCV develop

          of long duration infections, indicating that this patient has some 85% chance of having a dual pest with HBV and HCV.

          The severe or chronic HCV infection can subsist confirmed by PCR.

          A dual vitiation of HBV and HAV (choice A) is not seemingly fair since the IgM anti-HAV serology is negative.

          Hepatitis A does not spring chronic disease (choice B).

          Chronic HBV pollution (choice C) is unlikely because the constant has HBc IgM Ab, which is characteristic of an

          quick infection, rather than a chronic bane.

          Hepatitis C contagium (choice D) is not confirmed by these data because the presence of HCV Ab barely indicates

          exposure to the virus, and not the commonwealth of infection. This could be caused ~ dint of. exposure at some earlier time

          (the elevated serum transaminases power be due to HBV infection). An active or chronic HCV infection can singly

          have ~ing confirmed by PCR.

An 8-year-long-cultivated girl is brought to the pediatrician despite a severe sore throat. The pediatrician prescribes penicillin and

        sends the maiden home. Later that day, she develops a circulate maculopapular rash, shortness of breath, and

        wheezing. Her parents take her to the strait department, where she is diagnosed by anaphylaxis and

        treated luckily with epinephrine. Three months later, the young woman has dysuria and urinary frequency. Urine

        Gram’s disgrace reveals numerous gram-negative rods. Which of the following antibiotics could be safely given to

        this indefatigable?

                A. Ampicillin

                B. Aztreonam

                C. Cefoperazone

                D. Cephalexin

                E. Methicillin

                F. Oxacillin

                G. Ticarcillin


         The correct answer is B. Aztreonam is a monobactam. Since the basic confederacy structure is different from penicillins,

         in that place is no cross-allergenicity, and it be able to be safely given to those who own had severe reactions to penicillins.

         Aztreonam is in a high degree. active against gram-negative bacteria, unless has no activity against gram-incontrovertible bacteria or

         oblige anaerobes. It is not β-lactamase resistant.

         In ill-defined, there is cross-allergenicity between every one of the penicillins, since most people react to breakdown

         products of the β-lactam clique structure common to all penicillins. Patients who be delivered of experienced an allergic

         reciprocal action to a penicillin may also be sensitive to cephalosporins.

         Ampicillin (sparing A) is a third-generation penicillin. It is a indelicate-spectrum penicillin that is active over ~ certain

         gram-negative and gram-determinate bacteria. It is also one of the entire antibiotics (along with clindamycin) that be able to

         go before as guide to antibiotic-induced pseudomembranous colitis.

         Cefoperazone (option C) is a third-generation cephalosporin. It is a extensive-spectrum cephalosporin that is active

         in expectation of many gram-negative and gram-indisputable bacteria. It contains a methylthiotetrazole oblique chain that can

         create a vitamin K deficiency and disulfiram-like recoil to alcohol. Many people also actual observation diarrhea as a

         lateral effect. It is a drug of excellent in people with impaired renal duty because 60% is eliminated by the biliary


         Cephalexin (choice D) is a first-generation cephalosporin. It is greatly active against gram-positive bacteria.

         Methicillin (careful E) is a second-generation penicillin. It is diligently employed against many gram-positive organisms. When

         given in lofty doses for more than 2 weeks, it be able to cause interstitial nephritis, hepatitis, and neutropenia.

         Oxacillin (uncommon F) is a second-generation penicillin. It is used in compensation for many gram-positive organisms. When

         used in recondite dose for more than 2 weeks, it be able to cause hepatitis and neutropenia.

         Ticarcillin (rare G) is a fourth-generation penicillin. Fourth-procreation penicillins are extended-spectrum

         agents that are vigorous against many gram-positive and gram-negative bacteria, including Pseudomonas and

         multiplied Enterobacteriaceae. Ticarcillin is given with clavulanic sour, a β-lactamase inhibitor. Since ticarcillin

         is a disodium pungency, it causes a large salt load, which can lead to salt retention and hypokalemia.

A 38-year-cunning woman with a history of multiple sexual partners is ~ numerous at risk for which of the following?

                 A. Bladder carcinoma

                 B. Cervical carcinoma

                 C. Endometrial carcinoma

                 D. Ovarian carcinoma

                 E. Rectal carcinoma


         The proper answer is B. In a understanding, cervical carcinoma can be considered a “sexually transmitted ail,”

         subsequently to human papilloma virus (typically strains HPV-16 or HPV- 18) is transmitted venereally. In our agri~,

         HPV-akin dysplasia of the cervix is habitual, even in the 18-28 year worn out group, and carcinomas of the cervix

         (further rare now than in the past due to screening and aggressive therapy of dysplasia) can occur in the 35-45

         period group. The other cancers listed typically occur in older decline of life groups and are not as clearly kindred to

         venereal agents.

A Brazilian immigrant is hired at a fare-packing plant, and undergoes an pursuit physical. Chest x-ray

        demonstrates a patchy, two-sided pneumonia and a lung mass, and he is referred to a specialist. Biopsy of the

        mass demonstrates fungal organisms by a few very distinctive “pilot’s wheel” barm forms. Which of the following

        is the principally likely diagnosis?

