Procedures: Lumbar Puncture

Lumbar punture

Indications

CSF evaluation
-Meningitis
-Subarachnoid Haemorrhage.
-Neoplastic disease

CSF drainage
-Communicating hydrocephalus
-Pseudotumour cerebri
-CSF leak

Intracranial pressure measurement
-Communicating hydrocephalus
-Pseudotumour cerebri

Intrathecal drug administration
-Radioopaque contrast
-Antibiotics
-Antineoplastic Chemotherapy


Contraindications
-Noncommunicating hydrocephalus
-Intracranial mass ( tumour, abscess , hematoma)
-Coagulopathy or platelets ( less than 50K)
-Cellulitis at intended puncture site
-Complete spinal block above tap site
-Tethered cord syndrome


Instruments

-Sterile prep solution.
-Sterile gloves and towels
-22-gauge needle and 25 gauge needle
-22 gauge, 20 gauge , or 18 gauge spinal needle with stylet
-CSF collection vials
-Manometer with stopcock

Procedure
-Apply sterile preparation solution to the lower back and cover the region with sterile drape.
-Identify the target interspace. L4-L5
-Inject 1ml of lidocaine through a a skin wheal with a 22 gauge needle.
-Insert the spinal needle.
-Will encounter slight resistant, then pop will be felt.
-Remove the stylet and observe the csf.
-Place stopcock on end of spinal needle with manometer.
-Open stopcock and measure csf pressure in cmh20.
-Collect csf sample in tubes.
-Csf sent for analysis.
-Replace stylet and withdraw needle.
-Place sterile gauze over puncture site.
-Changes in mental status, vital signs and reactivity must be carefully monitored.


Complications
Tonsillar herniation
-manifest as altered mental status, followed by cranial nerves abnormality. 3rd nerve and respiratory difficulties and cushing response.( hypertension bradycardia, respiratory depression. Maybe rapidly fatal.

-Immediately remove needle and raise the head of the bed to improve venous system return from the brain.

-Administer 1g/kg of mannitol intravenously

-Emergent neurosurgical consult

Nerve root injury
-Withdraw needle immediately
-If pain or motor weakness persists, starts corticosterois

Spinal headache
-Keep patient as supine as tolerated
-Usually resolves within hours but can persist for days

Aortic or arterial pressure
-Withdraw needle immediately and keep the patient supine for 4-6 hours while monitoring hemodynamics.
-Vascular surgery consult.

CSF findings.
Bacterial meningitis
-Turbid appearance
-Cells/ml- 200- 20, 000
-Cells predominantly neutrophils
-Protein > 45 mg/dl
-Gram stain positive


Tubercular meningitis

-Cob web appearance
-Cells/ ml- 100- 1000
-Cells predominantly lymphocytes
-Protein > 100 – 800mg/dl
-Gram stain negative

Indications

1. Suspected CNS infection
2. Suspected subarachnoid hemorrhage
3. Therapeutic reduction of cerebrospinal fluid (CSF) pressure
4. Sampling of CSF for any other reason
5. Infusion of anesthetic, chemotherapy, or contrast agents into the spinal canal


Contraindications


Absolute contraindications to lumbar puncture are as follows:


Unequal pressures between the supratentorial and infratentorial compartments, usually inferred by characteristic findings on the brain CT scan:

• Midline shift
• Loss of suprachiasmatic and basilar cisterns
• Posterior fossa mass
• Loss of the superior cerebellar cistern
• Loss of the quadrigeminal plate cistern
• Infected skin over the needle entry site

Relative contraindications to lumbar puncture are as follows:

• Increased intracranial pressure
• Coagulopathy
• Brain abscess

Instruments:

• Spinal or lumbar puncture tray (including the items listed below)
• Sterile gloves
• Antiseptic solution with skin swabs
• Sterile drape
• Lidocaine 1% without epinephrine
• Syringe, 3 mL
• Needles, 20 and 25 gauge (ga)
• Spinal needles, 20 and 22 ga
• Three-way stopcock
• Manometer
• Four plastic test tubes, numbered 1-4, with caps
• Sterile dressing
• Optional: Syringe, 10 mL

Positioning

• Position the patient in the lateral recumbent position with hips, knees, and chin flexed toward the chest in order to open the interlaminar spaces. A pillow can be used to support the head.

• The sitting position may be a helpful alternative position, especially in obese patients (easier to confirm the midline). In order to open the interlaminar spaces, the patient should lean forward and be supported by a Mayo stand or another person.

