Dr. Loo -- CNS Infections Flashcards
Define meningitis
Inflammatory disease of the leptomeninges, the tissues surrounding the brain and the spinal cord
5 categories of meningitis
- Bacterial
- Viral
- Fungal
- Mycobacteria
- Parasitic
2 sub-categories of bacterial meningitis
- Community-acquired
- Healthcare-associated Post neurosurgical
4 pathogens associated with community-acquired meningitis in infants less than 1 month old
- *Streptococcus agalactiae *(Group B)
- E. coli
- Listeria monocytogenes
- *Klebsielle *spp.
5 pathogens associated with community-acquired meningitis from ages 1 - 23 months
- Strep. pneumoniae
- N. meningitidis
- S. agalactiae
- H. influenzae
- E. coli
2 pathogens associated with community-acquired meningitis from 2 - 50 years old
- N. meningitidis
- S. pneumoniae
4 pathogens associated with community-acquired meningitis >50 years of age
- S. pneumoniae
- N. meningitidis
- L. monocytogenes
- Aerobic Gram negative bacilli
2 most common pathogens for meningitis
- Streptococcus pneumoniae
- Neisseria meningitidis
Most common serogroup of N. meningitidis
Serogroup B (out of 12)
Age group with highest rates of meningitis
<20 years old
3 risk factors for *N. meningitidis *meningitis
- Complement deficiencies
- Functional or anatomic asplenia
- Household exposure to an infected person
Bacterial meningitis due to *N. meningitidis *transmission
Droplets; respiratory secretions
Bacterial meningitis due to *N. meningitidis *carriage
Nasal
Reason for decreased incidence of meningitis due to *S. pneumoniae * in 2005 and 2011
Introduction of conjugated pneumococcal vaccine PCV7 (2005) and PCV13 (2011)
*N. meningitidis *meningitis mortality
10 - 20%
*S. pneumoniae *meningitis mortality
20 - 25%
9 risk factors for *S. pneumoniae *meningitis
- Splenectomy or asplenic states
- Mulitple myeloma
- Hypogammaglobulinemia
- Alcoholism, chronic liver
- Renal disease
- Malignancy
- DM
- Children with cochlear implants with positioners beyond 24 months after implantation
- CSF leak
Reason that meningitis due to *H. influenzae *is rare
Vaccination since 1998
Group affected by H. influenzae meningitis (2)
- Unimmunized children
- Partially immunized children
*H. influenzae *meningitis transmission
Droplet
Acquisition of menigitis due to Listeria monocytogenes
Contaminated foods
- Coleslaw
- Raw vegetables
- Milk and cheese
- Processed meats
Mortality of *Listeria monocytogenes *meningitis
15 - 30%
Most common cause of bacterial meningitis in neonates
*Streptococcus agalactiae *(GBS)
Mortality of GBS meningitis
7 - 27%
Method of transmission of GBS meningitis
Through birth canal
3 pathogens of healthcare-associated bacterial meningitis
- Aerobic gram negative bacilli including P. aeruginosa
-
Staphylococcus
- Coagulase negative
- S. aureus
- Propionibacterium acnes
Virus responsible for 85 - 95% of viral meningitis
Enterovirus
Enterovirus transmission
Person-person
Enterovirus seasonality
Summer and fall
2 less common causes of viral meningitis
- Arboviruses – mosquitoes or ticks (can also cause encephalitis)
- Herpes simplex
6 non-specific clinical manifestations of viral meningitis in infants
- Fever
- Poor feeding
- Vomiting
- Lethargy
- Irritability
- Bulging Fontanelle
4 clinical manifestations of viral meningitis in older children
- Vomiting
- Photophobia
- Headache
- Neck stiffness
10 clinical manifestations of viral meningitis in adults
- Fever
- Headache
- Meningismus
- Altered mental status and sensorium
- Vomtiing
- Seizures
- Papilledema
- Neck stiffness
- Brudzinski’s sign
- Kernig’s sign
Define Brudzinski’s sign
- “Nape of the neck sign”
- Passive flexion of the neck results in flexion of the hips and knees
Define Kernig’s sign
- Patient supine with thigh flexed on the abdomen and the knee flexed
- Leg is passively extended
- In the presence of meningeal inflammation, patient resists leg extension
2 things rash may suggest
- N. meningitidis (75%)
- Enterovirus meningitis
What might cranial nerve findings suggest?