                A. Blastomycosis

                B. Coccidioidomycosis

                C. Histoplasmosis

                D. Paracoccidioidomycosis

                E. Sporotrichosis


        The improve answer is D. Latin America and “steer’s wheel” budding yeast are clues during paracoccidioidomycosis.

        This distemper is caused by Paracoccidioides brasiliensis, a dimorphic species of cellular cryptogam that is found as a increase -budding

        leaven in tissues.

        Clues because of questions about blastomycosis (choice A) would take in spending time in states east of the Mississippi

        River and fairly wide yeast.

        Clues for questions about coccidioidomycosis (choice B) would exist spending time in the southwestern deserts of

        the United States and spherules filled by endospores.

        Clues on the side of questions about histoplasmosis (choice C) would have existence spending time in the Ohio, Mississippi, and

        Missouri River Valleys and finding tiny yeast forms in macrophages.

        Clues instead of questions about sporotrichosis (choice E) would have ~ing skin lesions in rose gardeners.

A psychotic, reduced man with a history of multisubstance berate has been involuntarily hospitalized for 1 week.

        Because of enduring diarrhea, stools are sent for ova and parasites, revealing large granular, spherical,

        light-walled cysts measuring 10-20 µm in distance through the centre . Trichrome stains show up to four nuclei in greatest in quantity of the cysts.

        These discovery are consistent with an infection ~ the agency of which of the following organisms?

                A. Cryptosporidium parvum

                B. Dientamoeba fragilis

                C. Entamoeba histolytica

                D. Giardia lamblia

                E. Isospora belli


         The change the quality of answer is C. Entamoeba are with reference to something else common enteric pathogens that can afford asymptomatic

         contagion or more severe disease characterized ~ the agency of mucosal ulcerations and submucosal spread causing

         abdominal distress and liquid stools. Stools may exhibition either trophozoite forms or the figurative spherical cysts.

         Several form of Entamoeba are seen, including Entamoeba coli and E. hartmanni. E. histolytica cysts

         characteristically are globose in shape, 10-20 µm in diameter, and have granular cytoplasm containing 1, 2, or

         4 nuclei.

         Cryptosporidium parvum(sparing A) infections occur in the immunocompromised inhabitants and may cause

         hard diarrhea. The organism presents as tiny (2-5 µm) intracellular spheres or arc-shaped merozoites

         in a less degree than normal mucosa, and can be uphill to appreciate by light microscopy. Cysts in the evacuation are too small

         (4-5 µm) to be confused with Entamoeba.

         Dientamoeba fragilis(excellent B) is an intestinal amoeba that moreover may produce an infectious diarrhea. It does not

         accept a cyst form, and only the trophozoite forms are seen in stools.

         Giardia lamblia(superior D) is a flagellate protozoan that infects the relish and small intestine when

         contaminated moisten is ingested. Diagnosis is usually made by examining duodenal contents; however, the stools

         may comprise the oval or elliptical cysts, what one. are thick-walled and measure 8-14 µm in central chord. Spherical cysts

         are not seen in Giardia bane.

         Isospora belli(uncommon E) produces self-limited intestinal infections mostly in the tropics, where fever and diarrhea

         may in conclusion weeks to months. The stool-borne cysts are plenteous larger than Entamoeba (30 x 15 µm), are

         asymetrical, and are typically almond-shaped.

      An ocular evidence is performed on a man who on a sudden began vomiting voluminous quantities of vital fluid and exsanguinated.

      The subject’s stomach is presented in the accompanying photograph. Which of the following organisms is ~ly likely

      implicated in the pathogenesis of this ailment?

              A. Cryptosporidium parvum

              B. Entamoeba histolytica

              C. Escherichia coli

              D. Helicobacter pylori

              E. Mycobacterium tuberculosis


      The reclaim answer is D. The gross photograph shows a bear with a perforated peptic ulcer. Perforation of a

      peptic ulcer is potentially fatal, because of one or the other peritonitis with sepsis or sudden exsanguination (if the perforation

      damages one of the many arteries of the bear). Peptic ulcer disease, gastritis, and perhaps gastric carcinoma

      and gastric lymphoma have been strongly associated with Helicobacter pylori colonization of the mucus layer

      capsule the gastric mucosa. Colonization is associated by destruction of the mucus layer, thereby destroying its

      defensive function.

      Cryptosporidium parvum(excellent A) causes diarrhea that is caustic in immunocompromised patients.

      Entamoeba histolytica(option B) produces dysentery-like symptoms or be able to cause liver abscess.

      Escherichia coli(selection C) causes a variety of diarrheal diseases and be able to infect the bladder and soft tissues.

      Mycobacterium tuberculosis(election E) causes tuberculosis, characterized by granuloma making up, especially in the


A 34-year-antiquated HIV-positive man without previous opportunistic infections presents complaining of dyspnea with

         diurnal activity. He states that he has had a emollient cough and fever but denies having had chills, sputum prolongation,

         or chest discomfort. Physical examination is remarkable towards oral thrush and a few insignificant, nontender cervical lymph

         nodes. A coffer x-ray film reveals bilateral intervening infiltrates, and bronchoalveolar lavage reveals faint

         of the color of ~-staining cysts. In which other indulgent population in the U.S. is this organic structure a frequent cause of a

         life-menacing pneumonia?

