CSF glucose

CSF glucose or glycorrhachia is a measurement used to determine the concentration of glucose in cerebrospinal fluid (CSF).[1][2][3]

CSF glucose
Reference range2.5-4.4 mmol/L (45-80mg/dL)
LOINC2342-4 (MCnc), 14744-7 (SCnc)

Normal values in humans
Pathophysiology sample values
BMP/ELECTROLYTES:
Na+ = 140 Cl− = 100 BUN = 20 /
Glu = 150
K+ = 4 CO2 = 22 PCr = 1.0 \
ARTERIAL BLOOD GAS:
HCO3− = 24 paCO2 = 40 paO2 = 95 pH = 7.40
ALVEOLAR GAS:
pACO2 = 36 pAO2 = 105 A-a g = 10
OTHER:
Ca = 9.5 Mg2+ = 2.0 PO4 = 1
CK = 55 BE = −0.36 AG = 16
SERUM OSMOLARITY/RENAL:
PMO = 300 PCO = 295 POG = 5 BUN:Cr = 20
URINALYSIS:
UNa+ = 80 UCl− = 100 UAG = 5 FENa = 0.95
UK+ = 25 USG = 1.01 UCr = 60 UO = 800
PROTEIN/GI/LIVER FUNCTION TESTS:
LDH = 100 TP = 7.6 AST = 25 TBIL = 0.7
ALP = 71 Alb = 4.0 ALT = 40 BC = 0.5
AST/ALT = 0.6 BU = 0.2
AF alb = 3.0 SAAG = 1.0 SOG = 60
CSF:
CSF alb = 30 CSF glu = 60 CSF/S alb = 7.5 CSF/S glu = 0.6

The glucose level in CSF is proportional to the blood glucose level and corresponds to 60-70% of the concentration in blood.[4] Therefore, normal CSF glucose levels lie between 2.5 and 4.4 mmol/L (45–80 mg/dL).[5]

Abnormalities in CSF glucose concentration

Low CSF glucose levels

Hypoglycorrhachia (low CSF glucose levels) can be caused by CNS infections, inflammatory conditions, subarachnoid hemorrhage, hypoglycemia (low blood sugar),[3] impaired glucose transport, increased CNS glycolytic activity and metastatic carcinoma.[4]

CSF glucose levels can be useful in distinguishing among causes of meningitis as more than 50% of patients with bacterial meningitis have decreased CSF glucose levels while patients with viral meningitis usually have normal CSF glucose levels. Decrease in glucose levels during a CNS infection is caused due to glycolysis by both white cells and the pathogen, and impaired CSF glucose transport through the blood-brain barrier.[3][6]

High CSF glucose levels

There is no pathologic process that directly leads to hyperglycorrhachia (high CSF glucose levels) and therefore, high CSF glucose levels have no specific diagnostic importance.[3]

However, elevated blood sugar levels (hyperglycemia) result in elevated CSF glucose levels[3] as the CSF glucose level is proportional to the blood glucose level with glucose being actively transported as well as simply diffusing down the concentration gradient from blood to CSF. In addition, damage to small blood vessels during lumbar puncture (traumatic tap) can lead to an increased CSF glucose since the blood that enters the collected CSF sample contains higher levels of glucose.[4]

CSF glucose levels do not generally exceed 16.7 mmol/L (300 mg/dL).[3]

See also

References
  1. "MedlinePlus Medical Encyclopedia: CSF glucose". Retrieved 2009-03-04.
  2. Mohammadi M, Mohebbi MR, Naderi F (December 2003). "CSF Glucose Concentrations in Infants with Febrile Convulsions and the Possible Effect of Acetaminophen". Indian Pediatr. 40 (12): 1183–6. PMID 14722369.
  3. Seehusen DA, Reeves MM, Fomin DA (September 2003). "Cerebrospinal fluid analysis". Am Fam Physician. 68 (6): 1103–8. PMID 14524396. Archived from the original on 2008-05-15. Retrieved 2009-03-05.
  4. Lillian A. Mundt; Kristy Shanahan (2010). Graff's Textbook of Routine Urinalysis and Body Fluids. Lippincott Williams & Wilkins. p. 237. ISBN 978-1582558752.
  5. Karen Roos (2005). Principles of neurologic infectious diseases. New York: McGraw-Hill, Medical Pub. Division. p. 4. ISBN 978-0-07-140816-5.
  6. Nigrovic, MD MPH, Lise E.; Kimia MD, Amir A.; Shah MD MSCE, Samir S.; Neuman MD MPH, Mark I. (2012). "Relationship between Cerebrospinal Fluid Glucose and Serum Glucose". The New England Journal of Medicine. 366 (6): 576–8. doi:10.1056/NEJMc1111080. PMID 22316468.
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