1. Meningitis Commonly Asked Questions
Stephen J. Gluckman, M.D.

2. What are normal CSF findings?
Protein
0.45 gm/L
Elevated with Diabetes
Elevated with neuropathies of any cause
Elevated with increasing age
Elevated by bleeding into the CSF (SAH or traumatic)
0.01 gm/L for every 1000 RBC’s

3. What are normal CSF findings?
Glucose
60 % of blood glucose
In persons with hyperglycemia it takes several hours for CFS and blood glucose to equilibrate
Low CSF glucose
Bacterial infection
Tuberculosis, cryptococcosis, carcinomatous
SAH
Sarcoidosis
Occasional viral

4. What are normal CSF findings?
Cell count
<5 WBC (all mononuclear) and < 5 RBC considered “normal”
Traumatic tap
WBC/RBC ratio = 1:1000
Pressure
<20
In patients with bacterial meningitis
wide range
40% >30, 10% < 14

5. Look at the whole pattern!
Can the CSF reliably distinguish between a bacterial and non-bacterial cause of meningitis?
Usually
Look at the whole pattern!

6. Can the CSF reliably distinguish between a bacterial and non-bacterial cause of meningitis?
Glucose
<2.5 suggests bacterial
< 0.5 highly suggests bacterial
Protein
> 2.5 suggests bacterial
Cell count
>500 suggests bacterial
>1000 highly suggests bacterial
% polys
>50 suggests bacterial

7. Are there exceptions? Early viral can have a predominance of polys
Some viral can have low CFS glucose
Listeria can have predominance of mononuclear cells rather than polys
TB can have predominance of polys

8. How much does prior administration of antibiotics alter the CSF findings?
Not Much

9. How much does prior administration of antibiotics alter the CSF findings?
48-72 hours of prior intravenous antibiotic treatment has little effect on glucose, protein and cell count
It will rarely change the CSF from a “bacterial” to an “aseptic” formula
Prior antibiotic treatment will likely make the cultures negative.

10. What is the typical clinical presentation of bacterial meningitis?
History
Headache: 75-90%
Photophobia: uncommon
Examination
Fever: 95%
Stiff Neck: 85%
Altered mental status: 80%
All three: 40%
Any one of the three: 100%

11. How “good” are Kernig and Brudzinski signs?
Originally related to severe, advanced TB meningitis (not bacterial)
Not studied in a prospective study until 2002 (N=297)*
Sensitivity 5%
Specificity 95%
*Thomas KE et al. Clin Infect Dis. 2002;35:46-52

12. What are the common causes of bacterial meningitis?
It depends upon age and risk factors
Age
Neonates: listeria, group B streptococci, E. coli
Children: H. influenza
10 to 21: meningococcal
21 onward: pneumococcal >meningococcal
Elderly: pneumococcal>listeria
Risk factors
Decreased CMI: listeria
S/P neurosurgery or opened head trauma: Staphylococcus, Gram Negative Rods
Fracture of the cribiform plate: pneumococcal

13. What is the proper empirical antibiotic regimen for presumed bacterial meningitis?
It depends upon the clinical situation

14. What is the proper empirical antibiotic regimen for presumed bacterial meningitis?
Neonates
3rd generation cephalosporin and ampicillin
Children
3rd generation cephalosporin
Normal adult
3rd generation cephalosporin and vancomycin (if resistant pneumococci)
Problems with cell mediated immunity (AIDS, steroids, elderly)
Add coverage for listeria with ampicillin or co-trimoxazole
S/P CNS trauma or neurosurgery
Coverage for staphylococcus and gram negative rods with antipseudomonal beta-lactam and vancomycin

15. How important is the speed of initiating antibiotics in bacterial meningitis?
It is important
But it is not the critical prognostic factor

16. How important is the speed of initiating antibiotics in bacterial meningitis?
The clinical outcome is primarily influenced by the severity of the illness at the time antibiotics are initiated
Severity based on
Altered mental status
Hypotension
Seizures

17. How important is the speed of initiating antibiotics in bacterial meningitis?
No factors
9% with adverse outcome
One factor
33% with adverse outcome
Two or three factors
56% with adverse outcome
Therefore, though treatment should be administered ASAP, the impact of antibiotic delay is a function of the severity of disease at the time that treatment is initiated

18. Steroids or no Steroids?
(today)

19. Steroids or no Steroids?
Reduces morbidity and mortality*
Give before or at the same time as the first dose of antibiotics
Dose studied
Dexamethazone 10 mg Q6H x 4 days
*Only shown for pneumococcal meningitis in adults and haemophilus meningitis in children

