Week 8: cellulitis, sinusitis, OM Flashcards
What is acute, spreading pyogenic inflammation of there dermis and subcutaneous tissue
cellulitis
What does cellulitis usually complicate? (2)
wound or ulcer
What is the appearance of cellulitis?
warm, tender, swollen and erythematous
LACKS sharp demarcation from unaffected skin
When does impetigo mostly occur?
in children during hot humid weather
What is common with impetigo and what can that lead to?
pruritus is common, scratching resulting in secondary staph infection
How do you treat impetigo?
treat with benzathine PCN, single IM injection
What is a severe manifestation of s. aureus infection caused by exfoliative exotoxin?
staphylococcal scalded skin syndrome (SSSS)
What is a complication of SSSS in neonatal?
may produce epidemics in neonatal nurseries
What is the mortality rate of SSSS?
3%
How do you treat SSSS?
penicilinase-resistant PCN
Nafcillin
What is a pyoderma in the hair shafts?
folliculitis
What is the etiology of folliculitis?
s. aureus
pseudomonas
candida
What is the treatment for folliculitis?
local (topical) abx & antifungals
What is a deep inflammatory nodule?
furuncle
What is larger than a furuncle and extends into the subcutaneous fat (abscess)?
carbuncle
What causes furuncles and carbuncles?
staph aureus
What are predisposing factors of furuncles and carbuncles?
obesity
blood dycrasias
steroid treatment
diabetes
What is the treatment for furuncle and carbuncles?
antistaphlococcal antibiotic
Dicloxacillin (Dycill) 250mg po q6h
What is the treatment for furuncle and carbuncles if allergic to PCN?
clindamycin 150-300mg po q6h
What is the treatment for furuncle and carbuncles if possible MRSA?
Vancomycin, Linezolid or Daptomycin
What was previously associated with wool & animal hides?
chancriform lesion (Cutaneous Anthrax)
What is caused by spores of Bacillus anthracis?
chancriform lesions
With Chancriform lesions in 1-8 days, a _____ papule develops. As the lesion grows it becomes ______ & ______.
painless
hemorrhagic & necrotic
What should be avoided with chancriform (cutaneous anthrax) lesions?
incision & debridement
What is the treatment for chancriform (cutaneous anthrax) lesions?
cipro 500mg po q 12h for 7-10 days
60 for bioterror
What is a distinctive type of superficial cellulitis characterized by prominent lymphatic involvement?
erysipelas
What is the presentation of erysipelas?
painful, red, edematous lesion w/ raised border and sharply demarcated
What should be given to treat mild/early cases of erysipelas?
Pen V 250-500mg po q6h
Erythromycin 250-500mg po q6h
What should be given for extensive or hospitalized cases of erysipelas?
Pen G 2000 units IV q6h OR
Nafcillin 2g IV q4h or Cefazolin 1-2g IV q8H
What are the most common initializing sources of cellulitis from skin trauma?
staph or strep
What are the most common initializing sources of cellulitis from bites?
dogs/cats: pasteurella
humans: bacteroides, Eikenella
What are the most common initializing sources of cellulitis from wounds of body piercings?
staph, strep
What are the most common initializing sources of cellulitis from hot tubs/pools?
pseudomonas
What predisposes patients to cellulitis?
edema
What percentage of needle aspiration cultures and biopsies are gram (+) organisms?
80%
What are some of the Gram (+) organisms found with culture and bx?
staph aureus
group A or B streptococci
Viridans streptococci
E. faecalis (rarely)
Are cultures, and biopsies typical helpful? (esp swabs)
No- reveal typical skin flora
When are cultures and bx reserved for?
special cases (blisters)
Empiric treatment should focus on gram _____.
positive
What is the exception when empiric therapy should include anaerobic coverage?
diabetics
Necrotizing Fasciitis usually affects what areas?
extremities, abdominal wall, perianal and groin
What is Fournier’s Gangrene?
necrotizing fasciitis of the genitalia
What is the presentation of NF?
affected area is swollen, hot, and VERY PAINFUL that rapidly progresses over several days
What is the result of thromboses of subQ vessels?
necrosis
What may precede necrosis?
anesthesia
What is an important clue of NF?
disproportionate pain
What is the mortality of NF?
20-50% (10-20% for Fournier’s Gangrene)
Prompt diagnosis is crucial!
What are the empiric abx for NF?
ampicillin, gentamicin and clindamycin or metronidazole
What is the MOA of clindamycin and metronidazole?
inhibits exotoxin production
What is sinusitis usually secondary to?
cold (viral rhinosinusitis= VRS)
What percentage of viral rhino sinusitis progress to bacterial sinusitis?
1-2%
What favors bacterial overgrowth, resulting in Acute Bacterial Sinusitis (ABS)?
secondary obstruction
What are the most common(50%) organisms of acute bacterial sinusitis?
s. pneumoniae & H. influenza
When do VRS symptoms improve?
7-10 days
What are the clinical diagnosis findings to differentiate ABS (compared to VRS)?
symptom persistence >10 days
worsening symptoms after 5-7 days OR
(+) transillumination of the maxillary sinus
In general what are the current recommendations for ABS?
amoxicillin-clavulanate cefdinir cefpodoxime proxetil cefuroxime axetil levofloxacin moxifloxacin
10 days
What is the cure rate of ABS with 10 days of abx?
90%
What is the most common reason for abx in children?
otitis media
What are the common etiologies for acute otitis media?
S. pneumoniae 38% (pneumococcal vaccine)
H. influenza 27% (Hib vaccine)
M. catarrhalis 10%
What is significant about M. catarrhalis causing AOM?
most produce beta lactamase
What is required to diagnose AOM?
signs or symptoms AND
- inflammation (red tympanic membrane)
- fluid in the middle ear (bulging membrane)
Is a retracted eardrum AOM?
NO- It is painful but caused by negative middle ear pressure
Is a red membrane WITHOUT middle ear fluid AOM?
NO
What is a method of detecting middle ear fluid (effusion)?
otoscope (visual)
When are tympanocentesis indicated? (3)
patients critically ill at symptoms onset
toxic patients not responding in 48-72 hours
patients with altered host defenses (immune defect, newborn)
What is the drug of choice for AOM?
High dose of amoxicillin
80mg/kg/d
What are the alternative treatment in failed pts with amoxicillin?
amox/clav 80-90mg/kg/d BID
cefuroxime axetil (Ceftin) or cefdinir (Omnicef)
ceftriaxone (Rocephin )IM