Diseases of the Integumentary System and Wounds Flashcards
BIOL-2420 (31 cards)
Microbiota of skin
Gram-positive, salt-tolerant bacteria: Staphylococci, Micrococci, Diphtheroids
Chemicals excreted by skin
oleic acid;
urea;
sebum
Bacterial Skin Diseases
folliculitis;
scalded skin syndrome;
impetigo and erysipelas;
acne;
scarlet fever;
necrotizing fascitis;
cat scratch fever;
pseudomonas infection;
rocky mountain spotted fever;
cutaneous anthrax;
gas gangrene
Staphylococcal Skin Infections
Stapyococcal epidermidis: G+ cocci, coagulase-negative;
Staphylococcal aureus: G+ cocci, coagulase-positive
Staphylococcus aureus
possible virulence factors: antibiotic resistant
leukocidin
resists opsonization
servives in phagolysosome
lysozyme resistant
exfoliative toxin
superantigen
involved in:
folliculitis
impetigo and erysipelas
acne
SSSS
Staphylococcal Scladed Skin Syndrome
induced by epidermolytic exotoxins A & B (aka exfoliative)
causative agent: S. aureus
AKA: bullous impetigo; impetigo of newborn
symptoms: widespread formation of fluid filled blisters that are thin walled and easily ruptured
treatment: supportive care along w/ eradication of primary infection
Nafcillin
Oxacillin
Vancomycin
Impetigo and erysipelas
most common skin infection in children;
causative agent: S.aureus
signs and symptoms: local infections, characterized by isolated pustules that become crusted and rupture
transmission: mostly through contact: bacteria penetrate skin through minor abrasion or insect bite
causative agent: S. aureus
S. pyogenes
treatment:
topical antibiotic: Bactroban
systemic antibiotics: Cephalexin, Erythromycin
Classifications of acne
comedonal (mild)
inflammatory (moderate)
Comedonal (mild) acne
sebum channels are blocked w/ shed cells;
clogged pores, resulting in whiteheads (closed comedones) and black heads (open comedones)
treatment:
topical agents
Salicylic acid preparations: work by breaking down the thick outer layer of skin
retinoids: derived from Vitamin A; work by increasing cell turnover, stimulating collagen production, and improving overall skin health;
Adapaline: increases cell turnover, unclogs pores, reduces inflammation
Inflammatory (moderate) acne
causative agent:
Propionibacterium acnes (G+; anaerobic rod)
treatment: preventing sebum formation (isotretinoin)
antibiotics
Benzoyl peroxide to loosen clogged follicles
visible (blue) light kills P. acnes
Streptococcal Skin Infections
causative agent: Streptococcus pyogenes
possible virulence factors:
Group A beta-hemolyitc streptococci;
hemolysins;
Hyaluronidase (enzyme that degrades hyaluronic acid);
streptolysins (exotoxins; leukotoxic property; polymorphic cells are killed after ingestion of streptococci);
M proteins: surface expressed protein (antibody): ability to evade host’s immune system;
exotoxin A
Necrotixinf fasciitis
rare infection of deeper layers of skin and subcutaneous tissues
causative agent: Type I (polymicrobial infection): Group A streptococcus (Streptococcus pyogenes);
S. aureus;
Clostridium perfringens;
Bacteroides fragilis (common component of human colon bacteria);
Aeromonas hydrophila (G-, rod-shaped, bacterial skin & soft tissue infection);
Vibrio vulnificus (vomiting, diarrhea and abdominal pain)
type II (monobaterial infection): Group A streptococcus (S. pyogenes);
MRSA
treatment:
aggressive surgical debridement to keep it from spreading;
antibiotics w/ a combination of IV antibiotics: penicillin;
vancomycin;
dindamycin
Pseudomonas infection
causative agent: Pseudomonas aeruginosa;
infections are local and diffuse;
common predisposing factors: breakdwon of the integument which may result from trauma, burns or dermitis;
high moisture conditions such as those found in the ear of swimmers, toe webs, etc
symptoms: general inflammation, sepsis
Sepsis
a life-treatening condition in which a body’s response to an infection damages its own tissues and organs
Gas gangrene
bacterial infection that produces gas in tissues in gangrene (tissue death due to lack of bloodflow; discoloration, swelling, infection);
causative agent: Clostridium perfringens;
treatment: debridement and excision w/ amputation necessary in many cases;
antibiotics are not effective because they do not penetrate ischaemic muscles enogh to be effective
Viral Skin Diseases
Poxviruses;
warts;
chickenpox and shingles;
rubella;
measles;
HSV
Smallpox
highly contagious fatal viral disease caused by variola virus;
causative agents:
VaRiola major (ds DNA);
Variola minor (ds DNA)
symptoms:
lesions: macules (after fever and headache) -> papules -> vesicles -> pustules -> crust -> scar
treatment: vaccination;
no current drug is currently approved for the treatment of smallpox
Chikenpox and shingles
causative agent: Varicella zoster (HHV-3; ds DNA)
symptoms:
chickenpox: vesilcular skin rash in the center of the body and head rather than the peripheral body;
the rash does become itchy, leading to raw pockmarks
shingles: localized rashes; secondary infection of the Voricella zooster virus; headaches, fever and malaise
treatment:
chickenpox: symptomatic relief
shingella: to limit the severity and duration of pain: over-the-counter analgesics, Acyclovir (inhibits viral DNA polymerase by acting as an analog to deoxyguanosine triphosphate (dGTP); corticosteroids (mimic the effects of cortisol (stress, metabolism and immune system); used for their anti-inflammatory and immunosuppressive properties)
transmitted by respiratory route
causes pus-filled vesicles
virus main remain in the dorsal root ganglia
prevention: live attenuated vaccine
Measles
causative agent: measles virus - Paramyxovirus (enveloped; ss RNA)
symptoms: four-day fever
the three Cs: cough, coryza (cold head) and conjuctivitis
fever
anorexia
rashes
macular rash (discolored, flat spots: macules) and Koplik’s spots (tiny grey or bluish-white spots on the buccal mucosa)
encephalitis: 1 in 1000 cases
treatment: no specific treatment
transmission: respiratory route
Measles
rubeola, red measles
Paramyxovirus, Morbillivirus
primary patient: child
complications: pneumonia, encephalitis, subacute sclerosing panencephalitis
skin rash: extensive
Koplok’s spots: present
Rubella (German Measles)
3-day measles
Togaviridae: Rubivirus
primary patients: child, ferus
complications: birth defects
Skin rash: mild, spread out
Koplik’s spots: absent
Herpes Virus (HSV)
symptoms:
small, painful blisters
(fluid in blisters may be clear or cloudy; area under blisters is red; blisters break open so easily that they quickly become open sores)
may hurt to urinate
you may run a fever and have other flu-like symptoms
treatment: Acyclovir (prevents viral DNA polymerase from working by acting as an analog to dGTP (deoxyguanosine triphosphate)
Types of Herpes Virus (HSV)
Herpes Simplex Virus (HSV-1)
HSV-2
Herpes Simplex Virus (HSV-1)
cold sores, shed in saliva, contaminated hands, eating utensils, etc.
