Transcript Lumbar Puncture

Lumbar Puncture
Bucky Boaz, ARNP-C
CSF Formation
140 ml spinal and
cranial CSF
30 ml in the spinal cord
Production is approx.
0.35 ml/min
Net flow out of
ventricles 50 – 100
ml/day
Reduces brain weight
from 1400 to 50g.
Indications for Lumbar
Puncture
Primary indication for emergent spinal
tap is possibility of CNS infection
The second indication for an emergent
spinal puncture is a suspected
spontaneous subarachnoid
hemorrhage.
Infectious Indications
Fever of unknown origin
Children 1mo to 3yrs: fever,
irritability, and vomiting.
Cannot comfort child
Over age 3yrs: nuchal
rigidity, Kernig’s sign, and
Brudzinski’s sign
Petechial rash in a febrile
child
Partially treated children are
less likely to be febrile or
exhibit an altered mental
status
Subarachnoid
Hemorrhage
Diagnosis usually made by CT scan or by
blood in CSF.
Initial presentation: CT 92-98% accurate
Later than 24 hr presentation: 76% accurate
20-60% of aneurismal subarachnoid
hemorrhage will have “sentinel thunderclap”
or “warning clap”
After initial leak, CT is usually negative
Contraindications for LP
Absolutely contraindicated in the
presence of infection in the tissues near
the puncture site.
Relatively contraindicated in presence
of SOL or increased ICP
Caution advised when lateralizing signs
or signs of uncal herniation.
Equipment
Spinal needle



Less than 1 yr: 1.5in
1yr to middle childhood:
2.5in
Older children and
adults: 3.5in
Three-way stopcock
Manometer
4 specimen tubes
Local anesthesia
Drapes
Betadine
Interpretations
Pressure
Opening pressure is taken promptly,
avoiding falsely low values due to leakage
through and around the needle
 Normal pressure is between 70 and 180
mm H20

Interpretation
Appearance
If CSF is not crystal clear, a pathologic
condition of the CNS should be suspected
 Compare fluid to water
 Fluid may be clear with as many as 400
RBCs/mm3 and 200 WBCs/mm3

Interpretation
Cells



WBC counts over 5 cells/mm3 should be taken to
indicate the presence of pathologic condition
Polymorphonuclear leukocytes are never seen in
normal adults
Neutrophilic pleocytosis is commonly associated
with bacterial infections or early stages of viral
infections, tuberculosis, meningitis, hematogenous
meningitis, and chemical meningitis due to foreign
bodies.
Interpretation
Cells


Eosinophils are always abnormal and most
commonly represent a parasite infestation.
Eosinophils have also been reported in cases of
subarachnoid hemorrhage, lymphoma, Hodgkin’s
disease, brucellosis, fungal meningitis,
mycoplasma pneumonia infection, measles,
lymphocytic choriomeningitis, rickettsial infections,
leukemia, demyelinating disease, sarcoiodosis,
acute inflammatory demyelinating polyneuropathy,
allergic reactions, and idiopathic eosinophilic
meningitis.
Interpretation
Cells
Normal CSF RBCs are less than 10/mm3.
 Counts that are otherwise unexplained
may be due to a traumatic tap.
 Herpes simplex virus encephalitis may
elevate the CSF RBC count in many
patients.

Interpretation
Glucose
Low CSF glucose concentration indicates
increased glucose use in the brain and the
spinal cord.
 The normal range of CSF glucose is
between 50 and 80 mg/dl
 60-70% of serum glucose concentration
 Only low concentrations of glucose are
significance

Interpretation
Low CSF Glucose Syndromes
Bacterial meningitis
Syphilis
Tuberculous meningitis
Chemical meningitis
Fungal meningitis
Subarachnoid meningitis
Sarcoidosis
Mumps meningitis
Meningeal
carcinomatosis
Herpes simplex
encephalitis
Amebic meningitis
Hypoglycemia
Cysticercosis
Trichinosis
Interpretation
Protein
Increase in CSF total protein levels are a
nonspecific abnormality associated with
many disease states.
 Levels > 500mg/dl are uncommon and are
seen mainly in meningitis, in subarachnoid
bleeding, and with spinal tumors.

