Normal CSF FACTS

Reading time: 1 Minute

80% brain parenchyma, 10% cerebrospinal fluid, and 10% blood.

 

Average intracranial volume 1700 ml
Average brain volume  1200-1400 ml
The normal color of CSF Clear, Colorless
Average CSF volume  70-160 ml

(125 ml within the subarachnoid spaces

25 ml within the ventricles)

Total CSF Secretion 400 to 600 ml per day (varies between individuals)
Complete CSF renewal Four to five times per 24-hour period in the average young adult
The normal average cerebral blood flow (CBF) in adult humans 50 ml / ( 100 g min )

(lower values in the white matter [ ∼ 20 ml / ( 100 g min ) ] and greater values in the gray matter [ ∼ 80 ml / ( 100 g min ) 

Normal CSF protein 1. Ventricles – 5-15 mg/dl

2. Basal cisterns – 10-25 mg/dl

3. Lumbar cistern – 45-50 mg/dl

What are the protein fractions identified in CSF Alpha1, alpha2, beta1, beta2, gamma globulin, prealbumin, albumin
CSF: Osmolality- 295 mOsm/L

 pH: 7.33

 PCO2: 45-49 mmHg

 Bicarbonate: 23 mEq/L

 

(CSF is iso-osmolar to plasma but more acidic)

Normal CSF glucose 45-80 mg/dl (or 2/3 of blood glucose) 
Normal cells 0 – 5 (WBCs)/mm3
After an IV injection of glucose, how many hrs are required to reach CSF equilibrium? 2-4 hrs 
Normal CSF opening pressure in: ADULTS:      10-18 cmH2O      

                      (8-14 mmHg)

 

CHILDREN:   3-6 cmH2O (2.2 – 4.4 mm Hg)

The equation for CSF pressure venous pressure + (flow x resistance)
Increased ICP >20 cmH2O (>14.71 mmHg)
Intracranial hypotension: <= 5 cmH2O (< 3.6mm Hg)
The main contributor to CSF pressure Venous pressure (and not CSF outflow resistance!)
ICP at which the compliance curve begins its steep ascent Impaired compliance starts above

           ICP 33.98 cm H2O

     (25 mmHg) causing herniation

ICP at which CBF diminishes causing loss of consciousness Loss of consciousness at ICP  54.38- 67.97 cm H2O

         (40-50 mmHg)

Triad of NPH Gait ataxia >> dementia >> incontinence
Evans index normal Between 0.20 and 0.25, 

An index between 0.25 and 0.30 indicates possible or early ventriculomegaly, 

While a ratio of >0.30 indicates definite ventriculomegaly.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top