Unexpected Skin Bends--Why

[BDSC]

I am interested to see how my up coming Grand Cayman trip will go with again fairly aggressive boat dives and no readily available O2.

Lisa

It will go perfectly!

 

[guyharrisonphoto]

Hi Guy, unfortunately I can't attach them here without violating copyright laws. The full issue is available through the UHMS for about $25.

Best regards,
DDM

I just ordered a copy. Thanks!

 

[guyharrisonphoto]

I had my Dr. appointment today and here is what I was told.

1. My skin bends were type one and the Doctor said a chamber treatment would have been absolutely unnecessary.
2. He sees divers with skin bends with some regularity (diving in Jupiter is deep, square profile, strong current and, I must say, many divers in the area really push or exceed recreational time depths and limits). He viewed my profiles for the dives in question as "fairly conservative." Most of these divers keep on diving and have occasional recurrences but do not develop more severe DCS.
3. Once you have them, you are more likely to have recurrences. He often sees that divers can dive for months or years and then have recurrences grouped over a fairly short time (month or two depending on how active they keep diving) and then sometimes long periods again without any recurrence.
4. In his view, I can resume diving and continue even if I have an occasional recurrence. I asked him about waiting 4 to 6 weeks.and he said this was not needed. Obviously, he also agreed that if they recurred I should monitor my self for other more serious DCS symptoms, but he said a trip to the ER for O2 would be unnecessary if there were no other symptoms and they resolved within 24-48 hours. He also said that if they keep recurring on every dive trip that more follow up would be prudent, but the occasional recurrence should not be a cause for concern apart from monitoring for other symptoms.

We then had a general discussion about skin bends, which I found interesting and will put the major points here. I am not vouching for whether he is right or wrong, but I thought offering this information would be valuable for discussion and comment.

1. He says there is not a clear causal connection between skin bends and more serious DCS. While they have a common causitive factor (depth, ongassing, then offgassing), most cases of skin bends do not show more serious DCS, and most cases of serious DCS do not show skin bends. He believes that are different types of mechanisms going on in the skin tissues than in the other tissues affected by serious DCS, and that skin bends are nitrogen working its way out through the skin directly as opposed to internal bubbling, but he said little is understood about the precise mechanism and this was his theory based on a review of studies and not a proven fact. He said he has seen one case where a chamber treatment made the mild skin bends worse as (he believed) the nitrogen worked its way out through the skin even faster in a pure O2 environment, which indicated to him type 1 skin binds was not necessarily connected to offgassing through the respiratory system.

2. He does not see the need for the 4-6 week waiting period with type 1 skin bends and no symptoms of more serious DCS. He thinks that severe DCS injures tissues in a fundamentally different way, which makes the long waiting period justified in that case.

3. I asked about more conservatism, longer safety stops, and O2 at the safety stops. He said that there is no evidence that these make any decisive difference on skin bends (they do for more serious DCS, he said). I could dive the computer/table limits and not have skin bends for months or years, or be conservative and still have them, and they could still stop appearing and not recur for a long time either way, or could keep appearing either way. I could have recurrences throughout my life and never develop more serious DCS. Obviously, he agreed that more conservatism would not hurt, but he said there was no guarantee it would help, either, for the type of skin bends I had. Apparently his experience with divers getting type 1 skin bends with some regularity and continuing diving with no other more serious DCS issues has led him to believe that this type of skin bends does not pose, by itself, a serious threat (I am making an assumption here, but this seemed to be the view, which is based on more aggressive divers in this part of the State).

Anyway, my plan is:

1. Wait another month, just in case, give my skin time to recover.
2. Start with a shallower profile
3. When i do a deeper profile (deeper than 50'), go to a more conservative computer setting.
4. See what happens before I take any other measures.

Like most things about diving related illness, there is still a lot that is unknown (as the Doctor was clear to say) . . . .