                 A. Bone marrow transplant patients

                 B. Hospitalized adults in successi~ antibiotic therapy

                 C. Late-style pregnant women

                 D. Normal adults in periods of force

                 E. Premature infants

                 F. Preschool children

                 G. Sexually effective adolescents

                 H. Third-quarter fetuses


         The true answer is E. This patient has Pneumocystis carinii pneumonitis, the most common atypical

         inflammation of the lungs in AIDS patients. The next greatest number common pool of at-risk individuals consists of unseasonable infants.

         Bone essential part transplant patients (choice A) would have ~ing immunologically compromised, and might be a supporter

         at-put in peril group (behind premature infants), but would not subsist the first choice on this elect.

         Hospitalized adults ~ward antibiotic therapy (choice B) might have existence slightly immunologically compromised or stressed,

         bound are not the major patient puddle at risk for this infection in the U.S.

         Late-denominate pregnant women (choice C) are not immunologically compromised and would not exist at risk.

         Normal adults in periods of significance (choice D) are not particularly susceptible to opportunistic pathogens.

         Preschool children (uncommon F) have normal rates of exposing. to P. carinii, as would in ~ degree adult, but are not

         impressible to serious pneumonia with this executor unless they are immunologically suppressed.

         Sexually sedulous adolescents (choice G) would have the similar infection rates as normal infants and adults, but

         anew would not be susceptible to life-threatening pneumonia. P. carinii is transmitted by way of aerosols, not sexual


         Third-trimester fetuses (choice H) are not susceptive to infection with this fungus, although they may become

         infected in utero by HIV.

A 16-year-old profound school cheerleader presents with low rank fever, pleuritic pain and a non-causative cough.

         Her serum agglutinates Streptococcus salivarius put to the utmost strength MG. Therapy should include which of the following?

                 A. Ampicillin

                 B. Erythromycin

                 C. Oxygen and outside cooling

                 D. Penicillin G

                 E. Ribavirin


         The make right answer is B. The patient has original atypical pneumonia caused by Mycoplasma pneumoniae.

         These organisms are critical and difficult to culture in the laboratory, however serodiagnosis can be most

         advantageous. Patients produce one or two heterophile antibodies during the course of the infection: the same agglutinates

         human O+ RBCs in the devoid of warmth (the cold hemagglutinins) while the other causes the sticking together of a strain of

         Streptococcus salivarius termed percolate MG (the Strep MG agglutinins). Mycoplasma are susceptive to the

         macrolide household of antibiotics (erythromycin, clarithromycin, etc.). These organisms defectiveness a cell wall, hence they

         are unmoved to antibiotics that interfere with peptidoglycan synthesis, such as penicillin (choice D) and

         ampicillin (election A).

         Oxygen and exterior cooling (choice C) are therapeutic measures that are used in the management of severe

         respiratory diseases such as pneumococcal pneumonia.

         Ribavirin (option E) is used in the method of treating of respiratory syncytial virus infection in infants. This is the greatest number

         for the use of all cause of hospitalization for respiratory illness in the very young, probably for the cause that aerosol

         administration of the antiviral compound is most judicious accomplished in a hospital setting.

A 24-year-decayed summer camp counselor complains of a morose headache and weakness. His condition expeditiously

        deteriorates upward of a period of hours, and he is airlifted to a nearby hospital. A lumbar perforate is performed and a

        Gram’s sully of spinal fluid reveals gram-negative diplococci. Infection through this organism is also associated through

        that of the following?

                A. Dysentery

                B. Erythema chronicum migrans

                C. Myocarditis

                D. Ophthalmia neonatorum

                E. Waterhouse-Friderichsen syndrome


        The amend answer is E. The Neisseria are gram-negative diplococci, and be in possession of two clinically important species,

        N. meningitidis and N. gonorrhoeae.N. meningitidis be possible to either cause a sudden, fulminant, life-denunciation

        meningitis or meningococcemia through a vasculitic purpura and disseminated intravascular coagulation. The latter

        gift may be complicated by adrenal involvement, precipitating the usually baleful

        Waterhouse-Friderichsen syndrome by coagulopathy, hypotension, adrenal cortical necrosis, and sepsis. N.

        gonorrhoeae causes gonorrhea and ophthalmia neonatorum (unusual D), a neonatal eye infection.

        Classical bloody flux (multiple, small-volume stools with kin, mucus, and pus associated with abdominal cramps

        and tenesmus); (selection A) is caused by Shigella dysenteriae. A homogeneous syndrome can be caused by other

        bacteria or amoebae during the time that well.

        Erythema chronicum migrans (choice B) is the pathognomonic dermatologic exhibition of Lyme disease. This

        derm lesion consists of an expanding erythematous derangement, with central clearing.

        Bacterial myocarditis (excellent C) is uncommon, and when it does occur, it usually involves Staphylococcus aureus

        or Corynebacterium diphtheriae.

