Infectious Disease Flashcards
Name three toxin mediated diseases caused by staph aureus
scalded skin syndrome
toxic shock syndrome
staphylococcal epidermal necrolysis
What is the D test?
determines if ther is macrolide inducible clindamycin resistance. Must be done if organism is sensitive to clindamycin and resistant to erythromycin.
If positive D test, do not treat with clindamycin
Treatment of boil or abscess if a mild, moderate vs. severe infection.
Mild: can often only be treated with incision and drainage. If oral antibiotic: TMP/SMX (if strep unlikely), clindamycin or doxycycline if > 8 years old
Moderate: have fever but otherwise healthy. Prescribe oral antibiotic as above
Severe: toxic appearing, sick, immunocompromised. Admit with IV antibiotic, vancomycin.
If critically ill, consider vancomycin and nafcillin
What infection control measures are necessary for highly resistant staphylococcus aureus?
isolate patient to private room
gown and gloves
wash hands with soap and water and or alcohol rub
dedicated items (stethoscope)
face mask and eye protection if doing something that makes splashes
consult cdc, health department before dc or transfer
What complications should you suspect if a child has S. aureus bacteremia?
osteomyelitis, endocarditis, thromboembolism, empyema more likely to occur with pneumonia
What are the symptoms and the cause of toxic shock syndrome?
TSS toxin-1
generalized red skin, hypotension, fever, diarrhea and multiorgan system involvement, > 3 systems. Desquamation of hands, feet occurs 1-2 weeks after illness
Treatment of toxic shock syndrome
fluids, nafcillin or vancomycin if MRSA and clindamycin which decreases toxin production
blood cultures are usually negative
What causes staphylococcal scalded skin syndrome and what are the symptoms
exfoliative toxins A and B
Fever, minimal friction applied to skin results in removal of superficial layers of epidermis : Nikolsky sign
extensive sloughing can occur though this is less likely to occur in older children
Complications to watch out for with staphylococcal scaled skin syndrome?
dehydration and superficial infection due to extensive skin sloughing
what causes Staphylococcus aureus food poisoning? What is the timing of symptom onset and what are the symptoms?
Preformed enterotoxin.
In < 4-6 hours after eating suspect food
self limited abrupt onset nausea, vomiting, diarrhea, abdominal cramps
What is the most common cause of catheter related bacteremia?
S. epidermidis
Staph epidermidis is usually always resistant to what antibiotic?
methicillin
Treatment for s. epidermidis
vancomycin +/- rifampin +/- gentamycin
S. saprophyticus usually causes what type of infection? How should it be treated
UTI in adolescent females.
TMP/SMX, nitrofurantoin, cephalothin
No 3rd gen cephalosporins, not effective
When is staph epi a contaminate and when is it not?
Contaminate in single blood culture with out risk factors or indwelling device
True infection in those who are immunocompromised, have indwelling catheter, NICU baby
coagulase negative staph most common cause of late onset sepsis in preterm infants esp. those < 1500 g
Who is at increased risk for Strep pneumoniae infections
Asplenic Very old or very young those with hypogammaglobulinemia HIV infection cochlear implants Alaska natives and native americans < 2 congenital immunodeficiency chronic disease (cardiac, pulm, renal) CSF leals DM immunosuppressive therapy
What is the most common cause of otitis media and how do you treat?
Strep pneumoniae
High dose amoxicillin 80-90 mg/kg/day
if no response in 48 hours broaden to Augmentin or 2nd or 3rd generation cephalosporin
When can an otitis media be observed?
children 6months to 2 years with unilateral disease and no otorrhea. > 2 years unilateral or bilateral with out otorrhea
must have close follow up and start antibiotics if no improvement in 24-72 hours
What is the antibiotic choice for strep pneumoniae due to possible penicillin resistance?
For bacteremia: ceftriaxone or cefotaxime until susceptibility is known
Meningitis: ceftriaxone, cefotaxime and vancomycin
Antibiotic recommendations for otitis media for those who are penicillin allergic?
cephalosporin, clindamycin, doxycycline (adolescents)
What diseases are caused by group A strep or strep pyogenes
pharyngitis impetigo, erysipelas, cellulitis scarlet fever rheumatic fever streptococcal toxic shock syndrome acute glomerulonephritis
What clinical findings make streptococcal pharyngitis more likely.
Temp > 100
tender cervical lymphadenopathy
exudative tonsils
If child > 2 years and has cough, rhinorrhea etc likely viral
In those < 2, they have thick purulent nasal discharge, low grade fever and decreased feeding
How is streptococcal pharyngitis diagnosed
rapid strep throat testing
if negative send culture
may wait on culture results before giving antibiotics as long as antibiotics are started within 9 days of infection to prevent rheumatic fever
What are the complications of streptococcal pharyngitis
otitis media, sinusitis, cervical lymphadenitis, peritonsillar/retropharyngeal abscess
rheumatic fever, glomerulonephritis