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Neurology pro +1060 > CNS infections > Flashcards

CNS infections Flashcards

1
Q

Definitions:

  1. Menigitis?
  2. Encephalitis?
  3. Nosocomial infections?
  4. Abscess?
A
  1. Meningitis: Swelling and inflammation of the membranes covering the brain and spinal cord.
  2. Encephalitis: Inflammation of the brain.
  3. Nosocomial Infections: Originating or taking place in a hospital, acquired in a hospital, especially in reference to an infection.
  4. Abscess: A confined pocket of pus that collects in tissues, organs, or spaces inside the body
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2
Q

Community Acquired Bacterial Meningitis Epidemiology: Most common in…

  1. Newborns?
  2. Age 1-23 months?
  3. Age 2-18 years?
  4. Adults to 50 yrs old?
  5. Adults 50 and above?
A
  1. Newborn – 1 month
    Group B strep – 70%
  2. Age 1-23 months
    S. Pneumoniae – 50%
  3. Age 2-18years
    N. meningitidis—60%
  4. Adults to 50 years old
    S. pneumoniae—60%
  5. Adults 50 and above
    S. pneumoniae—70%
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3
Q

Nosocomial Bacterial Meningitis Epidemiology:

  1. Disease of which kind of pts? 2
  2. Most common organisms? 3
A
  1. neurosurgical patients, trauma, etc.
    • E. Coli,
    • K. Pneumoniae,
    • P. auruginosa
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4
Q

Predisposing Factors of Bacterial Meningitis: Sources of infection? 3

A
  1. Colonization of the nasopharynx (N. menigitidis, S. pnemoniae, H. influenzae)
  2. Invasion of the CNS following bacteremia due to localized source
  3. Direct entry of organisms into the CNS from contiguous infection, trauma, neurosurgery, a CSF leak, or medical device
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5
Q

Host risk factors for meningitis?

4

A
  1. Asplenia
  2. Corticosteroid use
  3. Immune-compromised/HIV infection
  4. Exposure to someone w/ meningitis
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6
Q

Describe the three steps to meningitis/encephalitis?

What does this eventually result in? 5

A
  1. Virulence factors of pathogen overcome host defense mechanisms and invade CSF
  2. CSF has inadequate humoral immunity so bacteria can multiply to high concentrations
  3. The bacteria produce an inflammatory response through inflammatory cytokines

Leads to

  • vasogenic brain edema,
  • increased intracranial pressure resulting in
  • brain ischemia,
  • cytotoxic injury (from bacterial secretions) and
  • neuronal apoptosis
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7
Q
  1. Describe the duration/progression of symptoms for meningitis?
  2. What is the triad of symptoms?
  3. Other symptoms? 5
A
  1. Duration of symptoms 2-3 days sometimes but it can also progress over hours
    • Fever: most (95%) have temp >38 C (100.4F) ‏
    • Nuchal rigidity (88%)‏
    • Change in mental status (lethargy most common)
    • Headache
    • Photophobia
    • Characteristic rash (N. meningitidis)‏
    • Nausea and vomiting
    • Neurologic complications—seizures, focal neurological deficits, papilledema
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8
Q
  1. What bacteria causes a characteristic rash?
  2. What is this due to?
  3. WHat parts of the body are affected?
  4. What happens to the rash under pressure?
  5. Describe the pathogenesis of exanthema? 5
A
  1. (N. meningitidis)‏
  2. Due to small hemorrhages under the skin
  3. All parts of the body are affected
  4. The rashes do not fade under pressure (nonblanching)
  5. Pathogenesis:
    - Septicemia
    - Wide spread endothelial damage
    - Activation of coagulation
    - Thrombosis and platelets aggregation
    - Reduction of platelets
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9
Q

Thorough physical exam should be performed, including complete neurological exam
Two tests specific to meningitis include?
Describe them

A

Kernig sign: supine position, flex hip 90 degrees, inability or reluctance to allow full extension of the knee when the hip is flexed

Brudzinski sign: spontaneous flexion of hips during attempted passive flexion of the neck

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10
Q

On exam, if the patient has negative symptoms of what three things, then meningitis is essentially ruled out?

The bottom line: The utility of the physical exam in detecting meningitis is not great. Given the seriousness of the illness, if you suspect meningitis, strongly consider __________________ to definitely rule it out.

