Lecture 34: CNS infections Flashcards by Emily Byford

What are some of the types of CNS Infections?

Meningitis, Encephalitis, Brain Abscess, Ventriculitis, Subdural Empyema, CSF shunts, etc…

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What is the Cerebronspinal Fluid and what are some of the normal characteristics of it?

CSF is a made from chorid plexus; acts a “shock absorber”; based on age
Characteristics: Clear, pH = 7.4, protein < 50, Glucose < 50-66%, WBC < 5 wbc/ml

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What is the meninges and what are the 3 separate membranes?

Ensheathed Protective covering
Dura Mater: outer layer connecting to skull
Arachnoid: middle layer Subarachnoid Spaces = meningitis happens
Pia Mater: Innermost layer connecting to brain

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Whare are the Two Distinct barriers within the CNS?

Blood Brain Barrier
Blood-CSF Barrier

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What is the Blood Brain Barrier?

Tightly joined capillary cells; Drugs can enter brain through these
BBB is > 5000 times bigger than BCSFB

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What is the Blood-CSF Barrier?

Tightly fused epednymal cells; resticts drugs into the CSF

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What are some of the antibiotics characteristics that affect the CNS/CSF penetration?

Lipid Solubility: highly lipid = high pen
Degree of Ionization: dependent on pKa & pH = diffusion
Protein binding: ONLY free drug can
Molecular Weight: low MW = pentration
Meningeal Inflammation: increased inflammation = increased penetration

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What is the pathogensis of Meningitis?

Inflammation of Meninges by pathogens
Once bacteria gets into CSF then body cannot conatin it

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What are the 3 ways that bacteria gets into the CSF?

Hematogenous Spread: blood to subarachnoid space most common; comes from nasopharyngeal
Contiguous Spread: Parameningeal focus
Direct Inoculation: from head trauma or surgery

Blood CSF = Meningitis
Blood Brain = Brain Abcess

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What are some of the common pathogens that can cause the Hematogenous Spread?

N. Meningitidis
H. Flu
S. Pneumoniae

They have Pili [holds on better], Capsule [incresaes resistance], IgA [enhacne coloincation]

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What is the etiology that depends on the age of the patient in Meningitis ?

Neonates? Infants? Childern/young adults? Adults? Elderly? Post-neurosugery? Head Tramua? immunocompormised?

Neonates: Group B Strep, E. Coli, Listeria
Infants: H. Flu, S. Pneumo, N. Meningitidis
Childern: N. Meningitidis, S. Pneumo
Adults: S. Pneumo, N. Meningitidis
Elderly: S. Pneumo, N. Meningitidis, GNR, Listeria
Post-Surgery: S. Aureus, GNR, S. Epidermidis
Head Trauma: S. Aures, GNR
Immunocom: S. Pneumo, N. Meningitidis, Listeria, GNR

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What is the characteristics of H. Fluenzae for Meningitis?

Hib vaccine has decreased it vaccine preventable disease
Coma and seizure are common early in infection

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What is the characteristics of N. Meningitids in Meningitis?

Happens in clusters [dorms, high schools, military…] that happens in winter and spring
5 Groups: A, B, C, Y, W-135
Meingoccemia: petechial or purpuric rash

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What are the characteristics of S. Pneumoniae in Meningitis?

Highest fatalit rate = 19-26%
Risk Factors: pneumonia, Endocarditis, CSF leaky
Could cause seizures, facial palsy, visual problems

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What are some of the clinical signs and symptoms of Meningitis in Adults, Infants, Elderly, Older Childern?

Adult: ABRUPT; Fever, Headache, Stiff Neck, Photophobia
Infants: Fever
Elderly: Low fever, Stiff neck
Older Childern: Confusion, Lethargy

Petechial RASH

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Where does the CSF get sent to for evaluation and what happens at each place?

Chemistry: CSF cloudy, Glucose low [increased glycolsis and transport], Protein high
Hematology: WBC high, >80% neutrophils
Microbiology: Stain of CSF is (+), Culture (+), BioFire PCR

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What are the general principles of treatemtn for acute bacterail meningitis?

Mortality within 24 -48h of onset; prompt treatment ESSENTIAL
Start Empiric antibiotics
High dose IV to help with penetration

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What is the goal for the treatment of Bacterail Meningitis?

Rapid Sterilization of CSF
Resolve Signs and Symptoms
Decrease Mortailty
Prevent neuro issues

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What is the empiric therapy for neonates in Bacterial Meningitis?

Pathogens?

Ampicillin + Cefotaxime

E. Coli, Group B Strep, Listeria

What is the empiric therapy for Children in Bacterial Meningitis?

Pathogens?

Ceftriaxone + Vancomycin

H. Flu, S. Pneumo, N. Meningitidis

What is the empiric therapy for Young Adults in Bacterial Meningitis?

Pathogens?

Ceftriaxone + Vancomycin

N. Meningitidis, S. Pneumo

What is the empiric therapy for Elderly & Immunosppressed in Bacterial Meningitis?

Pathogens>?

