The lumbar puncture,
or "LP", is a frequently performed procedure in emergency
departments, neurology and radiology clinics and hospital wards.
In the emergency department, LP can yield information that can rapidly
differentiate benign from emergent conditions.
In general, an LP may
be done to:
- analyse the
cerebrospinal fluid (CSF)
- measure the
- access the
intrathecal space for either drainage of CSF or injection of fluid
or to administer medications into the intrathecal space
- to perform
most common emergency department indications for a LP include clinical
suspicion of meningitis (bacterial, viral or fungal) or to rule
out subarachnoid hemorrhage.
not let LP (or CT scan) delay antibiotics and fluid
resuscitation in patients with probable meningitis.
neurology clinics and other settings, LP is used to detect disorders
with local immunoglobulin production in the CNS such as multiple
sclerosis and SSPE, malignant infiltrates such as acute leukemia
and lymphoma, and blockage of the spinal canal.
to lumbar puncture are:
or signs of raised intracranial pressure. These include a decreased
level of consciousness, localizing (focal) neurologic signs
and papilledema. LP in patients with raised ICP may lead to
uncal herniation and death,
severe bleeding diathesis or coagulation disorder or the patient
is on anticoagulation therapy,
infection at the planned site of the puncture
When performed correctly, the LP procedure can be rapidly completed
with little discomfort or risk to the patient. Using the sterile
conditions recommended in this learning module, the introduction
of infection by the LP procedure itself to the spinal cord would
be extremely rare. A small chance of bleeding at the site exists.
However "post-LP headache"
is a relatively common occurrence (in up to even greater than 30%
of patients depending on the LP needle type and caliber selected
- see Preparation). This headache begins usually within hours to
a few days after the LP procedure and is usually made worse with
a positional change to the upright posture. The headache can be
very severe and although the headache usually improves over time,
the headache can last up to 3 weeks. A "blood patch" may
be required to seal the hole in the lumbar meninges.
rest (although frequently recommended), whether prone or supine,
immediately after LP does not prevent the headache.
Cybertext / Postural Headaches from Lumbar Punctures, Dural Rents
non-postural headache after an LP is uncommon. If the onset is early,
consider a puncture-induced meningitis and for those headaches of
later onset consider a possible subdural effusion.
A signed informed
consent should be obtained from the patient or a substitute
decision maker after explaining the risks and benefits of the procedure.
The consent form should ideally be signed by the patient in the
presence of a witness. This should include a discussion of the likelihood
of "post-LP headache" and the small risk of bleeding or
patient information sheet for LP.