Arachnoid cyst

[Sue Sue]

What level of risk is there diving with a posterior fossa Arachnoid cyst?

 

[fisherdvm]

Might be a nidus or origin for seizures. Would not recommend diving, as oxygen toxicity and DCS can initiate seizures in some people.

 

[TSandM]

It's an unanswerable question, because the number of people with arachnoid cysts is small, and the intersection between that group and the group of divers is going to be smaller yet. And the majority of people with arachnoid cysts are asymptomatic, and the cyst is found as an incidental finding at neuroimaging done for another reason.

If that was the case, and the cyst was an incidental finding at CT or MRI done for, say, evaluation of minor head trauma, I would think it unlikely that there would be any contraindication to diving. On the other hand, I'd be worried about the symptoms that caused the neuroimaging to be done, if it were anything other than minor trauma.

This is not individual medical advice, but merely my analysis of the resource material I found on arachnoid cysts.

 

[shakeybrainsurgeon]

Posterior fossa cysts are not foci for seizures. In general, unless the cyst causes hydrocephalus or is associated with a tumor (both very rare), it is a congenital abnormality that should not be a contraindication for anything, including diving.

You should seek the advice of a neurosurgeon before diving, each case is different. But in my experience, arachnoid cysts are MRI abnormalities and rarely cause symptoms or limit lifestyle.

 

[TSandM]

Thanks, SBS!

 

[Sue Sue]

Dear all and especially SBS.. Yes, the cyst was an incidental finding to a CT scan done because of headache since February. The HA, per my PCP is most likely due to the wonderful Austin, TX Cedar Fever and Allergic Rhinitis symptoms. Most likely worse right now due to the crazy rain and extreme swings of the barometirc pressures we get here with the weather since, which started in February. Now as far as the Arachoid cyst, the MRI is on Thursday to confirm the CT findings. The fact that it is now 19 mm and does exert slight mass effect on the pons and adjacent cerebellum is the most concerning to me. Also, this finding may be why I have had brief episodes of vertigo. (Just thought it was hormones, and it still could be). Of course, I will follow up with my PCP and will go on to a neurosurgeon who has an area of expertise in the Arachnoid cyst area.

I truly love diving, however, IF this new problem, becomes and issue, and I must stop diving, then I will bid farewell to this part of my life. Right now, I am adjusting to the fact that I am carrying a bit a baggage in my head. Actually, I now understand where those voices are coming from !!!! Again, thanks to all. Sue Sue

 

[fisherdvm]

does exert slight mass effect on the pons and adjacent cerebellum is the most concerning to me.

If you find that you tend to scuba in circles, wearing a big fin on one side and a small fin on the other side might correct that tendency.

 

[shakeybrainsurgeon]

For most arachnoid cysts, worst case scenario is a shunt (a plastic tube/valve device inserted under the skin) to divert any fluid pressure build up into the abdomen. A shunt is not incompatible with diving...I personally have shunted people and returned them to diving without incident (including a commercial diver). Fluid is non compressible and shunts work above and below water. The diver just has to be careful that the mask strap doesn't compress the shunt under the skin.

There is a difference between deformity of the cerebellum and pons due to relatively recent pressure build up and deformities that are congenital, i.e., the pons and cerebellum developed into an abnormal shape early on. This finding is not by itself indicative of trouble.

Vertigo is a little worrisome. I would definitely see a surgeon before diving, but take heart. These cysts are not uncommon. I would ask: was the scan contrasted? Other things to note: is the posterior fossa bone thinner under the cyst (a sign of a very slow or congential process)? Are the lateral ventricles or fourth ventricle enlarged?

Keep us posted.

 

[Sue Sue]

SBS: Thanks for the info and also, thanks for the questions. The Ct was without Contrast and per the report ventricles were WNL. There is also subtle benign appearing remodeling of the adjacent petrous ridge. Otherwise negative. Tomorrow is the MRI so I will know more soon. Thank goodness. Even though I know that this is one of the more basic brain issues..I still have the thoughts of the "What if's" in the back of head, well, I guess I do, literally. However, onward and forward. Thanks again. sab

fisherdvm: I just got new black scuba pro split fins. I was using the yellow ones before. What happens, since one is more buoyant than the other, if I wear one of each AND go around in circles ? Picture that......

 

[fisherdvm]

fisherdvm: I just got new black scuba pro split fins. I was using the yellow ones before. What happens, since one is more buoyant than the other, if I wear one of each AND go around in circles ? Picture that......

In this case, you will not be going around in circle, you will be traveling in a straight line, but your body will spin in a rotational axis.