Clinical Pathology(Micro)

Front 1

Which of the following viruses is the most common cause of winter viral encephalitis?
A. lymphocytic choriomeningitis virus
B. Coxsackie A virus
C. Coxsackie B virus
D. human herpes virus 6
E. West Nile virus

Back 1

A. lymphocytic choriomeningitis virus.
LCMV is the most common cause of winter/spring viral encephalitis, while enteroviruses such as Coxsackie, are the main causes of summer/fall epidemics. LCMV is
spread to humans through contact with infected mouse feces.
QCCP2, Meningitis, specific agents

Front 2

Which feature separates the typeable from non-typeable strains of Haemophilus influenzae?
A. HA antigen
B. capsule
C. mecA gene
D. penicillin binding protein
E. growth at 42°C

Back 2

B. capsule.
The presence of a capsule separates the typeable (capsulated) from the non-typeable (unencapsulated). Furthermore, the typeable strains are categorized into serotypes
according to the type of capsule protein present - the most prevalent serotype being type B.
QCCP2, Meningitis, specific agents

Front 3

Patients with complement deficiencies are at an increased risk for meningitis caused by this infectious agent:
A. Streptococcus pneumoniae
B. Haemophilus influenzae
C. E. coli
D. Listeria monocytogenes
E. Neisseria meningitidis

Back 3

E. N.
N. meningitidis is associated with outbreaks of meningitis in children and adults in close living conditions, such as schools, dorms, barracks, or nursing homes (though
less prevalent in the elderly). Systemic meningococcemia is associated with a petechial rash and hemorrhagic adrenal infarction (Waterhouse-Friedrichsen syndrome),
both of which have a poor prognosis.
QCCP2, Meningitis, specific agents

Front 4

Which of the following organisms typically causes meningitis in a disproportionate number of both very young and very old patients?
A. group B Streptococcus
B. Staphylococcus aureus
C. Listeria monocytogenes
D. Streptococcus pneumoniae
E. Haemophilus influenzae

Back 4

C. L.
Besides age (<1 month and older than 70 years), predisposing factors toward the development of Listeria meningitis include diabetes and immunosuppression (steroids,
HIV, and transplantation).
QCCP2, Meningitis, specific agents

Front 5

Which of the following amoebae is most commonly the cause of primary amebic encephalitis?
A. Entamoeba histolytica
B. Acanthamoeba
C. Entamoeba coli
D. Endolimax nana
E. Naegleria fowleri

Back 5

E. N.
Naegleria infection is associated with fresh water exposure. The organism migrates through the nasopharynx and invades the brain through the cribriform sinus. Often
there is a history of trauma in fresh water (water skiing accident, diving accident). The infection is especially virulent, often causing death within days. Acanthamoeba
can also cause encephalitis, but with a granulomatous appearance. Acanthamoeba is also responsible for the majority of cases of amebic keratitis.
QCCP2, Meningitis, specific agents

Front 6

Which of the following etiologies of meningitis is consistent with CSF findings of glucose <45 mg/dL, protein >500 mg/dL, and a white blood cell count >1000
WBC/mL?
A. viral
B. amebic
C. aseptic
D. bacterial
E. chemical

Back 6

D. bacterial.
The cause of meningitis can be narrowed down with the CSF chemistry. Low glucose and high protein/WBC count is consistent with a bacterial meningitis. The WBC
differential is typically left-shifted with a predominance of neutrophils.
QCCP2, Laboratory evaluation

Front 7

Latex agglutination tests on CSF are commonly used for the diagnosis of all of the following causes of meningitis, except:
A. Haemophilus influenzae, type B
B. Neisseria meningitidis
C. group B Streptococcus
D. Listeria monocytogenes
E. Streptococcus pneumoniae

Back 7

D. L.
Listeria is a very difficult organism to identify in CSF. Gram stain sensitivity is less than 50% and there is no commercially available latex agglutination test at this time.
Culture is the main source of positive identification.
QCCP2, Laboratory evaluation

Front 8

All of the following criteria are used in the diagnosis of prosthetic joint infection, except:
A. joint pain with positive bacteremia in two successive blood cultures
B. growth of the same microorganism in two or more synovial fluid or periprosthetic tissue cultures
C. purulent synovial fluid or periprosthetic tissue
D. acute inflammation in periprosthetic tissue
E. presence of a sinus tract

