Inner Ear DCS

ROB DAVIE · 27th February 2006, 23:43

Quote: (Originally Posted by Pelagian)

We're arranging a consult with an ENT who is also a DIVe Doc to see if he can throw sone light on the subject(pun intended).

He has suggested that a roundwindow fistula or other barotrauma maybe the culrpit. He's not the only one who has suggested this.

I'll post what we find out.

Cheers

Seb

Seb,

I would have commented originally, but was thrown a bit by the lack of real depth, and the fact that it was on air.

I think the track you suggest above will turn out to be the right one. Hope your friend heals up fast!

Rob

babar · 1st March 2006, 02:11

Quote: (Originally Posted by Pelagian)

Dave

Thanks for the summary, my interpretation of the paper was the same.

The problem here is that this case did not involve helium or deep diving.

I know there is unlikely to be a cut'n'dry answer , just trying to find out as much as we can to help the diver in question assess his options for continuing his diving.

We're arranging a consult with an ENT who is also a DIVe Doc to see if he can throw sone light on the subject(pun intended).

He has suggested that a roundwindow fistula or other barotrauma maybe the culrpit. He's not the only one who has suggested this.

Apparently differential diagnosis between IEDCS and IE barotrauma's is tricky as many symptoms are the same, and since recompression treatment has so far proven less effective on IEDCS than other types, the 'lets see if it gets better in the chamber' approach is also proving inconclusive.

I'll post what we find out.

Cheers

Seb

IEDCS vs perilymph fistula is a very tricky differential diagnosis. At what point in the dive did it manifest? If it was directly after a forceful equalization, that might point more towards PF. Minutes to hours after the dive more likely IEDCS. When did it happen, and what symptoms did he have? and what treatment was done initially? Is he getting any better?

abowie · 1st March 2006, 06:20

Quote: (Originally Posted by Pelagian)

Dave

Thanks for the summary, my interpretation of the paper was the same.

The problem here is that this case did not involve helium or deep diving.

Seb

It doesn't necessarily have to.

Isobaric counterdiffusion is only one mechanism by which bubbles can form in the inner ear tissues/fluids.

Otto Molvaer has written an excellent chapter in Bennett and Elliott on the otorhinolaryngological aspects of diving. In this he reminds us that "the most common mechanism of bubble formation is too rapid a decompression". By this he means that while isobaric counterdiffusion may be the cause of IEDCS in some patients the bubble formation may simply have been caused by ordinary old DCS, independant of counterdiffusion.

Furthermore barotrauma can also cause injury to the middle and inner ear entirely independant of any decompression related bubble formation. This can cause symptoms identical to IEDCS and the two can coexist in the same patient.

Separating the three potential aetiologies in a patient with putative inner related symptoms can be difficult or impossible.

Pelagian · 1st March 2006, 23:44

Hey Andrew

I think we're on the same page.

My point was that IEDCS due to Helium CD has more information, and what I'm looking for is anything on IEDCS from plain old Nitrogen based single gas dive.

By all accounts his deco was minimal and his ceiling cleared by the time he reached 50ft on very slow ascening multilevel dive.

Having spoken again to the diver, it appears to be DCS rather than a Fistula or other barotrauma as his symptoms(nausea, vomiting, vertigo) onset 10 mins after surfacing. He also became asymptomatic upon reaching depth during his first treatment table(60ft 5-6hrs).

After 4 treaments he has been discharged with no follow up and minor nausea being the only residual which may well be due to O2 poisoning from the treatment.

As soon as we have anything from his ENT consult i'll put it up.

Thnaks again for eveyone's input.

Seb

abowie · 2nd March 2006, 08:09

Fair enough Seb; I didn't really fully read the thread before replying. Seems that you and others had already made the points I did.

**UWSojourner** · 2nd March 2006, 22:39

It seems that gas switching mid-stop, rather than upon arrival at or just before departure from any stop depth might help. If the stop is too brief, extending the stop before and after the switch might help if supersaturation is the problem.

Fred Evans · 3rd March 2006, 00:56

I had experience of treating vestibular bends when I was supervising air range diving in the north sea many years ago now. In neither case did there seem to be any reason for the hits, but we were diving in 130ft using US Navy tables so maybe that’s cause enough . One of the divers had reoccurrence on another two occasions and eventually lost his medical because of it.

Hope your student is luckier.

Regards, Fred

apitkin · 5th March 2006, 00:49

I've treated a few too. Same sort of thing, relatively innocuous dives. I think one was after a dive to 18 metres.

This type of bend (more than the others) seems to be down to bad luck.

