Lumbar puncture

Dr. Mohamed Haseen BashaAssistant professor

( Paediatrics)Faculty of Medicine

Al Maarefa College of Science and Technology

CSF Pathway

Indications

• Diagnostic: Suspected Meningitis, Encephalitis, Brain abscess,

Subarachnoid hemorrhage, Gullain Barre Syndrome.

• Additional : Peudotumor cerebri

Intrathecal antibiotics

Chemotherapeutic agent instillation

Indications in < 1yr

• Sepsis evaluation – neonate

• Atypical febrile seizures

• Febrile children with suspected bacterimia

• Mental status change with no identifiable cause

Contraindications

• Increased intracranial tension

• Cardiac, Pulmonary instability

• Soft tissue infection over lumbar spine area

• Severe bleeding or clotting disorder

Equipments

• 20 gauge spinal needle

• Syringes and needles (22 and 25 gauge) for spinal anesthesia

• Manometer with stopcock

• Sterile drapes, gauzes, brushes and bandages for prepping skin

• Local anesthetic

LP needles & stylet separated

• a – Ligamentum flavum

• b – interspinous ligament

• c – supraspinous ligament

Anatomy

Normal CSF Values

• Appears to be clear and colorless

• Opening Pressure ~ 120 mm/H20

• Protein level ~ 35 mg%

• Glucose level ~ 60 mg % (60% of serum glucose)

• Cells < 5 lymphocytic/monocytic

CSF Profile’s

Pressure Cells Protein Glucose

Bacterial Meningitis

(PMN’s)

to

Viral Meningitis

N to

to (Mono’s)

N

Procedure:• Apply local anesthetic cream if available.

• Position child in either the sitting position or lateral recumbent position, with hips,

knees, and neck flexed. Keep shoulders and hips aligned (perpendicular to

examining table in recumbent position) to avoid rotating the spine.

• Locate the desired intervertebral space (either L3-4 or L4-5) by drawing an

imaginary line between the top of the iliac crests.

• Prepare the skin in sterile fashion. Drape conservatively to make monitoring the

infant possible.

• Use a 20G to 22G spinal needle with stylet (1.5 inch for children <12 years, 3.5

inches for children ≥12 years). A smaller-gauge needle will decrease the incidence

of spinal headache and CSF leak.

• Overlying skin and interspinous tissue can be anesthetized with 1% lidocaine using

a 25G needle.

• Puncture the skin in the midline just caudad to the palpated spinous process,

angling slightly cephalad toward the umbilicus.

• Advance several millimeters at a time, and withdraw stylet frequently to check for

CSF flow. Needle may be advanced without the stylet once it is completely through

the skin. In small infants, one may not feel a change in resistance or “pop” as the

dura is penetrated.

• If resistance is met initially (you hit bone), withdraw needle to the skin surface and

redirect angle slightly.

• Send CSF for appropriate studies .

first tube for culture and Gram stain,

second tube for measurement of glucose and protein levels,

last tube for cell count and differential.

An additional tube can be collected for viral cultures, polymerase chain

reaction (PCR), or CSF metabolic studies if indicated.

• If subarachnoid hemorrhage or traumatic tap is suspected, send the first

and fourth tubes for cell count, and ask the laboratory to examine the CSF

for xanthochromia.

• Accurate measurement of CSF pressure can be made only with the patient

lying quietly on his or her side in an unflexed position. It is not a reliable

measurement in the sitting position.

• Once free flow of spinal fluid is obtained, attach the manometer and

measure CSF pressure. Opening pressure is recorded as the level at which

CSF is steady.

Position of patient

Incorrect Correct

Lumbar puncture site in sitting position.

Lumbar puncture site in lateral (recumbent) position.

Painting area

Starting point of painting

Draping

Local anaesthesia

Needle entry

After care

• Position after LP: head low for 24 hr

• Sterile dressing

• Headeche: Analgesics

Complications

• Local Pain, • Infection,• Bleeding, • Spinal Fluid Leak,• Hematoma,• Spinal Headache, • Cerebral Herniation