1. Lumbar Puncture LP is an invasive procedure for obtaining CSF.
First reports of CSF is in Edwin-Smith Surgical Papyrus written 3700 yrs ago.
Hippocrates reported CSF presence in brain cavities, 4 centuries B.C.
Galen described ventricular cavities 2 centuries A.C.
In 1891 Heinrich Quincke, of Kiel, Germany, introduced this procedure as we know it today. His original intent was to help babies suffering from hydrocephalus by draining away excess fluid, but from the outset he was also interested in lumbar puncture's use as a diagnostic tool, & examined CSF for its pressure, sugar, protein, & cell count.
Widal introduced CSF cytological studies in 1901.

2. LUMBER PUNCTURE
A lumbar puncture (or LP, and colloquially known as a spinal tap) is a diagnostic and at times therapeutic medical procedure.
Diagnostically it is used to collect cerebrospinal fluid (CSF) to confirm or exclude conditions such as meningitis and subarachnoid hemorrhage and it may be used in diagnosis of other conditions.
Therapeutically it may be used to reduce increased intracranial pressure.
It is regarded as a safe procedure, but post-dural-puncture headache is common.
The procedure is typically performed under local anesthesia and aseptic technique.
A needle is used to access the subarachnoid space and fluid collected.
Fluid may be sent for biochemical, microbiological, and cytological analysis.

3. LUMBER PUNCTURE
Open the spinal tray, change to sterile gloves, and prepare the equipment.
Open the numbered plastic tubes, and place them upright.
Assemble the stopcock on the manometer, and draw the lidocaine into the 10-mL syringe.
Use the skin swabs and antiseptic solution to clean the skin in a circular fashion, starting at the L3-L4 interspace.
Just before applying the skin swabs, warn the patient that the solution is very cold; application of an unexpectedly cold solution can be unnerving for the patient.
Wearing nonsterile gloves, locate the L3-L4 interspace by palpating the right and left posterior superior iliac crests and moving the fingers medially toward the spine.
Palpate that interspace (L3-L4), the interspace above (L2-L3), and the interspace below (L4-L5) to find the widest space.
Mark the entry site with a thumbnail or a marker. To help open the interlaminar spaces, ask the patient to practice pushing the entry site area out toward the practitioner.

4. LUMBER PUNCTURE EQUIPMENT
Local anesthesia is employed for lumbar spine
The patient is placed in the lateral recumbent position with the hips, knees, and chin flexed toward the chest so as to open the interlaminar spaces.
A pillow may be used to support the head.
The sitting position may be a helpful alternative, especially in obese patients, because it makes it easier to confirm the midline.
In order to open the interlaminar spaces, the patient should lean forward and be supported by a Mayo stand with a pillow on it, by the back of a stool, or by another person.
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)

5. Indications for lumbar puncture
Urgent:
Suspected CNS infection (with the exception of brain abscess or a parameningeal process).
Suspected subarachnoid hemorrhage (SAH) in a patient with a negative CT scan.
Nonurgent
BIH (pseudotumor cerebri)
Carcinomatous meningitis
Tuberculous meningitis
Normal pressure hydrocephalus
CNS syphilis
CNS vasculitis
Conditions in which LP is rarely diagnostic but still useful include:
Multiple sclerosis
Guillain-Barré syndrome
Paraneoplastic syndromes
LP is also required as a therapeutic or diagnostic maneuver in the following situations :
Spinal anesthesia
Intrathecal chemotherapy
Intrathecal antibiotics
Injection of contrast media for myelography or for cisternography

6. Indications for CT prior to LP
Patients who are older than 60 years
Patients who are immunocompromised
Patients with central nervous system (CNS) lesions
Patients who have had a seizure within 1 week of presentation
Patients with an altered level of consciousness
Patients with focal findings on neurologic examination
Patients with papilledema seen on physical examination, with clinical suspicion of an elevated ICP

7. LUMBER PUNCTURE Contraindications
Idiopathic (unidentified cause) increased intracranial pressure (ICP)
Rationale: lumbar puncture in the presence of increased ICP may cause uncal herniation
Exception: therapeutic use of lumbar puncture to reduce ICP
Precaution
CT brain is advocated, especially in the following situations
Age >65
Reduced GCS
Recent history of seizure
Focal neurological signs
Papilledema
Bleeding diathesis
Coagulopathy
Decreased platelet count (<50 x 109/L)
Infections
Skin infection at puncture site
Sepsis
Abnormal respiratory pattern
Hypertension with bradycardia and deteriorating consciousness
Vertebral deformities (scoliosis or kyphosis), in hands of an inexperienced physician

8. Lumbar Puncture Procedure: Sitting Lying down L2/L3 level downwards
Needle between 2 spinal processes
30* cephalad direction
Beveled tip direction depends to the aim of LP

