CNS/Opthalmic Infections Flashcards

1
Q

3 causes of bacterial meningitis in the neonate

A
  1. E. coli
  2. GBS
  3. Listeria monocytogenes
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2
Q

Causes of bacterial meningitis in adults

A
  1. S. pneumoniae
  2. N. meningitidis
  3. H. influenzae
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3
Q

Patho of bacterial meningitis

A
  1. Nasopharyngeal colonization
  2. Local invasion
  3. Bacteremia
  4. Endothelial cell injury
  5. Increased BBB permeability + meningeal invasion
  6. Subarachnoid space inflammation -> cerebral vasculitis
  7. Problems
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4
Q

Complications of bacterial meningitis

A
  1. Edema (vasogenic, interstitial, cytotoxic) results in increased ICP
  2. Increased ICP leads to decreased cerebral blood flow –> death
  3. Cerebral vasculitis can cause cerebral infarction, which may also decrease cerebral blood flow, causing death
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5
Q

Classic triad of meningitis

A
  1. Fever
  2. Neck stiffness
  3. Headache
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6
Q

Clinical Sx associate with meningitis

A
  1. Photophobia
  2. N/V
  3. Petechial rash = meningococcal meningitis
  4. Neurological symptoms (seizures etc.)
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7
Q

Findings suggestive of meningitis on physical exam

A
  1. Fever
  2. Petechial rash
  3. Neck stiffness
  4. Kernig sign
  5. Brudzinski sign
  6. Increased headache with jolt
  7. Cranial nerve palsies
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8
Q

What is Kernig’s sign?

A

Resistance or pain in lower back or posterior thigh when the knee is extended (when hip flexed to 90 degrees)

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9
Q

What is Brudzinski’s sign?

A

When passive neck flexion in the supine pt results in flexion of the knees and hips

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10
Q

What is papilledema?

A

Blurring of the edges of the optic disk, which indicates increased ICP

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11
Q

What investigations might you perform for suspected meningitis?

A
  1. LP to obtain CSF for: WBC diff, protein, glucose, Gram stain, culture
  2. CT or MRI head
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12
Q

When is a head CT indicated prior to doing a LP?

A

Concerned about increased ICP, where LP leads to cerebral herniation and death

  • Immunocompromised state
  • Focal neuro deficits
  • Hx of CNS disease
  • New onset seizures
  • Papilledema
  • Altered LOC
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13
Q

Tx of meningitis

A
  1. Start antibiotics ASAP
  2. If LP delayed, do blood cultures and start antibiotics
  3. Empiric Tx = Ceftriaxone + Vancomycin
  4. Can also add Ampicillin and/or dexamethasone
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14
Q

What is the prognosis for meningitis?

A
  1. Overall 15% mortality

2. 28% have neuro complications

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15
Q

What differentiates meningitis from encephalitis?

A

Encephalitis presents with brain function abnormalities, such as:

  1. Altered LOC
  2. Motor or sensory deficits
  3. Change in behaviour/personality
  4. Speech or mvmt disorder
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16
Q

Infectious causes of encephalitis

A
  1. Viral: HSV-1 (life threatening), VZV, other herpes viruses, Arboviruses, Enteroviruses, Measles
  2. Non-viral: tick-borne, bacteria, protozoa
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17
Q

Clinical presentation of encephalitis

A
  1. Fever
  2. Headache
  3. Altered mental status
  4. Seizures
  5. +/- rash
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18
Q

Dx approach to encephalitis

A
  1. LP and CSF analysis (culture, WBC, protein, glucose)
  2. PCR the CSF sample
  3. Serology for Arboviruses
  4. Brain biopsy as last resort
  5. CT head or MRI
  6. EEG
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19
Q

Tx for encephalitis

A
  1. Acyclovir IV
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20
Q

Risk factors for a brain abscess

A
  1. Immunosuppression
  2. Chronic cardiopulmonary conditions
  3. Penetrating head trauma
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21
Q

Cause of brain abscess

A
  1. Immunocompetent = polymicrobial

2. Immunocompromised = Toxoplasmosis, Cryptococcus, TB

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22
Q

Clinical presentation of brain abscess

A
  1. Headache
  2. Fever
  3. Focal neuro deficits - dependent on location in brain affected
  4. Change in mental status
  5. Seizures
  6. N/V
  7. Neck stiffness
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23
Q

How to Dx a brain abscess

A
  1. CBC - normal WBC

2. CT scan with contrast or MRI

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24
Q

Tx for brain abscess

A
  1. Aspiration
  2. Ceftriaxone + Metronidazole +/- Vancomycin, OR
  3. Meropenem +/- Vancomycin
  4. Dexamethasone when significant swelling
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25
Q

Risk of epidural abscess?

