post LP headaches (PLPH)

introduction

occurs in 18-32% of patients who undergo lumbar puncture
PLPH is believed to be caused by adenosine-induced cerebral vasodilatation
usually starts within 48hrs (but not within 1hr) of lumbar puncture or epidural procedures although may be delayed for up to 14 days.
bicranial, pulsatile, worse in upright position and on movement, median duration is 5 days with early onset usually more severe and longer lasting.

limit CSF leaks from lumbar punctures
avoid LP is possible
use small spinal needles eg 25G
- smaller needles than 25G increase failure rate
if using a cutting needle, ensure needle bevel is parallel with spine
- patients who underwent LP with a 27-gauge Quincke needle with the bevel of the needle perpendicular to the dural axis were almost 6 times more likely to experience PLPH
consider “atraumatic” needles such as Whitacre, Sprotte, Atraucan needles although evidence of benefit is not clear cut
- for atraumatic needles, reinserting the stylet immediately before withdrawing the needle decreases the incidence of PLPH.
although traditionally, prolonged rest in bed post-LP has been used, there is no clear evidence this is beneficial
amount of CSF removed is NOT associated with PLPH

non-steroidal anti-inflammatory drugs (NSAIDs)
antiemetics
if problematic, consider methylxanthines such as caffeine:
- iv caffeine 500mg appears to produce a response in ~71%
- if iv is not available:
  - oral caffeine 100mg up to 5 tabs per 24hrs can be used
  - or, aminophylline
patients with severe ongoing headache can be considered for epidural blood patch (EBP) which is usually performed by the anaesthetic department and involves autologous blood (10–15 mL) being injected epidurally at the puncture site of the prior lumbar puncture.
- efficacy is said to be 75-96%
- contraindications to EBP include:
  - leukocytosis
  - fever
  - patient refusal
  - infection at local site
  - technical difficulties.
- complications of EBP include:
  - exacerbation of headache in some patients
  - facial paralysis, vertigo, tinnitus, and ataxia have also occurred
  - residual complications such as backache and/or stiffness