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Pathology II - Infectious disease

Terms in this set (117)

Staph aureus is a major cause of infections in patients with
severe burns and surgical wounds
What is the number one causative agent of hospital acquired infections?
E. coli
Opportunistic infection in catherized patients, patients with prosthetic cardiac valves and drug addicts
Staph epidermidis
what is the toxin that is responsible for scalded skin syndrome in patients with a Staph aureus infection?
Exfoliative toxin
what are some soft tissue and skin infections caused by staph aureus?
folliculitis, furuncles, carbuncles, cellulits and fasciitis
Where would colonization of staph aureus in the respiratory tract most likely be?
upper airways
what are some skeletal infections caused by staph aureus?
osteomyelitis and septic arthritis
Scalded skin syndrome is usually a complication of
staph pharyngitis or conjunctivitis
Scalded skin will most likely occur in what type of patient population?
newborns, infants, and children less than 3
What is Toxic shock syndrome a complication of
staphylococcal vaginitis and could also be caused by streptococcur pyogenes
what are the signs and symptoms of toxic shock syndrome?
volume resistant shock, diffuse macular rash, sore throat, pronounced GI upset, myalgia, desquamation and high fever
What is the signs and symptoms of staphylococcal food poisoning?
nausea and vomiting, abdominal cramps, diarrhea; occurs 1-6 hours after ingestion of food and resolves in 12 hours
what are the complications of staphylococcal epidermidis
endocarditis, catheter and shunt infections, prosthetic joint infections
Group A strep species can cause
pharyngitis, scarlet fever, erysipelas, impetigo, rheumatic fever, glomerulonephritis and erythema nodosum
Group B strep species can cause
neonatal sepsis and UTI
What is the most common streptococcal disease
pharyngitis
skin erosions covered by "honey" crust
Impetigo
what are the Signs and symptoms of erysipelas?
rapdily spreading, cutaneous erythema; can begin on the face and spread to the body
Rash has a well demarcated border
Exanthum (diffuse punctate erythematous rash)
trunk and inner aspects of the thighs
Strawberry tongue

Associated with group A pharyngitis and tonsillitis
Scarlet fever
What are the nonsuppurative diseases associated with Group A streptococci
rheumatic fever
post streptococcal glomerulonephritis
what is the distribution of pneumococcal pneumonia?
lobar pneumonia more common than bronchopneumonia in out patients
If a hospitalized patient were to develop pneumococcal pneumonia what would be the distribution
diffuse involvement
besides pneumonia what else could S. pneumoniae cause?
sinusitis, otitis media and meningitis
where are places that will be more likely for a patient to develop Neisseriae meningitis infection
areas where young adults/adolescents are living in close contact -- dorms, barracks
what are the meningeal signs that a patient has N. meningitidis
headache, photophobia, change in mental status stiff neck
what is the transmission of N. meningitis
respiratory droplets; invasion with bacteremia
small petechial skin lesions; Waterhouse-Friderichsen syndrome, arthritis
Meningococcemia
in females where is the primary site of a N. gonorrhea infection
cervix
what is a complication in females associated with N. gonorrhea?
PID
What are the two stages of disseminated gonococcal infection
A bactermic stage (painful joints, can occur together with tenosynovitis and skin lesions)

