1. Lumbar Puncture Bucky Boaz, ARNP-C

2. CSF Formation 140 ml spinal and cranial CSF 30 ml in the spinal cord Production is approx. 0.35 ml/min Net flow out of ventricles 50 – 100 ml/day Reduces brain weight from 1400 to 50g.

3. Indications for Lumbar Puncture Primary indication for emergent spinal tap is possibility of CNS infection The second indication for an emergent spinal puncture is a suspected spontaneous subarachnoid hemorrhage.

4. Infectious Indications Fever of unknown origin Children 1mo to 3yrs: fever, irritability, and vomiting. Cannot comfort child Over age 3yrs: nuchal rigidity, Kernig’s sign, and Brudzinski’s sign Petechial rash in a febrile child Partially treated children are less likely to be febrile or exhibit an altered mental status

5. Subarachnoid Hemorrhage Diagnosis usually made by CT scan or by blood in CSF. Initial presentation: CT 92-98% accurate Later than 24 hr presentation: 76% accurate 20-60% of aneurismal subarachnoid hemorrhage will have “sentinel thunderclap” or “warning clap” After initial leak, CT is usually negative

6. Contraindications for LP Absolutely contraindicated in the presence of infection in the tissues near the puncture site. Relatively contraindicated in presence of SOL or increased ICP Caution advised when lateralizing signs or signs of uncal herniation.

7. Equipment Spinal needle Less than 1 yr: 1.5in 1yr to middle childhood: 2.5in Older children and adults: 3.5in Three-way stopcock Manometer 4 specimen tubes Local anesthesia Drapes Betadine

8. Interpretations Pressure Opening pressure is taken promptly, avoiding falsely low values due to leakage through and around the needle Normal pressure is between 70 and 180 mm H 2 0

9. Interpretation Appearance If CSF is not crystal clear, a pathologic condition of the CNS should be suspected Compare fluid to water Fluid may be clear with as many as 400 RBCs/mm 3 and 200 WBCs/mm 3

10. Interpretation Cells WBC counts over 5 cells/mm 3 should be taken to indicate the presence of pathologic condition Polymorphonuclear leukocytes are never seen in normal adults Neutrophilic pleocytosis is commonly associated with bacterial infections or early stages of viral infections, tuberculosis, meningitis, hematogenous meningitis, and chemical meningitis due to foreign bodies.

11. Interpretation Cells Eosinophils are always abnormal and most commonly represent a parasite infestation. Eosinophils have also been reported in cases of subarachnoid hemorrhage, lymphoma, Hodgkin’s disease, brucellosis, fungal meningitis, mycoplasma pneumonia infection, measles, lymphocytic choriomeningitis, rickettsial infections, leukemia, demyelinating disease, sarcoiodosis, acute inflammatory demyelinating polyneuropathy, allergic reactions, and idiopathic eosinophilic meningitis.

12. Interpretation Cells Normal CSF RBCs are less than 10/mm 3. Counts that are otherwise unexplained may be due to a traumatic tap. Herpes simplex virus encephalitis may elevate the CSF RBC count in many patients.

13. Interpretation Glucose Low CSF glucose concentration indicates increased glucose use in the brain and the spinal cord. The normal range of CSF glucose is between 50 and 80 mg/dl 60-70% of serum glucose concentration Only low concentrations of glucose are significance

14. Interpretation Low CSF Glucose Syndromes Bacterial meningitisSyphilis Tuberculous meningitisChemical meningitis Fungal meningitisSubarachnoid meningitis SarcoidosisMumps meningitis Meningeal carcinomatosis Herpes simplex encephalitis Amebic meningitisHypoglycemia CysticercosisTrichinosis

15. Interpretation Protein Increase in CSF total protein levels are a nonspecific abnormality associated with many disease states. Levels > 500mg/dl are uncommon and are seen mainly in meningitis, in subarachnoid bleeding, and with spinal tumors.

16. The Traumatic Tap It should not be difficult to distinguish between subarachnoid hemorrhage and a traumatic tap. In traumatic taps, the fluid generally clears between 1 st and 3 rd tubes.

17. CSF Analysis with Infections Bacterial Infections The Gram stain is of great importance, because this often dictates the initial choice of antibiotic. Gram-negative intracellular or extracellular diplococci are indicative of Neisseria meningitidis Small Gram-negative bacilli may include Haemophilus influenza, especially in children. Gram-positive cocci indicates Streptococcus pneumoniae, other Streptococcus species, or Staphylococcus. 20% of Gram stains may be falsely negative.