Back 8

A. joint pain with positive bacteremia in 2 successive blood cultures.
Each of the applicable criteria is fairly specific for prosthetic joint infection. There are several etiologies of joint infection. The most common is the direct introduction of
bacteria, though in a small percentage of late infection, hematogenous spread is the cause.
QCCP2, Prosthetic joint infection and other clinical syndromes

Front 9

What is/are the most common bacterium found in prosthetic joint infections?
A. Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococci spp
D. gram negative bacilli
E. Enterococcus

Back 9

B. S.
Coagulase-negative staph account for almost 1/2 of the cases of prosthetic joint infections, most often presenting months after surgery. This makes sense since coagnegative
staph is a normal skin flora microbe and the majority of joint infections are due to the introduction of bacteria during surgery. On the other hand, since it is
normal skin flora, coag-negative staph is a common cause of contamination of cultures.
QCCP2, Prosthetic joint infections and other clinical syndromes

Front 10

What is the causative agent of visceral larva migrans?
A. Ancylostoma brazilensis
B. Loa loa
C. Toxicara canis
D. Francisella tularensis
E. Chlamydia trachomatis

Back 10

C. T.
Ancylostoma is the causative agent of cutaneous larval migrans, while Loa loa inhabits the subcutis and conjunctiva. Francisella tularensis causes ulceroglandular fever.
Chlamydia trachomatis causes lymphogranuloma venereum and trachoma.
QCCP2, T3.2

Front 11

All of the following are causes of blood culture-negative endocarditis (BCNE), except:
A. prior antibiotic therapy
B. Libman-Sacks endocarditis
C. marantic endocarditis
D. viridans Streptococcus
E. Coxiella burnetti

Back 11

D. viridans S .
In addition to carcinoid heart syndrome and other difficult-to-culture infectious causes, such as Bartonella, Chlamydia, and Legionella, are common causes of blood
culture-negative endocarditis. Viridans Streptococci infections typically occur on damaged native valves and can be cultured.
QCCP2, Infectious endocarditis, differential diagnosis

Front 12

Which of the following is included in the Austrian syndrome?
A. infective endocarditis
B. pneumonia
C. meningitis
D. A & B
E. A, B, C

Back 12

E. A, B, C.
Austrian syndrome refers to the triad of endocarditis, typically caused by S. pneumoniae, with pneumonia and meningitis. The syndrome was first described by Robert
Austrian in 1957 and has been shown to be most closely associated with alcoholism.
QCCP2, Infectious endocarditis, specific agents

Front 13

Which of the following organisms is/are the most common cause of fungal endocarditis?
A. Aspergillus fumigatus
B. Aspergillus niger
C. Candida spp
D. Torulopsis glabrata
E. Leptothrix

Back 13

C. C spp.
While Torulopsis glabrata and Aspergillus spp account for a significant number of cases of fungal endocarditis, Candida spp are responsible for the majority. Certain
factors predispose toward fungal endocarditis - immunodeficiency, long term antibiotic use, and IV drug use.
QCCP2, Infective endocarditis, specific agents

Front 14

Which of the following is the optimal specimen for the diagnosis of infective endocarditis?
A. a single central venous line 50mL sample
B. paired peripheral blood samples from the same site
C. three peripheral blood samples drawn every 24 hours
D. valve biopsy
E. three peripheral blood samples every 8 hours for first 24 hours

Back 14

E. three peripheral blood samples every 8 hours for the first 24 hours.
In addition, the samples should be from 3 different sites and taken approximately 1 hour before a fever spike. Also, paired samples are encouraged (one aerobic, one
anaerobic). The documentation of continuous bacteremia is an important diagnostic tool.
QCCP2, Laboratory approach to diagnosis

Front 15

How does antibiotic therapy most commonly affect the diagnosis of bacterial endocarditis on valvular material?
A. the causative organisms are completely eradicated
B. treatment causes a shift toward other non-virulent organism growth
C. antibiotics bind to organisms and block staining
D. gram stain morphology of bacteria is often altered by antibiotics
E. bacteria cannot be identified on valvular material