A joint localized stage with suppurative arthritis (knees, elbows and more distal joints)
what is the differential diagnosis associated with disseminated gonococcal infection
reactive arthritis and acute RA
What are the clinical syndromes associated with E. coli?
septicemia, urinary tract infections, Abdominal cavity infections
which organism causes >80% of all community acquired UTIs?
E. coli
Major cause of diarrheal illness in poor countries; travelers diarrhea
Enterotoxigenic E. coli
Major cause of diarrheal illness in poor countries; affects infants and young children. Organism attaches to and deforms microvilli but no invasion
enteropathogenic E. coli
causes dysentery clinically and pathologically similar to that caused by shigella
Enteroinvasive E. coli
Serotype 0157:H7; causes bloody diarrhea occasionally folloed by hemolytic uremic syndrome
enterohemorrhagive E. coli
Describes a combincation of acute renal failure, thrombocytopenia and hemolytic anemia
Hemolytic uremic syndrome
what does klebsiella cause
pneumonia, UTI and septicemia
What are the characteristics of pneumonia caused by klebsiella?
bronchopneumonia with abscess formation and pleural involvement
Flagellated gram negative bacilli; cause food and water born gastroenteritis; typhoid fever
Salmonella
What is the reservoir for typhoid fever?
humans
which patient population is at the highest risk for developing typhoid fever?
infants, children and elderly
what are the signs and symptoms of typhoid fever?
fever, chills
abdominal pain
diarrhea alternating with constipation
Rose spots (red macules that blanch with pressure on the chest and abdomen)
direction invasion of the bowel wall
What is the reservoir for asymptomatic carriers of typhoid fever?
gallbladder
Salmonella species other than S. typhi would caused
fever, nausea, vomiting and diarrhea but is usually self-limited
term bacillary dysentery is reserved for disease cause by ______; can cause disease when ingested in small numbers
Shigellosis
what are the signs and symptoms of bacillary dysentry
water diarrhea changes to classic dysenteric stools; blood mucus sloughed pseudomembranes
what is the morphology of bacillary dysentery
edema, hyperemia of colonic mucosa early
pseudomembranes, lymphoid hypertrophy, ulceration and bacteremia
What is the pathogenesis of the shiga toxin?
binds to sites on host endothelial cells; blocks protein synthesis. Causes hemorrhagic colitis and hemolytic uremic syndrome
Gram negative, comma shaped
Vibrio cholera
t/f Vibrio cholerae is invasive
false
what does Vibrio cholera permanently turn on leading it its rice water diarrhea
cAMP
what is the cholera toxin nearly identical to?
E. coli enterotoxin
small pleomorphic gram negative bacilli that has a reservoir in water especially air conditioning systems
Legionella
what is legionella best visualized by?
immunofluorescence and silver stains
what is the mode of transmission of legionella
airborne droplets
what is distinctive of legionella?
facultative intracellular parasite of macrophages
follows inhalation of infectious aerosols in susceptible individuals; bacteria end up in terminal bronchioles or alveoli
Legionnaire's disease
Where does the legionnaire bacteria multiply
macrophages
what are the signs and symptoms of legionnaire's disease
dry cough, chest and abdominal pain, malaise, rapidly progressive
what is pontiac fever characterized by
fever, malaise, chills, myalgia
gram positive, motile facultative intracellular bacteria; causes severe food borne infections from diary products, chicken and processed meat
Listeria monocytogenes
what patient population is at increased risk for developing listerosis?
pregnant women, infants and immunosuppressed are at increased risk
what can listerosis cause?
abortion, stillbirth, neonatal infection
disseminated disease, meningitis
where does listero monocytogenes multiply
cytosol
what is the pathogenesis of a listeria infection
leucine rich proteins on the bacteria bind to E-cadherin on the host epithelial cells; induce phagocytosis
what is the most important toxin when dealing with C. perfringens?
alpha toxin
what does the alpha toxin of C. perfringens do
Phospholipase C
degrades lecithin, a major component of cell membranes; destroys RBC, platelets and muscle cells
leukocyte lysis
What are the associations of C. perfringens?
Cellulitis (originates in wounds; tissue destruction is disproportionate to the number of neutrophils and bacteria present)

