Infectious Diseases - Chapter 8

Question 1

Name the 7 categories of human infectious agents.

Answer 1

a. Prions
b. Viruses
c. Bacteria
d. Fungi
e. Protozoa
f. Helminths
g. Ectoparasites (Not in Robbins)

Question 2

The virulence of a microbial organism relates to its ability to _____,_____, and _____.

Answer 2

Adhere to host cells
Invade cells and tissues
Deliver toxins (Not in Robbins)

Question 3

Name the three lines of natural defense to virulent microorganisms.

Answer 3

Intact host skin, intact mucosal surfaces, and their secretory-excretory products (antimicrobial substances.) (p. 342)

Question 4

Define and differentiate septicemia and bacteremia.

Answer 4

Bacteremia is bacteria in the blood.
Septicemia is sustained bloodstream invasion and dissemination of pathogens (viremia, bacteremia, fungemia, or parasitemia) manifested by fever, low arterial pressure, and other systemic signs and symptoms of sepsis. If allowed to progress, the organism may multiply and cause DIC with widespread hemorrhages and thrombi. (Not in Robbins)

Question 5

A microbial disease occurring in an immunosuppressed individual is termed an ____________.

Answer 5

Opportunistic infection. (p. 386)

Question 6

A hospital acquired microbial disease is known as a _____________.

Answer 6

Nosocomial infection (Not in Robbins)

Question 7

Define suppuration.

Answer 7

Suppuration is the process of pus formation, characterized by predominantly neutrophilic inflammation, caused by the presence of pyogenic microorganisms. (p. 352)

Question 8

Name three types of pyogenic microorganisms.

Answer 8

Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes (p. 362)

Question 9

Define and differentiate furuncle from carbuncle and list the usual causative organism.

Answer 9

A furuncle is a focal suppurative inflammation of the skin and subcutaneous tissue, either solitary or multiple, or recurrent in successive crops.
A carbuncle is associated with deeper suppuration that spreads laterally beneath the deep subcutaneous fascia and then borrows superficially to erupt in multiple adjacent skin sinuses.
The usual causative organism is staphylococcus. (p. 364)

Question 10

Most cases of lobar pneumonia are caused by what organism?

Answer 10

Streptococcus pneumoniae (p. 362)

Question 11

What organisms are common causes of urinary tract infections?

Answer 11

Escherichia coli, Pseudomonas aeruginosa, Enterococcus species (p. 362)

Question 12

The most characteristic histologic hallmark of a Mycobacterium infection is ______.

Answer 12

A granulomatous inflammatory reaction that form both caseating and noncaseating tubercles (p. 375)

Question 13

The types of Mycobacterium that frequently cause disease in AIDS patients is_______.

Answer 13

Mycobacterium avium complex (p. 376)

Question 14

What is the basis by which Mycobacterial organisms receive the designation of acid fast organisms?

Answer 14

Mycobacteria are aerobic, non-spore forming, non-motile bacilli with a waxy coat that causes them to retain the red stain when treated with acid in the acid fast stains. (p. 371)

Question 15

What are the constituent parts associated with a primary tuberculosis infection and what is the eponym describing these parts?

Answer 15

Gray-white parenchymal focus under the pleura and hilar lymph nodes with caseation together referred to as the Ghon complex. (p. 374)

Question 16

Define and differentiate primary and secondary tuberculosis.

Answer 16

Primary Pulmonary Tuberculosis – lungs are usual location of primary infections. Initial focus of infection is the Ghon complex. The form of disease that develops in a previously unexposed, unsensitized person.
Secondary (reactivation) Pulmonary Tuberculosis – represents reactivation of an old possibly subclinical infection, usually located in one or both lung apices. Pattern of disease that arises in a previously sensitized host. (p. 374-375)

Question 17

Miliary tuberculosis is________.

Answer 17

Hematogenous dissemination of tuberculous lesions throughout the body.

Question 18

Miliary tuberculosis is caused by dissemination of Mycobacterial organisms by what route?