The Traumatic Tap
It should not be difficult to distinguish
between subarachnoid hemorrhage and
a traumatic tap.
In traumatic taps, the fluid generally
clears between 1st and 3rd tubes.
CSF Analysis with
Infections
Bacterial Infections





The Gram stain is of great importance, because
this often dictates the initial choice of antibiotic.
Gram-negative intracellular or extracellular
diplococci are indicative of Neisseria meningitidis
Small Gram-negative bacilli may include
Haemophilus influenza, especially in children.
Gram-positive cocci indicates Streptococcus
pneumoniae, other Streptococcus species, or
Staphylococcus.
20% of Gram stains may be falsely negative.
CSF Analysis with
Infections
Bacterial Infections



While the culture is pending, one may suspect a
bacterial infection in the presence of an elevated
opening pressure and a marked pleocytosis
ranging between 500 and 20,000 WBCs/mm3.
The differential count is usually chiefly neutrophils.
A count above 1000 cells/mm3 seldom occurs in
viral infections.
CSF Analysis with
Infections
Bacterial Infections
CSF glucose levels less than 40 mg/dl or
less than 50% of a simultaneous blood
glucose level should raise the question of
bacterial meningitis.
 The CSF protein content in bacterial
meningitis ranges from 500 to 1500 mg/dl.

CSF Analysis with
Infections
Viral Studies

The organisms most commonly isolated in
viral meningitis are enteroviruses and
mumps.
Enteroviruses: summer and fall
 Mumps: winter and spring

CSF Analysis with
Infections
Viral Studies
WBC count in viral meningitis and
encephalitis usually: 10 to 1000 cells/mm3.
 The differential count is predominantly
lymphocytic and mononuclear in type.
 Protein levels are usually mildly elevated
 Antibiotic coverage pending culture results
may be reasonably initiated pending
culture results if in doubt.

Complications
Headache After
Lumbar Puncture




Most common
complication
Occurs 5-30% of all
spinal taps
Usually starts up to
48 hours after to
procedure.
Usually lasts 1-2
days (occas 14 days)
Complications
Headache After Lumbar Puncture
Usually begins within minutes after arising
and resolves with recumbent position.
 Pain is mild to incapacitating and is usually
cervical and sub-occipital, but may involve
the shoulders and the entire cranium.
 Caused by leaking of fluid through dural
puncture site.

Complications
Headache After Lumbar Puncture
Incidence is higher in younger patients and
females, and those with headache history.
 Treatment: barbiturates, fluids, caffeine
(500mg in 2 ml NS IV push) more common
500mg in 2 L over 1 hr.
 Blood patch by anesthesia if no
improvement.

Procedure
Performed with the
patient in the lateral
recumbent position.
A line connecting the
posterior superior iliac
crest will intersect the
midline at approx. the
L4 spinous process.
Spinal needles entering
the subarachnoid space
at this point are well
below the termination of
the spinal cord.
Procedure
In the adult, the spinal cord
extends to the lower level
of L1 or the body of L2.
LP in adults and in older
children may be performed
from L2 to L3 interspace to
the L5 to S1 interspace.
At birth, the cord ends at
the level of L3.
LP in infant may be
performed at the L4 to L5
or L5 to S1 interspace.
Procedure
Almost all patients are afraid of an LP.
Explaining the procedure in advance
and discussing each step aids in
reducing anxiety.
Inquire about allergies to anesthetics.
Informed consent.
Procedure
Position the patient:




Generally performed in
the lateral decubitus
position.
A pillow is placed under
the head to keep it in the
same plane as the spine.
Shoulders and hips are
positioned. perpendicular
with the table.
Lower back should be
arched toward
practitioner.
Procedure
Sterile gloves MUST be used.
Wash back with antiseptic solution.
Sterile towel under hips.
The skin and deeper subcutaneous
tissue are infiltrated with local
anesthetic.
Warn patient of transient discomfort of
anesthetic.
Procedure
Anesthetizing the deeper subcutaneous
tissue significantly reduces the
procedure discomfort.
Some operators not only anesthetize
the interspinous ligament but also apply
local anesthesia in a vertical fanning
distribution on both sides of the spinous
processes near the lamina.
Procedure
The patient should be told to report any
pain and should be informed that he or
she will feel some pressure.
The needle is placed into the skin in the
midline parallel to the bed.
The needle is held with both thumbs
and index fingers.
Procedure
After the subcutaneous tissue has been
penetrated, the needle is angled toward
the umbilicus.
The bevel of the needle should be
facing laterally (toward patients side).
Procedure
a.
b.
c.
Ligament flavum is a
strong, elastic, yellow
membrane covering the
interlaminar space
between the vertebrae.
Interspinal ligaments join
the inferior and superior
borders of adjacent
spinous processes.
Supraspinal ligament
connects the spinous
processes
Procedure
The ligaments offer resistance to the
needle, and a “pop” is often felt as they
are penetrated.
Clear fluid will flow from the needle
when the subarachnoid space has been
penetrated.
Procedure
If bone is encountered,
withdrawal into
subcutaneous tissue
and redirect.
Attach a manometer
and record opening
pressure.
Turn stopcock and
collect fluid.
Withdrawal needle and
place a dressing.
Procedure
Tube 1 is used for determining protein
and glucose
Tube 2 is used for microbiologic and
cytologic studies
Tube 3 is for cell counts and serologic
tests for syphilis
Questions?