CNS infections Flashcards
What are the four questions that should be answered with CNS infections?
- Acute or chronic
- Etiology
- Work up?
- Treatment
What are the major non-infectious etiologies of CNS problems?
- Neoplasia
- Collagen vascular disease
- Meds
What is the best way to assess for infectious CNS infections?
Spinal fluid
What is the major confounding factor of spinal glucose levels?
Pts has DM
How do you assess spinal fluid glucose levels in the diabetic patient?
ratio of serum to CSF should be less than 0.6
What is the normal opening pressure of CSF?
50-195 in the lateral decubitus position
What commonly complicates CSF fluid samples?
Prior abx treatment
What is a high CSF opening pressure most commonly seen in? Why?
Cryptococcal meningitis
Occludes the arachnoid villi
india ink stain = ?
Cryptococcal neoformans
True or false: with elevated intracranial pressure from cryptococcus infx, doing an LP is both diagnostic and therapeutic
True
When is flow cytology useful with CSF samples?
Diagnosing lymphomas
What is xanthochromia?
Yellowish supernatant of CSF that is a result of RBC lysis, indicated the presence of oxyhemoglobin, methemoglobin, and bili
How long does it take for RBCs to breakdown in the CSF to cause xanthochromia? Why is this important?
2-4 hours
Means that a traumatic tap will not cause this–this is pathologic
What is the normal WBC count in CSF in children and adults?
Both 0-5 /mm^3
What are the three etiologies of elevated WBC in the CSF?
Meningitis
Encephalitis
Parameningeal focus
What is the formula for the true WBC in CSF?
Actual WBC - (WBC in blood x RBC in CSF/ RBC in blood)
What is pleocytosis?
Increased WBC in the CSF
What non-infectious condition can produce a transient CSF pleocytosis?
Seizures
White counts in CSF are usually highest in what type of infectious etiology?
bacterial
What WBC cell predominates with viral meningitis?
Mononuclear
What WBC cell predominates with bacterial meningitis?
PMNs
What WBC cell predominates with TB meningitis?
Mononuclear
What WBC cell predominates with cryptococcal meningitis?
Mononuclear
What is the WBC range for viral meningitis?
50-1000
What is the WBC range for bacterial meningitis?
1000-5000
What is the WBC range for TB meningitis?
50-300
What is the WBC range for cryptococcal meningitis?
20-500
What are the glucose levels with viral meningitis?
More than 45
What are the glucose levels with bacterial meningitis?
Less than 40
What are the glucose levels with TB meningitis?
Less than 45
What are the glucose levels with Cryptococcal meningitis?
Less than 40
What are the protein levels in viral meningitis?
Less than 200
What are the protein levels in viral meningitis?
Less than 200
What are the protein levels in bacterial meningitis?
100-500
What are the protein levels in TB meningitis?
50-300