Infectious Disease Flashcards

1
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Cellulitis

  • GAS and S. aureus = adults
  • HIB = in children <3 yo
  • 4 factors:
      1. erythema/hyperpigmentation
      1. warmth
      1. Edema
      1. pain
  • Diagnosis in immunocompromised host:
    • skin cx
    • aspirate/blood cx
    • mild leukocytosis with left shift and a mild increased sed rate
  • tx: empiric
    • cephalexin (keflex)
    • non-betalactam
      • clindamycin
      • tetracycline
    • elevate lower legs
    • cold compresses for pain
    • send to hospital if at risk for systemic disease
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2
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Erysipelas

  • **STREAKING**, does not involve the deeper layer (subcutaneous tissue)
  • caused by GAS and s.aureus in adults, HIB in children <3 yo
  • 4 factors:
    • 1.erythema
    • 2.warm
      1. pain
    • 4.edema
  • Diagnosis:
    • in immunocompromised host:
      • skin cx, aspirate/blood cx
    • Mild leukocytosis with a left shift, and a mild increased sed rate
  • tx: treat empirically
    • cephalexin (keflex)
    • non-beta-lactams
      • clindamycin or tetracycline
    • elevate legs and cold compresses
    • send to hospital if at risk for systemic infection
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3
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Impetigo

  • **caused by Staph**
  • erythema and Honey crusted
  • diagnosis:
    • gram stain and cx
  • tx:
    • acute: mupirocin ointment 2-3x/day for 10-14 days
    • oral abx:
      • cephalexin if concern for MRSA: doxycyline, clindamycin or BActrim
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4
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5
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bullous impetigo

  • Caused by S.aureus
  • favor trunk, can have fever and diarrhea
  • tx: mupirocen 2-3x/day for 10-14 days
    • oral:
      • cephalexin
      • if concern for MRSA: doxycyline, clindamycin, or bactrim
    • RECURRENT:
      • mupirocen BID for 2-3 weeks
        • wash the area with CLN cleansers or dilute bleach baths ( 1/2 cup in a full bath)
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6
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Furuncle/Abscess

  • furuncle involves hair follicle, abscess does not
  • **causative agent: S. aureus**
  • firm, fluctuant mass, painful to touch
  • exudes from the surface, with purulent material
  • diagnosis:
    • clinical, can cx if needed
  • tx: I&D with warm moist compresses as well
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7
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Pitted keratolysis

  • **caused by corynebacterium minutissimum (gram positive bacilli) **
  • tends to erupt on weight bearing surfaces and common in pts with hyperhidrosis
  • diagnosis:
    • clinical
  • tx:
    • promote dryness
    • topical clindamycin or erythromycin (BID)
    • wash feet with BPO wash
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8
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Erythrasma

  • **causative agent is Corynebacterium minutissimum** (gram positive bacilli)
  • reddish, brown patch that is uniformly scaly
  • non-inflammatory border and no advancing border
  • not very pruritic
  • Diagnosis:
    • Wood’s lamp: coral-red fluorescence
    • want to do KOH to r/o fungal
  • tx:
    • decrease moisture
    • topical clindamycin or erythromycin
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9
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Candidiasis

  • satellite pustules
  • **affects the scrotum**
  • erythematous patch
  • **causative agent candida albicans**
  • Diagnosis:
    • KOH wet prep
  • Tx:
    • ketoconazole 2% cream, fluconazole daily for 2-4 weeks
    • Mucosal:
      • clotrimazole trouch 5x/day
      • Nystatin swish and swallow
      • oral fluconazole
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10
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Tinea Corporis

  • **causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**
  • Annular, scaly borders, advancing, erythematous
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
    • oral:
      • fluconazole
      • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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11
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Tinea Incognito

  • **causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**
  • Annular, scaly borders, advancing, erythematous
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
    • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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12
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Tinea Cruris

  • **causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**
  • Annular, scaly borders, advancing, erythematous, does not affect the scrotum
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
  • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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13
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Tinea Manuum

  • **causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**
  • Tinea manum: “one hand, two feed syndrome”
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
  • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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14
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Tinea Pedis

  • interdigital, moccasin,inflammatory (vesicular)
  • **causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
  • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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15
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Tinea Faciei

  • unilateral erythematous face rash

**causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**

  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
  • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
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16
Q
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Tinea Capitis

**causative agent: Trichophyton rubrum and Trichophyton mentagrophytes**

  • Tinea capitis: requires oral tx with griseofulvin plus topical medicated shampoo (ketoconazole 2% shampoo)
  • Diagnosis:
    • KOH wet prep
    • Fungal Cx
  • tx:
    • Ketoconazole 2% cream (imidazoles) or Terbinafine 1% cream (allyamine)
  • oral:
    • fluconazole
    • terbinafine (for tinea unguium 250 mg QID for 6-12 weeks vs once weekly for 52 weeks)
17
Q
A

Tinea Versicolor

  • **caused by Malassezia furfur**
  • risk factors: high temps and humidity
  • Multiple brown, tan, or pink oval to round macules/patches or thin plques with subtle scales
  • common in upper trunk/shoulders
  • can be hyper/hypopigmented
  • diagnosis:
    • KOH wet prep
    • Wood’s Lamp: ywllo-green fluorescensce
    • DDx post-inflammatory hypo/hyperpigmentation
  • tx: ketoconazole 2% shampoo
    • OTC selenium sulfide or zinc shampoos
  • pt ed:
    • may take months for pigment to return
    • this is a chronic condition
      • weekly maintenance therapy
18
Q
A