Andy

Simon Mitchell · 7th March 2006, 17:55

Seb,

One of the points that David Doolette and I made in our paper was that inadequate decompression of the inner ear, combined with a probable susceptibility to adverse effects from formation of even very small bubbles, makes this organ vulnerable to DCS. Everyone seems to focus in on the isobaric counterdiffusion thing which is just another potential contributor. I guess we didn't make a good enough job of emphasising the former point. Anyway, inadequate decompression can occur with any breathing gas, including air. Isolated IEDCS certainly does occur in air diving, and there are several papers describing series of such cases. You could try:

Nachum et al. Inner ear decompression sickness in sport compressed-air diving.Laryngoscope. 2001 May;111(5):851-6.

Shupak A et al. Inner ear decompression sickness and inner ear barotrauma in recreational divers: a long-term follow-up. Laryngoscope. 2003 Dec;113(12):2141-7.

The latter paper also discusses the issue of distinguishing between IEDCS and IEB. I agree that this can be difficult, but there are usually a lot of clues available from a careful history and examination.

You could also try:

Klingmann C et al. Embolic inner ear decompression illness: correlation with a right-to-left shunt. Laryngoscope. 2003 Aug;113(8):1356-61.

This paper proposes a link between IEDCS and PFO. This is a very interesting finding and not at all incompatible with our theory of inadequate decompression of the inner ear. Indeed, I am drafting another paper (heavily dependent on David's modelling skills as usual) which addresses the "marriage" of our two hypotheses.

One of the problems you face in trying to understand this process, is that you are dabbling in an area that is at the limits of our current understanding.

Hope this helps.

Simon M

Pelagian · 8th March 2006, 22:07

Thank you Simon

That's incredibly helpful.

I found your paper to be just technical enough without overwhleming me.

I'll get cracking on the other papers.