Gas gangrene (life threatening, enzymatic necrosis of muscle, 1-3 days after injury)
what are the signs and symptoms of clostridial sepsis
fever, shock and intravascular hemolysis; usually fatal within hours
what causes tatanus
neurotoxin produced by C. tetani
what are the signs and symptoms of C. tetani
convulsive contraction ofvoluntary muscles; Lock jaw
what is the treatment for C. tetani
anti-toxin and supportive care
what are some places you would find C. borulinum
honey and improperly canned foods
what are the symptoms of botulism
descending paralysis (cranial nerves, blurred vision, diapraghm = respiratory arrest and coma)
causes 25-50% of antibiotic associated diarrhea
Clostridium difficile
how do you diagnose C. difficile
confirmed by detection of toxin in stool
what is the causative agent of syphilis
treponema pallidum
What is the primary condition associated with syphilis
chancre
what is the association of secondary syphilis
diffuse macular rash
what is tertiary syphilis characterized by
gummas, neurosyphilis and cardiovascular
when does secondary syphilis occur
2 to 10 weeks after the primary chancre
where will you find the mucocutaneous rash of secondary syphilis
usually macular on the palms and plantar aspect of the foot; white oral lesions
when would you develop tertiary syphilis?
years after the chancre; active inflammatory lesions of the heart, aorta and CNS
what are the three main manifestations of tertiary syphilis
cardiovascular syphilis, neurosyphilis and benign tertiary syphilis
what are the characteristics of the cardiovascular manifestation of tertiary syphilis
coronary ostial stenosis, aortic aneurysm, aortic valve incompetence
what are the characteristics of the neurosyphilis manifestations?
symptomatic: meningovascular, tabes dorsalis, general paresis

asymptomatic: accounts for about one third of neurosyphilis cases
what is tabes dorsalis?
posterior root involvement; especially in the lumbosacral region, degeneration of posterior columns
Patient that has a past medical history of a chancre develops unsteadiness, wide based gait, decreased proprioception and vibratory sensation, muscular hypotonia and hyporeflexia would be
tabes dorsalis
what is the argyll robertson pupils?
react poorly to light
react well to accommodation
formation of gummas in bone, skin and mucous membranes of the upper airway and mouth
Benign tertiary syphilis
Patient recently delivered a baby that possessed the following characteristics: hutchinson's teeth, 8th nerve deafness, Osteochondritis and osteitis, hepatosplenomegaly.

What does this describe
congenital syphilis
what are the non treonemal tests for syphilis
RPR and VDRL
what are the treponemal tests for syphilis?
FTA-ABS
TPPA
TPHA
the tests for syphilis are more sensitive for primary or secondary syphilis?
secondary syphilis
Nontreponemal antibody levels fall with time and are less sensitive for...
latent and tertiary syphilis
what are the two species that cause tuberculosis?
M. tuberculosis and M. bovis
what is the mode of transmission for mycobacterium tuberculosis?
aerosols
what is the mode of transmission for atypical mycobacteria
primarily infectious aerosols
what is the mode of transmission for mycobacterium bovis
ingestion of unpasteruized milk and milk products
what is the morphology of mycobacterium tuberculosis?
single lesion usually found in a subpleural location in the lower part of the upper lobe or the upper part of the lower lobe

Ghon focus
what are the clinical signs and symptoms of secondary TB
may be asymptomatic; more often will have fever, night sweats, weakness, fatigue, loss of appetite and weight

productive cough, hemoptysis
what is the morphology of secondary TB?
cavitary lesion
caseous necrosis
lesions located in the apex of the lungs
Widely disseminated TB
caused by hematogenous and lymphatic spread
small granulomas resembling "millet seeds"
Miliary TB
what is the likely causative agent of atypical mycobacteria
mycobacterium avium-intracellulare
what are the organisms that will cause fungal skin infections
trichophyon, microsporum and epidermophyton
what are the clinical signs and symptoms of a fungal skin infection
hair loss
itchy, circular, centrifugally spreading lesions
lymphadenitis in draining lymph node chain
what is the mode of transmission of sporothrix schenkii
direct inoculation usually in gardeners and farmers
what are the signs and symptoms of a sportrichosis
nodular lesion at the point of contact
later involvement of regional lymphatics
lesion then breaks down to form an ulcer
what is pathognomic for diagnosis of sporotrichosis?
cigar shaped PAS-positive budding yeast
what is the histo characteristic of histoplasma fungi
occasionally unequal budding
what is the histo characteristic of blastomyces
larger yeast that are double contoured
what is the histo characteristics of coccidioides
Spheres with endospores
what are the reservoirs for deep fungal infections
soil; bird and bat droppings
where is histoplasma common
ohio and mississippi river valley
where is blastomyces common
middle atlantic states and the mississippi and ohio river basins
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