assault / infectious diseases Flashcards
kochs postulates
1) criteria for linking a specific organism to a specific disease
2) organism is regularly found in lesions of the disease
3) organism can be isolated as single colonies
4) inoculated and infect someone
host barriers
1) skin
2) urogenital tract
3) respiratory tract
4) intestinal mucosa
skin
1) normal flora maintains an equilibrium
2 )keratin layer is constantly shed, eliminating most bugs
3) normal floral prevent access
4) low pH (5.5) and fatty acids inhibit growth
5) warm moist skin is susceptible to penetration (HPV)
6) microorganisms typically penetrate through lesions
- pricks, wounds, burns, needles, bites
urogenital
women have 10x more UTI
- low pH
2) pyelonephritis
- bladder to kidney
3) most pathogens are bacteria for perianal area into urethra
4) during reproductive years
- glycogen converted to lactic acid by lactobacilli
- low pH suppresses STD?
respiratory tract infection
1 )size of organisms important
2) damage to mucocilliary defense can be caused by smoking, cystic fibrosis, injury during intubation, aspiration of gastric juices
3) alveolar macrophages can phagocytose microbes
4) influenza inhibit ciliary motion and lower viscosity of mucus
5) tuberculosis escapes phagocytosis by killing macrophage
intestinal stract
1) pathogens transmitted by food and water with feces
2) normal defenses are mucociliary cover, gastric acids,, pancreatic enzymes, bilt salts, IgA
3) interference with gastric acids, antibiotics, bowel obstructions
4 )enveloped viruses are resistant to acids and enzymes
enteropathic bacteria
1) toxins that cause epithelial cells to secrete large amounts of fluid (e. coli)
2) shigella causes blood stool (dysentery)
3) cyst forms of protozoan parasites are resistant to acids
spread through
1) path of least resistance
2) regional lymph nodes
3) cellulistis that gets into the chest
4) HPV and fungi free in plasma
5) herpes, HIV, carried by WBCs
6) parasites in RBCs
7) dissemination leads to systemic inflammation due to cytokines
8) massive bloodstream invasions can be fatal (sepsis)
9) organisms can cause disease at sites different to entry
mother to child
1) transplacentally
2) treponema pallidum
- syphilis
- 2nd trimester
3) infection from vagina to uterus
4) child may have infections present in the vaginal fluid (HIV, HBV, chlamydia, herpes)
release of microbes
1) urination, defecation, coughing, sneezing, skin shedding
2) viruses in salivary glands can be transmitted through talking or kissing
immune evasion
C difficle in the intestine
- number 1 acquired in hospital
2) malaria sporozoites rapidly invade
3) cleave antibody, resist complement
4) survive phagocytosis
-carbohydrate capsule
5) shedding antigents
- makes vaccination difficult
6) causing immunosuppresion
- viruses that directly infect lymphocytes
special techniques for diagnosis
1) H and E
2) special stains
- gram, acid fast bacilli stain, per-iodic acid schiff
3) labelling with specific antibody probes
4) cultures are the only way to speciate and determine drug sensitivity
inflammatory responses
1) suppurative polymorphonuclear inflammation
2) mononuclear inflammation
3) chronic inflammation and scarring
4) ????
