Here's a query from a scuba instructor:

57 year old male, history of alcoholism & suffering cirrohsis of the liver. Very large, distended belly ( has the largest "outie" belly button you've ever seen! ), but otherwise not obese. Passed the N.A.U.I. pool test better than most of his classmates. Claims his drinking days are past & has non-diving physician, unrestricted approval to participate. No other medical contraindications noted on the standard N.A.U.I. medical questionaire. He is an educated man ( prof. engineer ) with previous sport diving experience years ago... What is your advice?

Answer:
It is highly likely that your diver has ascites (large quantities of free fluid in his abdomen surrounding his organs). In addition to his umbilical hernia (which can rupture easily under these circumstances) which has occurred in response to the excess pressure of the fluid - it is also highly likely that he has esophageal varices or dilated blood vessels in the lower end of his gullet.

Due to the effects of immersion on the blood supply of the body, during a dive blood is shunted from the periphery into the blood vessels of the gastrointestinal tract, liver and spleen. This would cause dilation and possible rupture of the esophageal varices with massive hemorrhage. Add to this the acid reflux changes that occur about the cardia (lower end of the gullet and upper stomach) due to the action of Boyle's law during ascent and we have a set up for rupture of not only the varices but the stomach.

This not just a theoretical possibility but has been reported.
 
Massive variceal bleeding caused by scuba diving.
Am J Gastroenterol. 2000 Dec;95(12):3677-8.
Nguyen MH, Ernsting KS, Proctor DD.
http://snipurl.com/3s76

Finally, cirrhosis of the liver to the extent that it causes ascites can have significant mental effects of obtundation of the intellect. Hepatic encephalopathy can cause apathy, confusion, disorientation, drowsiness and slurred speech. This alone would be dangerous enough to disallow diving.

Because of what I consider significant risk, I would not certify this person as fit to dive.