Lecture 34: CNS infections Flashcards
What are some of the types of CNS Infections?
- Meningitis, Encephalitis, Brain Abscess, Ventriculitis, Subdural Empyema, CSF shunts, etc…
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
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
Whare are the Two Distinct barriers within the CNS?
- Blood Brain Barrier
- Blood-CSF Barrier
What is the Blood Brain Barrier?
- Tightly joined capillary cells; Drugs can enter brain through these
- BBB is > 5000 times bigger than BCSFB
What is the Blood-CSF Barrier?
- Tightly fused epednymal cells; resticts drugs into the CSF
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
What is the pathogensis of Meningitis?
- Inflammation of Meninges by pathogens
- Once bacteria gets into CSF then body cannot conatin it
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
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]
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
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
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
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
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
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
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
What is the goal for the treatment of Bacterail Meningitis?
- Rapid Sterilization of CSF
- Resolve Signs and Symptoms
- Decrease Mortailty
- Prevent neuro issues
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?
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?
Duration?
- Amipicillin +/- Gentamicin
- Duration: 14-21 days
What is the Directed Therapy for S. Aureus in Bacterial Meningitis?
MSSA? MRSA> Duration?
- MSSA: Nafcillin [NOT Cefazolin]
- MRSA: Vancomycin
- Duration: 14-21 days
What is the Directed Therapy for L. Monocytogenes in Bacterial Meningitis?
Duration?
- Ampicillin +/- Gentamicin
- Duration: 21 day
What is the Directed Therapy for N. Meningitidis in Bacterial Meningitis?
Duration?
- Penicillin or Ceftriaxone
- Duration 7-10 days
What is the Directed Therapy for H. Influenzae in Bacterial Meningitis?
B-Lactamase (-) or (+)? Duration?
- bL(-): Ampicillin
- bL(+): Ceftriaxone
- Duration: 7-10 days
What is the Directed Therapy for Gram-negatives in Bacterial Meningitis?
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?
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?
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?
Opposite to Meningitis?
- Open pressure
- Chemistry: CSF clear; Glucose Low; Protein High
- Hematology: WBC High; Increasedm Lymphocytes
- Mircobiology: (-) stains; BioFire
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