CSF Flashcards
Why is CSF volume important
If too much: hydrocephalus
BBB compromised, intracranial pressure
CNS membranes
3
Dura mater (outermost)
Arachnoid
[CSF here]
Pia mater (innermost)
CSF production
Brain secretions and plasma filtrate
- One way reabsorption valves for waste
Selective filtration of plasma so chemical composition is different from ultrafiltrate plasma
Fluid output rate
20 ml/hr
Blood brain barrier
Tight capillary endothelium that creates CSF
- substances pass through the cells, atransport/diffusion
CSF volume for ages
Adults: 90-150 mls
Infants: 10-60 mls
CSF components compared to plasma
CSF has more: Na, Mg, Cl
less: glucose, K, bicarb, protein
CSF collection procedure
age, volume, pressure
Adults: between L3 L4
Children: between L4 L5
10-20 mls removed
50-180 mmHg pressure normal
Collection tube order
and why
- 1: chem/serology because least affected by blood or bacteria introduced as a result of the procedure
- 2: micro
- 3: heme/cell count
Collection tube storage
- Heme: fridge up to 4 hrs
- Micro: room temp
- Chem/sero: frozen
CSF that is colored: term
Xanthochromic
Pleocytosis
Increased wbcs and rbcs: cloudy specimen
Clotting in CSF
ALWAYS ABNORMAL
- fibrinogen and plasma proteins
- can be from pellicle formation after fridge
- common in traumatic taps
Proteins in CSF
15-45 mg/dl can be normal, prealbumin, albumin, transferrin
Increased: infections, tumors, hemorr, cns disorders
Decreased: dural tear, cranial pressure
Reasons for proteinsin CSF and difference
Impaired BBB: most cases, albumin
Increased synthesis: less common, IgG
Normal ratio for albumin
<9
Normal ratio for IgG
<8
IgG index formula
(IgG CSF/IgG serum) x (albumin serum/CSF albumin)
Normal: 0.3 - 0.7
- Increased: MS, neuro probs
- Decreased: BBB bad
BBB damage vs CNS synthesis in relation ot the ratios
BBB damage: increased albumin AND IgG ratio, decreased IgG index
CNS synthesis: normal albumin, IgG ratio and IgG index increased
Glucose in CSF
ratio compared to serum is 0.6 normal
Decrease: increased glycolysis, some cancers, transport issues
Increase: bloody tap, hyperglycemia
Lactate in csf
Normal: 11-22 mg/dk
Increase: tissue hypoxia
Viral: <30 mg/dl
Bacteria, other: >35 mg/dl]
Lactate dehydrogenase
Supports meningitis diagnosis
- LD 4, 5 in granulocytes = bacterial
- LD 2, 3 in lymphs = viral
Microbiological examination
gram stain, or acid fast
culture, always blood culture
- use sediment for smears and cultures
Cells in CSF amount with age
Decreases with age
Younger = more cells in CSF
Lymphs to monos ratio
70:30
WBC reference range %s
adult vs infants
Adults: 30-96% lymphs, 15-56% monos, 0-7% PMNs
Infants: higher monos, lower lymphs
Normal cells in CSF
Lymphs: dominating
- Increased: non bacterial infections, listeria, degenerative
Monos: not dominating
Macrophages in CSF
Not normal
- Hemorrhage or bleed, inclusions
< 12 hrs: RBCs, PMNs, lymphs, monos, macros
12-48 hrs: lymphs, macros, erythrophages
2-4 days: erythrophages, vacuolated macros, siderophages
1-8 weeks: siderophages, macrophages w/ hematin
Other cells in CSF
Lining cells
- Ependymal
- Choroid plexus
- PAM cells
More likely in kids, abnormal # after surgery, trauma
Bone marrow cells
Chondrocytes cartilage from vertebral disk
NRBCs, SECs
Bacterial vs viral meningitis
glucose, lactate, cell count, wbcs
Bacterial
- decreased <0.60 glucose
- increased >35 mg/dl lactate
- very increased >50,000/ul
- PMNs dominate
Viral
- normal to decreased glucose
- slight increase lactate 23-30 mg/dl
- increased but <50,000/ul cells
- lymphs dominate
Multiple sclerosis
Increased CSF IgG index
Oligoclonal bands
Plasma cells
