Lumbar Punctures - Clinical Departments

1889- First procedure to access the
dural space consisted of a cut down
procedure to help decrease
intracranial pressure in people in TB
meningitis by Walter Essex Wynter
1891- The first needle was used to
access the dural space by Heinriche
1893- Arthur H. Wentworth was the
first to perform the procedure at
Harvard, interestingly though he was
almost tossed in jail by antivivisectionists for his experimentation,
but was acquitted
1898- Karl August Bier and his
assistant August Hildebrandt
attempted first spinal anesthetic by
doing lumbar punctures on each other
with injection cocaine into the
intrathecal spaces
Palpate the posterior superior iliac crest bilaterally, and move medially to the
spine and find the L3-L4 intervertebral space with the patient in either fetal
position in a lateral recumbent position or hunched over in a sitting position as
determined by your needs
Palpate the L2-L3 and L4-L5 spaces above and below, mark the appropriate
space that you want to enter, preferably with the cap of a pen or something that
causes an indentation that won’t be erased during sterilization
Open the kit, and put on sterile and prep the kit, assembling the opening
pressure gauge and opening the bottles and having them lined up and numbered,
and having the lidocaine drawn up
Prep the area with betadine, avoid chloroprep as this can cause an aseptic
meningitis, then drape the area to create a sterile field
Anesthetize the area using initially a 25 gauge needle to raise a wheal, and then a 20
gauge needle to hit deeper structure create a wide arc during anesthetizing, in case
another level will need to be done, the needle should aspirated each time prior to
administration to ensure no blood is present (The lumbar puncture needle itself can be
used for deeper structures
Insert the needle in a cephalic direction towards the umbilicus, orient the bevel
parallel to the longitudinal dural fibers, to decrease the chance of you cutting them (**
in a lateral recumbent position this should mean the bevel is facing up, in a sitting
position, means the bevel should be facing sideways )
Advance the needle with occasionally removing the stylet to ensure no fluid return, in
normal adults the needle will have to inserted 4-5cm before getting close to the dural
space, if no fluid is returned replace the stylet and either advance or withdraw the
needle and recheck
- if bone is struck at shallow depth, redirect needle more cephalad;
- if at deeper depth – more caudally
After fluid return if the patient is a lateral recumbent position a manometer can
be attached for opening pressure reading (** the patient’s legs should be
straightened prior to checking opening pressure)
Collect around 3-4mL in each tube, if the flow is slow you can ask the patient to
Valsalva, rotate the needle 90 degrees to face cephalad, or have an assistant
press on the abdomen
Replace the stylet and remove the needle at the end, clean off the area, and
place a sterile dressing, and have the patient lay in a supine position for 1-2
Ruling out and/or determining the cause of meningitis, subarachnoid
hemorrhage, carcinamatous meningitis, inflammatory diseases
Determining an opening pressure e.g pseudotumour cerebri
Therapeutic intervention to reduce pressure for pseudotumour cerebri, TB
meningitis, cryptococcal meningitis etc.
Intrathecal administration of drugs (malignancy), contrast (myelogram), or
radioisotopes (CSF leak)
Consideration for spinal drain insertion
Elevated Intracranial pressure- head trauma, Intracranial mass (especially in the
posterior fossa)
Cutaneous infection overlying the site
Noncommunicating hydrocephalus
Coagulopathy (thrombocytopenia is relative contraindication though no trials
show increased risk of bleeding)
Uncal hernation
Epidural/perivertebral abscess
Paresthesias- temporary or permanent
Post lumbar puncture headache
Spinal or epidural bleeding (with some case reports of perforation of AVM’s)
Adhesive arachnoiditis
Late onset of epidermoid tumours to thecal sac
Back pain
 Making adjustments for opening pressures for sitting or in the flexed position in lateral
decubitus position has been attempted but most of these trials are small and in children
 1 small trial tried finding an adjustment for sitting versus lateral decubitus but this has
not been reproduced in larger trials
 General consensus at this time for opening pressure measurements is…
 Opening pressure is preferably taken in a lateral decubitus position with the legs
extended and head not flexed with the patient comfortable
 if anatomy precludes LP in lateral decubitus but opening pressure is critical: spinal
needle inserted in sitting position → needle withdrawn just out of thecal sac →
patient placed in relaxed, lateral decubitus position → needle readvanced slightly into
thecal sac.
 If opening pressure is > 35cm H20 then the needle should be removed immediately the
CSF from the manometer should be used for analysis and no further amount should be
 At opening pressures close to 35cm H20 the pressure should not be decreased by > 50%
to avoid risk of herniation
Addressed in 2001 trial at Yale-New Haven1. Trial enrolled 301 people, 78% of whom
underwent CT prior to lumbar puncture
Data was gathered about clinical features, socioeconomic background, and
immunocomprimising state
NIH stroke scale was used to monitor neurological function involving level or alertness,
answering questions, and neurological exam.
