A headache may follow intrathecal injection of drugs by 2 different mechanisms.
Mechanisms:
(1) direct effect of the injected drug
(2) chemical meningitis
Features in common:
(1) The headache is diffuse.
(2) The headache is present in the recumbent position.
(3) negative CSF cultures.
|
Parameter
|
Direct Effect
|
Chemical Meningitis
|
|
onset after injection
|
<= 4 hours
|
5 - 72 hours
|
|
duration
|
<= 14 days
|
|
|
CSF WBC changes
|
usually unchanged
|
pleocytosis
|
Differential diagnosis:
(1) bacterial meningitis due to injection contamination
(2) cerebrospinal fluid fistula
(3) post-lumbar puncture headache
