0114100830 - Mfm Ii - Skin Infections I, Ii, Iii (Biel)

Front 1

What three layers exist in the skin?

Back 1

epidermis, dermis, subcutaneous

Front 2

Can bacteria that invade epidermis spread systemically?

Back 2

nope. there is no blood or lymph in epidermis.

Front 3

After many days what happens to the bacterial load on the epidermis?

Back 3

bacteria that cannot grow rapidly will be sloughed off with dead skin cells.

Front 4

What three properties of skin provide prevention against bacterial growth?

Back 4

1) sloughing off
2) low pH
3) dryness

Front 5

Which three organisms routinely infect intact skin?

Back 5

1) Staph. aureus
2) Pseudomonas aeruginosa
3) Propionibacterium acnes

Front 6

Which bacterium infect hair follicles?

Back 6

Staph aureus, Pseudo. aeruginosa
Hair follicle infection is called folliculitis.

Front 7

Which bacterium infect sebaceous glands?

Back 7

Prop. acnes

Front 8

What happens when Staph. aureus is spread deeper than the hair follicle?

Back 8

Patients with carbuncles and fever most likely have septicemia. This can lead to endocarditis, osteomyelitis. These conditions are rare and is why it's important to not pick or squeeze lesions.

Front 9

What is the difference between septicemia and bacteremia?

Back 9

Once bacteria enter the blood then people have bacteremia. Symptom causing bacteremia is septicemia.

Front 10

What physical manifestations are caused by Staph. aureus skin infections?

Back 10

Front 11

Why does Pseudo. aeruginosa not usually cause folliculitis?

Back 11

it is usually not in great enough number to cause problems, BUTT it loves to grow in hot water.

Front 12

What is hot tub folliculitis?

Back 12

a usually simple infection of the skin caused by Pseudo. aeruginosa growing in hot tubs and people steeping themselves in these uncontrolled hot tubs.

Front 13

What is acne caused by?

Back 13

Proprionibacterium acnes is normal flora, but increases by some 100,000x before puberty which causes infections of the sebaceous gland -> acne.

Front 14

How do you treat Proprionibacterium acnes caused skin acne?

Back 14

antibiotics. washing the skin won't help since there is a sebaceous glad infection of the skin. effective tx occurs with topical benzoyl peroxide and antibiotics.

Front 15

How can you differentiate between Staph and Strep in a lab?

Back 15

Staph = catalase-positive
Strep = catalase-negative

Front 16

What are the the 5 infections caused by epithelial injury in which the stratum corneum is broke?

Back 16

1) Impetigo (lower layers of epidermis)
2) Erysipelas (dermis, lymphatics)
3) Cellulitis (subcutaneous fat)
4) Necrotizing fasciitis (fascial plane)
5) Myonecrosis (muscle)

Front 17

What causative agents result in Impetigo?

Back 17

Staphylococcus aureus and Streptococcus pyogenes.

Front 18

How does Impetigo present?

Back 18

The infection starts as a small red spot (macule). The macule becomes pus-filled and inflamed (pustule) with a red (erythematous) base. A crust
forms after the pustule ruptures.

Front 19

What demographic is usually infected by Impegito?

Back 19

children

Front 20

Where on the body is Impetigo usually found?

Back 20

face and limbs

Front 21

How does Erysipelas present physically?

Back 21

border is sharply demarcated, severe edema, painful inflammation. systemically fever and chills will accompany.

Front 22

What is the most common causative agent of Erysipelas?

Back 22

Streptococcus pyogenes

Front 23

What physical symptoms present with cellulitis?

Back 23

erythema, pain, swelling, warmth, margins are diffuse

Front 24

What are the most common causative agents for cellulitis?

Back 24

Streptococcus pyogenes and Staphylococcus aureus

Front 25

What are less common causative agents for cellulitis?

Back 25

If pt is exposed to contaiminated seawater, Vibrio vulnificus

Clostridium perfringens indicates polymicrobial infection that is anaerobic cellulitis.

Front 26

What are the physical symptoms present with necrotizing fasciitis?

Back 26

dark red swelling, severe pain, very quickly spreading skin darkness

Front 27

What are the two most common causative agents for necrotizing fasciitis?

Back 27

Streptococcus pyogenes and Staphylococcus aureus

Front 28

What is a less common causative agent for necrotizing fasciitis?

Back 28

Vibrio vulnificus when exposed to salt-water.

Front 29

What is the mortality rate of those with necrotizing fasciitis?

Back 29

30 - 50%; with renal failure -> 70%

Front 30

What are the symptoms of myonecrosis?

Back 30

severe pain, tenderness, local swelling, fever, apathy followed by shock and renal failure

Front 31

What is the mortality rate of myonecrosis?

Back 31

30 - 50%

Front 32

What is the most common causative agent of Myonecrosis?

Back 32

Clostridium perfringens, endospore forming anaerobe

Front 33

Where is Clostridia usually found?

Back 33

soil

Front 34

Gas gangrene is also known as

Back 34

myonecrosis

Front 35

What is a common contaminant of severe burn wounds?