CT scan was obtained and was read by 2 neuroradiologist who did not know the clinical
The scan was read as normal, focal abnl +/- mass effect, or nonfocal abnl +/- mass
Only 3 scans had a disagreement between the 2 neuroradiologists, at which time a 3rd
radiologist was brought in
High risk features on CT included midline shift, loss of suprachiasmatic and basilar
cisterns, posterior fossa mass, loss of the superior cerebellar cistern, loss of the
quadrigeminal plate cistern
Of the 234 that underwent CT 56 were found to have abnormal findings, with only 4 showing
mass effect that prompted the clinician to avoid doing LP, 2 of whom died from herniation
(29 had focal lesion without mass effect, 12 nonfocal lesion without mass effect, 9 focal
lesion with mass effect [3 of whom had severe mass effect], 2 nonfocal lesions with mild
mass effect, 4 combination of focal and nonfocal lesions with no mass effect)
- Nonfocal abnl were hydrocephalus, meningeal enhancement, or subarrachnoid hemorrhage
- Focal abnormalities were mass lesion, stroke, or disease or periventricular white matter
Remaining 52 with abnormal results and underwent LP had 0 herniations 1 week out
Factors identified with highest risk ratio were age >60, immunocomprimised, h/o CNS
disease, seizure in the last week, alertness, answering questions, following commands, and
abnl neuro exam
Mean time of admission from patients undergoing CT versus not was longer at 5.3hr versus 3
hours with P<.001
Trend was longer of initiation of antibiotics with patients that had to wait for CT
Patient with no significant clinical features had negative predictive value on head CT of 97%,
of the three that were misdiagnosed only 1 had mild midline shift, but all 3 were tapped with
no complications
Within 12 hours of bleed 3 retrospective trials in the 90’s showed 100% sensitivity with CT scan, and 93% sensitivity
after 12 hours
- CT needs to be a thin cut CT which is properly aligned with the hard palate
- CT is limited by motion artifact, blood becomes more isodense at Hgb <10, blood and bone become hard to
differentiate in small hemorrhage, and time from onset of symptoms allowing dynamics of cerebrospinal fluid and
spontaneous lysis can result in the rapid clearing of subarachnoid blood
Literature is very sketchy on head to head trials and most is consensus agreement
LP per current guidelines are recommended in patient’s with negative, equivocal, or technically inadequate head CT’s
when clinical suspicion is very high
Furthermore a negative head CT and negative lumbar puncture
Furthermore there is no clear consensus on if xanthochromia or non clearing bloody tap/erythrophagocytosis is better
for determining presence of subarrachnoid hemorrhage , as the former is complicated by in vitro lysis of cells or too
early to present the latter is complicated by traumatic tap
Consensus is that if either is present and clinical suspicion is high enough that a tap has either xanthochromia or non
clearing blood a more dedicated vascular imaging
- Atypical headache, severe/sudden headache, seizures, focal neurological sx’s, high risk history (smoker, etoh use,
HTN, connective tissue dz, polycystic kidney dz, sickle cell, alpha 1 antitrypsin)
This is has further been validated by several trials in annals of emergency medicine in 2008 which found a sensitivity
of 100%, specificity of 68%, PPR of 3.03, and NPR of 0 from a negative head CT and lumbar in excluding a diagnosis
of subarachnoid hemorrhage
Gram stain: Sensitive in 60-80% of bacterial meningitis and 40-60% range in partially
treated bacterial meningitis
Protein - can be adjusted to RBC by decreasing protein concentration by 1 mg/dL or .01g/L
for every 1,000 RBC/mm3 but both levels have to be drawn from the same tube.
- Is the most sensitive indicator of intracranial pathology but not very sensitive. Also, normal
levels vary a lot from lab to lab.
Glucose- normally 60% of serum glucose, though in severe hyperglycemia this ratio breaks
down as CSF glucose levels do not exceed 300mg/DL
Various PCR’s have a very high sensitivity and specificity ratio usually in the 95-100% range
Antibodies have large degree of variability associated with disease process
Oligoclonal bands: Nonsensitive indicator of inflammation
14-3-3, tau >12,000 pg/mL, neuron-specific enolase >35ng/mL- CSF proteins for prion
- Of note the sensitivity of prion disease in 1 large trial with >1000 patients was 94% with a
specificity of 84%9
CSF LDH: Several trial have the shown the utility of CSF LDH in not only
determining the prognosis of treatment
• CSF levels > 35 has a high negative predictive value of ruling out aseptic
meningitis and a 75% positive predictive value of encephalitis10
• CSF LDH can’t help determine between pyogenic and TB meningitis
• Few trials looked at CSF LDH and reponse to chemotherapy or progression of
leptomeningeal disease11
CSF cryptococcal Ag: 94% sensitivity, titers can not be used to guide fungal
therapy, higher initial titers have poor prognosis as expected
Characteristic CSF findings are elevated WBC with lymphocyte predominance with elevated protein and low
serum glucose, in the right clinical setting.
