Infectious Disease Flashcards
(45 cards)
Osteomyelitis best initial test, best second-line test, most accurate test
Best initial test: Plain X-ray; Best second-line test (if there is high clinical suspicion and x-ray is negative): MRI; Most accurate test: MRI
Osteomyelitis treatment
M.S.S.A: Oxacillin or Nafcillin IV x 4-6 weeks
M.R.S.A: Vancomycin, Linezolid, Daptomycin
GRAM (-) BACILLI: (salmonella & pseudomonas): treated with oral antibiotics; confirm is gram-negative bone biopsy, organism must be sensitive to antibiotics
Otitis externa: cause, testing, treatment
Cause: Swimming (washes out normal acidic environment), foreign objects (Qtips, hearing aids)
Testing: P/E, do not perform culture
Tx: Topical antibiotics (ofloxacin, polymyxin/neomycin), hydrocortisone (decrease swelling/itching), acetic acid & water solution (to reacidfiy the ear, can help eliminate infection)
Malignant Otitis Externa: cause, best initial test, most accurate test, treatment
Cause: osteomyelitis of skull from psuedomonas in diabetic pt.
Initial test: Skull X-ray or MRI; Accurate: Biopsy
Tx: Surgical debridement + antibiotics active against psuedomonas (cipro, piperacillin, cefepime, carbapanem, aztreonam)
Otitis media: Key features, Testing, Treatment
Redness, Bulging, Decreased hearing, loss of light reflex, Immobility of tympanic membrane
Testing: P/E
Best initial therapy: Amoxicillin 7-10 days (longer for younger pts, shorter for older pts)
Most accurate test: tympanocentesis/aspirate of tympanic membrane only if failed tx/persistent
Sinusitis: Features, Cause, Testing, Tx
Nasal discharge, headache, facial tenderness, tooth pain, bad taste, transillumination of sinus
Cause: Mostly viral; bacterial same as Otitis Media (S. pneumonia MCC, H.influenza, M. Catarrhalis)
Best initial: X-ray; Most accurate: Sinus aspirate for culture (more accurate than CT or MRI)
Tx: Same as for otitis media + inhaled steroids
Use Amox if: -Fever & pain - Persistent symptoms despite 7 days of decongestants and -Purulent nasal discharge
Pharyngitis: Key features, Testing, Tx
Diagnosis of streptococcal diagnosis is certain if the following is present:
-Pain/Sore throat -Exudate in pharynx -Adenopathy in neck -No cough/hoarseness
Testing: “Rapid strep test” (positive test is as specific as throat culture & determines if organism is group A strep). If (-), no further testing or abx
Tx: Penicillin or Amoxicillin;
Pen allergy: Azithromycin or Clarithromycin
What can streptococcal (group A strep) pharyngitis lead to?
Rheumatic Fever or Glomerulonephritis
Influenza (“the flu”): Features, Testing/next best step, Tx
Arthralgia, Myalgia, Cough, Headache, Fever, Sore throat, Tiredness
Testing/Next best step: Viral antigen detection of nasopharyngeal swab
Tx: >/=48 hrs: Osetlamivir (tamiflu) or Zanamivir - neuraminidase inhibitors against A/B
>48 hrs: symptomatic tx (rest, hydration, antipyretics, analgesics)
What are the strongest indications for vaccination against influenza? is the flu vaccine required for Ages 19-64? Ages 65+?
COPD, CHF, Dialysis, Steroid use, Healthcare workers, Age 50+
Ages 16-64: Every Year; Ages 65+: Every Year
Pneumococcal vaccination (S.pneumonia; pneumonia, meningitis, sepsis, etc): Recommendation for Ages 19-65? 65+?
19-64: 1 or 2 doses for high risk pts
65+: 1 dose
Tetanus, Diptheria, Pertussis (Td/Tdap) vaccination recommendations for Ages 19-64? 65+?
19-64: Tdap once as substitute for Td booster, then Td every 10 yrs.
65+: Tdap once as substitute for Td booster, then Td every 10 yrs.
Rabies Vaccination:
What are the two types?
Previously vaccinated person re-exposed? Previously unvaccinated person exposed?