Method

• Mark L4,L5 or L3 intervertebral space by gentle indention of thumb nail on the overlying skin.
• Wash hands. Wear a mask and sterile glove.
• Sterilize the back with iodine
• Open the spinal pack. check manometer fittings. Have 3 sterile tubes and 1 flouride tube ready.
• Inject 0.25-0.5 ml of 1% lidocaine under skin on marked site.
• Wait 1 min, then insert spinal needle (22G stilette in place) through the mark aiming towards umbilicus. Feel resistence of spinal ligaments and then the dura, then a give as the needle enters the subarachnoid space.
• Withdraw stilette. wait for csf
• Measure csf pressure with manometer.
• Catch fluid in 3 sequentially numbered bottles (< 5-10 ml total)
• Remove needle and apply dressing.
• Lying flat for 1 hour is advised.

Complications

• Post–spinal puncture headache – This is the most common complication of lumbar puncture, observed in 20-70% of patients. It usually begins 24-48 hours after the procedure and is more common in young adults. The probable etiology is continued CSF leak from the puncture site. The headache is usually fronto-occipital and improves in the supine position. This condition is usually self-limited (up to 7 d) and responds to analgesics and caffeine (300-500 mg q4-6h). Severe cases can be treated with an epidural blood patch that should be performed by an anesthesiologist or a pain specialist.
• Bloody tap – More than 50% of lumbar punctures have falsely present red blood cells in the CSF as a result of microtrauma caused by the spinal needle. This is an uncomplicated occurrence in healthy patients with a normal coagulation system.
• Dry tap – Dry tap is usually a result of misplacement of the spinal needle. The most common mistake is a lateral displacement that can be easily corrected by complete withdrawal of the needle, reevaluation of the patient’s anatomy, and reinsertion in the correct place and angle. In obese patients, the regular spinal needle might be too short and a longer one should be used.
• Infections – Cellulitis, skin abscesses, epidural abscesses, spinal abscesses, or diskitis can result from a contaminated spinal needle. Adherence to sterile technique, including gloves, gowns, hair covers, and face masks as well as thorough skin cleansing and disinfecting, should minimize this risk.
• Hemorrhage – Epidural, subdural, and subarachnoid hemorrhage are rare complications that might carry significant morbidity and mortality in coagulopathic patients. Lumbar puncture should be deferred in patients with low platelets counts (<50,000) or patients with other coagulopathies (eg, hemophilia, supratherapeutic international normalized ratio [INR]) until the abnormality is corrected.
• Dysesthesias – Nerves/nerve root irritation by the spinal needle can cause different lower extremity dysesthesias. Withdrawing the needle without replacement of the stylet can cause aspiration of a nerve or arachnoid tissue into the epidural space. Always replace the stylet before moving the needle to prevent this complication.
• Postdural puncture cerebral herniation – This is the most serious complication of a lumbar puncture. This is a very rare complication and debate exists in the literature regarding whether the lumbar puncture or the underlying disease process is the cause of the herniation. The body of evidence that a diagnostic lumbar puncture is safe even in patients with increased intracranial pressure (most patients with meningitis) is increasing, but no consensus exists regarding the safety of lumbar puncture in patients with increased intracranial pressure.

CSF Analysis

Pyogenic Tuberculous
Appearance Often turbid Often fibrin web

Predominant cell Polymorphs Mononuclear

Cell count/mm3 90-1000+ 10-1000

Glucose < 1/2 plasma <1/2 plasma

Protein(g/l) >1.5 1-5

Organisms In smear and culture Absent in smear

INDICATIONS

1. Suspected CNS infection
2. Suspected subarachnoid hemorrhage
3. Therapeutic reduction of cerebrospinal fluid (CSF) pressure
4. Sampling of CSF for any other reason

CONTRAINDICATIONS

1. Local skin infections over proposed puncture site (absolute contraindication)
2. Raised intracranial pressure (ICP); exception is pseudotumor cerebri
3. Suspected spinal cord mass or intracranial mass lesion (based on lateralizing neurological findings or papilledema)
4. Uncontrolled bleeding diathesis
5. Spinal column deformities (may require fluoroscopic assistance)
6. Lack of patient cooperation

INSTRUMENTS

1. Lumbar puncture tray (to include 20 or 22 gauge Quinke needle with stylet, prep solution, manometer, drapes, tubes, and local anesthetic)
2. Universal precautions materials


Preprocedure patient education

1. Obtain informed consent
2. Inform patient of possibility of complications (bleeding, persistent headache, infection) and their treatment
3. Explain the major steps of the procedure, positioning, and postpocedure care