Back 35

Pseudomonas aeruginosa

Front 36

What kind of infection is a burn wound infection?

Back 36

opportunistic infection

Front 37

What is the concern of a Pseudo. aeruginosa with burn wounds?

Back 37

Antibiotic resistant Gram(-) Pseudo. aeruginosa can cause bacteremia because the epidermis is compromised and the bacteria can gain access to the bloodstreadm

Front 38

What clinical sign should one look for when concerned with bacterial infection of a burn wound victim?

Back 38

1) change in wound color -> red, brown, black
2) change in color of surrounding tissue -> green, violet

Front 39

What less common contaminants of severe burn wounds?

Back 39

Staphylococcus aureus and Streptococcus pyogenes

Front 40

What are the four diseases that infect the skin and lead to systemic infection and their causative agents?

Back 40

1) Clostridium tetani causing tetanus
2) Leoptospira causing leptospirosis
3) Staph. aureus causing staylococcal scalded skin syndrome and toxic shock
4) Strep. pyogenes which causes toxic shock

Front 41

What is the causative agent for tetanus?

Back 41

Gram(+) anaerobe endospore forming Clostridium tetani

Front 42

What is the route of infection for tetanus?

Back 42

deep penetrating wound that infects wounds with spores. Spores germinate and in 7 - 21 days vegetative cells produce the tetanospasmin toxin

Front 43

tetanospasmin

Back 43

toxin produced by vegetative form of Clostridium tetani endospores that produce symptoms associated with tetanus disease by blocking the release of glycine and GABA from presynaptic terminals of motor neurons -> uncontrolled muscle contraction

Front 44

what muscles are most often involved in tetanus?

Back 44

large muscles of the back, jaw

Front 45

neonatal tetanus

Back 45

tetanus caused by umbilical cord infection

Front 46

tetanus dx and tx

Back 46

dx based on clinical findings. pathogen isolated to site of infection and takes too long to identify. if wait for lab findings, pt will be dead. give antibiotics, antibodies, and toxoid -> Ab production.

Front 47

What is the causative agent for leptospirosis?

Back 47

terminal hook-shaped spirochete Leptospira

Front 48

What is the route of infection for leptospirosis?

Back 48

wild mammals, rodents, dogs, cats, livestock are carriers. by handling meat, contaminated water, or urine containing specimens can cause infection through mucus membranes or any break in the skin

Front 49

What activities are at most risk for leptospirosis?

Back 49

farm workers, vets, pet shop owners, meat handlers, recreational activities

Front 50

What are the stages of leptospirosis?

Back 50

1) 7 - 12 day incubation
2) 4 - 7 days of fever, chills, weakness, myalgia when pathogen is in blood and CSF
3) bacteria present in urine, but not blood and CSF
4) usually self limiting

Front 51

How does severe leptospirosis present?

Back 51

jaundice, abdominal pain w/ diarrhea or constipation, renal and pulmonary dysfunction

Front 52

Icteric disease or Weil's disease

Back 52

severe leptospirosis in 10% of infected pts

Front 53

What is the most common causative agent of scalded skin syndrome?

Back 53

Staph. aureus in neonates

Front 54

Ritter disease

Back 54

staphycoccal scalded skin syndrome

Front 55

What causes symptoms associated with scalded skin syndrome?

Back 55

+ Nikolsky's sign
burned skin look because of Staph. aureus exfoliative toxin (serine protease) which spreads from mouth to rest of the body

Front 56

What is the expected steps of Ritter disease?

Back 56

1) Staph. aureus colonizes skin
2) Staph. aureus releases exfoliative toxin serine protease
3) visible redness starts at corners of mouth and spreads to entire epidermis
4) + Nikolsky's sign
5) epidermis is sloughed off
6) epidermis grows back

self limiting 7 - 10 days

Front 57

Nikolsky's sign

Back 57

slight pressure displaces the skin

Front 58

What is a milder form of scalded skin syndrome?

Back 58

Bullous impetigo, which causes isolated blistering

Front 59

What are the common symptoms of toxic shock syndrome?

Back 59

rapid onset of high fever, shock, hypotension, vomiting, diarrhea, headache, erythroderma

Front 60

What increases the risk for Staph. aureus toxic shock syndrome?

Back 60

women who use tampons

Front 61

What is the most common causative agents of toxic shock syndrome?

Back 61

Staph. aureus (TSST-1) or Strep pyogenes (SPE or pyrogenic exotoxins)

Front 62

What is the course of infection with Strep. pyogenes toxic shock syndrome?

Back 62

a wound causes a localized infection that spreads to the blood stream and becomes septic

Front 63

TSST-1 and SPE

Back 63

superantigens associated with toxic shock syndrome

Front 64

What is toxic shock syndrome secondary to for both Staph. and Strep. toxic shock?

Back 64

Staph. - vaginal infection
Strep. - skin wound

Front 65

What are the differentiating features of Staph. and Strep. toxic shock?