Back 15

D. gram stain morphology of bacteria is often altered by antibiotics.
Often, antibiotic therapy leads to a change in the morphology of bacteria, including their gram stain characteristics (positive, negative), which makes identification
difficult.
QCCP2, Laboratory approach to diagnosis

Front 16

What clinical feature dominates the presentation of encephalitis?
A. fever
B. mental status changes
C. headache
D. photophobia
E. stiff neck

Back 16

B. mental status changes.
The CNS infections can present along the spectrum from meningitis, both bacterial and viral, to encephalitis, often with overlapping features. The principal presentation
of encephalitis is usually mental status changes, whereas the other choices presented tend to dominate the presentation of meningitis.
QCCP2, Meningitis, differential diagnosis

Front 17

All of the following CSF findings are consistent with aseptic meningitis, except:
A. increased protein
B. increased glucose
C. low-level (<250/mL) leukocytosis
D. increased mononuclear cells
E. no growth on bacterial culture

Back 17

B. increased glucose.
Meningitis can be classified by CSF laboratory as well as microscopic results. Aseptic meningitis, which is most often viral in nature, typically presents with all the
features listed above, with the exception that glucose levels are usually normal or even slightly decreased.
QCCP2, Meningitis

Front 18

What is the most common cause of meningitis?
A. mycobacteria
B. bacteria
C. fungus
D. virus
E. amoeba

Back 18

D. virus.
Overall, aseptic meningitis is more common than bacterial meningitis and the most common causes of aseptic meningitis are viral. Of the viral causes, the most common
are in the family of Enteroviridae, such as poliovirus, Coxsackie A and B, and echovirus. The viruses cause encephalitis with a summer- and fall-predominant distribution.
QCCP2, Meningitis

Front 19

All of the following are common causes of neonatal bacterial meningitis, except:
A. Group B strep
B. gram negative anaerobes
C. Neisseria meningitidis
D. Listeria
E. enterovirus

Back 19

C. N. .
Neisseria meningitidis is a common cause of meningitis in infants through adults. H. influenzae used to be the predominant bacterial cause, but the advent of universal
vaccination led to a decrease in prevalence of H. influenzae meningitis.
QCCP2, Meningitis

Front 20

What is the most common cause of bacterial meningitis in adults?
A. Streptococcus pneumoniae
B. Neisseria meningitidis
C. Listeria monocytogenes
D. E. coli
E. Klebsiella pneumoniae

Back 20

A. S. .
The pneumococcus reigns supreme in adults, both in cases of meningitis and pneumonia. The remaining choices are listed in rough order of decreasing prevalence as
causes of bacterial meningitis.
QCCP2, Meningitis

Front 21

Which of the following viruses most commonly presents with anterior frontotemporal hemorrhagic encephalitis?
A. HHV6
B. HHV8
C. St. Louis encephalitis virus
D. HSV-1
E. Coxsackie A virus

Back 21

D.HSV-1.
Temporal encephalitis is associated with HSV-1. There is an interesting set of cerebral topographic-related syndromes associated with HSV encephalitis, such as aphasia
and phantom perception of odors and tastes. Another tip-off to HSV is RBCs in the CSF. The prognosis for HSV encephalitis is poor.
QCCP2, Meningitis, specific agents

Front 22

What is the animal reservoir of West Nile virus?
A. mice
B. rats
C. domestic cats
D. birds
E. rabbits

Back 22

D. birds.
Remember to stay away from dead birds! The host organism is the bird, which passes on the virus through a mosquito vector to humans. Arboviruses in general (to
include Eastern equine, St. Louis, California, etc.) are best diagnosed through serological means.
QCCP2, Meningitis, specific agents

Front 23

What's the most common means of transmission of EBV?
A. saliva
B. blood
C. fecal oral
D. respiratory droplet
E. solid organ transplantation

Back 23

A. saliva.
They don't call it the kissing disease for nothing! A less common means of transmission is through blood transfusion or solid organ transplantation. Nearly 90% of people in
the world have been infected with EBV.
QCCP2, EBV

Front 24

Which cell surface antigen is the receptor for the Epstein-Barr virus?
A. P antigen
B. CD21
C. insulin-degrading enzyme
D. CD4
E. Cd81

