Monday, February 25, 2008

Okay, what's up with the numbers here?

I was curious about survival records for babies with anenecphaly. I found First-year mortality and survival among infants with selected congenital anomalies in Texas, 1995 to 1997

Anomalies with the lowest survival were anencephaly (5.13%), trisomy 13 (7.41%), and trisomy 18 (10.29%).

Am I reading this right? Because this looks as if 5% of the babies with anencephaly lived at least one year! This, if it's true, it flies in the face of everything else I've seen.

I wish I had access to the full article, so I could find out more. Another bit of research found that 5% of anencephalic babies lived more than 5 days. So it seems a bit odd that another study would find that same percentage surviving a full year! A study in Singapore found the longest survival to be 16 days.

Prolonged survival of two anencephalic infants. -- "Two infants with anencephaly survived for 7 and 10 months without the need for prolonged assisted mechanical ventilation."

I've been also looking for updates on Marcela de Jesus Galante Ferreira, who survived at least five months and is considered a total miracle. I haven't been able to confirm that she's still alive or that she died.

But everything still points at a 0% 1-year survival rate. This site indicates a 5% one week survival rate, far from a 5% one-year survival rate.


Anonymous said...

I remember reading a story in the Reader's Digest magazine *many* years ago (10-15?) of a baby who I think was diagnosed w/anencephaly at birth. What I remember is that doctors said she had only a brain stem, but for some reason put a shunt into her skull to drain the cavity of the excess fluid. The mom tirelessly operated the shunt (by pressing it in a certain way), and the baby lived longer than they expected. At a follow-up X-ray, the doctors were flabbergasted to find that she had a brain partially filling her skull. The explanation was that this baby had so much fluid in her head that her brain was compressed to the point where it looked like she just had a brain stem, but shunting the fluid out allowed her brain to decompress and function. I believe this baby had some mental disabilities, but she was definitely functioning. Her doctors said she wouldn't live or would just be a vegetable; I wonder how many babies diagnosed with anencephaly could similarly be helped.

Christina Dunigan said...

I know there was a case of a man -- I think in Europe -- who had a skull x-ray or a cat scan or something, and they discovered that his head had very little in it but fluid. He was a fellow that was normal in every way, though a dull normal.

There was another similar case in the UK, where they had to do a head x-ray for some reason and discovered that this unremarkable man who had never had any trouble had just a skull mostly of fluid, with just a thin layer of brain pressed against the skull.

But those weren't cases of anencephaly. In those cases, the skull actually never closes, and it's this that causes the problem of no brain developing.

Anonymous said...

I'm a researcher into congenital anomalies, and I'm investigating this phenomenon right now. The 10 month child reported by McAbee et al is the oldest specific survivor reported in the literature (as far as I can tell). So why are so studies reporting mortality rates of only 95% at 1 year (leaving a miraculous 5% surviving)?

I think the answer is that the methods they used to identify deaths are not 100% reliable, thus they miss one or two - if you miss one death from 20 live births, that leaves a spurious survival rate of 5%. It might sound careless, but it's actually VERY difficult to trace and match x-thousand deaths, so I have sympathy, although I don't understand why they haven't explained these nuances in their articles.

Christina Dunigan said...

Anon, so it sounds like they're counting as survivors any child whose death they don't learn about, meaning that the 5% is probably lost to follow up, not alive. Which would be easy enough to tabulate!

Anonymous said...

Exactly GrannyGrump. Unfortunately, their linking methods make it impossible to know exactly how many were lost to follow up, but I would guess somewhere around 5%!

Christina Dunigan said...

I've found that Baby K lived for over two years, with intensive support and over the vociferous objections of the nursing staff, who considered the care "futile".

kcho said...

Found this post while searching about anencephaly in Google. In case you're still curious:

Christina Dunigan said...

Let's convert that into a link!

I'm not clear if Nicholas is anencephaly or a very severe case of microcephaly. You can't trust that news report -- it says that anencephaly is "a genetic disorder" when it's not. It's nice to see a baby defy the odds, either way.

Mikk said...

I think the boy mentioned in the story, Nicholas, has hydranencephaly rather than anencephaly. Anencephalic babies literally don't have the top of their skull, so you can see the tissue--they have to wear bandages 24/7 to avoid infection. Hydranencephaly is similar; the baby lacks a brain, however the skull and head is closed up and filled with fluid.

Trisomy 13 Life with Natalia ~ Transformed by Love said...

Thanks for posting this, I've shared and passed it on.