Details about Lumbar Puncture

1. LUMBAR PUNCTURE
(Lumbar)
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2. Indication
• Diagnosis :
– CNS infection, eg. meningitis, encephalitis and CNS syphilis
– Subarachnoid hemorrhage (SAH)
– Normal pressure hydrocephalus
• Evaluation and diagnosis of demyelinating or
inflammatory CNS processes
– Multiple sclerosis
– Guillain-Barré syndrome
– Paraneoplastic syndromes
• Infusion of anesthetic, chemotherapy, or contrast
agents into the spinal canal
• Treatment of idiopathic intracranial hypertension
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3. Contraindication
1. Idiopathic or Suspicion of increased ICP d/t cerebral
mass
• Brain tumor
• Cerebral hemorrhage
• Abscesses
• Epidural or subdural hematomas
– Rationale: LP in increased ICP may cause uncal herniation
– Exception: Therapeutic use of LP to reduce ICP
– Precaution
• CT brain is advocated by some, especially in the following
situations
– Age >65
– Reduced GCS
– Recent history of seizure
– Focal neurological signs
• Ophthalmoscopy for papilledema
Signs of Increase ICP:
• Decreased levels of consciousness
• Focal neurological signs
• Papilloedema
Low-pressure shunt is formed LP site
where CSF can escape. As the CSF
pressure drops in the spinal column,
CSF and brain mass may then shift
towards the low-pressure outlet (the LP
site). This cause either trans-tentorial
or uncal herniation & acute
neurological deterioration.
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5. Increase ICP
Mass effect
Obstruction
to CSF flow or
absorption
Generalized
brain swelling
Increase in
Venous
pressure
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6. 2. Bleeding diathesis
• Uncorrected Coagulopathy
• Clotting defects such as disseminated intravascular coagulation, hemophilia
or thrombocytopenia (<50 x 109/L)
• Heparin, Warfarin
– Reversal of warfarin with Vitamin K or fresh frozen plasma
– Replacement of a hemophiliac's clotting factors
– Transfusion of platelets to the thrombocytopenic patient
3. Skin infection
– Skin infection near the site of the lumbar puncture > increases the risk
of carrying the infection into the CSF with the LP needle >sepsis
4. Abnormal respiratory pattern
5. Hypertension with bradycardia and deteriorating consciousness.
6. Vertebral deformities (scoliosis or kyphosis),
7. Acute spinal trauma
8. Obtunded state with poor peripheral perfusion or hypotension
9. Seizures-prolonged or recent (within 30 minutes)
10. Inexperienced physician
Tr(x) for safe LP
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7. Anatomy
• At birth inferior end of the spinal cord is opposite the
body of the third lumbar vertebrae (L3)
• As the child grows, the vertebral column grows much
faster than the spinal cord itself.
• Adulthood  the spinal cord only reaches the inferior
border of the L1 vertebra, or the superior aspect of L2. In
order to avoid transfixing the spinal cord during LP, the
needle is placed distal to L2. This means the needle
enters the subarachnoid space at the level of the mobile
cauda equina.
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10. WHERE TO INSERT THE NEEDLE ??
• The imaginary line that crosses the lumbar
region of the back joining the posterior superior
iliac crests will cross the L3-L4 interspace
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11. • The tissues pierced are (in order): skin, subcutaneous
tissue, supraspinal ligament, interspinal ligament,
ligamentum flavum, dura mater, the arachnoid mater
and into the subarachnoid space.
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12. THE LP KIT
• three cleaning sponges
• a 20 gauge spinal needle
• a 25 gauge and a 20 gauge needle for anesthetic
infiltration
• a 3cc syringe
• a vial of 1% lidocaine for anesthesia
• a pressure manometer with tubing
• four collection vials and a Band-Aid.
The other tools you may need include sterile gloves,
gown, proviodine cleaning solution
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13. Equipments
A spinal or lumbar puncture tray should
include the following items:
• Sterile dressing
• Sterile gloves
• Sterile drape
• Antiseptic solution with skin swabs
• Lidocaine 1% without epinephrine
• Syringe, 3 mL
• Needles, 20 and 25 gauge
• Spinal needles, 20 and 22 gauge
• Three-way stopcock
• Manometer
• Four plastic test tubes, numbered 1-
4, with caps
• Syringe, 10 mL (optional)
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15. Patient Preparation
• Local anesthesia is
employed for lumbar
puncture
• The patient is placed in
the lateral recumbent
position with the hips,
knees, and chin flexed
toward the chest so as to
open the inter-laminar
spaces or interspinous
distance
• A pillow may be used to
support the head
• Inter-laminar space
• Inter-spinous diameter
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16. Lateral Decubitus Position
• Apply topical anesthetic 30-45 min prior to procedure
• Spinal cord ends at L1-L2, so sites for puncture are located at
L3-L4 or L4-L5
• Restrain patient in lateral decubitus position
– Maximally flex spine without compromising airway
– Keep alignment of feet, knees and hips
– Position head to left if right handed or vice versa

