LUMBAR PUNCTURE
Indications
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Suspected meningoencephalitis
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Suspected subarachnoid hemorrhage despite negative CT
Contraindications
Risk for cerebral herniation:
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Altered mentation
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Focal neurologic signs
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Papilledema
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Seizure within the previous week
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Impaired cellular immunity
Other:
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Infected skin over the needle entry site
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Coagulopathy (e.g. anticoagulant or antiplatelet use, renal failure) is a relative contraindication
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Prior
Prepare the Patient
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Inform the patient about the procedure
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Position the patient in the lateral recumbant or sitting position with the hips, knees and chin flexed towards the chest
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Identify the L3-L4 interspace which is at the level of the posterior superior iliac crests. Identify the L2-L3 interspace and the L4-L5 interspace. Mark the interspace which is widest.
Prepare the Equipment
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Mentally rehearse the procedure steps and assemble the necessary equipment
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Procedure
Sterilize and Drape
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Don sterile gloves
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Clean the skin over the L2-L4 area using antiseptic solution
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Place sterile drapes around the work area
Analgesia
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Administer local anesthetic under the surface of the skin at the target site +/- anesthetize the deeper tissue
Needle Insertion
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Insert the spinal needle, with the bevel parallel to the spine, at a slightly cephalad angle, aiming towards the umbilicus, and advance the needle approximately 3-4 cm.
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Remove the stylet and check for fluid return; if no fluid i obstained, replace the stylet, advance a few millimeters and repeat the process until CSF is obtained.
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Attach the manometer and note the height of the fluid column. The patient’s legs should be straightened during pressure measurement.
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Collect cerebrospinal fluid in each of 4-5 tubes (10 drops – 1 ml in each tube)
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Replace the stylet and remove the needle
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Apply a sterile dressing
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Post
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Cerebrospinal Fluid Analysis depending on the context:
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Cell count and differential (first and the last tube)
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Glucose and protein levels
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Direct microscopy, Gram stain, bacterial cultures, PCR for HSV etc.
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Spectrophotometry if the setting of suspected subarachnoid hemorrhage