Oostenbrink et al developed a CSF score based on laboratory values to help evaluate children with meningeal signs. This can help aid in the decision to treat with antibiotics or not. The authors are from the University of Utrecht in The Netherlands.
Parameters:
(1) absolute PMN (neutrophils) count in the CSF
(2) ratio of CSF to blood glucose, based on specimens collected at the same time
absolute PMN count in the CSF =
= (percent PMNs in differential count) / 100 * (white blood cell count per µL in CSF)
ratio of CSF to blood glucose =
= (CSF glucose in mg/dL) / (blood glucose in mg/L) =
= (CSF glucose in mmol/L) / (blood glucose in mmol/L)
|
Parameter |
Finding |
Points |
|
absolute PMN count in CSF |
0 to 9 per µL |
0 |
|
|
10 to 99 per µL |
1 |
|
|
100 to 999 per µL |
2 |
|
|
1,000 to 9,999 per µL |
3 |
|
|
>= 10,000 per µL |
4 |
|
ratio of CSF to blood glucose |
< 0.10 |
0 |
|
|
0.10 to 0.19 |
1 |
|
|
0.20 to 0.29 |
2 |
|
|
0.30 to 0.39 |
3 |
|
|
0.40 to 0.49 |
4 |
|
|
0.50 to 0.59 |
5 |
|
|
0.60 to 0.69 |
6 |
|
|
0.70 to 0.79 |
7 |
|
|
0.80 to 0.89 |
8 |
|
|
0.90 to 0.99 |
9 |
|
|
>= 1.00 |
10 |
from footnote to Table 3, page 1192
where:
• The points assigned for the absolute PMN count based on rounding down the LOG10(count).
• The points for the glucose ratio is based on 10 * (round down ratio to 1 decimal place).
CSF score =
= (points for absolute PMN count in the CSF) – (0.5 * (points for ratio of CSF to blood glucose))
Interpretation:
• minimum CSF score: -5
• maximum CSF score: 4
• The scores are not continuous, and change with increments of 0.5.
• The higher the score, the more likely that bacterial meningitis is present and antibiotics should be administered.
|
CSF Score |
Percent with Bacterial Meningitis |
|
-5 to -3 |
6% (3 of 48) |
|
-2.5 to –1.5 |
13% |
|
-1.0 to 1.5 |
55% |
|
2 to 4 |
98% |
from Table 4, page 1192; percent for –5 to –3 given as 3% in table
Performance:
• The area under the ROC curve was 0.93 (95% CI 0.89 to 0.97).
Use in conjunction with the Clinical Risk Score (see below)
|
CSF Risk Score |
Treat with Antibiotics if Clinical Risk Score is |
|
-5 to –3.5 |
>= 20 |
|
-3.0 to –2.5 |
>= 13.0 |
|
-2.0 to +0.5 |
>= 10.5 |
|
1.0 to 4.0 |
>= 9.5 (any value) |
from page 1192
Specialty: Infectious Diseases, Neurology
