4 4L Neuro Csf Interpretation Em

Front 1

What is the normal CSF opening pressure in adults? Neonates and children?

What could low pressure be due to?

Can pressure be measured while pt is sitting for LP?

Back 1

Adults 70-180mm H2O
Infants/ young Children <85
Neonates <50

Low pressure - obstruction of needle by meninges, spinal block (anaesthetic). Rarely following trauma, neurosurg procedures

Can only be measured in lateral position

Front 2

Xanthochromia:
1. appears after a SAH by how many hours?
2. Disappears by how many days/weeks?
3. Is due to which three pigments?
4. Can a traumatic tap produce xanthrochromia?
5. What can cause a false positive result?

Back 2

1. within 2 hours
2. all components disappear by 14-30 days
3. Oxyhaemaglobin, bilirubin, methaemoglobin
4. Yes (uncommon) if RCC exceeds 30,000/microL. Otherwise a promptly examined CSF (e.g. less than 2/24 after traumatic tap) will not show xanthochromia
5. High CSF protein values plus systemic elevations of bilirubin

Front 3

WCC
1. More than which absolute no. of WCC in the CSF is considered pathological?
2. Which cell type reflects parasitic infections?
3. CSF pleocytosis after seizure is common - up to 30%. Does it have any significance?

RCC
1. What is a normal RCC?
2. An elevated RCC is common with with CNS infection?
3. Traumatic tap can be distinguished from SAH by...

Back 3

WCC
1. >5 cell/micro L - these 'normal' 5 cells are almost exclusively lymphocytes and monocytes. Neonates up to 32 WCC, prominent NP's, infants 4-8 weeks 22 WCC
2. Eiosinophils
3. It may indicate the seizure is secondary to infection or other underlying neurologic disorder (subdural haematoma, SAH, CVA)

RCC
1. <10/microL
2. HSV
3. Absence of xanthochromia if CSF examined within 2 hours. Reduction between 1st and 3rd tubes in counts assists but may represent layering of cc in a recumbent pt in a recent SAH. Presence of clot favours traumatic tap

Front 4

Glucose
1. Normal percentage in CSF vs. blood.
2. What is the significance of purulent CSF+decreased gluc
3. Glucose is normal in viral meningitis EXCEPT sometimes in...
4. Is it sufficient to measure CSF glucose alone?

Protein
1, What is the normal range in g/L
2. What other CSF finding may falsely elevate protein?

Back 4

1. CSF is 60-70% of concentration in blood. Ratio of <0.5 is abnormal. Higher in infants - 0.6 is abnormal
2. = bacterial meningitis
3. Mumps meningitis and HSV, HZV (decreased)
4. NO must always compare to serum glucose - hyperglycaemia may mask low CSF glucose

Protein
1. 0.15-0.45g/L after 3/12 age, may be triple this in first few days of life
2. Blood in CSF. Correct by subtracting 0.01mg/L per 1000RCC/mL

Front 5

Infections in CSF
1. Why is prompt CSF analysis important?
2. GNDC, GNB, GPC - which organisms do they usually represent?
3. Significance of negative gram stain?
4. What is the expected WCC range in bacterial meningitis? In viral?
5. Expected glucose change in viral vs bacterial?
6. What change may be observed with LDH in bacterial and fungal meningitis?
7. Antigen studies are available for which organisms? What is their value?
8. PCR has limited availability but is rapid, very sensitive and specific. Which organisms have PCR tests?

Back 5

1. CSF cells begin to lyse within a hour (slow by refrigeration) - meningococcal particularly fast, so may miss dx if there is a delay
2. GNDC NM, GNB HIB, GPC Strep and staph.
3. 20% are false negative - too few organisms to be seen
4. 500 - 20,000WCC/microL
5. <50% in bacterial meningitis, usuallly normal in viral
6. LDH will increase, usually normal in viral
7. Strep pneumo, NM, HIB, Crytopcoccus, Group B strep. Rapid, sensitive. Improve sensitivity by simultaneously culturing blood and urine. Persist after Antibiotic therapy (unlike G stain)
9. HSV and TB