A

no fever,
no neck stiffness
no altered mental status

lumbar puncture

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11
Q

Meningitis workup
Labs? 4
Procedures? 2

A

Labs:

  1. CBC with differential
  2. CMP
  3. UA
  4. Blood cultures x2 : 50-75% (+)

Procedures

  1. Lumbar puncture (LP)‏
  2. Possible CT to r/o mass lesion or other causes of increased intracranial pressure or route of infection
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12
Q

What can we do if the lumbar puncture is delayed or deferred?

A

IF LP is delayed or deferred obtain blood cultures and start empiric antibiotic therapy

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13
Q

Meningitis Workup:
Which patients need a head CT before lumbar puncture? 6

Rarely indicated in patient with suspected acute meningitis

A

Proceed to head CT prior to LP if any of the following are present at baseline:
1. Immunocompromised or impaired cellular immunity

  1. History of seizure within one week prior to presentation

Any of the following neurologic abnormalities:

  1. History of CNS disease (mass lesion, stroke, or focal infection)
  2. Papilledema
  3. Altered level of consciousness
  4. Focal neurologic deficit
  5. Patients with these risk factors should have CT done to identify possible mass lesion and other causes of increased ICP
    - –Concerns for brain herniation although studies do not really support
  6. Mandatory in patient with possible focal infection
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14
Q

CT in Bacterial Meningitis
when?
4

A
  1. Used to identify contraindications to LP and complications that require prompt neurosurgical intervention, such as symptomatic hydrocephalus, subdural empyema and cerebral abscess
  2. Indicated in patients who have evidence of head trauma, sinus or mastoid infection, skull fracture and congenital anomalies
  3. May identify cerebral edema, effusion, hydrocephalus, abscess
  4. May reveal the cause of the infection
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15
Q

MRI:
Very helpful in investigating potential complications developing later in clinical course such as what?
2

A
  1. venous sinus thrombosis

2. subdural empyema

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16
Q

Normal LP values:

  1. Pressure?
  2. Appearance?
  3. CSF total protein?
  4. Gamma globulin?
  5. CSF glucose?
  6. CSF cell count?
A
  1. Pressure: 70 - 180 mm H20
  2. Appearance: clear, colorless
  3. CSF total protein: 15 – 45 mg/dL
  4. Gamma globulin: 3 - 12% of the total protein
  5. CSF glucose: 45 - 85 mg/100 mL (or greater than 2/3 of blood sugar level)
  6. CSF cell count: 0 - 5 white blood cells(all mononuclear), and no red blood cells
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17
Q

LP findings in bacterial meningitis

  1. Pressure?
  2. Appearance?
  3. White count?
  4. Protein?
  5. Glucose?
A
  1. Elevated opening pressure
  2. Cloudy, purulent appearance
    3, Leukocytosis (1000 to 5000, with > 80% neutrophils)
  3. Protein of 100 to 500 mg/dL
  4. glucose
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18
Q

Name the following for bacterial, viral, Neoplastic and Fungal meningitis?

  1. OP (40mg/dL)
  2. Protein (
A

Bacterial

  1. > 300mm
  2. > 1000
  3. > 80%
  4. less than 40
  5. > 100
  6. +
  7. _

Viral

  1. 200mm
  2. less than 1000
  3. 1-50%
  4. > 40
  5. > 80
  6. _
  7. _

Neoplastic

  1. 200
  2. less than 500
  3. 1-50%
  4. less than 40
  5. > 100
  6. -
  7. +

Fungal

  1. 300mm
  2. less than 500
  3. 1-50%
  4. less than 40
  5. > 100
  6. _
  7. +
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19
Q
  1. Empiric Treatment is mainly aimed at who?

2. What meds? 3

A
  1. Mainly aimed at S. pneumoniae and meningococcal
    • Cefotaxime 2gm IV q4-6 (Claforan) or
    • ceftriaxone 2gm IV q12 (Rocephin) +
    • vancomycin 15-30mg/kg IV q12‏
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20
Q

1-2. What meds should we use for For L monocytogenes (age >50)?
2

3-4. Alternatives? 2

A
  1. Ampicillin or penicillin G 6million units q4 +
  2. gentamincin 5mg/kg q day for synergy (all IV)–
  3. alternative in pcn allergic pts is Trimethoprim-sulfamethoxazole (TMP-SMX) 5-10mg/kg q12 or
  4. meropenem 2g q8 (Merrem)
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21
Q
  1. What meds should we use for Noscomial meningitis?

