Microscopic examination of cerebrospinal fluid

Cerebrospinal fluid microscopy provides a basis for judging various diseases by counting and classifying cerebrospinal fluid cells. Cerebrospinal fluid cell count should be carried out in time, generally within 1 hour; puncture damage to blood vessels, leading to bloody cerebrospinal fluid, the total number of cells is meaningless, white blood cell counts must be corrected before meaningful; cell count, if more red blood cells are found Shrinkage or swelling should be described to assist the clinician in identifying stale or fresh bleeding. Basic Information Specialist classification: cardiovascular examination classification: microscopy Applicable gender: whether men and women apply fasting: not fasting Tips: Cerebrospinal fluid cell count should be carried out in time, generally within 1 hour; puncture damage to blood vessels, leading to bloody cerebrospinal fluid, the total number of cells is meaningless, white blood cell count must be corrected to make sense. Normal value 1. Normal human cerebrospinal fluid has a small amount of white blood cells and no red blood cells. The number of cells is adult (0~8)×106/L children (0~15)×106/L. 2. The cells in the cerebrospinal fluid are mostly large mononuclear cells and lymphocytes, the ratio of which is about 37, and occasionally endothelial cells. Clinical significance Abnormal result 1. The number of cerebrospinal fluid cells can be increased, and the degree of increase and the type of cells are related to the nature of the lesion. May be a central nervous system lesion. 2, the number of cerebrospinal fluid cells can be moderately increased, often based on lymphocytes, for central nervous system viral infection, tuberculosis or fungal meningitis. 3, the number of cerebrospinal fluid cells increased significantly, mainly neutrophils, such as purulent meningitis when bacterial infection. 4, when the brain parasitic disease, more eosinophils can be seen. 5. When the ventricles or subarachnoid hemorrhage, most red blood cells are seen in the cerebrospinal fluid. 6, sometimes can find lupus cells in the cerebrospinal fluid, for lupus. 7, purulent meningitis after effective antibiotic treatment, the total number of cells decreased rapidly; tuberculous meningitis patients in the early stage of neutral lobular nucleated cells, more lymphocytes later; cerebrospinal fluid in the cerebrospinal fluid of patients with cerebrospinal fluid The reduced number, combined with clinical, indicates that bleeding will either stop or have stopped. Need to check the central nervous system infectious diseases, cerebrovascular disease, brain parasitic diseases, central nervous system tumors. Precautions Taboo before inspection: None. Requirements for examination: Cerebrospinal fluid cell count should be carried out in time, generally within 1 hour; puncture damage to blood vessels, leading to bloody cerebrospinal fluid, the total number of cells is meaningless, white blood cell count must be corrected before meaningful; cell count, if found Many red blood cells have shrinkage or swelling, which should be described to help clinicians identify old or fresh bleeding. When counting cells, be careful to distinguish red blood cells or lymphocytes from Cryptococcus neoformans: 1. Cryptococcus neoformans have "germination" "Phenomenon, insoluble in acetic acid, after adding 0.35mol / L of acetic acid, the original shape remains under the microscope, while the red blood cells are dissolved by acetic acid, and the nucleus and cytoplasm of lymphocytes are more obvious. 2, drop a drop of Indian ink, add a cover glass, see the new cryptococcal sclerotium film under high magnification, no coloration, and red blood cells or lymphocytes do not have this phenomenon. After the cell counting plate is used up, it is sterilized with 75% alcohol for 60 minutes. Do not use phenol to disinfect, because it is harmful to the scale of the counting pool. Inspection process There are five main inspections: First, the total number of cells 1, direct counting method is suitable for cerebrospinal fluid specimens are relatively clear or slightly mixed. Draw a small amount of the mixed cerebrospinal fluid sample with a dropper, directly into the cell counting plate, fill it into the counting cell, and let it stand for 2~3 minutes. Under the low magnification microscope, count the four corners in the two pools and the central large grid. The number of cells in the inside is 1 μl of the total number of cells in the cerebrospinal fluid (the total number of red and white blood cells). When writing a report, it is converted to the total number of cells in each cerebrospinal fluid. 