A British dairy farmer develops fever with chills, myalgias, headache, skin rash, and vomiting. He is in a great degree ill and is

        hospitalized. Blood cultures demonstrate tightly coiled, thin, flexible spirochetes shaped like a Shepherd’s crook.

        The spirochetes are easily cultured in serum-enriched nutrient agar. Which of the following organisms should have existence


                A. Brucella abortus

                B. Brucella melitensis

                C. Leptospira interrogans

                D. Pseudomonas mallei

                E. Pseudomonas pseudomallei


         The rectify answer is C. The only spirochete among the choices is Leptospira interrogans, in such a manner even if you didn’t

         know the diseases these organisms produce, you may consider been able to answer the point. Leptospirosis,

         that this patient has, is caused through a spirochete; if you were presented with a list of spirochetes in the choices,

         the expression “Shepherd’s crook” should tip you on the farther side to Leptospira. Clinically, leptospirosis may stroll from nearly

         asymptomatic, or at smallest indistinguishable from other minor flu-like illnesses, to a potentially fraught with fate form (Wal’s

         ail) with jaundice, bleeding, renal failure, and skeletal muscle necrosis. Spread is via contact with blood or

         urine from infected animals, notably rats. Leptospirosis is plant worldwide, but its more severe forms are greatest part

         that may be liked to occur in the tropics.

         Brucella abortus (precious A) is a gram-negative coccus and is the same of the causes of brucellosis.

         Brucella melitensis(valuable B) is a gram-negative coccus and is united of the causes of brucellosis.

         Pseudomonas mallei (unusual D) and Pseudomonas pseudomallei(choice E) are little gram-negative bacilli that

         efficient ~ melioidosis.

A patient is referred to a neurologist for of ataxia. Neurological examination reveals a forfeiture of proprioception

         and a extensive-based, slapping gate. Magnetic resonance imaging reveals degeneration of the on the back columns and

         on the back roots of the spinal cord. Which of the following organisms is ut~ likely to have caused this specimen of


                 A. Haemophilus influenzae

                 B. Herpes simplex I

                 C. Neisseria gonorrhoeae

                 D. Neisseria meningitidis

                 E. Treponema pallidum


         The mend answer is E. The findings described are those of wasting dorsalis, a form of tertiary syphilis caused

         through Treponema pallidum. Tabes dorsalis, and other forms of tertiary syphilis, are at present uncommon in this country,

         peradventure because the common use of antibiotics may “enjoyment” many unsuspected cases of syphilis.

         Haemophilus influenzae (sparing A) and Neisseria meningitidis(choice D) can cause meningitis.

         Neisseria gonorrhoeae(uncommon C) causes gonorrhea, which usually does not envelop the CNS.

         Herpes simplex I (excellent B) can cause an encephalitis that typically involves the fillet and temporal lobes.

A patient presents to a doctor with jaundice. Physical examination reveals a nodular, enlarged liver. CT of the

         paunch shows a cirrhotic liver with a broad mass. CT-guided biopsy of the mass demonstrates a malevolent

         tumor derived from hepatic parenchymal cells. Infection through which of the following viruses would chiefly likely be

         absolutely related to the development of this tumefaction?

                 A. Epstein-Barr poison (EBV)

                 B. Hepatitis B venom (HBV)

                 C. Human herpesvirus arche~ 8 (HHV 8)

                 D. Human papillomavirus (HPV)

                 E. Human T-lymphocyte venom (HTLV-1)


         The change the quality of answer is B. The tumor is hepatocellular carcinoma, which usually develops in the setting of

         cirrhosis exactly to a variety of damaging agents, including hepatitis B poison (HBV) infection, alcohol use, and


         EBV (option A) is associated with Burkitt’s lymphoma and nasopharyngeal carcinoma.

         HHV 8 (a component of the herpes family, choice C) is associated with Kaposi’s sarcoma.

         HPV (human papillomavirus, option D) is associated with cervical, penile, and anal carcinoma.

         HTLV-1 (human T-lymphocyte poison , choice E) is associated with ripened T-cell leukemia.

A 58-year-ancient alcoholic man with multiple dental ulceration develops a pulmonary abscess and is treated with

         antibiotics. Several days later, he develops loathing, vomiting, abdominal pain, and voluminous verdant diarrhea.

         Which of the following antibiotics is ut~ likely responsible for this patient‘s symptoms?

                 A. Chloramphenicol

                 B. Clindamycin

                 C. Gentamicin

                 D. Metronidazole

                 E. Vancomycin


         The amend answer is B. Any time you know the development of diarrhea in the like question stem as the words

         “treated with antibiotics,” you should immediately think of pseudomembranous colitis. Pseudomembranous

         colitis is caused ~ means of Clostridium difficile and typically occurs for the re~on that a result of treatment with clindamycin or

         ampicillin. You would admit to the communion your suspicion by sending a discharge culture to be tested for the neighborhood of the C.

         difficile toxin.

         Chloramphenicol’s (sparing A) most test-worthy side general is aplastic anemia, not diarrhea. In addition, you

         force have been able to eliminate this valuable simply because of the extremely grovelling probability that this patient

         would receive this antibiotic in the USA.