2

A

Cover gram-neg (E.Coli, K pneumoniae and Pseudomonas) & gram-pos
1. Ceftazidime (Fortaz) 2gm q8 + vancomycin

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22
Q

How long should the duration of meds be for the following?

  1. H. influenzae
  2. N. meningitidis
  3. S. pneumoniae
  4. L. monocytogenes
  5. Group B strep
  6. GNRs

Treatment duration is doubled in who?

A 
Pathogen              Duration of Rx (d)
H. influenzae                      7
N. meningitidis                   7
S. pneumoniae               10-14
L. monocytogenes         14-21
Group B strep                  14-21
GNRs                                   21
	*Treatment duration usually doubled in immunocompromised patients.
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23
Q

Risk Factors for Drug-Resistant
S. pneumoniae (DRSP)
7

A
  1. Extremes of age
  2. Recent ATB Rx
  3. Significant comorbid disease
    4 HIV infection or other immunodeficiency
  4. Day care or day care parent/sib
  5. Recent hospitalization
  6. Congregate settings (correctional facilities, military, college dorms)
24
Q

Neurological Complications of Bacterial Meningitis
4

Whats a non-neurological complications?

A
  1. Increased ICP and cerebral edema
  2. Seizures ‏
  3. Cranial nerve palsies 5-11%
  4. Hemiparesis

Sensorineural hearing loss—greater w/ S pneumoniae as cause
‏

25
Q

Role of Steroids:
Adding 1._________ 0.15 mg/kg q6 IV before or w/ start of antibiotics reduces mortality and neurologic disability in pts w/ Glasgow Coma Scale (GCS) scores of 2.____ and 3._________ diagnosis

  1. Should be given when?
  2. Continued for 4 days if what?
A
  1. dexamethasone
  2. 8-11
  3. pneumococcal
  4. Must be given early for best results
  5. gram stain and/or culture consistent w/ S. pneumoniae
26
Q

Vaccines that can prevent meningitis?

5

A
  1. Haemophilus influenzae type b (Hib) vaccine – part of routine childhood immunizations
  2. Pneumococcal conjugate vaccine (PCV13) – also part of routine childhood immunizations
  3. Pneumococcal polysaccharide vaccine (PPSV23) – for older children and adults (Menomune)
  4. Meningococcal conjugate vaccine (Menactra)- older children and adults- 11-12 yrs old (and up to 18)
  5. Serogroup B meningococcal vaccine (Bexsero)
    Menomune, Menactra and Bexsero protect against the serogroups most commonly seen in the US
27
Q

Adults should get a quadravalent meningococcal conjugare vaccine (Menactra) if:
7

A
  1. Complement deficiency
  2. Functional or anatomic asplenia
  3. Microbiologist routinely exposed to N. meningitidis
  4. Traveling to countries where the disease is common
  5. Part of a population identified to be at risk because of an outbreak
  6. First year college student living in a residence hall
  7. Military recruit
28
Q
  1. What is Aseptic Meningitis?

2. What are the most common causes? (most common?

A
  1. Clinical and lab evidence for meningeal inflammation w/ neg bacterial cultures,

most common cause is
2. enterovirus, but other etiologies include myco-bacteria, fungi, spirochetes, parameningeal infections, medications and malignancy

29
Q

Presentation of aseptic meningitis?
4

How is it different from bacterial?

A

Presentation:

  1. Fever,
  2. HA,
  3. stiff neck
  4. photophobia

Contrast to bacterial meningitis: Aseptic meningitis is a self-limited course that resolves without specific therapy

30
Q

Aseptic Meningitis Approach

4

A
  1. Comprehensive history—travel, exposure, exanthems, drugs
  2. If CSF with LP is fairly clear, you can observe pt without antibiotics
  3. If uncertain, start on antibiotics and wait 24-48 hrs for culture results
  4. Treatment is supportive
31
Q

What is encephalitis?

Causes? 5

A

Encephalitis is inflammation of the brain parenchyma, manifested by neurologic dysfunction.

  1. Viral
  2. Postinfectious
  3. Autoimmune
  4. Paraneoplastic
  5. Medication induced
32
Q

Encephalitis Findings
Clinical presentation?
8
(most common?)