 

[scubadada]

So....why did you go so long with nothing, and then have 2 episodes of skin bends without known provocation? You're certainly accurate, we don't know everything

 

[guyharrisonphoto]

So....why did you go so long with nothing, and then have 2 episodes of skin bends without known provocation? You're certainly accurate, we don't know everything

He acknowledged no ready explanation as to "why me?". I gave him my lifetime dive history (2500+ dives over 45 years), my recent (December) liveaboard trip with 4 dives per day for a week, my seven deeper dives in Palm Beach and Jupiter this year before this happened. He only said that he has seen other divers with similar experience, less experience, and more experience, have skin bends even within computer limits, sometimes have a group of incidents, and then not have them for a long time, or not have them ever again. Because the mechanism is not understood, neither is a particular individual's susceptibility except that if you have them once, you are more likely than other divers to have them again but not necessarily . .

 

[uncfnp]

Thank you for posting your followup. If I might ask. My understanding is that there are two types of skin bends, one a relatively benign rash that matches much of what you said above and the other cutis marmorata that can herald a much more serious Type 2 event. How did the physician determine the type of skin bends you had? Are there photos? Or does he believe that all skin bends are created equal?

 

[KeithG]

Thank you for posting your followup. If I might ask. My understanding is that there are two types of skin bends, one a relatively benign rash that matches much of what you said above and the other cutis marmorata that can herald a much more serious Type 2 event. How did the physician determine the type of skin bends you had? Are there photos? Or does he believe that all skin bends are created equal?

Interesting thread. I am interested to understand more about type 1 vs type 2 skin bends. A few years ago my divebuddy developed skin bends in the middle of the night (around 1am-ish) on a LOB trip in the T&C.

We dive conservatively, do not go deep and do not push NDLs. So this was a surprise as we had been on the boat almost a dozen times.

After a thorough checklist of symptoms the boat captain diagnosed skin bends (he said type 2) and then she went on O2 for 2 hours and then 2 more hours. The captain also called DAN and the local dive doctor in T&C. They all agreed on the assessment. The pain and itchiness went away after the O2 but there was still some slight discoloration. Diving was done for the rest of the week.

Once back home we went to the local DAN doctor who knew nothing about diving. He claimed dive computers were totally untrustworthy and that no one should do more than 1 dive a day. He did have lots of very large DAN advertisements in his lobby. This made me wonder if DAN recommended Doctors have the same qualifications as Wine Spectator Restaurants?

We waited 6 months for the next dive trip (back on the same boat!) and she limited herself to 2 dives a day (instead of 3 or 4, never 5) with a max depth of 50 feet. No issues on that trip or our recent trip on a LOB in Belize.

 

[chillyinCanada]

I've had two episodes of skin bends.

What I noticed was that while the episodes occurred on separate trips,I'd been diving the same boat each time with back roll off the gunwales. This particular boat is too high for me and I've always had a bit of a struggle getting up onto the gunwale for the roll. Too me it was combination of weight gain and compression from the contortions. I've kept the weight off and dive nitro with (knock on wood) no further trouble.

I'd been diving approx 60 dives per year for many years at that point.

 

[BertStevens]

and dive nitro with (knock on wood) no further trouble.

Wow! You dive with nitro?!? Surprised you didn’t go BOOM on hitting the water!

 

[uncfnp]

Interesting thread. I am interested to understand more about type 1 vs type 2 skin bends. A few years ago my divebuddy developed skin bends in the middle of the night (around 1am-ish) on a LOB trip in the T&C.

We dive conservatively, do not go deep and do not push NDLs. So this was a surprise as we had been on the boat almost a dozen times.

After a thorough checklist of symptoms the boat captain diagnosed skin bends (he said type 2) and then she went on O2 for 2 hours and then 2 more hours. The captain also called DAN and the local dive doctor in T&C. They all agreed on the assessment. The pain and itchiness went away after the O2 but there was still some slight discoloration. Diving was done for the rest of the week.

Once back home we went to the local DAN doctor who knew nothing about diving. He claimed dive computers were totally untrustworthy and that no one should do more than 1 dive a day. He did have lots of very large DAN advertisements in his lobby. This made me wonder if DAN recommended Doctors have the same qualifications as Wine Spectator Restaurants?

We waited 6 months for the next dive trip (back on the same boat!) and she limited herself to 2 dives a day (instead of 3 or 4, never 5) with a max depth of 50 feet. No issues on that trip or our recent trip on a LOB in Belize.

There is a lot of info out there. Here is a post from another thread with some links...