17. Sitting Position
• Restrain infant in the seated
position with maximal spinal
flexion
– Hold infant’s hands between flexed
legs with one hand and flex head
with the other hand
• Drape patient below buttocks and
fenestrated drape opening over
puncture site
• Insert needle so bevel is parallel to
spinal cord (Bevel left or right)
• Cannot measure pressure
accurately in this position

18. Paramedian (Lateral) Approach
• Use for patients who
have calcifications
from repeated LPs or
anatomic
abnormalities
• Needle passes
through erector
spinae muscles, and
ligamentum flavum
– Bypasses supraspinal
and interspinal
ligaments
• Less incidence of
spinal headache

19. Equipment
• Spinal needle,
usually 22 gauge
– 1.5 in for < 1 yr
– 2.5 in for 1 year to
middle childhood
– 3.5 in for older
children and
adolescents
– Larger for large
adolescents
• Atraumatic needles,
less spinal
headaches

20. Procedure
• Cleanse skin with povidone iodine from puncture
site radially out to 10 cm and ALLOW TO DRY
• Drape below patient and around site with
fenestrated drape
• Anesthetize with lidocaine if topical not used by:
– Intradermally raising a wheal at needle insertion site
– Advance needle through wheal to desired interspace
• Careful not to inject into a blood vessel or spinal canal
• Insert spinal needle with stylet with bevel up to
keep cutting edge parallel with nerve and
ligament fibers
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21. Procedure
• Aim towards umbilicus directing
needle slightly cephalad
• Hold needle firmly

22. Procedure
• A “pop” of sudden
decrease in
resistance
indicates that
ligamentum
flavum and dura
are punctured
• Remove stylet and
check for flow of
spinal fluid

23. Procedure
• If no fluid, then:
– Rotate needle 90°
– Reinsert stylet and advance needle slowly checking
frequently for CSF
• Jugular vein compression can increase CSF pressure in
low flow situations
• If bony resistance is felt immediately then you are not
in the spinal interspace
• If bony resistance is felt deeply, then withdraw needle
to the skin surface and redirect more cephalad and
increase patient flexion
• If bloody fluid that does not clear or that clots results,
then withdraw needle and reattempt at a different
interspace
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24. Manometry
• When CSF flows, attach manometer to obtain
opening pressure if desired
• Pressure can only be accurately measured in
lateral decubitus position and in the relaxed
patient
• Attach manometer with a 3-way stopcock
when free flow of CSF is obtained
• Read column when highest level is achieved
and respiratory variation is noted
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25. PROCEDURE
1. Positioning
2. Landmark
LP site
3. Marking LP
site
4. Tray opening
& set-up
5. Prep &
drape
6. Cutaneous
anaesthesia
7. Deep
anaesthesia
8. Lumbar
puncture
9. Attach
manometer
& obtain
opening
pressure
10. Collect
CSF
11. Finishing
up
 
 
 
 