Back 65

Staph. - flu symptoms, generalized erythroderma, bacteremia uncommon

Strep. - no flu symtpoms, no erythroderma, bacteremia common

Front 66

What are the 6 diseases and causative organisms caused by arthropod bites?

Back 66

1) Borrelia burgdorferi causing Lyme disease
2) Francisella tularensis causing tularemia
3) Yersinia pestis causing plague
4) Rickettsia rickettsii causing Rocky Mountain spotted fever
5) Rickettsia akari causing rickettsialpox
6) Rickettsia typhi causing Murine (endemic or flea-borne) typhus

Front 67

What is the causative agent and vector for lyme disease?

Back 67

Borrelia burgdorferi carried by ticks that remain on the skin for ~48 hrs

Front 68

What is the most common first symptom of lyme disease?

Back 68

Erythema migrans of round or oval shape. The lesion will spread to form a large red spot sometimes with a clearing and red dot in the middle, sometimes not.

Front 69

What are the other common presenting symptoms occur with lyme disease?

Back 69

low-grade fever, fatigue, headache, myalgia, athralgia

Front 70

What is indicative of multiple lesions when there was a single initial lesion appearing on a suspected lyme's disease patient?

Back 70

spread of infection in the blood

Front 71

What if Lyme's disease is left untreated?

Back 71

the skin lesions will fade and hematogenous dissemination can cause cardiac dysfunction, meningitis, facial palsy and even arthritis months or years later

Front 72

What is the most common causative agent of Tularemia?

Back 72

Francisella tularensis

Front 73

How often is Tularemia found in TN?

Back 73

endemic!

Front 74

What is the most common clinical presentation of tularemia?

Back 74

ulceroglandular form:
an ulcer forms at the site of the bite
organism spreads lymphatically causing regional lymphadenopathy
pneumonia may develop after hematogenous spread

Front 75

What are the vector paths for tularemia?

Back 75

1) tick bite -> human
2) tick -> cat/rabbit -> human

Front 76

hematogenous spread

Back 76

spreading through the blood

Front 77

Is there human to human spread of tularemia?

Back 77

nope

Front 78

Typhoidal tularemia

Back 78

second common form of tularemia
abrupt onset fever, chills, malaise, fatigue with no ulcers or lymphadenopathy

Front 79

What is the common causative agent for the plague?

Back 79

Yersinia pestis

Front 80

What are the normal vectors for the plague?

Back 80

rats, squirrels, rabbits, cats which are infected, spread infection by fleas

Front 81

Why is it called bubonic plague?

Back 81

once infected, organisms travel to lymph and cause lymphadenopathy (commonly axillary) which are called buboes.

Front 82

Pneumonic plague

Back 82

hematogenous spread that gets to lungs, can be spread from person to person and is major cause of epidemics as mortality approaches 100%

Front 83

Septicemic plague

Back 83

plague that skips the lymph node infection and goes directly to the blood. no buboes are formed.

Front 84

Rocky Mountain Spotted Fever causative agent and vector

Back 84

Rickettsia rickettsii carried by ticks

Front 85

What fluids can all Rickettsia bugs spread through?

Back 85

Via blood or lymph

Front 86

What is special about identifying Rocky Mountain Spotted Fever caused by Rickettsia rickettsii as well as Murine typhus caused by Rickettsia typhi in the lab?

Back 86

they are unlikely to culture because it is a strict intracellular pathogen

Front 87

What is the physical presentation of Rocky Mountain Spotted Fever?

Back 87

macular rash, mild fever, headache and myalgia.

first is the onset of fever. the rash will start 2 to 6 days after the fever at the wrists and ankles and spread to the rest of the body (including palms and soles).

Front 88

What is a major concern with Rocky Mountain Spotted Fever that is not visible upon physical inspection?

Back 88

Disseminated intravascular coagulation

Front 89

What epidermal epithelial cells are uniquely involved in Rocky Mountain Spotted Fever?

Back 89

palm and sole

Front 90

What is the differentiating features of Rickettsialpox and Rocky Mountain Spotted Fever?

Back 90

c Rickettsialpox ulcer at the site of initial infection and less severe/self-limiting and no palm or sole involvement

Front 91

What is the causative agent and vector for Rickettsialpox?

Back 91

Rickettsia akari and ticks.
This is almost identical to Rocky Mountain Spotted Fever... almost.

Front 92

What is the causative agent and vector for Murine Typhus?

Back 92

Rickettsia typhi carried by rats, passed to humans by fleas

Front 93

How does the Murine Typhus rash spread?

Back 93

from trunk to limbs

Front 94

What bug is transferred through Cat or Dog bites or scratches because it's part of their normal flora?

Back 94

Pasteurella multocida

Front 95

What is the drug of choice for all Rickettsia bug diseases?

Back 95

doxyclycline

Front 96

What is the general antibiotic type that is used for Pasterurella infection per dog and cat attacks?

Back 96

polymicrobial, broad spectrum antibiotic because Pasterella just establishes infection and gives opportunistic bugs that change to settle in.

Front 97

What infections can dog/cat bites lead to?

Back 97

cellultis
abscesses
osteomyelitis
septic arthritis