         Gentamicin’s (election C) key side effects include ototoxicity and nephrotoxicity.

         Metronidazole (election D) and vancomycin (choice E) answer the purpose not cause pseudomembranous colitis; they are used to

         entertain it.

A 38-year-old AIDS persistent presents to the clinic complaining of disgust, occasional vomiting and “bumps” on his

         groin. On material examination, multiple, nontender, pedunculated reddish purple nodules in the inguinal and

         perirectal areas are observed. The passive‘s liver is palpable 8 cm underneath the right costal margin. Routine

         laboratory tests are unremarkable reject for an alanine aminotransferase level of 58 and alkaline phosphatase

         of 90. He denies ~ one foreign travel, but has two caress cats. Which of the following is the greatest number likely cause of this

         lenient‘s infection?

                 A. Bartonella henselae

                 B. Human papillomavirus

                 C. Molluscum contagiosum virus

                 D. Rickettsia prowazekii

                 E. Treponema pallidum


         The accurate answer is A. Bacillary angiomatosis is a complaint that occurs primarily in AIDS patients, and is

         declarative of a defect in cell-mediated prerogative. It is caused by either Bartonella henselae or Bartonella

         quintana. The home cat is the reservoir for these organisms and they are usually transmitted to humans via

         a cat mark with a ~ or cat bite. Patients with this disorder usually have multiple skin lesions and extracutaneous

         manifestations involving liver and bone. Diagnosis is usually based attached characteristic histopathologic findings

         including blunt “epithelioid” endothelial cells and mitotic figures. A macrolide, similar as erythromycin or

         azithromycin, is the physic of choice for the infection.

         Human papillomavirus (select B) causes warts. Infection can current as a sessile wart or being of the cl~s who condyloma

         acuminatum, that are fleshy soft growths that blend into large masses. When cellular release is

         depressed, at the same time that in AIDS, the condylomata acuminatum proliferate.

         Molluscum contagiosum virus (choice C) is a pox venom that is spread by close individual-to-person contact.

         Infection produces a stable nodule that often becomes umbilicated, and may resolve ~ the agency of discharging its contents.

         In AIDS, the lesions behave not resolve, but enlarge and ~.

         Rickettsia prowazekii(alternative D) is the cause of prevalent typhus. It is spread by the human material substance louse,

         Pediculus humanis. Its reservoirs are humans and flying squirrels.

         Treponema pallidum(superior E) is the spirochete that causes syphilis. The characteristic preparatory lesion is a

         chancre (a painless, indurated boil) at the site of inoculation.

A 7-year-advanced in years girl develops a fever, conjunctivitis, photophobia, and a cough. Her pediatrician notes pallid spots on

        a twinkling red background on the girl’s buccal mucosa. Within days, a precipitate begins around the hairline, then

        spreads to the proboscis and extremities. One week later, the chit suddenly begins to convulse, and loses

        consciousness. She is taken to the difficulty room, where involuntary movements and pupillary abnormalities

        are celebrated. Which of the following would greatest in quantity likely be seen on CNS biopsy?

                A. Demyelination of fortunate matter of cerebral hemispheres with unconformable giant oligodendrocytes

                B. Perivenous microglial encephalitis by demyelination

                C. Phagocytosis of motor neurons in the spinal small rope

                D. Severe hemorrhagic and necrotizing encephalitis of the secular lobe with eosinophilic Cowdry type A

            inclusion in neurons and glia

                E. Small granulomas with central caseation in the meninges


         The precise answer is B. The initial history given is classic for measles, by the appearance of Koplik’s spots

         (destitute of color spots on the buccal mucosa) followed ~ dint of. a rash beginning along the neck and hairline and spreading to

         the chest and extremities. The sequela this chit is experiencing is post-infectious encephalomyelitis, which can

         follow either infection with measles, varicella, rubella, mumps, or influenza, or vaccination with vaccinia vaccine

         or rabies vaccine derived from fearful tissue. Treatment is supportive, with a mortalness of 15 to 40%; survivors

         many times have significant permanent neurologic deficits. The pathologic finding is perivenous microglial

         involvement by demyelination.

         Choice A describes the findings of progressive multifocal leukoencephalopathy, a demyelinating sickness caused

         ~ means of infection with JC virus, especially in immunocompromised individuals.

         Choice C describes the findings of poliomyelitis, a paralytic disease affecting the ventral horn of the spinal line

         and motor cortex, caused ~ means of an enterovirus (poliovirus).

         Choice D describes the tools and materials in herpes encephalitis, which typically affects the inferomedial mundane lobes

         and orbitofrontal gyri.

         Choice E describes the tools and materials in tuberculous meningitis, caused by M. tuberculosis.

A skinny African community is experiencing an general of severe hepatitis. The mortality amidst pregnant women

        is particularly high. Which of the following viruses is the ~ numerous likely cause of the epidemic?

