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Abnormal CSF Diagnosis and Lumbar puncture
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- 4. FUNCTIONS • Mechanical :a water-jacket for brain and spinal cord. • If there is an increase in arterial pressure, blood content, or brain volume, there is a decrease in the amount of CSF, and vice versa….. • Homeostasis : equilibrium with the extracellular fluid of the brain. a medium for the transfer of substances from within the brain and spinal cord to the blood stream
- 5. BLOOD-BRAIN BARRIER • Site =level of the pial-glial membranes and the cerebral capillaries. • The capillaries in the brain are distinguished by having tight endothelial cell junctions • Restrict the passive movement of macromolecular substances across the cellular barrier. • Specialized transport systems that regulate selective transport of certain substances also form part of the bbb.
- 6. BLOOD-BRAIN BARRIER • Substances thatare highly lipid soluble enter more easily than those with low lipid solubility. • Substances highly bound to serum proteins are unable to penetrate the BBB. • Some areas of the CNS lack a BBB, : the chemoreceptor trigger zone , in the floor of the fourth ventricle, anterior wall of • the third ventricle, the median eminence of the hypothalamus, choroid plexus and the pineal and posterior pituitary glands. • Many drugs produce • nausea and vomiting as a prominent side effect because the lack of a BBB allows unfettered access directly from the blood stream to the area chemoreceptor trigger zone.
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- 8. LUMBAR PUNCTURE • new typeof atraumatic (Sprotte) needle is available in addition to the traditional Quincke (cutting tip) needle, and appears to lower the incidence of post-LP complications, • the CSF pressure and the CSF composition.
- 9. OPENING PRESSURE (OP) • Normalis up to 180 mm of CSF, values of 180 to 200 are borderline • most reliable indicator of the intracranial pressure. • In some circumstances the only LP abnormality is an elevated OP, as in pseudotumor cerebri includes cell • count, differential, protein, and glucose.
- 10. CSF COMPOSITION • Includescell Count, differential, protein, and glucose. • It requires about 2 hours for the blood sugar to equilibrate with the csf sugar. • For accurate csf Glucose determinations, the blood sample should be drawn 2 hours prior to LP, or the LP done in a fasting State.
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- 12. Condition Cells ProteinSugar Acute bacterial infection Markedly increased cell count, with the cells consisting primarily of polymorphonuclear Lymphocytes An elevated protein Decreased sugar. Less than 10 Mg/dl Aseptic pattern (viral infections, tuberculosis, fungal infection, partially Treated bacterial meningitis etc ) Elevated cell count with predominantly Mononuclear cells Elevated Normal Guillain-barré syndrome (albuminocytologic ) In the absence of an increased cell count Extremely elevated Protein - MS elevation of IgG in the spinal fluid must be compared with - -
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- 14. INCREASED INTRACRANIAL PRESSURE • ICP increasesthere are two major deleterious consequences. • herniation of brain structures out of their normal location • The second is a decrease in cerebral perfusion pressure (CPP). • cerebral blood flow can usually be maintained until the CPP decreases below 40 to 60 mm Hg; below this level cerebral perfusion suffers and leads to secondary ischemic damage • hydrocephalus , cerebral oedema , intracranial space occupying mass lesions
- 15. CLINICAL MANIFESTATIONS • Headache :exacerbated by coughing, straining, or changes in position , often worse at night • Pressure on the autonomic centers in the brainstem nausea, vomiting, increased blood pressure, changes in respiration, and bradycardia. • If the increase in ICP occurs before the cranial sutures have fused there may be separation of suture lines, bulging of the anterior fontanelle, or head enlargement • Cushing triad consists of hypertension, bradycardia, and slowing of respiration due to brainstem compromise.
- 16. THANK YOU Dr. PreetMehta| | pnmehta99@gmail.com