intrathecal pump question

[TIVAndy]

one of my few remaining pump patient story.. i need some input from the board

80 something year old i inherited few years ago, i tried weaning from pump but she realized pump was helping her pain significantly.
last year was end of life for pump, so i replaced the pump.
Intraop aspiration of catheter port did not aspirate CSF well, decision was made to cut the catheter, tie it off and insert a new catheter and pump.

few months after implant, i've noticed some fluctuance at the site of implant. fluid collection was noted on ultrasound.
i've decided to observe, and 1 month later pump site fluctuance increased
symptom wise patient endorsed some generalized fatigue, but no headache.

i aspirated the pump site - fluid was serosanguinous - sent out for beta 2 transferrin but was negative (thus prob not CSF)
drained about 50ml. catheter was still intact on dye study. no dye leakage was seen

3 months later on pump refill - fluctuance is back, i drain it again and prescribe some binder.

she returned again last week - recurrence of fluctuance, i drained about 60cc now the fluid seems a bit more sanguinous.

any thoughts on what could be the cause?
i discussed with patient that i can explore the site but may not find any source of leakage.
could this be just a seroma formation?
still CSF despite negative lab test?

how would you proceed?

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[BobBarker]

It is csf.

 

[TIVAndy]

It is csf.

do you mind explaining your reasoning. to my knowledge beta 2 transferrin is pretty sensitive and specific test

 

[Orin]

aspiration of catheter port did not aspirate CSF well, decision was made to cut the catheter, tie it off and insert a new catheter and pump.

Tying off and leaving the catheter is fine; I normally remove it and purse string to reduce the CSF leak through the prior track.

few months after implant, i've noticed some fluctuance at the site of implant

I assume you mean at the reservoir site. I assume there's no fluid at the anchor incision. Assuming this is the Ascenda and not a silastic catheter, that tubing acts like a wick/drain so fluid tends to track anterior and posterior. Draining it is fine at a month, but I would've sent it for gram stain, cultures, in addition to the beta-2 transferrin.

3 months later on pump refill - fluctuance is back, i drain it again and prescribe some binder.

At this point, I'm more worried about a slow indolent infection than a long standing leak, but either way I would want to consider my options and work it up further.

Beta-2 transferrin levels can be negative due to the type of assay, if there is contamination with regular seroma fluid reducing concentrations, or in rare circumstances, due to infection.

You could get a simple CT with/without contrast to evaluate it, but if the thing is looking bloody now, send the fluid for gram stain/culture and consider weaning the pump in case you've got to explant it for a little bit. I would check the ESR/CRP/procalcitonin as this point they should be low. If tests are positive, it's probably a low pathogenicity bacteria/fungus so oral/IV agents might be reasonable if she wants to avoid surgery at that age, but explanting, dropping a drain, and re-implanting in 4 - 8 weeks with ID's blessing is safest.

 

[TIVAndy]

Tying off and leaving the catheter is fine; I normally remove it and purse string to reduce the CSF leak through the prior track.

I assume you mean at the reservoir site. I assume there's no fluid at the anchor incision. Assuming this is the Ascenda and not a silastic catheter, that tubing acts like a wick/drain so fluid tends to track anterior and posterior. Draining it is fine at a month, but I would've sent it for gram stain, cultures, in addition to the beta-2 transferrin.


At this point, I'm more worried about a slow indolent infection than a long standing leak, but either way I would want to consider my options and work it up further.

Beta-2 transferrin levels can be negative due to the type of assay, if there is contamination with regular seroma fluid reducing concentrations, or in rare circumstances, due to infection.

You could get a simple CT with/without contrast to evaluate it, but if the thing is looking bloody now, send the fluid for gram stain/culture and consider weaning the pump in case you've got to explant it for a little bit. I would check the ESR/CRP/procalcitonin as this point they should be low. If tests are positive, it's probably a low pathogenicity bacteria/fungus so oral/IV agents might be reasonable if she wants to avoid surgery at that age, but explanting, dropping a drain, and re-implanting in 4 - 8 weeks with ID's blessing is safest.

your knowledge continues to amaze me. thanks for the guidance again. i've also discussed this case with my neurosurgeon colleague he thinks it could be the tracking of previous catheter and csf. i'll do some infectious work up and r/o infection.