07 - Infectious diseases

Question 1

Most common form of extrapulmonary TB

Answer 1

scrofula

Question 2

Enumerate: Hutchinson’s triad:

Answer 2

• Hutchinson’s teeth
• CN VIII paralysis
• interstitial keratitis

Question 3

Most common sexually transmitted bacterial disease in the world:

Answer 3

Chlamydia trachomatis

Question 4

Leading cause of blindness in sub-Saharan Africa (what organism?)

Answer 4

Onchocerca volvulus

Question 5

Usual pattern of inflammation, observed in infections with extracellular Gram-positiv cocci, and Gram-negative rods (pyogenic organisms).

Answer 5

Suppurative

Question 6

Usual pattern of inflammation observed in chronic infections, and acute viral and intracellular bacteria and parasites.

Answer 6

Mononuclear

Question 7

Usual pattern of inflammation observed in tuberculosis, fungal infections and schistosome eggs; response to infectious agents that are not easily eliminated.

Answer 7

Granulomatous

Question 8

Usual response to viral infections that involves cytopathic changes in cells (inclusion bodies and multinucleated giant cells) or proliferation of host cells.

Answer 8

Cytopathic/Cytoproliferative

Question 9

Usual response to clostridial infections, E. histolytica, HBV in liver, and Herpesviruses in brain.

Answer 9

Tissue necrosis

Question 10

Usually a sequela of chronic inflammation, seen in chronic HBV infection (cirrhosis), and schistosoma (pipestem fibrosis).

Answer 10

Chronic inflammation and scarring

Question 11

Multinucleated giant cells with eosinophilic nuclear and cytoplasmic inclusions, seen in measles.

Answer 11

Warthin-Finkeldey cells

Question 12

Pink to purple intranuclear inclusion bodies, seen in Herpes simplex virus (HSV) infections.

Answer 12

Cowdry Type A inclusion bodies

Question 13

Infection with Varicella-Zoster virus (VZV) produces this kind of lesion.

Answer 13

Intraepithelial vesicles

Question 14

Large, atypical cells with Owl’s eye nuclei are seen in this viral infection.

Answer 14

Cytomegalovirus (CMV)

Question 15

There are no morphologic hallmarks for this viral infection, but it induces lymphoid cell proliferation (peripheral blood lymphocytosis); associated with nasopharyngeal carcinoma, Burkitt lymphoma, and some forms of HL.

Answer 15

Epstein-Barr virus (EBV)

Question 16

Main difference between staphylococcal and streptococcal infections.

Answer 16

More extensive tissue destruction in staphylococci

Question 17

Suppuration with grayish pseudomembrane formation, is seen in what bacterial infection? Clue: Chinese characters appearance of organism

Answer 17

Corynebacterium diphtheriae

Question 18

Gram-positive intracellular bacilli in CSF are diagnostic of what bacterial infection? Clue: diagnosis is granulomatosis infantiseptica.

Answer 18

Listeria monocytogenes

Question 19

Suppuration with tissue necrosis and hemorrhagic lesions are diagnostic of what bacterial infection?

Answer 19

Bacillus anthracis

Question 20

Gram-negative intracellular diplococci are diagnostic of what bacterial infection?

Answer 20

Neisseria gonorrheae

Question 21

Fleur-de-lis pattern of necrotizing pneumonia and perivascular infiltration of organisms producing a perivascular blue haze?

Answer 21

Pseudomonas aeruginosa

Question 22

Buboes, pneumonia and neutrophilic sepsis are clinical forms of what bacterial infection?

Answer 22

Yersinia pestis

Question 23

Myobacterial infection that causes disseminated disease in patients with profound immunodeficiency (AIDS and transplant patients); histologically, there is no granuloma formation; rather, macrophages with AFB are seen, due to profound loss of CMI.

Answer 23

Mycobacterium avium complex (MAC)

Question 24

Form of leprosy associated with asymmetric peripheral nerve involvement; formation of granulomas, and positive lepromin skin test, due to an intact cell-mediated immunity.

Answer 24

Tuberculous (paucibacillary) leprosy

Question 25

Form of leprosy associated with symmetric peripheral nerve involvement; formation of lipid-laden macrophages (lepra cells) with globi (AFB), and a negative lepromin skin test, due to a depressed cell-mediated immunity.

Answer 25

Lepromatous (multibacillary) leprosy

Question 26

Lesion in syphilis characterized by central coagulation necrosis, rimmed by palisading macrophages, and fibroblasts, plasma cell-rich infiltrate, and few organisms.

Answer 26

Syphilitic gumma

Question 27

Characteristic lesion in syphilitic aortitis.

Answer 27

Obliterative endarteritis of the vasa vasorum

Question 28

Forms of neurosyphilis.

Answer 28

Meningovascular, Paretic, and Tabes dorsalis

Question 29

Myonecrosis with gas bubble formation is caused by Clostridium perfringens. What enzyme is responsible for the tissue necrosis?

Answer 29

a-toxin (lecithinase)

Question 30

Pseudomembranous colitis, characterized by mucopurulent exudate reminiscent of a volcano, is associated with C. difficile. What are the toxins elaborated by this organism?

Answer 30

Toxin A: chemokine Toxin B: cytotoxin

Question 31

Most common sexually transmitted bacterial disease in the world.

Answer 31

Chlamydia trachomatis

Question 32

Main difference between gonococcal and chlamydial urethritis.

Answer 32

Absence of organisms in chlamydial urethritis

Question 33

Gray-white, dirty-looking pseudomembrane, with underlying mucosal hyperemia and inflammation, is characteristic of what fungal infection?

Answer 33

Candidiasis

Question 34

Infection with this fungus produces granulomas in immunocompetent hosts, and soap-bubble lesions in CNS, in immunocompromised hosts.

Answer 34

Cryptococcus neoformans

Question 35

Fungus with septate hyphae, branching at acute angles (40 deg).

Answer 35

Aspergillus

Question 36

Non-septate hyphae, branching at right angles.

Answer 36

Mucor

Question 37

Causative agent of malaria, diagnosis depends on demonstration of asexual stages WITH hemozoin pigment.

Answer 37

Plasmodium

Question 38

Causative agent of babesiosis; diagnosis depends on demonstration of parasites in peripheral blood WITHOUT hemozoin, with the characteristic Maltese cross pattern.

Answer 38

Babesia

Question 39

Etiologic agent of a parasitic disease transmitted by sandflies; has cutaneous and visceral forms; parasites in macrophages are characteristic.

Answer 39

Leishmania sp.

Question 40

Etiologic agent of a parasitic disease transmitted by Glossina sp. (Tse-Tse fly); has hemolymphatic and cerebral phases; diagnosis relies on demonstration of trypanosomes on blood smears.

Answer 40

Trypanosoma brucei

Question 41

Trypanosome related disease transmitted by Triatoma sp. (reduviid bug), primarily affects skeletal, smooth, and cardiac muscle (heart, esophagus and colon).

Answer 41

Chagas disease (Trypanosoma cruzi)