Back 24

B. CD21.
The C3d receptor, or CD21, functions as the target for EBV cell entry. P antigen (associated with Donath-Landsteiner ab), paroxysmal nocturnal hemoglobinuria, neutralized
by pigeon egg and hydatid cyst fluid) is the parvovirus receptor. Insulin-degrading enzyme is the putative receptor for varicella-zoster virus, while CD4 is the receptor for
HIV. Recent studies suggest that CD81 may have a role as a receptor for HCV.
QCCP2, EBV

Front 25

All of the following clinical syndromes are caused by EBV, except:
A. infectious mononucleosis
B. shingles
C. primary effusion lymphoma
D. post-transplant lymphoproliferative disease
E. oral hairy leukoplakia

Back 25

B. shingles.
Shingles is associated with VZV infection. There are myriad clinical syndromes associated with EBV infection, especially long-term latent effects. In addition to the
conditions presented above, primary CNS lymphoma, Burkitt lymphoma, Hodgkin lymphoma, lymphomatoid granulomatosis, and nasopharyngeal carcinoma are all
associated with latent EBV infection.
QCCP2, T3.9

Front 26

Which of the following disorders, also known as Duncan disease, is characterized by hepatic necrosis with a profound NK/T cell infiltrate?
A. Reye syndrome
B. immunoreactive cirrhosis
C. hepatitis mononucleosis
D. primary hepatic lymphoma
E. X-linked lymphoproliferative disorder

Back 26

E. X-linked lymphoproliferative disorder.
As an X-linked disorder, primarily men are affected. The range that disease can manifest extends from the previously mentioned hepatic necrosis and death to less severe
agammaglobulinemia or B-cell lymphoma. The disorder is due to a defect in the SAP gene, which leads to uncontrolled NK/T cell activation.
QCCP2, EBV

Front 27

All of the following are considered Hoagland criteria for the diagnosis of infectious mononucleosis, except:
A. leukocytosis >50% lymphocytes, >10% atypical lymphocytes
B. fever
C. pharyngitis
D. positive culture
E. positive serological testing

Back 27

D. positive culture.
Adenopathy is the missing criterion. While positive culture can occur with EBV, it is neither routinely performed, nor required for the diagnosis. These criteria are very
restrictive and may miss many cases. Partial fulfillment of criteria can be seen in many other diseases, such as strep pharyngitis, which can have both fever and
adenopathy, while the leukocytosis can be seen with CMV or Toxoplasma infections.
QCCP2, EBV

Front 28

Which of the following antibodies can be produced in response to EBV infection?
A. anti-i
B. ANA
C. Paul-Bunnell heterophile antibodies
D. A & B
E. A, B, C

Back 28

E. A, B, C.
In addition, rheumatoid factor levels may be increased. For this reason and because the culture of EBV is difficult, routine diagnosis is usually made serologically.

Front 29

What's the best definition of heterophile antibodies as produced in EBV infections?
A. IgM antibodies with an affinity for sheep and horse red blood cells
B. IgM antibodies with an affinity for the capsule of all DNA viruses
C. IgA antibodies directed against protein-antigens often consumed in a normal diet
D. IgG antibodies secreted in tears with an affinity pigeon egg antigens
E. IgG antibodies with an affinity for plant antigens

Back 29

A. IgM antibodies with an affinity for sheep and horse red blood cells.
Heterophile antibodies are a fairly specific, though not very sensitive indicator of EBV infection. They are also the basis of the Monospot EBV detection agglutination assay.
QCCP2, EBV

Front 30

Which of the following antibodies is most helpful in distinguishing an acute EBV infection from a remote EBV infection?
A. IgM anti-EA
B. IgM anti-VCA
C. IgG anti-EA
D. IgM anti-VCC
E. IgG anti-EE

Back 30

B. IgM anti-VCA.
Anti-viral capsid antibodies (VCA) are the only EBV antibodies with a high specificity for the acute phase of infection. This IgM antibody is the first antibody to appear with
acute infection but quickly decreases in titer with time. IgM anti-VCA recedes to undetectable titers with convalescence but quickly reappears with virus reactivation.
QCCP2, EBV