A

Can expand and compress the spinal cord, leaving neuro complications

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26
Q

Risk factors for epidural abscess

A
  1. Manipulation of epidural space
  2. Spread from other infection
  3. IVDU
  4. DM, alcoholism, HIV
  5. Trauma
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27
Q

Top 4 causes of epidural abscess

A
  1. S. aureus
  2. Gram -ve bacilli
  3. Streptococci
  4. CNS
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28
Q

Patho of epidural abscess

A

Damage to spinal cord from:

  1. Direct compression
  2. Cutting of blood supply
  3. Bacterial toxins and inflammatory mediators
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29
Q

Clinical presentation of epidural abscess

A

Initially non-specific (fever and malaise)

Classic triad = Fever, back pain, neuro deficits

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30
Q

Progression of untreated epidural abscess

A

Back pain -> nerve root pain -> motor weakness, sensory changes, bladder or bowel dysfunction -> paralysis

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31
Q

Preferred Dx imaging for epidural abscess

A

MRI (can use CT, but X-ray not very good)

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32
Q

Specimen collection for Dx of epidural abscess

A
  1. Abscess content
  2. Blood
  3. CSF
33
Q

Management of epidural abscess

A
  1. Surgery and drainage

2. Antibiotics, empiric Tx = Ceftriaxone + Metronidazole + Vancomycin

34
Q

Prognosis of epidural abscess

A
  1. 5% mortality

2. 4-22% irreversible paraplegia

35
Q

What are the viral causes of conjunctivitis?

A
  1. Adenoviruses

2. Enteroviruses (and coxsackieviruses)

36
Q

Clinical presentation of viral conjunctivitis (AKA pink eye)

A
  1. Watery discharge (morning crust of eyebrows)
  2. Irritation
  3. Burning/itching of eyes
  4. Conjunctival hyperemia
  5. Conjunctival edema (chemosis)
37
Q

Key negatives for viral conjunctivitis

A
  1. No eye pain

2. Vision not affected

38
Q

Adenoviral conjunctivitis is associated with what 2 clinical manifestations

A
  1. Pharyngoconjunctival fever

2. Epidemic keratoconjunctivitis

39
Q

What is the clinical presentation of pharyngoconjunctival fever?

A
  1. Pharyngitis
  2. Fever
  3. Conjunctivitis
  4. Pre-auricular adenopathy
40
Q

Clinical presentation of keratoconjunctivitis

A
  1. Subconjunctival bleeding

2. Conjunctival membranes

41
Q

Epidemic keratoconjunctivitis

A
  1. Inflammation of conjunctivitis and cornea
  2. May be vision threatening
  3. Lasts 1-3 weeks
42
Q

Dx of viral conjunctivitis

A
  1. Clinical

2. Viral swab for PCR

43
Q

Tx of viral conjunctivitis

A
  1. Cold compress, eye lubricant drops, decongestant eye drops
  2. May be excluded from school/work, should resolve within 2 wks
  3. Epidemic keratoconjunctivitis needs opthalmology referral
44
Q

Prevention of viral conjunctivitis

A

HIGHLY contagious

  1. Frequent hand washing
  2. Avoid sharing towels, eye drops, eye make up, contact lens solution
  3. Proper sterilization of clinic instruments
45
Q

Top 4 pathogens that cause acute bacterial conjunctivitis

A
  1. S. aureus
  2. S. pneumoniae
  3. H. influenzae
  4. GAS
46
Q

Clinical presentation of acute bacterial conjunctivitis

A
  1. Redness in eye
  2. Greenish-yellow discharge (matted eyelids)
  3. Conjunctival hyperemia
  4. Eyelid swelling
47
Q

Clinical presentation of hyperacute bacterial conjunctivitis caused by N. gonorrhea

A
  1. PROFUSE purulent discharge
  2. Chemosis, hyperemia, and eyelid edema
  3. Severe - vision threatening
  4. Transmitted from genitals to hands to eyes
  5. Send to Opthalmologist
48
Q

What is the most common cause of preventable blindness in the world?

A

C. trachomatis (chlamydial conjunctivitis)

49
Q

Dx bacterial conjunctivitis

A
  1. Clinical

2. Culture eye discharge

50
Q

Prophylaxis for gonococcal conjunctivitis in the newborn

A

Erythromycin ointment

51
Q

Tx for opthalmia neonatorum

A
  1. N. gonorrhea = Ceftriaxone IV

2. C. trachomatis = Erythromycin

52
Q

Tx of gonococcal and chlamydial conjunctivitis in adults

A
  1. Gonococcal = Ceftriaxone IV/IM

2. Chlamydial = Doxycycline PO

53
Q

What are red flags for an opthalmogy referral?