The is so much info on this, SB and dive medicine internet based. I will try and link a few and will write more of what I know if I have time but basically there are two catagories of "skin bends." One is a fairly benign mild reaction that typically resolves without intervention. Traditionally considered a DCS I. Then there is the more serious version called cutaneous marmorata. This is the rash that is of concern because it can herald a more serious DCS neurological hit, brain and/or spinal cord. This is the rash associated with a PFO. It is the rash that chillyinCanada is describing.

Ask DAN: Skin Bends

Alert Diver | Skin Bends

Divers Alert Network, Cutaneous DCS with Transient Neurological Symptoms after a Hot Shower

Then there is the closely related lymphatic DCS that a SB regular recently experienced.

Dcs & Then Some

And Dr Simon Mitchell

Hello Islanddream.

I agree with DDM that there is no science behind these decisions.

My personal view is that if all you had was the rash, with no other manifestations, then a 6 month wait to dive is excessively conservative. As DDM has implied, the cutis marmorata form of rash is generally viewed as more "serious" but this perception arises because it is more frequently associated with other more serious symptoms (particularly spinal DCS) than the hive-like rash that he mentions. It is not that the cutis marmorata rash per se will harm you. If all you experienced was the rash with no other symptoms, then we would still view this as a mild episode of DCS. Put another way, the significance of cutis marmorata is that when we see it we are more alert to the possibility that more serious symptoms might arise. If no more serious sumptoms arise then the rash itself is essentially harmless.

We would normally advise divers in the latter situation (cutis marmorata rash but no other symptoms) to have a month off diving. This advice is not based on science, but there is a lot of experience with it, and there is no signal in our experience that it is insufficient time. Having said that, even a diver who waits six months or a year could suffer another event the next time they go diving just on the basis of bad luck. So whenever diving physicians give this sort of advice it is always heavily contextualised with a clear statement that there are NEVER any guarantees that there will not be a repeat event, no matter how long you wait. It follows that the decision to dive again, and when to dive, has to be made by you and you must take responsibility for that decision.

DDM mentioned the study which has shown that pigs may exhibit cutis marmorata after brain arterial gas embolism. Unfortunately this study has led to a fairly uncritical acceptance that cutis marmorata is (or may be) caused in this way in human divers. The truth is that a cutis marmorata appearance of the skin may be caused in many ways, and one of them is a significant adrenergic (think of it as an intense fight or flight) response. This can occur in a variety of medical settings. For example we see a cutis marmorata-like rash in illnesses like septic shock, or shock of any cause for that matter. Non diving brain injury can also cause it - we see it sometimes in brain bleeding events. It is not surprising therefore that cutis marmorata may be seen in severe stroke-like events caused by bubbles (as in the pigs in the study).

Two things get overlooked in conversations about this study. First, the pigs in the study were anaesthetised. Second, the doses of air used to elicit the cutis marmorata response would have produced significant stroke like symptoms if the pigs were awake. But in the vast majority of cases of cutis marmorata in human divers we don't see symptoms of brain injury. Indeed, it is very common to see cases like yours with no other symptoms at all. Thus, it seems that the dose of arterial gas required to elicit the response in pigs is simply not encountered in the vast majority of human cases. It certainly cannot be concluded on the basis of this study that human divers with cutis marmorata must have suffered from arterial gas embolism.

A proponent of the brain embolism hypothesis might argue that maybe you don't need such large doses of gas going to the brain to elicit the response in humans. But this reasoning can also be challenged. Humans undergoing strongly positive bubble contrast echo studies for PFO inevitably have their cerebral circulation showered with bubbles of relevant size to those which "often" enter the arterial circulation from the veins after diving. This happens every day in cardiology suites where PFO tests take place. Sometimes we even see transient cerebral symptoms after such studies, but we NEVER see cutis marmorata. If "sub-clinical" cerebral arterial bubble exposure were the cause of cutis marmorata in human divers, we would expect to see it more often in strongly positive PFO tests, but we never do.

I am not dismissing the study out of hand. It seems likely that cutis marmorata could be seen after serious arterial gas embolism in humans, but this would be accompanied by stroke like brain injuries, and the majority of cutis marmorata cases in divers (who do not exhibit such injuries) do not seem to be caused in that way.

Simon M