Chapter 33: Skin and Soft Tissue Infections. Answers Explained

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MULTIPLE CHOICE 1. What is the most common bacterium found on the skin? a. Coagulase-negative staphylococci b. Coagulase-negative streptococci c. Escherichia coli d. Pseudomonas aeruginosa ... A Usual flora of the skin consists of those microbes able to adapt to the high salt concentration and drying effects of the skin. Important microflora includes gram-positive cocci, such as staphylococci and streptococci. Coagulase-negative staphylococci, such as Staphylococcus epidermidis, are permanent skin residents; coagulase-positive Staphylococcus aureus is a transient colonizer. REF: 805 OBJ: Level 1: Recall 2. Which of the following organisms are responsible for impetigo? a. Staphylococcus epidermidis b. Streptococcus pyogenes c. Enterococcus faecalis d. Streptococcus agalactiae B Impetigo is a common pyoderma that is most often seen in children. Historically, the majority of cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years. REF: 809 OBJ: Level 1: Recall 3. A group of swim team members breaks out in a rash (folliculitis) the day after swimming at the pool. What organism is probably responsible for this outbreak? a. Staphylococcus aureus b. Enterococcus c. Escherichia coli d. Pseudomonas aeruginosa D Folliculitis is an inflammation and infection of hair follicles. S. aureus is the most common etiologic agent of folliculitis, although P. aeruginosa has been implicated in cases acquired from contaminated swimming pools or whirlpools. REF: 811 OBJ: Level 2: Interpretation 4. What is a form of folliculitis in bearded men? a. Sycosis barbae b. Furuncle c. Carbuncle d. Impetigo A Sycosis barbae is a form of folliculitis occurring in bearded men. REF: 811 OBJ: Level 1: Recall 5. Which of these is an abscess that extends more deeply into the subcutaneous fat and may have multiple draining sites? a. Furuncle b. Carbuncle c. Folliculitis d. Impetigo B A carbuncle is an abscess that extends even more deeply into the subcutaneous fat and may have multiple draining sites. Staphylococcus aureus is the most common causative pathogen. REF: 811 OBJ: Level 1: Recall 6. Besides antimicrobial therapy, how are most carbuncles treated? a. Teabags to draw the poison out b. Moist heat, then cold compresses c. Surgical drainage d. Squeezing to express the pus and necrotic tissues C Furuncles usually can be managed by the application of moist heat and antimicrobial therapy. Surgical drainage is generally needed for most carbuncles. REF: 811 OBJ: Level 1: Recall 7. What condition presents as a localized area of mildly painful erythema, warmth, and swelling of the skin with poorly demarcated margins? a. Impetigo b. Carbuncles c. Furuncles d. Cellulitis D Cellulitis is a diffuse inflammation and infection of the superficial skin layers. It appears as a localized area of mildly painful erythema, warmth, and welling of the skin with poorly demarcated margins. REF: 810 OBJ: Level 2: Interpretation 8. What is erysipelas? a. Inflammation of hair follicle b. A deep form of cellulitis c. A synonym for furuncle d. A synonym for carbuncle B Erysipelas is a deeper form of cellulitis that involves not only the superficial epidermis but also the underlying dermis and lymphatic channels. Erysipelas is characterized as a painful, indurated area of cellulitis with a raised, sharply demarcated border and a typical deep crimson hue. REF: 810 OBJ: Level 1: Recall 9. What is the most infamous type of myonecrosis? a. Tetanus b. Flesh-eating Streptococcus c. Gas gangrene d. Ebola hemorrhage C Clostridial myonecrosis, also known as gas gangrene, is the most infamous type of myonecrosis and is caused by histotoxic clostridia, which include Clostridium septicum, C. perfringens, C. novyi, C. histolyticum, and C. sordellii. REF: 813 OBJ: Level 1: Recall 10. What condition causes the nail margin to become painful, red, warm, and swollen with pus? a. Furuncle b. Carbuncle c. Erysipelas d. Paronychia D Paronychia is an infection of the cuticle surrounding the nail bed. Cases generally follow minor trauma, such as removing a hangnail. The involved part of the finger at the nail margin becomes painful, red, warm, and swollen, and pus may be expressed from around the nail bed. REF: 811 OBJ: Level 2: Interpretation 11. What organism is known to cause severe necrotic cellulitis and primary sepsis? a. Vibrio vulnificus b. V. parahaemolyticus c. Campylobacter spp. d. Staphylococcus aureus A V. vulnificus, a halophilic vibrio, has been recognized as a virulent pathogen since 1976 when it was first described. The organism is known to cause severe necrotic cellulitis and primary sepsis. REF: 808 OBJ: Level 1: Recall 