A
  1. Altered mental status***
  2. Seizures common
  3. Focal neurologic abnormalities can occur
  4. Exaggerated DTRs and/or pathologic reflexes
  5. Motor or sensory deficits
  6. Altered behavior and personality changes
  7. Speech or movement disorders
  8. Hemiparesis, flaccid paralysis and parasthesias
33
Q

Imaging for encephalitis?

3

A
  1. CT can R/O space-occupying lesion or brain abscess
  2. MRI detects demyelination and certain pattern clues to specific etiologies
  3. EEG often abnormal
34
Q

Complications from encephalitis?

6

A
  1. status epilepticus
  2. cerebral edema
  3. inappropriate secretion of antidiuretic hormone
  4. cardiorespiratory failure
  5. disseminated intravascular
    coagulation (DIC)
  6. death
35
Q

What is the important distinguishing feature between encephalitis and meningitis in most cases?

Describe this
2

A

The presence or absence of normal brain function

  1. Patients with meningitis may be uncomfortable, lethargic, or distracted by headache, but their cerebral function remains normal.
  2. In encephalitis, however, abnormalities in brain function are expected, including altered mental status, motor or sensory deficits, altered behavior and personality changes, and speech or movement disorders.
36
Q

Meningitis versus Encephalitis:
1. Symptoms and signs of meningeal irritation (photophobia and nuchal rigidity) are usually absent with what?

  1. The distinction between the two entities is frequently blurred since some patients may have WHAT? with clinical features of both.
  2. The patient is usually labeled as having meningitis or encephalitis based upon which features predominate in the illness although _______________ is also a common term that recognizes the overlap.
A
  1. pure encephalitis.
  2. both a parenchymal and meningeal process
  3. meningoencephalitis
37
Q

Etiologies more likely to be what in encephalitis?

What types?
10

A

More likely to be viral
Etiology only found in 35% cases

  1. Herpes Simplex Virus type 1
  2. Arboviruses (arthropod vectored)
  3. 3 α (alpha) – viruses
  4. West Nile Fever,
  5. St. Louis Encephalitis*,
  6. Japanese B encephalitis,
  7. Dengue, and
  8. Yellow Fever
  9. Bunyviruses
  10. California encephalitis
38
Q

Non-viral/Post-infectious
of encephalitis?
5

A
  1. Lyme disease
  2. Rocky Mountain spotted fever
  3. Rabies encephalitis
  4. Syphilis
  5. Tuberculosis

History depending on travel, activity, area, time of year can give clues to etiologies

39
Q

Viral Encephalitis Findings
CSF?
3

A
  1. May have increased WBCs with differential showing mostly lymphocytes
  2. Elevated protein, but less than 150 mg/dL
  3. Normal glucose
40
Q

Viral encephalitis - Diagnosis

2

A
  1. Knowledge of patients immune status critical
  2. Diagnosis: after all other tests a brain biopsy can be done as a last resort, but in the majority of cases of aseptic meningitis and encephalitis the cause is not determined
41
Q

West Nile Virus:
1. Symptoms? 6

  1. Signs? 4
A

1.

  • Fever
  • Malaise
  • Stiff Neck
  • Sore Throat
  • Nausea and Vomiting
  • Stupor → Convulsions → Coma
  1. Signs of an upper motor neuron lesion
    - exaggerated DTRs,
    - absent superficial reflexes,
    - pathologic reflexes
    - spastic paralysis
42
Q

West nile virus:
CSF findings?
3

The most significant risk factor for developing severe neurological disease is what?

Treatment is supportive and ________ has now been substantiated as helpful

A
  1. CSF Protein increased
  2. opening pressure increased
  3. lymphocytic leukocytosis

advanced age

RIBAVARIN

43
Q

Rocky Mountain Spotted Fever

  1. Caused by what bacteria?
  2. What category of bacteria is this?
  3. What does it cause at the microscopic level?
  4. What area of the country and when?
  5. What kind of bugs transmit this? 2
  6. Symptoms? 4
  7. Lab findings? 3
  8. CSF?3
A
  1. Rickettsia rickettsii
  2. Gram negative intracellular bacteria
  3. Endothelial cells: small vessel vasculitis
  4. Southeast, summer
  5. Dog Tick, Wood Tick
    2nd most common tick-borne illness
  6. Symptoms?
    - Fever
    - headache
    - nausea
    - Rash: blanching maculopapular, palms/soles, spreads centrally, later petechial and purpuric
    • Hyponatremia,
    • thrombocytopenia
    • Mild increase in LFTs
  8. CSF:
    - increased lymphocytes/PMN’s,
    - increased protein,
    - neg gram stain
44
Q