macrophage activation adn sensitization in TB
1) class II MHC presents antigen to CD4 t cells
2) cytokines are released
- initiate delayed hypersensitivity reaction
3) increase phagocytosis
bacteria
1) prokaryotes that lack nuclei and ER
2) large numbers are normal colonizers of skin, mouth and gut
2) most extracellular
4) some intracellular facultative
5) pyogenic
- pus forming (abscesses and suppurative exudate)
- cocci bacteria
mechanism of bacteria induced injury
1) adhesins bind bacteria to host cells
2) superantigens bind to MHC II molecules on APCs
- stimulate t cells to secrete IL-2
- overproduction of cytokines
- fever, shock, multisystem organ failure
- Toxic shock syndrome
gram -
1) pili adhere to epithelium
gram +
1) fimbriae to adhere
diptheria
1) inhibitions of cellular protein synthesis
neutrophilic leukocytosis
1) shift to the left
- more immature neutrophils seen
actinomyces
1) clump together
2) can be fulminant
3) seen at PA
other infections
1) pneumococci
2) hemophilus influenzae
3) gonococci
impetigo
1) typically childhood disease
2) staph and strep infection
3) skin of face
4) highly contagious
5) direct contact to areas of trauma
6) vesicles and crusting ulcers
7) no systemic symptoms
tonsillitis and pharyngitis
1) strep throat
- streptococcal
2) beta-hemolytic streptococcal infections
- scarlet fever, strawberry tongue
tuberculosis
1) collection of histicytes
2) primary TB occurs in previously unexposed people
- involves the lungs
TB of the oral cavity
1) 20% people with active TB have oral lesions
2) most represent secondary infection from primary lung infection
3) gingival mucobuccal fold
4) area with trauma or periodontal disease
primary TB
1) ghon focus
- primary site of infection in mid portion of one lung
2) ghon complex
- when regional lymph nodes are involved
3) miliary TB
- spread to distant organs in other parts of body 4)
TB diagnosis and treatment
1) biopsy granulomatous inflammation
2) purified protein derivative skin test PPF
3) chest xray for active disease
4) combination therapy
actinomycosis
1) actinomyces is the causitive organism in the majority
2) in the oral cavity
3) ulcers in mouth, periodontal disease
- entry via injury
4) high dose, long term antibiotics
syphilis
1) treponema pallidum
- spirochete
2) three stages of infection
- primary: highly infection, regional lymphadenopathy, goes away
- secondary: most infections, remit, but can recur
- tertiary: non infection, palatal lesions
congenital syphilis
1) transferred from infection mother to fetus
2) may cause serious and irreversible damage
3) dental abnormalities
- Hutchenson incisors
- mulberry molars
syphilis treatment
1) biopsy with heavy plasma cell infiltrate
2) VDRL test
3) one shot pf penicillin
osteomyelitis
1) acute: may arise from odontogenic infection
2) chronic: long standing
3) radiation, immunosuppression, medications, may complicate the problem
bacteriophage, plasmids, transposons
1) infect bacteria and indirectly cause disease
2) non pathogenic bacteria to virulent ones
2 )some antibiotic resistant
- MRSA
chlamydia, rickettsiae, mycoplasma
1) chlamydia
- female sterility
2) rickettsiae
- hemorrhagic vasculitis
-arthopod vectors
3) mycoplasma
- can spread through aerosol
fungi
1) thick, ergosterol cell walls
2) perfect and imperfect form
- candida that are fruiting bodies
3) dermatophytes
- damage hair shaft and nails
4) deep fungal infections
- spread in immunocompromised
5) opportunistic fungi
- normal residents that cause life threatening illness in the immunocompromised
6) some are limited to certain geographic regions
- histoplasma
- coccidioides
candida
1) yeast infection
2) normal oral flora in spore form
2) hyphal form is pathologic
- dry mouth
4) treated with nystatin or fluconazole
5) taste changes, angular chelitis. thrush
candidal overgrpth
1) xerostomia
2) infancy
3) chemotherapy
4) a lot of stuff
deep fungal infection
1) primarily involve the lung
viruses
1) obligate intracellular agents
2) RNA or DNA
3) spherical or cylindrical
4 )chronic or latent infection
5) inclusion bodies
- viral particle aggregates in cells
6) many species cause same pathologic features
7) single species can cause different clinical manifestations
virus induced injury
1) viral tropism
2) viral binds receptors
3) endocytosis
4) assembly and DNA replication
5) new viruses expelled
6) neoplastic cell proliferation
7) cell lysis
8)balloon degeneration with viral inclusion bodies
squamous papilloma
1) removed and can go away
verruca vulgaris
1) common wart of skin
dysplastic oral warts in HIV+
1) dome shaped nodular lesions
2) incidence in HIV is 1-3%
3) studies suggest incidence in HAART
4) most common HPV subtypes 7,32
5) surgical excision when necessary
HPV in head and neck squamous cell carcinoma
1) HPV is a causative agent for some HNSCC
- overwhelmingly HPV 16
- nasopharyngeal HPV 33
2) HPV associated HNSCC
- location is palatine and lingual tonsils
- younger and non smoking patients
oral herpes simplex
1) small, viral induced vesicles that become ulcers
2) primary: follows initial HSV, fever and malaise, oral lesions at any SITE
3) secondary: reactivation of HS virus in regional ganglia, no systemic symptoms, oral lesions on keratinized mucosa
varicella zoster
1) primary infection causes chicken pox
2) latent virus resides in sensory ganglia, reactivation causes shingles
3) nerve distribution for unilateral recurrence
coxsackie virus
1) herpangina
- vesicles on soft palate, fever, malaise, sore throat, dysphagia,
2) hand foot and mouth disease
- 5 years or younger
exposure to HIV
1) no infection
2) infection
- acute disease
3) lymphadenopathy (asymptomatic)
4) constitutional signs and symptoms
5) AIDs