Saturday, April 21, 2007

Underlying Diseases

Organ transplants don't often "just happen." For a vital organ to lose so much function that it needs to be replaced, some disease has progressed to the point that it's causing serious problems. While the underlying cause is sometimes unknown (a single-digit percentage of cases), some underlying diseases are pretty frequent in the transplant world. Despite the commonalities of the transplant experience between patients, specific diseases tend to share an even more common experience. Also, many of these diseases have effects, stories, and communities that go beyond the subset that are transplant-specific. To highlight some of the places where transplant patients come from, this post is a summary of four specific underlying diseases.

Diabetes

Diabetes mellitus is what happens when the body has a lack of insulin activity, either because insulin can't be produced (Type 1 diabetes) or it can't be used (Type 2 diabetes). It's an extremely common disease, affecting 20.8 million Americans in 2005. Diabetes doesn't just affect sugar metabolism, but the use of carbohydrates, fats, and proteins. It can affect almost every organ system, including kidneys, peripheral nerves, eyes, and blood vessels of all types. A number of treatments are available, from medications of all types to injected insulin to insulin pumps to better regulate blood glucose levels to transplants.

Diabetes has a strong interplay with transplantation. It isn't just the indication for essentially all pancreas transplants; diabetic nephropathy is also the #1 disease causing the need for kidney transplants as well. Beyond those who have a transplant for diabetes, many transplant patients have diabetes as an additional disease. Also, diabetes can be a side effect of immunosuppression after transplantation, which is categorized as post-transplant diabetes mellitus (PTDM). Finally, type 1 diabetes is an autoimmune disease, and both diabetes and chronic rejection of transplants affect blood vessels, so basic research in diabetes and transplantation play off each other to lead to new advances for both groups.

Any disease that is so common is bound to have a large community on the Internet and in medicine in general. The American Diabetes Association is the center of this community, supporting everything from educational resources to research funding and advocacy. Unfortunately, there aren't too many blogs about diabetes or kidney or pancreas transplants related to diabetes. There are a couple in the "Adult Kidney & Pancreas Transplant Blogs" section, and other great blogs about diabetes in general such as Diabetes Mine and Six Until Me. Still, beyond the blogs or broadcasted stories, diabetes is an important part of transplantation.

Biliary Atresia

Biliary atresia is the most common underlying disease for pediatric liver transplants, responsible for about half of all pediatric cases and a much greater proportion of those in the youngest age groups. Biliary atresia is a rare and poorly understood disease. The number of new cases each year number in the hundreds, and the cause is not congenital, not genetic, not contagious (though possibly infectious), and...not known. The ultimate problem is that bile ducts "drop off" and don't develop fully enough to drain bile from the liver. No organ does well when it's not drained, and the liver is no exception, which leads many biliary atresia patients into cholestatic liver failure. The stories between patients are shockingly similar: initially assuming it was typical neonatal jaundice, undergoing a Kasai portoenterostomy to attempt to restore bile flow, and children going through the transplant experience at a very young age, with parents and families thrown into this world with them. Even though the condition is extremely rare, and everyone's life is different, the number of commonalities can make biliary atresia quickly seem like a relatively familiar disease.

Those with biliary atresia seem to have taken to blogging in great numbers, and an incredible number of individual stories are available in the "Pediatric Liver Blogs" section here. In addition, there are a few blogs of people facing biliary atresia but not requiring transplants, such as Imagine Bright Futures. Beyond blogs and Internet communities, those affected by pediatric liver diseases have assembled larger organizations such as Liver Families and C.L.A.S.S. (Children's Liver Association for Support Services).

Short Bowel Syndrome

Short bowel syndrome has a unique position in transplantation: the most common indication for the rarest type of transplant (intestinal transplant). The causes of short bowel syndrome fill an entire textbook of pediatric surgery, but the consequences are surprisingly uniform. The problems include intolerance to feeding (malabsorption, diarrhea, etc.), difficulties with vascular access for total parenteral nutrition (TPN), and the need for transplantation either from liver damage due to TPN or from losing sites for vascular access. "Tummy problems" sound a lot less exciting than heart, lung, or brain diseases, but the complications of short bowel syndrome can be as serious or deadly as any condition out there.

Short bowel syndrome and intestinal transplantation are a uniquely cloistered community. Only a handful of centers even attempt intestinal transplantation, and only a few of these have programs of any significant volume. Most people with short bowel syndrome end up at one of the institutions that have dedicated efforts in this area. Furthermore, many patients go between centers for second opinions, which leads to an even tighter network in this group. The short bowel community uses the Internet to the fullest, with a web site and mailing list (Gifts From Heaven), several blogs (such as The Short Gut News) and even a wiki.

Cystic Fibrosis

Cystic fibrosis is both simple and complex. For the simple part, it's caused by mutations in a single gene, for a single protein, with the general effect of impairing salt movement across membranes (specifically chloride ions). Water follows salt, and a lack of water movement makes various secretions thicker than usual. The complex part is the effects. Thick mucus in the respiratory system causes chronic and repeated lung infections (and sinus abnormalities) which get worse over time. In the gastrointestinal system, it can cause bowel obstruction in infants, liver disease, and pancreatic damage leading to diabetes. Cystic fibrosis is also unique in that it is always present from birth (though may not be recognized for years) and is a lifelong affliction. The survival of cystic fibrosis patients has improved incredibly, but just about all patients born with cystic fibrosis will die of cystic fibrosis, which means that there's far more to be done.

The vast majority of transplanted cystic fibrosis patients have lung transplants, with a few needing liver transplants, intestinal or multivisceral transplants, or heart-lung transplants. Cystic fibrosis is one of the top three diseases leading to the need for lung transplantation, and about two-thirds of pediatric lung transplants are for cystic fibrosis.

The cystic fibrosis community is uniquely organized and expressive. For the organizational end, the Cystic Fibrosis Foundation has led efforts ranging from research funding to center establishment to patient support. A recent New Yorker article by Atul Gawande discusses the extreme persistence and diligence needed in cystic fibrosis care, and the role of specific CF centers, the Cystic Fibrosis Foundation, and the CF community in striving for the absolute highest quality of care possible. As for Internet resources, the web site CysticFibrosis.com consolidates an incredible number of resources on the Internet, from foundations and support groups to mailing lists, blogs and wikis. The "Lung Blogs" section here has a number of blogs by cystic fibrosis patients and they tend to be especially well-written and vivid descriptions of living with both an organ transplant and chronic illness in general.

3 comments:

Aaron said...

Thanks for the wealth of information here. I learned quite a lot, especially about cystic fibrosis.

Paul Levy said...

Not related to this, but please check out Grand Rounds today at http://runningahospital.blogspot.com/2007/10/grand-rounds-volume-4-number-6.html. Some moving and insightful stories about experiences in hospitals. Thanks.

Medical Information said...

very informative post. I like it, good information about Diabetes you have provided over here.