(1) Rabies immune globulin for passive immunization (2) Rabies vaccine for active immunization
Previously vaccinated person re-exposed :
only active w/rabies vaccine
Previously unvaccinated person exposed:
both active and passive immunization
Impetigo: cause, testing, treatment
Cause: S. pyogenes, S. Aureus
Testing: Look for weeping, crusting, oozing of skin
Tx:
Mild disease: Topical agents - Mupirocin or Retapamulin
Severe disease: Oral agents - Dicloxacillin or Cephalexin
CA-MRSA: TMP/SMZ, Clindamycin
Penicillin allergy–
Rash: Cephalosporins are safe.
Anaphylaxis: Clindamycin
Severe infection with anaphylaxis: Vancomycin, Telavancin, Linezolid, Daptomycin
Erysipelas: Cause, Features, Best Initial Tx
Cause: Group A streptococcal infection of the skin
Features: bright red, hot, swollen lesion, well-demarcated lesion on face
Best initial tx: Oral Dicloxacillin or Cephalexin
If confirmed group A streptococci: Penicillin K
Cellulitis: Risk factors, Cause, Features, Testing, Tx
Risk factors: IV drug use, DM, IC, Obesity
Cause: S. aureus = S. pyogenes
Features: warm, red, swollen, tender skin
Testing: If on leg –> Lower extremity Doppler
Tx: Minor disease: Dicloxacillin or cephalexin orally
Severe disease: Oxacillin, nafcillin, Cefazolin IV
Penicillin allergy: Use cephalosporins (Cefazolin)
Anaphylaxis/severe: Vanc, Linezolid, Daptomycin
Anaphylaxis/minor: Macrolides or Clindamycin
Folliculitis<Boils –
Cause, Testing, Tx
Cause: S. Aureus
Testing: Based on appearance
Tx: For larger infections (boils) - drainage;
Antibiotic therapy is identical to cellulitis –
Minor disease: Dicloxacillin or cephalexin orally
Severe disease: Oxacillin, nafcillin, Cefazolin IV
Penicillin allergy: Use cephalosporins (Cefazolin)
Anaphylaxis/severe: Vanc, Linezolid, Daptomycin
Anaphylaxis/minor: Macrolides or Clindamycin
What can pts with skin infections develop? And not develop?
Can develop post-streptococcal glomerulonephritis
Cannot develop rheumatic fever
Fungal infections: Presentation of Tineas? Tinea capitis? Tinea Unguium/Onychomycosis?
Tineas: Pruritic, erythematous, scaly plaques with central clearing
Capitis: Itching of scalp, dandruff, bald patches
Unguium: Nails may be thickened, yellow, cloudy, fragile or broken
Fungal infections: Best initial test, Most accurate test
Best inital test: KOH preperation
1) Scrape skin or nail
2) Place scraping on slide with KOH prep & acid & heat it
3) Epithelial cells will dissolve and leave fungal forms behind, visible on slide
Most accurate test: Fungal culture
Fungal infections: Treatment:
Topical antifungal medications (if not hair/nails):
Clomitrazole, miconazole, ketoconazole, econazole, terconazole, nystatin, ciclopirox
Oral antifungal meds (hair/nail involvement):
Terbinafine: Increased LFTs, must monitor
Itraconazole
Griseofulvin (for tinea capitis): has less efficacy than terbinafine or itraconazole
S/e of Terbinafine?
Increased LFTS
Fungal infections: body, hand, foot, groin, scalp, nail beds
Tinea corporus = body, manus = hand, pedis = foot, cruris = groin, capitis = scalp, unguium/onychomycosis = nail beds
Urethritis: Features, Cause, Testing, Treatment
*Urethral discharge +/- dysuria (burning, urgency, frequency); Cause: chlamydia, gonorrhea
Testing: Urethral swab for Gram stain, WBC count, culture, DNA probe, Nucleic acid amplification
(Single best test for chlamydia/gonorrhea)
Tx: 2 medications due to coinfection risk; drug active against gonorrhea & against chlamydia
–Gonorrhea meds: Ceftriaxone IM, Cefpodoxime oral, Ciprofloxacin oral (2nd line), Ceftriaxone IM (pregnant pts)
–Chlamydia meds: Azithromycin (single dose), Doxycycline (1 week), Azithromycin (pregnant pts)