9. Lumbar Puncture

10. Lumbar Puncture

11. Lumbar Puncture

13. Lumbar Puncture
Quinke needles
Sprotte needle
Touhy needle

14. Lumbar puncture Technique
The patient is placed in a lateral position with the knees bent in full flexion up to the chest(fetal position) (sit and bend position also possible)
Clean off the skin preparation solution.
Introduction of 1% lidocain into the subcutaneous space
Insertion of a spinal needle into the subarachnoid space at the L3-L4 or L4-L5 interspinal spaces (inserted until the second “give”- subarachnoidal space).
Removal of the stylet of the needle in order to collect the fluid

15. LUMBER PUNCTURE
Apply a sterile dressing, and place the patient in the supine position.
If the CSF has been collected cytological, microbiological, biochemical studies are now performed.
Immunoglobulin titers may be obtained; the last are of special importance with diseases in which peripheral manifestations fade while central nervous system (CNS) symptoms persist
Different institutions have different protocols for the studies performed on the various CSF. The classic approach is to send the 4 CSF tubes for studies:
Tube 1 - Cell count and differential
Tube 2 - Glucose and protein levels
Tube 3 - Gram stain, culture and sensitivity (C&S)
Tube 4 - Cell count and differential

16. LUMBER PUNCTURE Xanthochromia
The best way of distinguishing RBs related to intracranial bleeding is to examine the centrifuged supernatant CSF for xanthochromia (yellow color).
Although xanthochromia can be confirmed visually, it is more accurately identified and quantified in the laboratory.
Xanthochromia may be produced by a very high serum bilirubin level (> 15 mg/dL), patients with severe hyperbilirubinemia. usually have been identified before lumbar puncture.
With this exception, xanthochromia in a freshly spun specimen is evidence of preexistent blood in the subarachnoid space.
Extremely high CSF protein level, as seen in Froin’ Syndrome, also renders the fluid xanthochromic, though without RBCs.

17. LUMBER PUNCTURE
Patients with aneurysmal leaks (e.g., sentinel hemorrhages) may present days after the onset of headache, and this increases the likelihood of a false-negative head CT scan.
In some cases, the CSF may be another color that strongly suggests a diagnosis. For example, pseudomonal meningitis may be associated with bright-green CSF.
Xanthochromia can persist for as long as several weeks after a subarachnoid hemorrhage (SAH). Thus, it has greater diagnostic sensitivity than computed tomography (CT) of the head without contrast, especially if the SAH occurred more than 3-4 days before presentation.

18. LUMBER PUNCTURE Glucose assessment
The CSF glucose level normally approximates 60% of the peripheral blood glucose level at the time of the tap.
A simultaneous measurement of blood glucose (especially if the CSF glucose level is likely to be low) is recommended.
A low CSF glucose level is usually associated with bacterial infection (probably due to enzymatic inhibition rather than to actual bacterial consumption of the glucose).
This finding is also seen in tumor infiltration and may be one of the hallmarks of meningeal carcinomatosis, even with negative cytologic findings.
A high CSF glucose level has no specific diagnostic significance and is most often spillover from an elevated blood glucose level.

19. LUMBER PUNCTURE
Cytological assessment
A larger-than-usual number of white blood cells (WBCs) suggests an infection or, more rarely, leukemic infiltration.
Bacterial infections are associated with a preponderance of polymorphonuclear leukocytes (PMNs).
Many cases of viral meningitis and encephalitis also show a high percentage of PMNs in the acute phase of the illness.
In addition, inflammation from any source (e.g., CNS vasculitis) can raise the WBC count.
A traumatic tap, of course, introduces WBCs and RBCs into the CSF.
An approximation of 1 WBC for every 1000 RBCs can be made, though a repeat tap may be preferable.
Multiple lumbar puncture examinations may be required in testing for leptomeningeal malignancies.
At least 3 negative cytologic evaluations (i.e., 3 separate samplings) are required to rule out leptomeningeal malignancy.

20. CSF analysis - Colour Crystal clear- normal finding, viral meningitis
Turbid- indicates the presence of >200WBC’s or >400 RBC’s, bacterial meningitis
Xantochromia- yellow, orange or pink discoloration (in more than 90% subarachnoid hemorrhages), physiologic in newborns
Yellow: RBC’s breakdown, high bilirrubin levels, high protein levels >150mg/dL , tubercular and fungal meningitis (viscous)
Pink: RBC’s breakdown
Orange: RBC’s breakdown; high carotenoid intake
Green: hyperbiliruminemia , purulent CSF,(bacterial meningitis)
Brown: meningeal melanomatosis

21. CSF analysis- cell count
Measured with a column manometer (fetal position is optimal)
Increased pressure:
Congestive heart failure
Cerebral edema 
Subarachnoid hemorrhage
Hypo-osmolality resulting from hemodialysis
Purulent or tuberculous meningitis
Hydrocephalus, or 
Pseudotumor cerebri.
Decreased pressure:
Complete subarachnoid blockage,
leakage of spinal fluid.
Severe dehydration,
Hyperosmolality, or circulatory collapse