A
  1. Reduced vision
  2. Photophobia
  3. Severe foreign body sensation
  4. Corneal opacity
  5. Severe headache and nausea
54
Q

What is keratitis?

A

Inflammation of the cornea

55
Q

Patho of keratitis

A
  1. Disrupted corneal epithelium
  2. Entrance of microbes to corneal stroma
  3. Microbe proliferation –> ulcerations
  4. Infected epithelium and stroma swell and become necrotic
  5. May lead to inflammation in anterior chamber (hypopyon)
56
Q

Risk factors for keratitis

A
  1. Prolonged wear of contact lenses
  2. Eye trauma
  3. Eye surgery
  4. Chronic ocular surface disease
  5. DM
  6. Topical corticosteroids
57
Q

Bacterial causes of keratitis

A
  1. S. aureus
  2. S. pneumoniae
  3. GAS
  4. Gram -ve organisms
58
Q

Viral, fungi, and parasitic causes of keratitis

A
Viral = HSV-1, adenovirus, VZV
Fungi = Fusarium spp.
Parasites = Acanthamoeba spp.
59
Q

Clinical presentation of keratitis

A
  1. Eye pain
  2. Decreased vision
  3. Foreign body sensation
  4. Photophobia
  5. Tearing and discharge
  6. Corneal infiltrate or ulcer (change in transparency)
  7. SEND to Opthalmologist
60
Q

Dx of keratitis

A
  1. Slit lamp exam

2. Corneal scrapings (bacterial/viral/fungal culture, PCR, staining/microscopy)

61
Q

Tx for bacterial keratitis

A
  1. Non-contact user = fluoroquinolone drops

2. Contact user = aminoglycoside + pipercillin drops

62
Q

Tx for viral keratitis

A
  1. Trifluridine drops or Acyclovir ointment
63
Q

Difference btw conjunctivitis and keratitis

A
  1. Moderate to severe eye pain with keratitis
  2. Reduced vision with keratitis
  3. Hazy cornea with keratitis
64
Q

What is endopthlamitis?

A

Infection of the vitreous and/or aqueous humors

65
Q

Clinical presentation of endopthalmitis

A
  1. Decreasing vision
  2. Eye ache
  3. Conjunctiva may be edematous
  4. Hypopyon
66
Q

Dx for endopthalmitis

A
  1. Aspiration of aqueous and vitreous humor
  2. Vitrectomy
  3. Send sample for culture
67
Q

Causes of endopthalmitis

A
  1. CNS
  2. S. aureus
  3. Streptococci
  4. Gram -ve organisms
  5. Candida spp.
68
Q

Tx for endopthalmitis

A

This is an emergency

  1. Intravitreal antibiotics (Vancomycin + Ceftazidime)
  2. Vitrectomy (severe)
  3. Systemic antibiotics (severe)
69
Q

What is periorbital cellulitis?

A

Infection of the anterior portion of the eyelid

70
Q

What might lead to periorbital cellulitis?

A
  1. Local trauma (bites, surgery, foreign body)
  2. URTI
  3. Dacrocystitis
  4. Sinusitis
71
Q

What are infectious causes of periorbital cellulitis?

A
  1. S. aureus
  2. S. pneumoniae (and other strep)
  3. Anaerobes
  4. H. influenzae
72
Q

Clinical presentation of periorbital cellulitis

A
  1. Ocular pain
  2. Eyelid swelling
  3. Erythema
73
Q

How to Dx periorbital cellulitis

A
  1. Hx
  2. Physical (full eye ROM, no double vision, no increase in pain with eye mvmt, no eye bulging)
  3. CT of orbits and sinuses
74
Q

Tx for periorbital cellulitis

A
  1. Clindamycin OR

2. TMP-SMX + Amoxicillin (or amox-clav)

75
Q

Clinical presentation of orbital cellulitis

A
  1. Ocular pain
  2. Eyelid swelling with redness
  3. Pain with eye mvmt
  4. Proptosis (eye bulging)
  5. Limitation of eye mvmt (opthalmoplegia)
  6. Double vision
  7. Fever
  8. Chemosis
76
Q

What are 2 complications of orbital cellulitis?

A
  1. Vision loss

2. Brain abscess

77
Q

How to Dx orbital cellulitis

A
  1. Blood or surgical cultures
  2. Imaging (CT or MRI of orbits/sinuses): inflammation of extraocular muscles, fat stranding, and anterior displacement of the eye
78
Q

Tx for orbital cellulitis

A
  1. Vancomycin IV + Pip-taz IV
  2. Vancomycin IV + Ceftriazone IV/Cefotaxime IV
  3. Surgery for poor response to antibiotics, worsening vision, or abscess
79
Q

Common causes of viral meningitis

A
  1. Enteroviruses (coxsackieviruses, echoviruses)

2. Herpesviruses