A low CSF glucose is found in patients with bacterial, tuberculous, fungal, and protozoal meningitis, almost always in combination with other abnormal CSF parameters.

Hypoglycorrhachia, or a low glucose level in the cerebrospinal fluid (CSF), can suggest bacterial, fungal, or tuberculous meningitis.

When blood sugar drops too low, the level of insulin declines and other cells in the pancreas release glucagon, which causes the liver to turn stored glycogen back into glucose and release it into the blood. This brings blood sugar levels back up to normal.

Chemical meningitis, inflammatory conditions, subarachnoid hemorrhage, and hypoglycemia also cause hypoglycorrhachia (low glucose level in CSF). Elevated levels of glucose in the blood is the only cause of having an elevated CSF glucose level.

The reason for the reduced glucose levels associated with bacterial meningitis was believed to be the need for glucose as fuel by infiltrating immune cells in response to infection. However, the possibility that the bacteria itself could manipulate glucose concentrations in the brain had not been explored before now.

Interpretation of CSF results from lumbar puncture (LP)

1. Appearance: Clear.
2. Opening pressure: 10-20 cmCSF.
3. WBC count: 0-5 cells/µL. < 2 polymorphonucleocytes [PMN])
4. Glucose level: >60% of serum glucose.
5. Protein level: < 45 mg/dL.
6. Consider additional tests: CSF culture, others depending on clinical findings.

Insulin helps the cells absorb glucose, reducing blood sugar and providing the cells with glucose for energy. When blood sugar levels are too low, the pancreas releases glucagon. Glucagon instructs the liver to release stored glucose, which causes blood sugar to rise.

Hypoglycemia also triggers the release of body hormones, such as epinephrine and norepinephrine. Your brain relies on these hormones to raise blood sugar levels. The release of these hormones causes additional symptoms of tremor, sweating, rapid heartbeat, anxiety and hunger.

Low levels of protein in your CSF could mean your body is leaking cerebrospinal fluid. This could be due to a traumatic injury such as head or spine trauma.

Glucose levels in CSF are compared with blood plasma levels of glucose. CSF protein concentration. Increases may mean brain or spinal cord disease. CSF leukocyte, or white blood cell, count. It’s usually high if you have an infection.

Normal Results The glucose level in the CSF should be 50 to 80 mg/100 mL (or greater than 2/3 of the blood sugar level). Note: Normal value ranges may vary slightly among different laboratories.

Glucose levels in CSF normally reflect the levels seen in the blood. There may be a 2–4 hour lag in the CSF level when compared to the blood level. Whilst not diagnostic, low glucose levels, as compared to plasma levels, are seen in bacterial meningitis, cryptococcal meningitis, malignant involvement of the meninges and sarcoidosis.

When CSF protein levels are low it can indicate rapid CSF production. Glucose levels in CSF normally reflect the levels seen in the blood. There may be a 2–4 hour lag in the CSF level when compared to the blood level.

A low CSF glucose in combination with a normal cell count, a normal protein level, and a low to normal CSF lactate is the diagnostic marker for GLUT1DS, a genetic neurometabolic disorder in which glucose transport into the brain is disturbed.

There may be a 2–4 hour lag in the CSF level when compared to the blood level. Whilst not diagnostic, low glucose levels, as compared to plasma levels, are seen in bacterial meningitis, cryptococcal meningitis, malignant involvement of the meninges and sarcoidosis.