2. The dilution counting method is applicable to cerebrospinal fluid if the cells of the cerebrospinal fluid are excessive, turbid or bloody. 20 μl of the mixed cerebrospinal fluid can be aspirated by a hemoglobin capillary pipette, and added to a small test tube with a red blood cell dilution of 0.38 μl, mixed and dropped into a counting cell, and the total number of cells of 4 large squares is counted by a low power microscope, multiplied by 50, that is, The total number of cells per microliter of cerebrospinal fluid is finally reported as the total number of cells per liter of cerebrospinal fluid. Second, white blood cell count 1. Direct counting: non-blood specimens, all of which are blown out after sucking glacial acetic acid with a pipette, so that only a little glacial acetic acid is attached to the tube wall, and then a small amount of mixed cerebrospinal fluid sample is taken by the same pipette. After a few minutes, the red blood cells will completely dissolve, and then drop. Into the counting pool, count by the above method. 2, dilution count: If too many white blood cells, can be diluted with white blood cell dilution, according to the above method, note that the counting results should be multiplied by the dilution factor. 3. Correction of bloody specimens The cerebrospinal fluid specimens mixed with blood were mixed and diluted with 1% glacial acetic acid solution and still counted according to the above method. In order to eliminate white blood cells caused by bleeding, the following formula can be used for correction. White blood cell corrections per microliter of CSF = number of uncorrected white blood cells per microliter of CSF - Third, white blood cell classification count 1. Direct classification: After direct counting of white blood cells, high-power microscope observation, classification according to cell shape and nuclear morphology, 100 white blood cells and endothelial cells were counted, and the proportion of mononuclear cells and neutrophils was calculated. , expressed as a percentage. If the total number of white blood cells is less than 100, the specific numbers of mononuclear cells and neutrophils are directly written. If the total number of white blood cells is below 30, it is not necessary to perform direct classification and counting or to change the classification of staining. 2, staining classification: cerebrospinal fluid specimen centrifugation, take the precipitation smear, made a uniform film, placed in room temperature or 37 ° C incubator, dried and then stained with Wright, oil microscopic classification. Expressed as a percentage. Fourth, pathogen morphology examination 1. When the bacteria are clinically suspected of epidemic cerebrospinal meningitis or suppurative meningitis, a bacteriological smear should be performed. The operation is as follows: (1) Cerebrospinal fluid specimen 2~3ml, centrifuged at 3000rpm for 15 minutes, remove the supernatant, apply the precipitate on clean glass plate, make two pieces together, smear naturally or dry in 37 °C incubator, and do not Fixed with a flame. (2) After the smear is fixed, one is stained with methylene blue and the other is stained with Gram. (3) Gram staining smear is used to check pneumococci, influenza bacillus, staphylococcus, Pseudomonas aeruginosa, streptococcus, Escherichia coli, etc., methylene blue staining is used to check meningococcus. If bacteria are found, they are reported according to their dyeing properties and morphology. (4) If tuberculous meningitis is suspected, the cerebrospinal fluid specimen can be allowed to stand for 24 hours, and the liquid film smear is taken and dried in a 37 ° C incubator for acid-fast staining. (5) Pay attention to pollution when collecting specimens. Microscopic observation should pay attention to the bacterial morphology inside and outside the cell, which should be described when reporting. 2, fungal examination - inspection of new cryptococcus (1) Take the cerebrospinal fluid specimen, centrifuge at 2000 rpm for 10 minutes, smear the precipitate, add a drop of filtered fine ink, mix and cover with a cover glass microscope. (2) First observe with a low power microscope. If it is found that there is a circular light-transmitting small spot on a black background, there is a round material with a cell size in the middle, that is, the structure is carefully observed by a high power microscope, and the diameter of the new Cryptococcus is 5-20 μm. , visible thick thick film, surrounded by strong refraction, and sprouted spherical spores. (3) If the above characteristics are found, the ink smear can be reported to find "Cryptococcus". Further fungal culture is required. Not suitable for the crowd Inappropriate crowd: None.

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