Answer 18

Lymphohematogenous (p. 376)

Question 19

Syphilis is caused by what microorganism, and what is the morphology of this organism?

Answer 19

Treponema pallidum is the microaerophilic spirochete that causes syphilis. (p. 378)

Question 20

Differentiate the three stages of syphilis.

Answer 20

1. primary stage – occurs 3 weeks after contact with an infected individual, features a single firm, nontender, raised, red lesion located at the site of treponemal invasion. The chancre heals in a few weeks with or without therapy.
2. Secondary stage – occurs 2-10 weeks after the primary chancre, is characterized by a diffuse rash, particularly of the palms and soles, that may be accompanied by silvery-gray oral lesions, fever, lymphadenopathy, malaise, and arthritis, and weight loss. Symptoms last several weeks.
3. Tertiary stage – occurs years after the primary lesion.
   3 main manifestations – cardiovascular syphilis, neurosyphilis, and benign tertiary syphilis
   (p. 379)

Question 21

21. The histologic hallmark of the inflammatory reaction associated with syphilis is _________.

Answer 21

Intense infiltrate of plasma cells, with scattered macrophages and lymphocytes and a proliferative endarteritis. (p. 379)

Question 22

Although rarely seen today, what is the most common complication of tertiary syphilis?

Answer 22

Aortitis (p. 379)

Question 23

Gas gangrene is caused by what microorganism?

Answer 23

Clostridium perfringens (p. 362 & 382)

Question 24

The organism listed above is especially virulent in deep wound infections because it is a ______.

Answer 24

Gram positive bacillus that grow under anaerobic conditions. (p. 382)

Question 25

Name three types of herpes virus.

Answer 25

Herpes simplex 1 and 2, Cytomegalovirus, Varicella Zoster virus (p. 357)

Question 26

Candidiasis of the oral cavity is known as _______.

Answer 26

Thrush (p. 386)

Question 27

Non-septate , irregularly wide fungal hyphae with frequent right angle branching, causing opportunistic infections in immunocompromised persons and diabetics are commonly referred to as __________.

Answer 27

Zygomycosis (Mucormycoses) (p. 389)

Question 28

Two special stains most frequently ordered for the identification of fungi are ____ and ____.

Answer 28

Gomori methenamine silver stain and Periodic acid Schiff (PAS) (p. 386 & 353)

Question 29

Proliferating masses of hyphae of Aspergillus within pulmonary abscess cavities are known as_____.

Answer 29

Fungus balls (p. 388)

Question 30

In invasive aspergillosis, pulmonary lesions of necrotizing pneumonia with sharply delineated, rounded, gray foci and hemorrhagic borders are referred to as ______ ______.

Answer 30

Target lesions (p. 388)

Question 31

The yellow granules often seen on the cut surface of hypertrophic tonsils are known as _____.

Answer 31

Sulfur granules (actinomyces) (Not in Robbins)

Question 32

The classic histopathologic changes of a pulmonary infection with the above organisms are ____.

Answer 32

Alveolar spaces filled by a foamy, amorphous material, composed of proliferating parasites and cell debris. There is an accompanying mild interstitial inflammatory reaction, with widening of the septa, protein, and fibrin exudation, pneumocyte proliferation, escape of red cells, and formation of hyaline membranes. (Not in Robbins)

Question 33

Lymphedema resulting from obstruction of the lymphatics by chronic filariasis is known as _____.

Answer 33

Elephantiasis (p. 370)

Question 34

Parasitic cysts frequently encountered in the liver are caused by what parasite?

Answer 34

Echinococcus granulosus (p. 395)

Question 35

The classic histologic finding associated with cytomegalic inclusion disease is:

Answer 35

Prominent intranuclear basophilic inclusions spanning half the nuclear diameter usually set off from the nuclear membrane by a clear halo. (p. 359)

Question 36

Congenital cytomegalic inclusion disease closely resembles what other neonatal condition?

Answer 36

Erythroblastosis fetalis (p. 359)