Difficult area as the gold standard has always been culture which has required four large taps of 15mL of
CSF per tap with results needing 4-8 weeks with only sensitivity at 86% despite all this, this further
increased if staining is only done on CSF sediment
TB PCR has shown some promise with a high specicity of 86%; however, continues to have a sensitivity of
50%, though recently developed PCR using several genes for amplification have brought this up to 85%,
though these are currenlty in trials.7
Negative CSF examination for acid-fast bacilli or M. tuberculosis DNA neither excludes the diagnosis of TBM
nor obviates the need for empiric therapy if the clinical suspicion is high
CSF chloride was classically used as a marker for TB meningitis, where depressed values were considered
pathognomonic. However, numerous trials of shown that it is more a reflection of serum chloride levels and
depletion is more due to dehydration from frequent vomiting due to high ICP then any part of the actual
disease process
CSF adenosine deaminase: Meta analysis showed that ADA can not help differentiate between TB
meningitis and bacterial meningitis but a range in the values help increase the probability of the patient
having TB meningitis. Ranges identified in the meta analysis include levels of 1-4U/L w/ sensitivity of > 93%
and specificity of <80% in excluding TB. Values between 4-8 could not provide help. Values > 8 had a
sensitivity of <59% and specificity of >96% in improving the diagnosis of TB.
Causes for tapping patient’s with neurosyphilis- High RPR titers, Signs or symptoms of
neurosyphilis, immunocomprimised state, or congenital syphilis
The serum VDRL is positive in 72% of patients with primary syphilis, nearly 100% of
patients with secondary syphilis, 73% of patients with latent syphilis, and 77% of
patients with tertiary syphilis.
Estimates of a negative CSF VDRL in the setting of neurosyphilis are unknown but
expected to be > 25%.
Treponema Ab test are unable to used because any minute contamination will cause
false positive along with IgG passing through the blood brain barrier.
Current thought process, especially in setting of HIV is
- Definite neurosyphilis: Positive serology FTA Abs, MHA-TP + CSF VDRL
- Probable neurosyphilis: Positive serology – CSF VDRL with (CSF monos > 10 or protein
>60) and neurological symptoms
- Possible neurosyphilis: Positive serology – CSF VDRL with (CSF monos > 10 or protein
>60) but no neurological symptoms
Rodrigo Hasbun, M.D., James Abrahams, M.D., James Jekel, M.D., and Vincent J. Quagliarello, M.D. (12/13/01). Computed Tomography of
the Head before Lumbar Puncture in Adults with Suspected Meningitis. N Engl J Med 2001; 345:1727-1733. A
Perry JJ, Spacek A, Forbes M, Wells GA, Mortensen M, Symington C, Fortin N, Stiell IG. Is the combination of negative computed tomography
result and negative lumbar puncture result sufficient to rule out subarachnoid hemorrhage? Ann Emerg Med. 2008 Jun;51(6):707-13.
Arendt , Katherine. (11/2009). Atraumatic Lumbar Puncture Needles- After All These Years, Are We Still Missing the Point?. The Neurologist
• Volume 15, Number 1, 17-20.
Elias J, De Coning JP, Vorster SA, Joubert HF. The rapid and sensitive diagnosis of tuberculous meningitis by the detection of tuberculostearic
acid in cerebrospinal fluid using gas chromatography-mass spectrometry with selective ion monitoring. Clin Biochem. 1989 Dec;22(6):463-7.
Grace E. Marx 1 and Edward D. Chan. Tuberculous Meningitis: Diagnosis and Treatment Overview. Tuberc Res Treat. 2011; 2011: 798764.
8), Neurosyphilis, 12/12/12 6:10PM.
I. Zerr, MD, M. Pocchiari, MD, S. Collins, MD.
T. John*, C. Ittycheria, J. George, C. Jacob, A. Jacob, A. George. CSF LDH estimation to differentiate pyogenic and viral meningitis and its role
in tuberculous meningitis..
Twijnstra Albert, Zanten, Anton. Serial lumbar and ventricle CSF LDH activities in patients with leptomeningeal disesae from solid and
haemotological disease. Journal of neurology 1987;50(3) 313-320.
Spinello Antinori*, Anna Radice and Laura Galimberti.
Analysis of EEG and CSF 14-3-3 proteins as aids to the diagnosis of Creutzfeldt–Jakob disease. Neurology
September 26, 2000 vol. 55 no. 6 811-815.
The Role of Cryptococcal Antigen Assay in Diagnosis and Monitoring of Cryptococcal Meningitis . J. Clin.
Microbiol. November 2005 vol. 43 no. 11 5828-5829