12. Purpura fulminans, a skin manifestation of DIC, is associated with which condition? a. Hepatitis b. Meningococcemia c. Encephalitis d. Salmonella B A skin manifestation of DIC is purpura fulminans. This syndrome has classically been associated with meningococcemia, but bloodstream infections with S. aureus, Streptococcus pneumoniae, and Haemophilus influenzae have also been associated. It is characterized by rapidly developing skin hemorrhage and necrosis, and peripheral gangrene accompanied by shock syndrome. REF: 817 OBJ: Level 2: Interpretation 13. What happens in the late stages of toxic shock syndrome as a result of the production of TSST-1? a. Bruising b. Disseminated intravascular coagulation (DIC) c. Desquamation d. Bacteremia C Cutaneous desquamation occurs in toxic shock syndrome (TSS) because of the production of staphylococcal exotoxins. TSS clinical presentations include a diffuse sunburn-like erythroderma appearing early in the course and accompanied by fever, hypotension, and evidence of multiorgan dysfunction. Desquamation of skin, especially on the palms and soles, occurs during the convalescent stage of the illness. REF: 829 OBJ: Level 2: Interpretation 14. What causes scarlet fever? a. S. aureus b. Endotoxin c. Proteases d. Erythrogenic toxin D Scarlet fever is a form of GAS disease that can occur when the infecting strain produces streptococcal pyrogenic exotoxins (SPEs). It occurs mostly in children and concomitantly with pharyngeal infection, although it can also be seen with infections at other sites. REF: 830 OBJ: Level 1: Recall 15. What organism produces “rat bite fever?” a. Streptobacillus moniliformis b. Staphylococcus aureus c. Borrelia burgdorferi d. Chlamydia trachomatis A Two bacterial diseases, rare in the United States, are included under the general term rat-bite fever: streptobacillosis, caused by Streptobacillus moniliformis, and spirillosis, caused by Spirillum minus (minor). REF: 830 OBJ: Level 1: Recall 16. What organism causes the Buruli ulcer? a. Streptococcus agalactiae b. Mycobacterium ulcerans c. Corynebacterium jejuni d. Mycobacterium leprae B M. ulcerans infection usually occurs as a single, pruritic ulcer with undermined edges, also known as a Buruli ulcer. M. ulcerans infection is associated with swamps and may be a chronic infection in tropical climates. REF: 819 OBJ: Level 1: Recall 17. What is the most sensitive method of diagnosing cutaneous infections? a. Culture b. Enzyme immunoassay (EIA) c. Polymerase chain reaction (PCR) d. DNA probe A Culture is still the most sensitive method of diagnosing cutaneous infections. Agents of primary infections are recovered in routine culture using primary nonselective media, such as blood and chocolate agars, and selective media, such as MacConkey agar. REF: 817 OBJ: Level 1: Recall 18. The clinical syndrome of Rocky Mountain spotted fever (RMSF) can be confused with which of the following conditions? a. Lyme disease b. Atypical measles c. Smallpox d. Allergic reactions B The clinical syndrome of RMSF may be confused with atypical measles, meningococcal bloodstream infection, and other forms of bacterial sepsis, secondary syphilis, typhoid fever, enteroviral infection, and leptospirosis. REF: 831 OBJ: Level 2: Interpretation 19. What organism, which usually causes respiratory infections, causes maculopapular and vesicular rashes, urticaria, and immunologically mediated erythema nodosum and erythema multiform? a. Streptococcus pneumoniae b. Klebsiella pneumoniae c. Mycoplasma pneumoniae d. Haemophilus influenzae C Although a primary pathogen of the respiratory tract, Mycoplasma can cause a variety of dermatologic findings including maculopapular and vesicular rashes, urticaria, and the hypersensitivity reactions erythema nodosum and erythema multiforme (EM), including EM major (Stevens-Johnson syndrome). REF: 819 OBJ: Level 2: Interpretation 20. What is a circumscribed, hyperkeratotic, rough-textured, painless papule called? a. Skin tick b. Mole c. Freckle d. Wart D There are over 100 types of human papillomaviruses (HPV), with most human infections being asymptomatic or leading to warts, benign proliferations of skin, or mucosal cells. Common warts (circumscribed, hyperkeratotic, rough-textured, painless papules varying in size from several millimeters to large masses), plantar warts (flat, hyperkeratotic lesions of the plantar surface of the feet that may be painful), and flat warts (smooth, slightly elevated, usually multiple lesions varying in size from 1 millimeter to 1 centimeter) are typical cutaneous manifestations. REF: 824 OBJ: Level 2: Interpretation 21. What disease results from a reactivation of the varicella-zoster virus that demonstrates a vesicular eruption in a