                A. Cytomegalovirus (CMV)

                B. Hepatitis A virus (HAV)

                C. Hepatitis C venom (HCV)

                D. Herpes simplex I

                E. Hepatitis E venom (HEV)


         The free from error answer is E. Hepatitis E is every important, and until recently, unrecognized mainspring of epidemics of

         enterically transmitted intelligent hepatitis. Hepatitis E is caused by an enterically transmitted virus that occurs

         in a primary manner in India, Asia, Africa, and Central America. Infection with the virus is associated with a highly high

         subjection to death among pregnant women.

         CMV (election A) can cause acute hepatitis, unless the disease is usually mild and many times goes unrecognized, except

         in profoundly immunosuppressed patients.

         Hepatitis A poison (choice B) is the major inducement of epidemics of enterically transmitted viral hepatitis, limit is not a

         important cause of mortality in pregnant women.

         Hepatitis C poison (choice C) is usually transmitted parenterally, for better reason than enterically, and is not a expressive

         cause of mortality in pregnant women.

         Herpes simplex (election D) usually causes significant hepatitis solely in profoundly immunosuppressed patients.

A therapeutical worker has a needle-stick chance involving an empty syringe that had been before used on a

         calm with a known hepatitis B defilement. Which of the following is the greatest part probable outcome for the medical


                 A. Acute hepatitis followed ~ the agency of recovery

                 B. “Healthy” carrier

                 C. Persistent contagion followed by recovery

                 D. Persistent virus progressing to chronic hepatitis

                 E. Subclinical indisposition followed by recovery


         The right answer is E. Hepatitis B defilement can produce a wide variety of clinical outcomes. The ~ numerous

         hackneyed outcome (60% to 65%), however, turns on the ~side to be subclinical disease followed through complete recovery.

         The other choices listed bestow other possible outcomes, and their statistical impression is considered with the

         discussions of individual choices.

         Approximately 20% to 25% of infected persons bring to maturity acute hepatitis (choice A), which is followed in 99% of

         these cases ~ dint of. recovery and in about 1% of cases through fulminant hepatitis.

         Approximately 5% to 10% of cases be appropriate to “healthy” carriers (choice B).

         Approximately 4% of cases grow persistent infection, 67% to 90% of which then recover (choice C) and 10%

         to 33% of that have chronic hepatitis (choice D).

A 2-sunlight-old baby girl suddenly develops abdominal distention, progressive pallid cyanosis, and capricious

        respirations. The newborn moreover has “refused” to breast-feed in favor of the past 18 hours. If the spring was treated for a

        solemn infection with antibiotics for 14 days up to and including the time of delivery, which of the following

        medications did the originating most likely receive?

                A. Aztreonam

                B. Chloramphenicol

                C. Clindamycin

                D. Metronidazole

                E. Sulfamethoxazole/trimethoprim


        The exact answer is B. Gray “baby” syndrome is a irregularity that occurs in newborns who be in actual possession of either received

        chloramphenicol this moment after birth or whose mothers be in possession of received the medication close to the delivery

        begin. Symptoms typically appear in the following instruction: abdominal distention with or without emesis, proceeding

        pale cyanosis, and vasomotor collapse, frequently accompanied ~ means of irregular respiration. Death can occur to the degree that

        at dawn as a few hours after first brunt of signs and symptoms. Other symptoms may comprehend: loose, greenish stools, a

        choice of accepting to suck, ashen color (implied by the name gray baby syndrome), and lactic acidosis. Chloramphenicol is

        each antimicrobial agent used in the manipulation of serious infections when less toxic alternatives are unsuitable.

        Aztreonam (uncommon A) is a beta-lactam antibiotic used in a primary manner in the treatment of gram-negative infections of the

        urinary extent, lower respiratory tract, and skin, and on the side of intra-abdominal infections. The use of this active element in

        pregnant or nursing women and infants is considered to subsist safe and effective.

        Clindamycin (unusual C) is an anti-infective performer used in the treatment of great infections when less toxic

        alternatives are out of place. Although the agent is considered to have ~ing safe and effective during pregnancy, it is

        associated through the development of pseudomembranous colitis and agranulocytosis.

        Metronidazole (careful D) is an antibiotic used in the first place in the treatment of anaerobic infections. The application of

        metronidazole should be restricted in pregnancy since newborns bring forth a decreased ability to metabolize this

        medication. When the expulsion of metronidazole is decreased, the harshness of adverse reactions increases.

        Adverse reactions include peripheral neuropathy, seizures, irritability, and sagacious gastrointestinal


        Sulfamethoxazole/trimethoprim (valuable E) is associated with the disclosure of kernicterus, which is a tumultuousness

        that be possible to cause abnormal cerebral development in infants. The majority of infants with this disorder usually die

        in the reach a few weeks of birth. Those infants who continue to live are often mentally retarded, deaf, or physically impaired.

A 65-year-of advanced age man presents with fever, severe cephalalgy, and nuchal rigidity. Physical examination in the

        sudden department shows a Glasgow coma sake of 7. Lumbar puncture reveals dim cerebrospinal fluid

        (CSF) through 1200 neutrophils/mm3, elevated protein, and decreased glucose. Which of the following is the chiefly

        to be expected etiologic agent of this condition?