Ceftriaxone + Vancocmycin + Ampicillin [+/- Cefepime]

S. Pneumo, GNR [Pseudo], Listeria

What is the empiric therapy for Neruosurgery in Bacterial Meningitis?

Pathogens?

Ceftriaxone or Cefepime + Vancomycin

S. Aures, GNR

What is the empiric therapy for Head Trauma in Bacterial Meningitis?

Pathogens?

Ceftriaxone or Cefepime + Vancomycin

S. Aures, GNR

What is the **Directed Therapy** for **S. Pneumoniae** in Bacterial Meningitis? ## Footnote PSSP? PRSP? Durtation?

- PSSP: Pen G or Ampicillin - PRSP: Vancomycin + Ceftriaxone - Duration: 10-14 days

What is the **Directed Therapy** for **Group B Strep** in Bacterial Meningitis? ## Footnote Duration?

- Amipicillin +/- Gentamicin - Duration: 14-21 days

What is the **Directed Therapy** for **S. Aureus** in Bacterial Meningitis? ## Footnote MSSA? MRSA> Duration?

- MSSA: Nafcillin [NOT Cefazolin] - MRSA: Vancomycin - Duration: 14-21 days

What is the **Directed Therapy** for **L. Monocytogenes** in Bacterial Meningitis? ## Footnote Duration?

- Ampicillin +/- Gentamicin - Duration: 21 day

What is the **Directed Therapy** for **N. Meningitidis** in Bacterial Meningitis? ## Footnote Duration?

- Penicillin or Ceftriaxone - Duration 7-10 days

What is the **Directed Therapy** for **H. Influenzae** in Bacterial Meningitis? ## Footnote B-Lactamase (-) or (+)? Duration?

- bL(-): Ampicillin - bL(+): Ceftriaxone - Duration: 7-10 days

What is the **Directed Therapy** for **Gram-negatives** in Bacterial Meningitis? ## Footnote Duration?

- Ceftriaxone or Cefepime

What is the role of **steroids** in the treatment of Bacterial Meningitis?

- Dexmethasone for **S. pneumoiae** - Inhibits IL-1 and TNF - Good in **pediatrics**; give with 1st does of antibiotics or 10-15 mins before

What is important to know about the **Prophylaxis** against Bacterial Meningitis? ## Footnote Regimens?

- Given to those with Close contact [200-1000 times higher with H. Flu or N. Men] - N. Men & H. Flu: Adults = Rifampin 600mg & Children = Rifampin 10mg/kg

What is the **pathogensis** of **Brain Abscess**?

- **Contiguous Spread**: bacteria into brain tissue by close infections [**COMMON**] - **Hematogenous Spread**: Travels from distant infection - **Direct Inoculation**: Trauma or Surgery

What is the **etiology** that depends on the **Predisposing Factors** of the patient of Brain Abscess? ## Footnote Otitis Media? Sinusitis? Dental Sepsis? Head Trauma? Endocarditis? Lung Abscess? HIV?

- Otitis: Strep, Bacteroides, Prevotella, GNR - Sinusitis: Strep, Bacteroides, GNR, S. Aureus, H. Flu - Dental: Viridans - Head trauma: S. Aureus, Strep, GNR - Endocarditis: S. Aureus, Viridians - Lungs: Viridians - HIV: Toxo

What are some of the **Clinical Presentaions** of Brain Abscess?

- Headache - Altered Mental Status - Focal Neurologic Deficits - Fever - Seizures - N/V

What is the **Treatment** for **Otitis Media** in Brain Abscess?

- Ceftriaxone + Metro

What is the **Treatment** for **Sinusitis** in Brain Abscess?

- Ceftriaxone + Metro

What is the **Treatment** for **Dental Sepsis** in Brain Abscess?

- Pencillin + Metro

What is the **Treatment** for **Trauma or Neurosurgery** in Brain Abscess?

- Vancomycin + Ceftriaxone or Cefepime

What is the **Treatment** for **Endocarditis** in Brain Abscess?

- Vancomycin + Gentamicin

What are the most comon **etiologies** Viral Encephalitis?

- **Enteroviruses**: Coxsackie Virus A & B; Echovirus, Poliovirus **Fecal Oral** - **Arbovirus**: West Niles Virus, St. Louis Encephalitis; **Mosquitoes & Birds** - **Herps**: HSV 1 & 2, CMV, VZV; **sexual activity people**

What are the **Clinical Presentations** of Viral Encephalitis?

- Fever - Headache - Altered Mental Status

What is the **Diagnosis** of viral encephalitis? ## Footnote Opposite to Meningitis?

- Open pressure - **Chemistry**: CSF clear; Glucose Low; Protein High - **Hematology**: WBC High; Increasedm Lymphocytes - **Mircobiology**: (-) stains; BioFire ## Footnote West Nile Virus is a Separate test

What is the **treatment and duration** for Viral Encephalitis?

- MOST are self-limiting with full recovery in **7-10 days**; given supportive carem fluids, analgesics, antipyretices - **HSV or VZV**: Acyclovir 10mg/kg q8h x 2-3w - **CMV**: Gancicolvir + Foscarent IV