L. monocytogenes
7 ways to manage meningitis
- ABCs
- Level of consciousness; possible intubation
- Circulatory – BP
- Blood cultures
- Lumbar puncture
- Empiric antibiotics
- CT scan in certain cases
5 situations where you should do CT scan in even of meningitis
- Immunocompromised
- Focal neurologic signs
- Seizure
- Papilledema
- Decreased level of consciousness
Difference between bacterial vs. viral meningitis: Cell count (cells/mm3)
- Bacterial = 1000 - 5000
- Viral = 100 - 1000
Difference between bacterial vs. viral meningitis: protein lab findings
- Bacterial = 1.0 - 5.0
- Viral = 1.0 (moderate increase)
Difference between bacterial vs. viral meningitis: glucose
Bacterial = low
Viral = normal
Difference between bacterial vs. viral meningitis: gram stain vs. blood culture
Bacterial = positive 60 - 90%
Viral = pasitive 10 - 90%
Appearance of N. meningitis
Gram negative cocci in pairs
Appearance of H. influenzae
Gram negative coccobacilli
Appearance of *s. pnuemoniae *and GBS
Gram positive coccin in pairs
Appearance of listeria monocytogenes
Gram positive rods
Empiric antibiotics for neonatal bacterial meningitis patients
Ampicillin IV + Cefotaxime IV
Empiric antibiotics for infants 1 - 3 months old with bacterial meningitis
Ampicilliln IV + Vancomycin IV + Cefotaxime or Ceftriaxone IV
EMpiric antibiotics for bacterial meningitis patients that are pediatrics and adult up to 50 years old
Cefotaxime or Ceftriaxone IV + Vancomycin IV
Empiric antibiotics for adult (>50 years) and immunocompromised patients with bacterial meningitis
Ampicillin IV + Vancomycin IV + Cefotaxime or Ceftriaxone IV
Antibiotic regimen for empiric therapy of healthcare associated bacterial meningitis (2)
Vancomycin and Ceftazidime
OR
Vancomycin and Meropenem
Antibiotics for *S. pneumonia *bacterial meningitis and duration
- Penicillins
- Cefotaxime or Ceftriaxone IV
10 - 14 days
Antibiotics for N. meningitidis bacterial meningitis and duration
Penicillins IV or Cefotaxime/Ceftriaxone IV
5 - 7 days
Antibiotics for H. influenzae type B bacterial meningitis and duration
Cefotaxime or Ceftriaxone IV
10 - 14 days
Antibiotics for GBS bacterial meningitis and duration
Beta lactam IV + aminoglycoside IV
10 - 14 days
Antibiotics for L. monocytogenes bacterial meningitis and duration
Beta lactam IV + aminoglycoside IV
21 days
2 causes of meningitis where IV dexamethsone is recommended as an adjunct
- H. influenzae at any age
- *S. pneumoniae *in adults
Rationale for using adjunctive steriods in the treatment of bacterial meningitis
Prevent neurological damage (esp. to hearing) due to an inflammatory and cytokine influx after antiobitics cause lysis of bacteria and release of pro-inflammatory factor into the closed brain space
3 prophylactic antibiotics for *N. meningitidis *and H. influenzae meningitis
- Rifampin
- Ceftriaxone
- Ciprofloxacin
Define encephalitis
Inflammatory process of the brain parenchyma
7 associated clinical findings of encephalitis
Findings of brain dysfunction:
- Altered mental status (range = subtle deficits to complete unresponsiveness)
- Motor and sensory deficits
- Altered behavior and personality changes
- Speech or movement disorders
- Meningeal irritation (i.e. nuchal rigidity usually absent)
- Seizures
- Hemiparesis, craniael nerve palsies
NOTE: Meningitis = usually NORMAL brain function
2 most frequent age groups affected by encephalitis
- Infants <1 year
- Elderly > 65 years
3 possible etiologies of encephalitis
- Usually infectious
- Predominantly viral
- Non-infectious unusual
- Autoimmune disorders (i.e. collagen vascular diseases)
- Paraneoplastic syndromes
Virus that can cause encephalitis from animal bites
Rabies
Virus that can cause encephalitis from bats or pigs
Nipah virus
Virus that can cause encephalitis from rodents
Lymphocytic choriomeningitis
Seasonality of encephalitis
Summer (mosquitoes)
5 diagnostic lab tools for encephalitis
- CSF analysis
- Gram stain and culture
- Mycobacteria, funal, viral culture
- PCR
- Serology
- West Nile serology
5 viruses for which PCR could be used to diagnose encephalitis
- HSV
- Enterovirus
- Immunocompromised:
- VZV
- EBV
- CMV
4 findings from CSF analysis for encephalitis
- Increased WBC (but usually <250/mm3)
- Predomniance of lymphocytes
- Increased protein (usually <1.5 g/l)
- Normal glucose usually
- Decreased in HSV and mumps
- Red cells suggest necotizing encephalitides (i.e. HSV)
3 imaging techniques to diagnose encephalitis
- MRI
- CT
- EEG
MRI or CT scan findings that suggests HSV as cause of encephalitis
Temporal lobe involvement
MRI or CT scan finding to suggest arbovirus as cause of encephalitis
Thalamus or basal ganglia
EEG finding for encephalitis that suggests HSV as cause
Focality in the temporal lobe
Therapy for HSV encephalitis
Acyclovir 10 mg/kg IV q 8h (adjust for creatinine clearance)
Potential sequelae of encephalitis (4)
- Difficulty concentrating
- Behavioral
- Speech
- Memory
Bacterial meningitis triad
- Fever
- Headache
- Nuchal rigidity
NOTE: Not all patients have