Cheers

Seb

27th February 2006, 23:43	#11 (permalink)
ROB DAVIE Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: HOUSTON, REPUBLIC OF TEJAS Posts: 1,120	Re: Inner Ear DCS Quote: (Originally Posted by Pelagian) We're arranging a consult with an ENT who is also a DIVe Doc to see if he can throw sone light on the subject(pun intended). He has suggested that a roundwindow fistula or other barotrauma maybe the culrpit. He's not the only one who has suggested this. I'll post what we find out. Cheers Seb Seb, I would have commented originally, but was thrown a bit by the lack of real depth, and the fact that it was on air. I think the track you suggest above will turn out to be the right one. Hope your friend heals up fast! Rob
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1st March 2006, 02:11	#12 (permalink)
babar Curmudgeon Current Rebreather/s: Evolution Sport Kiss Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Other CCR Join Date: Apr 2005 Location: Southern California Posts: 417	Re: Inner Ear DCS Quote: (Originally Posted by Pelagian) Dave Thanks for the summary, my interpretation of the paper was the same. The problem here is that this case did not involve helium or deep diving. I know there is unlikely to be a cut'n'dry answer , just trying to find out as much as we can to help the diver in question assess his options for continuing his diving. We're arranging a consult with an ENT who is also a DIVe Doc to see if he can throw sone light on the subject(pun intended). He has suggested that a roundwindow fistula or other barotrauma maybe the culrpit. He's not the only one who has suggested this. Apparently differential diagnosis between IEDCS and IE barotrauma's is tricky as many symptoms are the same, and since recompression treatment has so far proven less effective on IEDCS than other types, the 'lets see if it gets better in the chamber' approach is also proving inconclusive. I'll post what we find out. Cheers Seb IEDCS vs perilymph fistula is a very tricky differential diagnosis. At what point in the dive did it manifest? If it was directly after a forceful equalization, that might point more towards PF. Minutes to hours after the dive more likely IEDCS. When did it happen, and what symptoms did he have? and what treatment was done initially? Is he getting any better? __________________ Babar Evolution Plus Sport kiss
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1st March 2006, 06:20	#13 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 574	Re: Inner Ear DCS Quote: (Originally Posted by Pelagian) Dave Thanks for the summary, my interpretation of the paper was the same. The problem here is that this case did not involve helium or deep diving. Seb It doesn't necessarily have to. Isobaric counterdiffusion is only one mechanism by which bubbles can form in the inner ear tissues/fluids. Otto Molvaer has written an excellent chapter in Bennett and Elliott on the otorhinolaryngological aspects of diving. In this he reminds us that "the most common mechanism of bubble formation is too rapid a decompression". By this he means that while isobaric counterdiffusion may be the cause of IEDCS in some patients the bubble formation may simply have been caused by ordinary old DCS, independant of counterdiffusion. Furthermore barotrauma can also cause injury to the middle and inner ear entirely independant of any decompression related bubble formation. This can cause symptoms identical to IEDCS and the two can coexist in the same patient. Separating the three potential aetiologies in a patient with putative inner related symptoms can be difficult or impossible. __________________ Andrew Bowie Rebreather-friendly Buddy
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1st March 2006, 23:44	#14 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	Re: Inner Ear DCS Hey Andrew I think we're on the same page. My point was that IEDCS due to Helium CD has more information, and what I'm looking for is anything on IEDCS from plain old Nitrogen based single gas dive. By all accounts his deco was minimal and his ceiling cleared by the time he reached 50ft on very slow ascening multilevel dive. Having spoken again to the diver, it appears to be DCS rather than a Fistula or other barotrauma as his symptoms(nausea, vomiting, vertigo) onset 10 mins after surfacing. He also became asymptomatic upon reaching depth during his first treatment table(60ft 5-6hrs). After 4 treaments he has been discharged with no follow up and minor nausea being the only residual which may well be due to O2 poisoning from the treatment. As soon as we have anything from his ENT consult i'll put it up. Thnaks again for eveyone's input. Seb __________________ 'Because... I was Inverted!'
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2nd March 2006, 08:09	#15 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 574	Re: Inner Ear DCS Fair enough Seb; I didn't really fully read the thread before replying. Seems that you and others had already made the points I did. __________________ Andrew Bowie Rebreather-friendly Buddy
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2nd March 2006, 22:39	#16 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 556	Re: Inner Ear DCS It seems that gas switching mid-stop, rather than upon arrival at or just before departure from any stop depth might help. If the stop is too brief, extending the stop before and after the switch might help if supersaturation is the problem.
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3rd March 2006, 00:56	#17 (permalink)
Fred Evans Old Bull Current Rebreather/s: Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: Indonesia, Jakarta Posts: 51	Re: Inner Ear DCS I had experience of treating vestibular bends when I was supervising air range diving in the north sea many years ago now. In neither case did there seem to be any reason for the hits, but we were diving in 130ft using US Navy tables so maybe that’s cause enough . One of the divers had reoccurrence on another two occasions and eventually lost his medical because of it. Hope your student is luckier. Regards, Fred
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5th March 2006, 00:49	#18 (permalink)
apitkin New Member Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Cloud Cuckoo Land Posts: 102	Re: Inner Ear DCS I've treated a few too. Same sort of thing, relatively innocuous dives. I think one was after a dive to 18 metres. This type of bend (more than the others) seems to be down to bad luck. Andy
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7th March 2006, 17:55	#19 (permalink)
Simon Mitchell New Member Current Rebreather/s: MK 15.X Other Rebreather/s: Join Date: May 2005 Location: New Zealand Posts: 177	Re: Inner Ear DCS Seb, One of the points that David Doolette and I made in our paper was that inadequate decompression of the inner ear, combined with a probable susceptibility to adverse effects from formation of even very small bubbles, makes this organ vulnerable to DCS. Everyone seems to focus in on the isobaric counterdiffusion thing which is just another potential contributor. I guess we didn't make a good enough job of emphasising the former point. Anyway, inadequate decompression can occur with any breathing gas, including air. Isolated IEDCS certainly does occur in air diving, and there are several papers describing series of such cases. You could try: Nachum et al. Inner ear decompression sickness in sport compressed-air diving.Laryngoscope. 2001 May;111(5):851-6. Shupak A et al. Inner ear decompression sickness and inner ear barotrauma in recreational divers: a long-term follow-up. Laryngoscope. 2003 Dec;113(12):2141-7. The latter paper also discusses the issue of distinguishing between IEDCS and IEB. I agree that this can be difficult, but there are usually a lot of clues available from a careful history and examination. You could also try: Klingmann C et al. Embolic inner ear decompression illness: correlation with a right-to-left shunt. Laryngoscope. 2003 Aug;113(8):1356-61. This paper proposes a link between IEDCS and PFO. This is a very interesting finding and not at all incompatible with our theory of inadequate decompression of the inner ear. Indeed, I am drafting another paper (heavily dependent on David's modelling skills as usual) which addresses the "marriage" of our two hypotheses. One of the problems you face in trying to understand this process, is that you are dabbling in an area that is at the limits of our current understanding. Hope this helps. Simon M Last edited by Simon Mitchell : 7th March 2006 at 21:54.
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8th March 2006, 22:07	#20 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	Re: Inner Ear DCS Thank you Simon That's incredibly helpful. I found your paper to be just technical enough without overwhleming me. I'll get cracking on the other papers. Cheers Seb __________________ 'Because... I was Inverted!'
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