Lice

  • caused by **Pediculus humanus capitis**
  • erythema, scaling, excoriations, lymphadenopathy
  • High yield locations: above the ears and lower occipital scalp
  • Diagnosis:
    • clinical
  • Tx:
    • Permethrin shampoo = first line
    • Malathion = second line
    • Ivermectin ⇒ DO NOT GIVE TO CHILDREN <15kg
    • 7 days in bag or washed in HOT water
19
Q
A

Scabies

  • caused by Sarcoptes scabiei hominis
  • mite lives in the stratum corneum
  • severe pruritus worse at night/ in shower
  • Diagnosis:
    • delta-wingjet sign
    • Biopsy: but difficult to capture the organism
    • Mineral Oil Prep: very time consuming
  • Tx:
    • Permethrin 5% applied before bed twice, separated by one week
    • 10 days of storage for clothing/bedding or washed in HOT water
  • pt ed:
    • pruritus and lesions will last 2-4 weeks after tx
20
Q
A

Condyloma accuminatum

  • Causative agent: **HPV**
  • tiny, painless papules that evolve into soft, fleshy cauliflower-like (barnacle like) lesions
  • Diagnosis:
    • clinical or serologies
  • Tx:
    • 80% resolve on their own
    • salicylic acid
    • cryotherapy (liquid nitrogen)
    • electrocauterization or surgical remove
  • Prevention: HPV vaccine
21
Q
A

Herpes Simplex Virus​

  • dsDNA virus
  • small round vesicle on erythematous base
  • PAINFUL, burning grouping of vesicles
    • may become umbilicated or pustular
    • then experience erosion/ulceration and crust with scalloped border
  • diagnosis:
    • Viral cx :but sensitivity = 50%
    • PCR: higher sensitivity than cx
    • Tzank smear = multinucleated giant cells
  • tx:
    • valacyclovir
    • acyclovir
    • protection from sun
    • consider prophylaxis
22
Q
A

Verrucae vulgaris

  • warts caused by HPV (dsDNA)
  • hyperkeratotic dome shaped papules or plaques with punctated black dots (thrombosed capillaries)
  • diagnosis:
    • clinical
    • serologies
  • tx: 80% will resolve on their own
  • salicylic acid
  • cryotherapy
  • electro cauterizatiion/surgery
  • prevention:
    • HPV vaccine
23
Q
A

Verrucae planae

  • flat warts, made worse by shaving
  • caused by HPV (dsDNA)
  • diagnosis:
    • clinical
    • serologies
  • tx: 80% will resolve on their own
    • salicylic acid
    • cryotherapy
    • electro cauterizatiion/surgery
  • prevention:
    • HPV vaccine
24
Q
A

Verrucae vulgaris

  • plantar/palmar warts: tender to pressure
  • diagnosis:
    • clinical
    • serologies
  • tx: 80% will resolve on their own
    • salicylic acid
    • cryotherapy
    • electro cauterizatiion/surgery
  • prevention:
    • HPV vaccine
25
Q
A

Molluscum contagiosum

  • caused by **DNA poxvirus**
  • spread via skin2skin contact
  • tends to appear near skin folds, lateral trunk, thighs, buttocks, genitals and FACE
  • diagnosis:
    • clinical diagnosis
    • serologies
  • tx:
    • should spontanously resolve in immunocompetent patients
    • tx underlying eczema
    • encourage daily skin hydration
    • cantharidin = creates more inflammation which triggers an immune response
    • can do curettage (VERY PAINFUL)
    • cryotherapy
    • retinoid
26
Q
A

Herpes Zoster

  • aka shingles
  • Hutchinson’s sign: involvement of CN V1 = urgent referral to OPTHALMOTHOLOGIST
  • diagnosis:
    • often clinical
    • viral PCR or viral cx from a new vesicle
  • tx: acyclovir or valacyclovir ASAP
  • pt ed:
    • may have post-herpetic neuralgias
      • tx: gabapentin, tricyclic antidepressants, lidocain patches
27
Q
A

Fifth’s Disease

  • **caused by Parvovirus B19** ssDNA aka slap cheek
  • erythema infectiosum
  • Bright red, macular erythema on cheeks 7-10 days after prodromal sxs
  • lacy, reticulated pattern of erythematous macules favors extremities > trunk
  • diagnosis:
    • clinical
  • tx:
    • supportive care
  • complications:
    • hydrops faecalis
    • arthralgias of the small joints of the hands
28
Q
A

Hand, Foot and Mouth Disease

  • caused by **coxsackievirus A16**
  • ssRNA virus
  • Enterovirus A71: much more severe, can be fatal
  • msot common in summer and fall
  • onychomadesis:
    • fingernails/toenails fall off 1-2 months later (especially with coxsackie virus A16)
  • diagnosis:
    • clinical
  • tx:
    • resolves within 1-2 weeks
  • complications:
    • otitis media
    • pneumonia
    • encephalitis
29
Q
A

Measles

  • aka rubeola caused by RNA paramyxovirus (ssRNA)
  • Prodromal sxs:
    • cough, coryza, conjunctivitis
    • fever
  • ​Koplik spots
  • exanthem that spreads cephalocaudally
  • Morbillaform rash
  • diagnosis:
    • clinical
    • serologies
  • Tx:
    • supportive