18. CSF Analysis with Infections Bacterial Infections While the culture is pending, one may suspect a bacterial infection in the presence of an elevated opening pressure and a marked pleocytosis ranging between 500 and 20,000 WBCs/mm 3. The differential count is usually chiefly neutrophils. A count above 1000 cells/mm 3 seldom occurs in viral infections.

19. CSF Analysis with Infections Bacterial Infections CSF glucose levels less than 40 mg/dl or less than 50% of a simultaneous blood glucose level should raise the question of bacterial meningitis. The CSF protein content in bacterial meningitis ranges from 500 to 1500 mg/dl.

20. CSF Analysis with Infections Viral Studies The organisms most commonly isolated in viral meningitis are enteroviruses and mumps. Enteroviruses: summer and fall Mumps: winter and spring

21. CSF Analysis with Infections Viral Studies WBC count in viral meningitis and encephalitis usually: 10 to 1000 cells/mm 3. The differential count is predominantly lymphocytic and mononuclear in type. Protein levels are usually mildly elevated Antibiotic coverage pending culture results may be reasonably initiated pending culture results if in doubt.

22. Complications Headache After Lumbar Puncture Most common complication Occurs 5-30% of all spinal taps Usually starts up to 48 hours after to procedure. Usually lasts 1-2 days (occas 14 days)

23. Complications Headache After Lumbar Puncture Usually begins within minutes after arising and resolves with recumbent position. Pain is mild to incapacitating and is usually cervical and sub-occipital, but may involve the shoulders and the entire cranium. Caused by leaking of fluid through dural puncture site.

24. Complications Headache After Lumbar Puncture Incidence is higher in younger patients and females, and those with headache history. Treatment: barbiturates, fluids, caffeine (500mg in 2 ml NS IV push) more common 500mg in 2 L over 1 hr. Blood patch by anesthesia if no improvement.

25. Procedure Performed with the patient in the lateral recumbent position. A line connecting the posterior superior iliac crest will intersect the midline at approx. the L4 spinous process. Spinal needles entering the subarachnoid space at this point are well below the termination of the spinal cord.

26. Procedure In the adult, the spinal cord extends to the lower level of L1 or the body of L2. LP in adults and in older children may be performed from L2 to L3 interspace to the L5 to S1 interspace. At birth, the cord ends at the level of L3. LP in infant may be performed at the L4 to L5 or L5 to S1 interspace.

27. Procedure Almost all patients are afraid of an LP. Explaining the procedure in advance and discussing each step aids in reducing anxiety. Inquire about allergies to anesthetics. Informed consent.

28. Procedure Position the patient: Generally performed in the lateral decubitus position. A pillow is placed under the head to keep it in the same plane as the spine. Shoulders and hips are positioned. perpendicular with the table. Lower back should be arched toward practitioner.

29. Procedure Sterile gloves MUST be used. Wash back with antiseptic solution. Sterile towel under hips. The skin and deeper subcutaneous tissue are infiltrated with local anesthetic. Warn patient of transient discomfort of anesthetic.

30. Procedure Anesthetizing the deeper subcutaneous tissue significantly reduces the procedure discomfort. Some operators not only anesthetize the interspinous ligament but also apply local anesthesia in a vertical fanning distribution on both sides of the spinous processes near the lamina.

31. Procedure The patient should be told to report any pain and should be informed that he or she will feel some pressure. The needle is placed into the skin in the midline parallel to the bed. The needle is held with both thumbs and index fingers.

32. Procedure After the subcutaneous tissue has been penetrated, the needle is angled toward the umbilicus. The bevel of the needle should be facing laterally (toward patients side).

33. Procedure a. Ligament flavum is a strong, elastic, yellow membrane covering the interlaminar space between the vertebrae. b. Interspinal ligaments join the inferior and superior borders of adjacent spinous processes. c. Supraspinal ligament connects the spinous processes

34. Procedure The ligaments offer resistance to the needle, and a “pop” is often felt as they are penetrated. Clear fluid will flow from the needle when the subarachnoid space has been penetrated.

35. Procedure If bone is encountered, withdrawal into subcutaneous tissue and redirect. Attach a manometer and record opening pressure. Turn stopcock and collect fluid. Withdrawal needle and place a dressing.

36. Procedure Tube 1 is used for determining protein and glucose Tube 2 is used for microbiologic and cytologic studies Tube 3 is for cell counts and serologic tests for syphilis

38. Questions?