22. CSF analysis- cell count
Normal cell count: < 5 WBC’s/mm in adults and < 20 WBC’s/mm in newborns (70% lymphocytes, 30% monocytes).
99% of patients with bacterial meningitis have >100 WBC’s/mm (less than that is only common for viral meningitis)
Viral meningitis: predominance of lymphocytes T
Bacterial meningitis: predominance of PMN’s
Fungal and tubercular meningitis: predominance of lymphocytes and high content of proteins, decrased glucose
RBC’s: abnormal finding(be careful with traumatic taps, 3 samples are needed)

23. CSF Interpretation of abnormal results
White cell count
Biochemistry
Neutrophils
(x 106 /L)
Lymphocytes
(x 106/L)
Protein
(g/L)
Glucose
(CSF:blood ratio)
Normal term
neonate 0*
 < 20
< 1.0
≥ 0.6 (or ≥ 2.5 mmol/L)
Bacterial meningitis
100-10,000
(but may be normal)
Usually < 100
> 1.0
< 0.4
Viral meningitis
Usually <100
0.4-1
Usually normal
TB meningitis
1-5
< 0.3
Gram stain may be negative in up to 60% of cases of bacterial meningitis even without prior antibiotics.
Neither a normal Gram stain, nor a lymphocytosis excludes bacterial meningitis.
Neutrophils may predominate in viral meningitis even after the first 24 hours.
CSF findings in bacterial meningitis may mimic those found in viral meningitis (particularly early on). It may be possible with modest accuracy to judge whether bacterial or viral is more likely based on CSF parameters. However if the CSF is abnormal the safest course is to treat as if it is bacterial meningitis.

24. Protein assessment
Assessment of CSF protein level can be a clue to otherwise unsuspected neurologic disease.
The high protein levels in
Demyelinating polyneuropathies
Postinfectious states, can be informative
Inflammatory diseases of CNS
A traumatic tap can introduce protein into the CSF.
An approximation of 1 mg of protein for every 750 RBCs may be used, but a repeat tap is preferable.

25. Antibiotics prior to lumbar puncture
CSF analysis – other tests
Antibiotics prior to lumbar puncture
Prior antibiotics usually prevent the culture of bacteria from the CSF.
Antibiotics are unlikely to significantly affect the CSF cell count or biochemistry in samples taken <24 hours after antibiotics.
Seizures
Recent studies support that seizures do not increase cell counts in the absence of meningitis.
PCR
PCR is routinely available for Neisseria meningitidis, Herpes Simplex and Enterovirus.
Help with decisions concerning discontinuing treatment.
Enterovirus PCR should be requested with clinical and/or CSF features of viral meningitis.
HSV PCR should be requested for patients with clinical features of encephalitis.
Meningococcal PCR is particularly useful in patients with meningococcal meningitis, but who have received prior antibiotics.

26. LUMBER PUNCTURE COMPLICATIONS
Possible lumbar puncture–related complications include the following
Post–spinal puncture headache
Bloody tap
Dry tap
Infection
Hemorrhage
Dysesthesia
Post–dural puncture cerebral herniation
Bloody tap
More than 50% of lumbar punctures are falsely positive for RBCs 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.

27. Dry tap LUMBER PUNCTURE COMPLICATIONS
Dry taps usually result from misplacement of the spinal needle. The most common mistake is a lateral displacement.
Can easily be corrected by withdrawing the needle completely, and reinserting the needle in the correct place and at the proper angle.
In obese patients, the regular spinal needle might be too short, in which case a longer one should be used.
If the patient is dehydrated, a falsely negative dry tap may be obtained as a result of very low CSF volume and pressure. If this is suspected, attempt to rehydrate the patient before the procedure

28. LUMBER PUNCTURE COMPLICATIONS
Post–spinal puncture headache
Headache is the most common complication of LP, observed in 20-70% of patients.
It usually begins hours after the procedure and is more common in young adults.
The probable etiology is continued leakage of CSF from the puncture site.
The headache is usually fronto-occipital and improves in the supine position.
This condition is usually self-limited (≤7 days) and responds to analgesics and caffeine ( mg every 4-6 hours).
Pencil-tip (Whitacre) needles are associated with a significantly lower incidence of post–spinal puncture headaches than are standard bevel-tip (Quincke) needles
Infection
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.

29. LUMBER PUNCTURE COMPLICATIONS
Hemorrhage
Epidural, subdural, and subarachnoid hemorrhage are rare complications that might carry significant morbidity and mortality in coagulopathic patients.
LP should be deferred in patients with:
Low platelets counts (< 50,000/µL)
Coagulopathies (e.g., hemophilia)
High[INR]) until the abnormality is corrected.
Dysesthesia
Irritation of nerves or nerve roots by the spinal needle can cause different lower-extremity dysesthesias.
To prevent this complication, always replace the stylet before moving the needle.
Post–dural puncture cerebral herniation
Cerebral herniation is the most serious complication of a lumbar puncture.
It is very rare.
There is increasing evidence that a diagnostic LP is safe in patients with increased ICP, such as most patients with meningitis.
There is no firm consensus regarding the safety of lumbar puncture in patients with undetrminedICP.
Avoid LP in (deteriorating LOC and brainstem signs including pupillary changes, posturing, irregular respirations, and very recent seizure.

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