PROCEDURE

1. Assess indications for procedure and obtain informed consent as appropriate
2. Provide necessary analgesia and/or sedation as required
3. Position patient: lateral decubitus position with “fetal ball” curling up, or seated and leaning over a table top; both these positions will open up the interspinous spaces
4. Locate landmarks: between spinous processes at L4-5, L3-4, or L2-3 levels . On obese patients, find the sacral promontory; the end of this structure marks the L5-S1 interspace. Use this reference to locate L4-5 for the entry point. You will aim the needle towards the navel.
5. Prep and drape the area after identifying landmarks. Use lidocaine 1% with or without epinephrine to anesthetize the skin and the deeper tissues under the insertion site
6. Assemble needle and manometer. Attach the 3-way stopcock to manometer
7. Insert Quinke needle bevel-up through the skin and advance through the deeper tissues. A slight pop or give is felt when the dura is punctured. Angle of insertion is on a slightly cephalad angle, between the vertebra (Figure 3). If you hit bone, partially withdraw the needle, reposition, and re-advance

8. When CSF flows, attach the 3-way stopcock and manometer. Measure ICP…this should be 20 cm or less. Note that the pressure reading is not reliable if the patient is in the sitting position
9. If CSF does not flow, or you hit bone, withdraw needle partially, recheck landmarks, and re-advance
10. Once the ICP has been recorded, remove the 3-way stopcock, and begin filling collection tubes 1-4 with 1-2 ml of CSF each

Tube 1: glucose, protein, protein electrophoresis
Tube 2: Gram’s stain, bacterial and viral cultures
Tube 3: cell count and differential
Tube 4: reserve tube for any special tests

POST PROCEDURE CARE : After tap, remove needle, and place a bandage over the puncture site. Instruct patient to remain lying down for 1-2 hours before getting up

COMPLICATIONS: bleeding from puncture site, infection at puncture site, post-tap persistent headache


A. Meningitis

Bacterial Meningitis
Tuberculous Meningitis
Protein
Elevated
Elevated (extreme)1
Glucose
<50% blood glucose
<50% blood glucose
Cells
Poly's
Lymphs
+poly's
Other
Tests
Gram stain for
Culture
AFB Stain for
Culture
(20 ml CSF)
PCR

Lumbar Puncture

Indications:
1)Diagnostic
-Meningitis
-Encephalitis
-Subarachnoid hemorrhage
-Others eg. Multiplse sclerosis, neurosyphilis, sarcoidosis, neoplastic involvement, pyrexia of unknown origin etc

2)Therapeutic
-Intrathecal injection of contrast media and drugs
-Measurement and removal of CSF eg idiopathic intracranial hypertension

3)Spinal Anaesthesia

Contraindications:
-Suspicion of a mass lesion in brain or spinal cord
-Any causes of increase intracranial presuure
-Local infections at the site of puncture
-Congenital lesions in the lumbrosacral region
-Platelet count below 40 x 109/L
-Clotting disorder
-Spinal deformity

Materials:
1-Material for sterile technique(only gloves and mask are necessary)
2-Spinal Needle, 20 and 22-gauge
3-Manometer
4- Three-way stopcock
5-Sterile drapes
6-1% lidocaine without epinephrine in a 5-cc syringe with a 22 and 25-gauge needles
7-Material for skin sterilizationn
8- Adhesive dressing
9- Sponges - 10 X 10 cm

Procedures:
-Procedure should be explained carefully to the patient and consent has to be obtained
-Patient is placed on the edge of the bed in left lateral position with the knee and chin as close together as possible.
-Identify the 4th lumbar spine which corresponding to iliac crest
-Using sterile methods, 1% lignocaine is injected into dermis either the 3rd or 4th lumbar interspace.
-Spinal needle is pushed through the skin in the midline between L3 and L4
-When the needle is felt to penetrate the dura mater, the stylet is withdrawn and a few drop of CSF are allowed to escape
-CSF pressure can be measured by connecting a manometer to the needle.
-Specimens of CSF are collected in the 3 sterilized test tubes and sent to the lab.
-Record also the macroscopic appearance of the CSF: clear, cloudy, yellow or red.
-Patient is asked to lie flat after the procedure to avoid post-LP headache.

Postprocedure complications and care:

• Headache, prevent by post-LP rest and analgesic
• Spinal and epidural bleeding
• Trauma by spinal cord and spinal nerve root
• Introduce infection

A) Bacterial Meningitis
·*Physical characteristics: Yellowish and turbid
·Cytology (cells/microL) : Lymphocytes: 5-50; Polymorphs: 200-2000
·Proteins (g/L) : 0.5 - 2.0
·Glucose (mmol/L) : <2.0
·Stained deposit : Bacteria
·Culture : Positive

B) Tuberculous Meningitis
·Physical characteristics: Colourless, sometimes viscous or yellow
·Cytology (cells/microL) : Lymphocytes: 100-300; Polymorphs: 0-100
·Proteins (g/L) : 5.0-15
·Glucose (mmol/L) : <2.0
·Stained deposit : Tubercle bacilli in CSF in most cases
·Culture : Positive