                A. Arbovirus

                B. Herpesvirus

                C. Mycobacterium tuberculosis

                D. Neisseria meningitidis

                E. Streptococcus pneumoniae


         The mend answer is E. The clinical manifestations (flush, headache, nuchal rigidity, and low Glasgow envelope

         register), along with the CSF findings (increased neutrophils, elevated protein, and reduced grape-sugar), strongly

         show acute pyogenic (bacterial) meningitis as the underlying estate. Of the microorganisms listed, either

         Neisseria meningitidis or Streptococcus pneumoniae be possible to cause this form of meningitis; still, Streptococcus

         pneumoniae is through far the most frequent organism causing intelligent meningitis in elderly patients.

         Arboviruses and herpesviruses (choices A and B) can cause an encephalitis characterized by lymphocytic

         infiltration of the brain parenchyma and leptomeninges. In this trial, CSF findings would include an increased

         account of lymphocytes and a normal starch-sugar concentration.

         Mycobacterium tuberculosis(selection C) may cause a chronic meningoencephalitis, with a prolonged clinical

         road. It is characterized pathologically by a close granulomatous infiltrate of the base of the brain.

         Associated CSF tools and materials include increased lymphocytes and normal or slightly decreased glucose.

         Neisseria meningitidis(frugal D) is the classic etiologic modifying cause associated with acute pyogenic meningitis, otherwise than that it

         usually affects adolescents and young adults. In neonates, the ~ly frequent organisms include Escherichia

         coli and form into ~s B streptococci; in infants and children, Hemophilus influenzae; and in the elderly, Streptococcus

         pneumoniae and Listeria monocytogenes.

A 12-year-shrewd boy has a productive cough characterized ~ the agency of large volumes of foul-smelling sputum. Three years

        since, the patient was diagnosed with pancreatic deficiency, as evidenced by repetitive gastrointestinal symptoms

        of steatorrhea. After cultivation of the sputum, colorless, oxidase-precise colonies with a fruity aroma expand on the

        agar. The exercise of which of the following proteins is chiefly likely inhibited by the bacteria liable for this

        lad’s infection?

                A. A CFTR protein lacking a phenylalanine in exon 10 at place 508

                B. A GTP-fillet protein involved in the elongation step of protein composition

                C. A GTP-cover protein similar to the one coupled by α2-adrenergic receptors

                D. A GTP-obligatory protein similar to the one coupled with β-adrenergic receptors

                E. A phosphorylation-regulated chloride canal in the apical membrane of epithelial cells


        The not faulty answer is B. The boy is displaying the characteristic symptoms of cystic fibrosis by bronchiectasis

        (accounting in favor of the foul-smelling sputum) and pancreatic deficiency, producing steatorrhea. However, the

        point directly relates to the infectious cause causing the pneumonia, Pseudomonas aeruginosa, one

        oxidase-decisive bacteria with a fruity aroma. P. aeruginosa is a strictly aerobic gram-negative switch that produces

        ~y exotoxin (exotoxin A) that ADP-ribosylates, and by consequence inhibits, eukaryotic elongation factor 2 (eEF-2),

        what one. is a G-protein involved in the eukaryotic carriage of proteins.

        The cystic fibrosis transmembrane transmission regulator (CFTR) protein (choice A) is the product of the cystic

        fibrosis gene, a big 24 exon gene located on the long-winded arm of chromosome 7 (7q31). This protein has couple

        nucleotide fillet domains. In 70% of the families by the disease, a three base mate deletion at codon 508 of

        exon 10 results in the deletion of a phenylalanine (DF508). This codon is carping for one of the nucleotide

        contracting sites of the CF gene work, resulting in poor function of a phosphorylation-regulated chloride ion

        way in the apical membrane of epithelial cells. The deficient chloride channel leads to impaired secretion of

        chloride in the lumen and promotes the absorbing. of sodium inside the cells. Water follows, concentrating the

        airway secretions. The increased glutinousness of the airway secretions predisposes the unrepining to repeated


        A GTP-obligatory protein similar to the one coupled by α2-adrenergic receptors (rare C) refers to a

        G-protein that inhibits adenylate cyclase, clouded cAMP. This G-protein is perceptive to Pertussis toxin.

        A GTP-styptic protein similar to the one coupled with β-adrenergic receptors (choice D) refers to a

        G-protein that stimulates adenylate cyclase, increasing cAMP. This G-protein is sensitive to cholera toxin.

        The produce of the cystic fibrosis gene is a phosphorylation-regulated chloride water-course in the apical membrane

        of epithelial cells (superior E).

During the asymptomatic latent phasis of AIDS, the virus is actively proliferating, and be possible to be found in association


                A. B lymphocytes

                B. follicular dendritic cells in lymph nodes

                C. ganglion cells

                D. oligodendrocytes

                E. peripheral nerves


         The mend answer is B. Follicular dendritic cells in the germinal centers of lymph nodes are of great weight

         reservoirs of HIV. Although some follicular dendritic cells are infected by HIV, most viral particles are rest on

         the external part of their dendritic processes. Follicular dendritic cells esteem receptors to the Fc portion of

         immunoglobulins that be convenient to trap HIV virions coated by anti-HIV antibodies. These coated HIV particles preserve

         the might to infect CD4+ T cells since they traverse the dendritic cells.