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26. What to do with the CSF ??
• The recommended studies include (this order can be
changed): Collect 1ml of CSF in each of vials
o Tube#1 : Gram stain, Culture and Sensitivity
o Tube#2 : Glucose, Protein
o Tube#3 : Cell Count and Differentials
o Tube#4 : Any special studies you require
(fungal/viral/chemical studies)
• Check closing pressure with manometer, if desired
• Reinsert stylet and remove needle in one quick motion
• Cleanse back and cover puncture site
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27. Opening pressure 90-180 mm H2O / 6.6 – 13.2 mmHg (with
patient lying in lateral position)
Appearance and color Clear, colorless
Blood cell count and differential • White blood cells: < 5 (all mononuclear)
• Red blood cells: 0
Glucose 2.8 – 4.4 mmol/L, 50 - 80 mg/dL (or greater than
two-thirds of blood glucose)
Total protein 15-45 mg/dL
Bacteria (Gram stain, culture, VDRL) Negative
pH 7.28-7.32
Antibodies, viral DNA None
Lactate dehydrogenase (LDH) < 2.0-7.2 U/mL
Lactate • Newborns 10-40 mg/dL
• Older children and adults 10-25 mg/dL
Chloride 110-125 mmol/L
Cancerous cells None
Cryptococcal antigen None
Glutamine 6-15 mg/dL
Normal CSF Parameter
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28. CSF Analysis
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30. Study
Bacterial
Meningitis
Viral Meningitis SAH
Opening
Pressure
Often elevated
Normal to mildly
elevated
Often elevated
Appearance Clear to turbid Often clear Clear to bloody
Xanthochromia Negative Negative Often present
RBC's <5 per mm3 <5 per mm3 >50 per mm3
WBC's
Elevated. Many
PMNs
Elevated. Many
lymphocytes
Slightly increased
Glucose Low Normal Normal
Protein Elevated Elevated Elevated
Gram Stain
May show
organisms
Normal Normal
A review of the CSF values in common disorders shows:
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32. Conditions associated with a reactive CSF lymphocytosis include the
following:
• Meningitis
• Syphilitic meningoencephalitis
• Parasitic CNS infection
• Multiple sclerosis
• Guillain-Barré syndrome
• Polyneuritis
Conditions associated with CSF monocytosis include the following:
• Chronic or treated bacterial meningitis
• Syphilitic, viral, fungal, amebic meningitis
• Intracranial hemorrhage
• Cerebral infarct
• CNS malignancy
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33. Conditions associated with increased CSF polymorphonuclear neutrophils
include the following:
• Bacterial meningitis
• Acute viral meningitis
• Tuberculous and fungal meningitis
• Amebic encephalomyelitis
• Brain abscess
• Subdural empyema
• CNS hemorrhage
• Cerebral infarct
• Malignancies
• Previous lumbar puncture
• Intrathecal chemotherapy
• Seizure
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34. Complication of Lumbar Puncture
1. Post LP headache (most common)
• Usually begins 24-48 hours after the procedure
• Probable etiology is continued leakage of CSF
• Bilateral pressure or throbbing that is intensified in the upright position
• Self-limited (≤7 days), uncommon less than 10 yo
2. Post LP back pain
• Occasionally with short-lived referred limp
• Disc herniation if needle advanced too far
3. Bloody tap / Dry tap
• Bloody: Micro-trauma caused by spinal needle
• Dry: misplacement, dehydrated patient (low csf)
4. Infection to the CSF
• Can occur with breaks in sterile technique, use of contaminated equipment
and placement of the needle through infected skin
• Cellulitis, skin abscesses, epidural abscesses, spinal abscesses
5. Hemorrhage (low platelets counts /coagulopathies)
6. Dysesthesia (impairement of sensation)
7. Post–dural puncture cerebral herniation (most serious but very rare)
• risk of herniation is 0 –5 % in those patients who are known to have
intracranial masses
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35. Spinal Headache
• Most common complication
• Risk factors:
– female
– age 18-30
– lower BMI
– hx of Headache
– prior spinal headache
• Bilateral Headache, improves when supine
• Can last hours to weeks
• Treatment
– Supine position for at least 2 hours
– Hydration
– Caffeine either PO or IV
– Epidural blood patch
• Prevention:
– Can avoid by:
• Passing needle bevel parallel to longitudinal fibers of dura
• Replacing stylet before removing needle
• Using small diameter needles
• Using atraumatic needles
– Bed rest or PO intake after LP does not reduce incidence of headache
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36. Nerve Root Trauma/Irritation
• Can feel electric shocks or dysesthesias
• Back pain can persist for months
– Consider disc herniation
• Rarely permanent
• Withdraw needle immediately
• If pain or motor weakness persists, start
corticosteroids
• Electromyogram/nerve conduction velocity
studies should be scheduled if pain persists
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37. Herniation
• Manifests initially as altered mental status,
followed by cranial nerve abnormalities and
Cushing triad
• May be rapidly fatal.
• Immediately remove needle and raise the head of
bed to 30-45° improve venous return from the
brain.
• Mannitol or 3% Saline
• Intubate patient and hyperventilate
• Emergent neurosurgical consult
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38. Epidermal Inclusion Cyst
• Very rare due to use of stylet
• Occurs when a core of skin is driven into
spinal or paraspinal space with hollow needle
• Do not remove stylet until through the skin

39. Failure of Procedure
• If sample of CSF is critical several alternatives are
available:
– Have someone else try
• Anesthesia
• Neurology
– Bedside ultrasound for difficult LPs
– Radiographic guided procedure
• Fluoroscopy
• Ultrasound
• CT
– Cisterna Magna tap