RMSF: Diagnosis

4

A
  1. Clinical suspicion
  2. Low threshold to empirically treat
  3. Rash may be absent in 20%
  4. RMSF serologies: initial may be negative; need convalescent titers several weeks later
45
Q

RMSF: Treatment

A

Doxycycline 100 BID x 7 days

Do not delay

46
Q

RMSF: Big Points:

  1. If suspected what do we do?
  2. In North Carolina, any of which symptoms will need treatment?
  3. What do we need to know about serology?
  4. Three labs to remember for this?
  5. What can we not wait for to treat?
A
  1. Empiric Treatment if even suspected
  2. In North Carolina, any fever, HA, neuro syndrome will need treatment
  3. First serology titers NOT reliable
    • Hyponatremia,
    • low platelets,
    • elevated LFTs, think RMSF…
  5. Do not wait for the rash…
47
Q
  1. Lyme disease is caused by what bacteria?
  2. What bug transmits it?
  3. What area of the country?
  4. What are the three stages and describe them?
A
  1. Borrelia burgdorferi
  2. Deer Tick (smaller)
  3. NE/Great Lakes, but reported in almost all states
    Most common cause of tick-borne disease
  4. Stages
    1: erythema migrans rash, viral-like syndrome
    2: multiple EM lesions and/or neurologic and/or cardiac findings
    3: late/chronic: intermittent or persistent arthritis and possibly subtle encephaolopathy or polyneuropathy
48
Q

Treatment of early lyme disease?

3 options

A
  1. Doxycycline - 100 mg BID for 21 to 18 days
  2. Amoxicillin - 500 mg TID for 21 to 28 days
  3. Cefuroxime (Ceftin) - 500 mg BID for 21 days
49
Q

Treatment of Late or severe
lyme disease?
2

A
  1. Cefotaxime (Claforan) 2g every 8 hours

2. Penicillin G 18-24 million units every 4 hours

50
Q
  1. What is a brain abcess?

2. What kind of infection is this?

A
  1. Pus-filled cavity ringed by granulation tissue & outer fibrous capsule surrounded by edematous brain tissue
  2. Focal pyogenic infection
51
Q

What can a brain abcess develop from?

10

A

Hematogenous spread

  1. Chronic pulmonary infections, such as lung abscess and empyema
  2. Skin infections
  3. Pelvic infections
  4. Intraabdominal infections
  5. Esophageal dilation and endoscopic sclerosis of esophageal varices
  6. Bacterial endocarditis (brain abscess complicates 2 to 4% of cases)
  7. Cyanotic congenital heart diseases (most common in children)
  8. Contiguous (middle ear, sinus, teeth)
  9. Trauma
  10. Post-neurological procedures
52
Q

Clinical Features of Brain Abscess

  1. Classic Triad?
  2. What is rare?
  3. What could be affected to cause homonymous superior quadrant visual field deficit or aphasia?
  4. ________-limb incoordination or nystagmus
  5. What would cause hemipareis?
A
  1. HA, fever, focal deficit
    less than 1/3 of cases
  2. Toxic appearance is rare
  3. Temporal lobe
  4. Cerebellum
  5. frontal lobe affected
53
Q

Diagnisos if brain abcess?
2

What do we not do?

A
  1. CT with contrast or MRI
  2. Needle guided biopsy or aspiration for confirmation or to direct treatment in cases not responding
  3. LP contraindicated
54
Q

Presumed Source treatment?

  1. Otogenic? 1
  2. Sinogenic or odontogenic? 2
  3. Penetrating trauma or neurosurgery? 2
  4. Hematogenous? 2
  5. No obvious source? 2
A
  1. Cefotaxime 2g IV q8h
  2. Pen 24 million units/d IV divided q4h
    +
    Flagyl 1g IV then 500mg q6h
  3. Nafcillin 2g IV q4h
    +
    Ceftazidime 2g IV q8h
  4. Pen 24 million units/d divided q4h
    +
    Flagyl 1g then 500mg q6h
  5. Cefotaxime 2g IV q6h
    +
    Flagyl 1g IV then 500mg q6h
55
Q

The usual CSF findings in patients with bacterial meningitis are what?
3

A
  1. elevated white blood cell count,
  2. elevated protein and
  3. low glucose.

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