Infectious Disease Flashcards
What is the Class Triad of clinical features of bacterial meningitis?
Fever, headache, and neck stiffness
What is the median age of bacterial meningitis?
42 years
From where does bacteria enter subarachnoid space most commonly?
Bloodstream
What is the most common organism that causes bacterial meningitis in patients under 2 months of age?
Group B Strep
What is the most common organism that causes bacterial meningitis in patients between 2 and 23 months of age?
Pneumococcus (50%)
What is the most common organism that causes bacterial meningitis in patients between 23 months and 34 years of age?
Meningococcus (40%) and Pneumococcus (40%)
What is the most common organism that causes bacterial meningitis in patients over 35 years of age?
Pneumococcus (50-70%)
What is a normal WBC count for adults in the CSF?
What is a normal WBC count for newborns in the CSF?
What is a normal protein count for adults in the CSF?
18-50 (avg 35) mg/dL
What is a normal protein count for newborns in the CSF?
What is a normal glucose value for adults in the CSF?
2/3 of serum glucose (50-60)
What is a normal glucose value for newborns in the CSF?
2/3 of serum glucose (variable)
What is a typical WBC count in the CSF with bacterial meningitis?
100-10,000
What is a typical WBC count in the CSF with viral meningitis?
10-2,000
What is a typical WBC count in the CSF when encephalitis is present?
10-2,000
What is the main WBC cell type in the CSF with bacterial meningitis?
PMN (80-90%)
What is the main WBC cell type in the CSF with viral meningitis?
Mononuclear (lymphocyte)
What is the main WBC cell type in the CSF when encephalitis is present?
Mononuclear (lymphocyte)
What is the main WBC cell type in the CSF when a brain abscess is present?
Mononuclear (lymphocyte)
Is CSF glucose high low or normal with bacterial meningitis?
Low
Is CSF glucose high low or normal with viral meningitis?
Normal
Is CSF protein high low or normal with bacterial meningitis?
High
Is CSF protein high low or normal with viral meningitis?
Normal or slightly elevated
What is the initial empiric therapy to treat bacterial meningitis in neonates and infants?
Ampicillin and cefotaxime
What is the initial empiric therapy to treat bacterial meningitis in children and adults 3 months-50 years?
Ceftriaxone or cefotaxime, and vancomycin
What is the initial empiric therapy to treat bacterial meningitis in adults over 50 years?
Ceftriaxone or cefotaxime, and vancomycin, AND ampicillin
What is the initial empiric therapy to treat bacterial meningitis in hospital acquired, recent head trauma/neurosurgery, immunocompromised, and alcoholics?
Vancomycin and meropenem +/- ampicillin
Which antibiotic is added when treating bacterial meningitis caused by Listeria?
Ampicillin
When are steroids added to the treatment of bacterial meningitis?
Before or at the start of antibiotic treatment (only with pneumococcal meningitis)
What are the common viruses that cause viral meningitis?
Enteroviruses, HSV-2, and arboviruses (WNV)
What is the most important diagnostic tool for viral meningitis?
PCR amplification of viral genome
What is the most common virus that causes viral encephalitis in the summer or early fall?
Arboviruses (WNV)
What is the most common virus that causes viral encephalitis in the fall and winter?
LCMV
What is the most common virus that causes viral encephalitis in the winter and spring?
Mumps
What is a common virus that causes viral encephalitis in any season?
Herpes simplex
What are 4 diagnostic tests used in the diagnosis of viral encephalitis?
PCR amplification, CSF pleocytosis, EEG, and CT/MRI
What medication is used to treat viral encephalitis caused by HSV or VZV?
Acyclovir
