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* 正常 CSF :
- Pressure : 12~20 cmH2O
- Glucose (0.4~0.6 of blood sugar)
- WBC 0-5
* Viral : Pressure & Glucose 正常, WBC & Protein 微上升
* Rule of 2s : Glc < 20, TP > 200, CSF WBC > 2000 --> 98% Spe 細菌性
* CSF/Serum Glucose ratio < 0.4, Lactate >35 --> Prefer bacterial
A non-contrast head CT has 100% sensitivity within the first 6 hours;
after this time window, a CT by itself cannot be used to exclude SAH.
https://oxlesson.blogspot.com/2018/10/csf.html
* Xanthochromia :
正常 CSF 清澈無色
傳染性和非感染性過程都可以改變腦脊液的外觀
200 WBC / microL or 400 RBC/ microL 將導致CSF出現混濁
進入 CSF 後, RBC Lysis
RBC 進入蛛網膜下腔後 2-4小時 即可檢測到黃色變色
RBC 進入蛛網膜下腔後 2-4小時 即可檢測到黃色變色
因此常用於 SAH 診斷
在出血後12小時內, 90% 以上 SAH 存在黃色變色, 此後可持續2至4週
Yellow or pink discoloration that can sometimes be seen in your CSF sample.
This is due to the breakdown of hemoglobin into oxyhemoglobin and later into bilirubin.
These degradation products often do not appear until 12 hours after blood enters the CSF
Xanthochromia can either interpreted by the use of CSF analysis via spectrophotometry or by visual inspection
Xanthochromia is highly suggestive of SAH, but can be found in rare cases with
severe systemic hyperbilirubinemia, traumatic tap, or in the context of highly elevated CSF protein
a normal CT scan and negative xanthochromia (provided that the LP was done between 12 hours and 2 weeks)
was sufficient to rule out SAH with a sensitivity of 100% 一定要 12 小時以後做的 LP 沒有 Xanthochromia 才有意義
* Clearing of RBCs
if there are fewer RBCs in tube 4 than tube 1,
the likelihood of a traumatic tap is high, and the probability of SAH is lower.
the likelihood of a traumatic tap is high, and the probability of SAH is lower.
Theoretically, in SAH, the RBC count will remain relatively constant from tube 1 to tube 4.
CSF RBC count of < 500 in final tube + RBC decrease from tube 1 to 4 of at least 70%
definitively exclude SAH (no formal consensus)
http://www.emdocs.net/the-bloody-csf-tap-pearls-and-pitfalls/
* Traumatic tapping :
RBC & WBC 的對比大約是 500 - 1500 RBC : 1 WBC
可藉此換算 CSF data 裡 WBC 總量是否符合比例
1 WBC : 500 RBC ratio, whereas others recommend 1 WBC:1,000 RBC
* Cell count
Bacterial : Segment predominence
Virus : Lymphocyte predominence
不過在最早期 (1-2天內) 可能都有反過來的情形, 後續再追蹤的 CSF 會更準
* Total protein
一般 60mg/dL 以下
如果 > 1000 mg/dL 要考慮 TB meningitis 或 Spinal block
導致 CSF 回流和吸收不順暢導致的高蛋白
導致 CSF 回流和吸收不順暢導致的高蛋白
蛋白升高可能在腦膜炎恢復後持續數週或數月
在評估治愈或對治療的反應方面幾乎沒有用處
在評估治愈或對治療的反應方面幾乎沒有用處
蛋白濃度 > 220 mg / dL 可將病毒感染的概率降低到 1%
* Lactate
CSF Lactate 診斷準確性在區分細菌和無菌性腦膜炎
優於 CSF WBC count, Glucose, Total protein
CSF lactate > 35 mg/dl could be optimal cut-off value
for distinguishing bacterial meningitis from aseptic meningitis
CSF lactate is produced by bacterial anaerobic metabolism or ischemic brain tissue.
However, clinicians should be aware that CSF lactate is also increased in several CNS diseases :
such Stroke (2 - 8 mmol/l), Convulsion (2 - 4 mmol/l), Cerebral trauma (2 - 9 mmol/l),
Hypoglycemic coma (2 - 6 mmol/l)
- Opening pressure 超高 (Cryptococcus)
- 目視下 Trauma tap 紅色逐管變淺
SAH可見 xanthochromia 或連續 4 管紅色不變
SAH可見 xanthochromia 或連續 4 管紅色不變
- 怕的是 Onset > 6hrs SAH, CT 可能 False negative
還是強烈懷疑SAH才會做 Lumbar puncture
還是強烈懷疑SAH才會做 Lumbar puncture
https://oxlesson.blogspot.com/2018/10/csf.html
https://www.facebook.com/groups/1055763321109570/permalink/1469048716447693/
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