unilateral dermatomal distribution? a. Shingles b. Chicken pox c. Infectious mononucleosis d. Rubella A Varicella-zoster virus is a herpesvirus that exhibits, like other members of the family Herpesviridae, lifelong latency in the human host. With reactivation, the virions move along peripheral sensory nerves of the skin, leading to the appearance of a vesicular eruption in a unilateral dermatomal distribution. The resulting condition is called herpes zoster or shingles. REF: 825 OBJ: Level 2: Interpretation 22. What is herpetic whitlow? a. Primary herpetic lesions of the genitals b. Primary herpetic lesions of the finger c. Primary herpetic lesions of the anus d. Primary herpetic lesions of the lip B A presentation of cutaneous HSV is herpetic whitlow, or primary herpetic lesions of the finger (Figure 33-22). This can be caused by either HSV-1 or HSV-2. Usually a single digit is involved, with the appearance of one or more deep vesicles that may coalesce. REF: 823 OBJ: Level 1: Recall 23. What causes rubeola? a. Calicivirus b. Herpesvirus c. Paramyxovirus d. Torovirus C Rubeola (measles) is caused by a paramyxovirus and is spread by direct contact with respiratory secretions of infected persons. REF: 824 OBJ: Level 1: Recall 24. What causes rubella? a. Calicivirus b. Herpesvirus c. Paramyxovirus d. Togaviridae D Rubella, also known as German measles, is a viral infection of children and adults that resembles measles. It is characterized by fever, rash, and lymphadenopathy. The virus is in the Togaviridae family (genus Rubivirus). REF: 822 OBJ: Level 1: Recall 25. What causes erythema infectiosum? a. Parvovirus b. Herpesvirus c. Paramyxovirus d. Togaviridae A Erythema infectiosum, or fifth disease, is one of the common viral exanthems of childhood. It is caused by the human parvovirus B19 (genus Erythrovirus, family Parvoviridae), which replicates in erythrocyte precursor cells. Erythema infectiosum, or fifth disease, is one of the common viral exanthematous diseases of childhood. REF: 822 OBJ: Level 1: Recall 26. All of the following viruses cause a characteristic viral syndrome, which includes severe bleeding manifestations except: a. Ebola. b. rabies. c. Junin. d. Marburg. B A number of viruses of the Togaviridae (e.g., yellow fever and dengue virus), Arenaviridae (e.g., Junin and Machupo viruses), and Bunyaviridae (e.g., Hantavirus) families, as well as several ungrouped viruses (e.g., Ebola, Marburg, and Lassa fever viruses), may cause a characteristic viral syndrome (fever, headache, myalgias, nausea vomiting, abdominal pain, prostration) accompanied by severe bleeding manifestations (e.g., gastrointestinal bleeding, hematuria). REF: 822 OBJ: Level 1: Recall 27. What is ringworm? a. A parasitic skin infection b. A bacterial skin infection c. A fungal skin infection d. A viral skin infection C The classic lesion of a dermatophyte infection is a circular scaly patch of erythema with a raised border. Often the edges are more inflamed than the center. These infections are also known as ringworm, reflecting the tendency of some lesions to expand annularly. REF: 826 OBJ: Level 1: Recall 28. What is thrush? a. Tinea unguium b. Tinea corporis c. Dermatophytosis d. Oral candidiasis D Thrush is a type of candidiasis involving the oral mucosa and is characterized by white, curdlike patches on the tongue, palate, or buccal mucosa. These patches adhere to the mucosa but can be removed by scraping, leaving a raw, erythematous base. REF: 808 OBJ: Level 1: Recall 29. What is swimmer’s itch? a. When cercariae larvae penetrate human skin, causing dermatitis b. When arthropods deposit larvae in human skin, causing dermatitis c. When food or water causes dermatitis d. When Pseudomonas spp. causes dermatitis A Dermatitis caused by schistosomes is most often seen when the infective larvae of bird and animal schistosomes infect humans. Free-living larvae, or cercariae, that have developed in snails penetrate the skin of humans bathing or swimming in infected waters. This results in an intensely pruritic, papular eruption known as cercarial dermatitis or “swimmer’s itch.” REF: 807 OBJ: Level 1: Recall 30. What is river blindness? a. Infection with Naegleria fowleri b. Infection with Onchocerca volvulus c. Infection with Strongyloides stercoralis d. Infection with Entamoeba histolytica B Onchocerca volvulus is transmitted by black flies, and causes subcutaneous nodules and river blindness. The most important manifestation of onchocerciasis, (so named because transmission is most often in rural villages near rapidly flowing streams), is the result of this infiltration of the eye by the organisms. REF: 826 OBJ: Level 1: Recall [Show More]

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