07 - Infectious diseases Flashcards
Most common form of extrapulmonary TB
scrofula
Enumerate: Hutchinson’s triad:
- Hutchinson’s teeth
- CN VIII paralysis
- interstitial keratitis
Most common sexually transmitted bacterial disease in the world:
Chlamydia trachomatis
Leading cause of blindness in sub-Saharan Africa (what organism?)
Onchocerca volvulus
Usual pattern of inflammation, observed in infections with extracellular Gram-positiv cocci, and Gram-negative rods (pyogenic organisms).
Suppurative
Usual pattern of inflammation observed in chronic infections, and acute viral and intracellular bacteria and parasites.
Mononuclear
Usual pattern of inflammation observed in tuberculosis, fungal infections and schistosome eggs; response to infectious agents that are not easily eliminated.
Granulomatous
Usual response to viral infections that involves cytopathic changes in cells (inclusion bodies and multinucleated giant cells) or proliferation of host cells.
Cytopathic/Cytoproliferative
Usual response to clostridial infections, E. histolytica, HBV in liver, and Herpesviruses in brain.
Tissue necrosis
Usually a sequela of chronic inflammation, seen in chronic HBV infection (cirrhosis), and schistosoma (pipestem fibrosis).
Chronic inflammation and scarring
Multinucleated giant cells with eosinophilic nuclear and cytoplasmic inclusions, seen in measles.
Warthin-Finkeldey cells
Pink to purple intranuclear inclusion bodies, seen in Herpes simplex virus (HSV) infections.
Cowdry Type A inclusion bodies
Infection with Varicella-Zoster virus (VZV) produces this kind of lesion.
Intraepithelial vesicles
Large, atypical cells with Owl’s eye nuclei are seen in this viral infection.
Cytomegalovirus (CMV)
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.
Epstein-Barr virus (EBV)
Main difference between staphylococcal and streptococcal infections.
More extensive tissue destruction in staphylococci
Suppuration with grayish pseudomembrane formation, is seen in what bacterial infection? Clue: Chinese characters appearance of organism
Corynebacterium diphtheriae
Gram-positive intracellular bacilli in CSF are diagnostic of what bacterial infection? Clue: diagnosis is granulomatosis infantiseptica.
Listeria monocytogenes
Suppuration with tissue necrosis and hemorrhagic lesions are diagnostic of what bacterial infection?
Bacillus anthracis
Gram-negative intracellular diplococci are diagnostic of what bacterial infection?
Neisseria gonorrheae
Fleur-de-lis pattern of necrotizing pneumonia and perivascular infiltration of organisms producing a perivascular blue haze?
Pseudomonas aeruginosa
Buboes, pneumonia and neutrophilic sepsis are clinical forms of what bacterial infection?
Yersinia pestis
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.
Mycobacterium avium complex (MAC)
Form of leprosy associated with asymmetric peripheral nerve involvement; formation of granulomas, and positive lepromin skin test, due to an intact cell-mediated immunity.
Tuberculous (paucibacillary) leprosy
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.
Lepromatous (multibacillary) leprosy
Lesion in syphilis characterized by central coagulation necrosis, rimmed by palisading macrophages, and fibroblasts, plasma cell-rich infiltrate, and few organisms.
Syphilitic gumma
Characteristic lesion in syphilitic aortitis.
Obliterative endarteritis of the vasa vasorum
Forms of neurosyphilis.
Meningovascular, Paretic, and Tabes dorsalis
Myonecrosis with gas bubble formation is caused by Clostridium perfringens. What enzyme is responsible for the tissue necrosis?
a-toxin (lecithinase)
Pseudomembranous colitis, characterized by mucopurulent exudate reminiscent of a volcano, is associated with C. difficile. What are the toxins elaborated by this organism?
Toxin A: chemokine Toxin B: cytotoxin
Most common sexually transmitted bacterial disease in the world.
Chlamydia trachomatis
Main difference between gonococcal and chlamydial urethritis.
Absence of organisms in chlamydial urethritis
Gray-white, dirty-looking pseudomembrane, with underlying mucosal hyperemia and inflammation, is characteristic of what fungal infection?
Candidiasis
Infection with this fungus produces granulomas in immunocompetent hosts, and soap-bubble lesions in CNS, in immunocompromised hosts.
Cryptococcus neoformans
Fungus with septate hyphae, branching at acute angles (40 deg).
Aspergillus
Non-septate hyphae, branching at right angles.
Mucor
Causative agent of malaria, diagnosis depends on demonstration of asexual stages WITH hemozoin pigment.
Plasmodium
Causative agent of babesiosis; diagnosis depends on demonstration of parasites in peripheral blood WITHOUT hemozoin, with the characteristic Maltese cross pattern.
Babesia
Etiologic agent of a parasitic disease transmitted by sandflies; has cutaneous and visceral forms; parasites in macrophages are characteristic.
Leishmania sp.
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.
Trypanosoma brucei
Trypanosome related disease transmitted by Triatoma sp. (reduviid bug), primarily affects skeletal, smooth, and cardiac muscle (heart, esophagus and colon).
Chagas disease (Trypanosoma cruzi)
