Lumbar Puncture and CSF Examination



Lumbar Puncture and CSF Examination





Lumbar Puncture (LP)


Indications

See Table 18.1.








Table 18.1 Indications for Lumbar Puncture








Essential for diagnosis:

  • Infections: meningitis (bacterial, fungal, Whipple, Lyme)
  • Tumor of meninges (carcinoma, lymphoma, glioma)
  • Viral meningitis or encephalomyelitis (for antibodies, PCR)
  • Sporadic prion disease (14-3-3 protein test)
  • Neurosyphilis
  • Intracranial bleeding (if CT negative but suspect subarachnoid hemorrhage)
Helpful in diagnosis:

  • Ascertain absence of blood before starting anticoagulant therapy for stroke
  • Disorders of intracranial pressure
  • Normal-pressure hydrocephalus
  • High-pressure normocephalus (idiopathic intracranial hypertension, pseudotumor cerebri)
  • Intracranial hypotension
  • Peripheral neuropathies (GBS, CIDP, Lyme neuropathy, Dejerine-Sottas syndrome)

    • MS, transverse myelitis
    • Granulomatous angiitis of the brain
    • KSS
PCR, polymerase chain reaction.


Contraindications

Infection of skin over the spine, at site of planned puncture.


Mass lesion or edema on head CT. If no evidence of mass lesion or edema on brain imaging, papilledema is not a contraindication to LP.

Platelet count ≤50,000/mm3: LP only for urgent clinical indications. Platelet count ≤20,000/mm3 or dropping rapidly: platelet transfusion recommended just before LP.

Patients taking heparin: hold heparin drip for ≥1 hour; consider giving protamine. Heparin therapy should not start for at least 1 hour after bloody tap.

Patients taking warfarin: hold warfarin; consider vitamin K or fresh frozen plasma.


Complications

Worsening of brain herniation or spinal cord compression; headache (occurs in about 25%); subarachnoid hemorrhage; diplopia; backache; radicular symptoms.


CSF Pressure

Normal lumbar CSF pressure: 60–200 mm H2O (up to 250 mm in obese people).


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Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on Lumbar Puncture and CSF Examination

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