20. Do you need to do a CT scan before an LP?
Usually not
A CT scan should never delay therapy (obtain blood cultures)

21. Do you need to do a CT scan before an LP?
Prospective studies*
N = 412
Predictors of CNS mass lesion
History
> 60 years old
Immunocompromised
Hx of prior CNS disease
Hx of seizure w/in 1 week prior to onset
Examination
Focal neurological findings
Altered mental status
Papilledema
*Gopal et al. Arch Intern Med. 1999;159:2681-5
Hasbun and Abrahams. N Engl J Med 2001:345:

22. How contagious is meningitis? Are we at risk when we care for a patient?
Not really
The only bacterial meningitis that is spread from person to person is meningococcal
The risk is very low
Household contacts have about a 1% risk
Health care workers have not been shown to have a risk
After 24 hours of treatment this is no risk

23. What is “Aseptic” meningitis?
It is a term used to mean non-pyogenic bacterial meningitis
It describes a spinal fluid formula that typically has:
A low number of WBC
A minimally elevated protein
A normal glucose
It has a much bigger differential diagnosis than viral meningitis.

24. What are the treatable causes of aseptic meningitis/encephalitis syndrome?
Infectious
HSV 1 and 2
Syphilis
Listeria (occasionally)
Tuberculosis
Cryptococcus
Leptospirosis
Cerebral malaria
African tick typhus
Lyme disease
Non-Infectious
Carcinomatous
Sarcoidosis
Vasculitis
Dural venous sinus thrombosis
Migraine
Drug
Co-trimoxazole
IVIG
NSAIDS

25. Generally advanced with CD4 < 100 Sub-acute onset: fever, headache
What are the important things to know about AIDS- associated cryptococcal meningitis?
Generally advanced with CD4 < 100
Sub-acute onset: fever, headache
Stiff neck is rare
Mortality with treatment is about 15%!
Predictors of death
Altered Mental status, low CSF WBC count, high CSF cryptococcal antigen titer

26. What are the important things to know about AIDS- associated cryptococcal meningitis?
CSF findings
Elevated pressure is the usual (>70%)
Rest of CSF findings are often unimpressive
WBC <50
Glucose: normal or slightly low
Protein: normal or slightly elevated
25% have normal WBC, glucose and protein
CSF cryptococcal antigen: % sensitive

27. What are the important things to know about AIDS- associated cryptococcal meningitis?
Treatment
Medical
Induction: amphotericin B 0.7mg/kg x 2/52
(flucytosine)
Consolidation: fluconazole 400 mg x 8/52
Maintenance: fluconazole 200 mg
Pressure
Daily LP’s to keep opening pressure <20
If LP’s are still needed after 1 month shunt

28. Questions from the Audience?

30. Meningitis – Who was awake?
Which of the following are true statements?
Early viral meningitis can have a predominance of polys
Some viral meningitis can have low CSF glucose
Listeria meningitis can have predominance of mononuclear cells rather than polys
All of the above

31. Meningitis – Who was awake?
Which of the following are true statements?
Early viral meningitis can have a predominance of polys
Some viral meningitis can have low CSF glucose
Listeria meningitis can have predominance of mononuclear cells rather than polys
All of the above

32. Meningitis – Who was awake?
To correct CSF protein concentrations for blood in the CSF the proper ratio is approximately 0.01 gm/L of protein for every 100 RBC’s
True
False

33. Meningitis – Who was awake?
To correct CSF protein concentrations for blood in the CSF the proper ratio is approximately 0.01 gm/L of protein for every 100 RBC’s
True
False

34. Meningitis – Who was awake?
Which of the following are true about cryptococcal meningitis?
a. A normal CSF effectively rules out cryptococcal meningitis
b. If the CSF pressure is elevated one should not remove more than 10 ml at a time
c. Everyone with HIV infection is at increased risk for cryptococcal meningitis.

35. Meningitis – Who was awake?
Which of the following are true about cryptococcal meningitis?
a. A normal CSF effectively rules out cryptococcal meningitis
b. If the CSF pressure is elevated one should not remove more than 10 ml at a time
c. Everyone with HIV infection is at increased risk for cryptococcal meningitis.
None

36. Meningitis: References
1. Gopal AK, Whitehouse JD, Simel DL, Corey GR. Cranial computed tomography before lumbar puncture. A prospective clinical evaluation. Arch Intern Med. 1999;159:2681-5
2. Hasbun R, Abrahams J, Jekel J, Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med 2001:345:
3. Blazer S, Berant M. Bacterial meningitis: Effect of antibiotic treatment on spinal fluid. Am J Clin Pathol. 1983;80:386
4. de Gans J, van de Beek D. N Eng J Med. 2002;347:
5. Hussein AS, Shafran SD. Acute bacterial meningitis in adults. Medicine 2000;79:360-68
6. Aronin S, Peduzzi P, Quagliarello VJ. Community acquired bacterial meningitis: Risk stratification for adverse clinical outcome and effect of antibiotic timing. Ann Intern Med 1998;129:862