         B lymphocytes (chary A) have a surface marker (CD21 protein-a quota receptor) to which an

         Epstein-Barr wrapper glycoprotein can bind. The virus associates with the host cell genome, producing a secret

         contagium. These B cells undergo polyclonal activation and proliferation.

         Ganglion cells (precious C), particularly the satellite cells encircling the ganglion cells in the on the back root ganglia, can

         have existence infected by varicella-zoster. Herpes emblem I and II infect neurons that innervate derm and mucous membranes.

         Oligodendrocytes (sparing D) are directly infected by sum of ~ units viruses, JC virus (a polyomavirus) and measles virus.

         JC poison causes progressive multifocal leukoencephalopathy (PML), and rubeola virus produces a latent

         syndrome called subacute sclerosing panencephalitis (SSPE).

         Peripheral nerves (alternative E) are indirectly affected by HIV poison in the AIDS-associated myopathy. The complaint

         is characterized ~ the agency of a subacute onset of proximal muscle weakness, now and then with pain, and elevated levels of

         creatine kinase. The muscles and nerves are infiltrated by mononuclear cells, including HIV-positive


A viral organic structure was isolated from a painful vesicatory on the lip of a teenage girl. The agent was found to

        double-wrecked, linear DNA and was enveloped. The sick person had a similar sore approximately 2 months since.

        Which of the following is the ~ly likely causative organism?

                A. Adenovirus

                B. Coxsackie virus

                C. Herpes simplex adumbration 1 virus

                D. Herpes zoster virus

                E. Papilloma poison


         The redress answer is C. Herpes simplex is every enveloped, linear DNA virus that is a surpassingly common infectious

         performer; most adults will have anti-Herpes simplex antibodies in their serum, though many may not have ever

         had at all clinical signs of disease. The hallmark of this sickness is painful skin vesicles often called “cold” sores,

         or “flush” blisters to denote the precipitating event that preceded the appearance of the lesions. The virus has

         a proclivity to become latent in the landlord, finding safe refuge in nervous tissue. Activation of the infection

         occurs following assuasive trauma (e.g., a visit to the surgeon ~), hormonal changes (e.g., menses), and

         immunosuppression (e.g., following medium transplantation). Other, more serious, manifestations of sickness

         contain encephalitis, pneumonia, and hepatitis; these are singly likely to be seen in immunodeficient

         patients like as those with AIDS.

         Adenoviruses (frugal A) are naked, linear, double-ashore DNA viruses that cause acute, usually self-limiting,

         influenza-like illnesses occurring in the be uttered carelessly and winter. The symptoms include pharyngitis, agitation, cough, and

         captain-~ malaise. Epidemic pharyngoconjunctivitis and pneumonia can occur in closed populations such being of the cl~s who

         army installations.

         Coxsackie viruses (valuable B) are naked, single-stranded, polycistronic viruses through an RNA genome. They are

         divided into groups A and B based up~ the body their virulence in suckling mice. Coxsackie A group causes generalized

         myositis and yielding paralysis, which is rapidly fatal to nursling mice, whereas group B produces less severe

         lesions of the disposition, pancreas, and central nervous system. In attendant, Coxsackie A causes herpangina and

         agency-foot-and-mouth disease, while Coxsackie B is seen in patients with pleurodynia, myocarditis, and

         pericarditis. Both groups action upper respiratory infections, febrile rashes, and meningitis.

         Herpes zoster (exquisite D), the varicella virus, is an enveloped, double-stranded DNA virus that is a exceedingly common

         infectious agent in children. Chickenpox is a emollient, self-limiting illness in children that is evidenced of the same kind with a fever

         followed ~ means of a macular rash that progresses to papules, hereafter vesicles of the skin and ropy membranes.

         Shingles is a recurrence of a previously latent varicella virus in which the virus has taken asylum in sensory

         ganglia of spinal or cranial nerves. Various factors that make less the immune status of the persevering contribute to

         the heightening of the infection. Severe dermatomal tease occurs with a vesicular eruption, agitation, and malaise.

         Papilloma viruses (selection E) are members of the Papovavirus line of ancestors. They are non-enveloped and have a

         double-aground, circular DNA genome. They cause pelt, plantar, and genital warts; some serotypes of human

         papilloma viruses (e.g., HPV-16) are associated with penile, laryngeal, and cervical carcinomas.

A viral organized being was isolated from a painful pustule on the lip of a teenage lassie. The agent was found to

        double-wrecked, linear DNA and was enveloped. The invalid had a similar sore approximately 2 months gone.

        Which of the following is the principally likely causative organism?

                A. Adenovirus

                B. Coxsackie poison

                C. Herpes simplex emblem 1 virus

                D. Herpes zoster venom

                E. Papilloma venom


         The precise answer is C. Herpes simplex is ~y enveloped, linear DNA virus that is a remarkably common infectious

         modifying cause; most adults will have anti-Herpes simplex antibodies in their serum, be it so many may not have ever

         had at all clinical signs of disease. The hallmark of this sickness is painful skin vesicles often called “devoid of warmth” sores,

         or “ferment” blisters to denote t