What is Hydranencephaly?

In my early days after hearing my son's diagnosis, I was living in a bit of a fog. I remember how determined I was for answers, I felt deep down that death wasn't the only option although it was the only one given to us by doctors...it was not a denial feeling as some mistook it for, but a true motherly intuition. I knew he wasn't dying, not soon, and I knew I was determined to give him the best quality of life possible.

Going against the many advisories to not look up information online, I found the Rays of Sunshine homepage at www.hydranencephaly.com. I was so excited, and crushed all in one hours worth of reading...but upon continuing to read story after story of amazing hydran miracles, my sense of hope was restored. I also joined the Yahoo groups and interacted with other hydran families I found there. It was a God-send to find the information, and some of the people, when I did. Now I'm hoping to consolidate the continuing research I've done here on my own blog, in my own words, in my own experiences.

According to Wikipedia, mostly...I've added my own information along the way:
Hydranencephaly is a type of cephalic disorder, meaning it is a congenital condition that stems from damage to or abnormal development of the nervous system. This is a rare condition in which the cerebral hemispheres are absent and replaced by sacs filled with cerbrospinal fluid, which is basically the fluid that the brain would normally "float" in. Many people, doctors included, confuse this with hydrocephalus, which is an accumulation of cerebrospinal fluid in the ventricles around the brain itself, not in place of.
In "hemihydranencephaly", only half of the brain is filled with fluid.
Usually the cerebellum and brainstem are formed normally, although in some cases the cerebellum may also be missing completely. In Bray's instance he has a smaller than normal but fully functioning cerebellum and completely normal brainstem. Most infants with hydranencephaly appear completely normal at birth or may have some distortion of the skull and upper facial features due to fluid pressure inside the skull, as Brayden definitely had. It's oftentimes called "baby-doll face" with "sunsetting eyes". The infant's head size and spontaneous reflexes such as sucking, swallowing, crying, and moving the arms and legs may all seem normal, depending on the severity of the condition. However, after a few weeks the infant usually becomes irritable and hypertonia, increased muscle tone, becomes obvious. Luckily, Bray only suffers from moderate hypertonia and we've been very fortunate to have reduced much of that with massage and stretching exercises. Generally after several months of life, various types of seizures and hydrocephalus (excess fluid build-up in the head) may develop. Other symptoms may also include visual impairments of varying degrees, lack of growth, deafness, blindness, spastic quadriparesis (paralysis), and intellectual deficits.
Some infants may have additional abnormalities at birth including seizures, myoclonus (involuntary sudden, rapid jerks), and respiratory problems.
Causes
Hydranencephaly is an extreme form of porencephaly, which is characterized by a cyst or cavity in the cerebral hemispheres, and may be caused by vascular insult or injuries, infections, or traumatic disorders after the 12th week of pregnancy. Occasionally it's discovered that twin-to-twin trasfusion has caused one infant to be blocked from crucial developmental stages. Ultimately, I've found, that it's believed that a stroke has been suffered in utero for some reason or another...however, most often the exact cause can never be determined for sure.
Diagnosis
MRI confirmed Bray's diagnosis at birth, previous to that they didn't seem to know for sure what was going on by viewing ultrasound images alone. I've read that normally it can be confirmed from high-resolution ultrasounds, so now I wonder if the doctors just didn't want to confirm anything because they were so convinced he wouldn't survive to term. Diagnosis after delivery, in some cases, may be delayed for several months because the infant's early behavior appears to be relatively normal. Transillumination, an examination in which light is passed through body tissues, usually confirms the diagnosis. Every parent should be prepared for this, since it's a traumatic time when a doctor discovers that your child's head turns into a glow-bulb...and suddenly you feel like your baby is a science experiment and not a baby anymore. I've heard horror stories of less than empathetic doctors doing just that, but fortunately Bray has not endured this examination at any time.
Prognosis
There is no standard, medical, treatment for hydranencephaly itself. Treatment is symptomatic and supportive according to complications that may arise as they do so. The hydrocephalus may be treated with a shunt, and Bray had a VP shunt placed after much fighting at one month of age.
The prognosis for children with Hydranencephaly is generally quite poor. Death usually occurs in the first year of life.In a survey completed by 88 families of children with Hydranencephaly from 2006-2007, 69% of the children who had died, did so after their first birthday. The oldest of the children who had died was in their 20s. 62% of the children represented in the survey were over the age of 1 at the time it was filled out. The first year is the hardest for children with Hydranencephaly but survival is possible, regardless of the questions of quality of life.

That ends with the question of "quality of life". People wrongly assume that you must have all of your brain to function and live a happy and fulfilled life...let me state again, WRONGLY ASSUME. Hydranencephalic children only make up a tiny portion of the population who function "typically" using only a small portion of their brain...in some of those instances, the general population has absolutely no idea.

In Prolonged survival with hydranencephaly: a report of two patients and literature review in the publication Pediatric Neurology, Volume 23, Issue 1, July 2000, Pages 80-84 by Gary N. McAbee, DO, JD, Allison Chan BS, and Edmund L. Erde PhD.
"Infants with hydranencephaly are presumed to have a reduced life expectancy, with a survival of several weeks to months. Rarely, patients with prolonged survival have been reported, but these infants may have had other neurologic conditions that mimicked hydranencephaly, such as massive hydrocephalus or holoprosencephaly. We report two infants with prenatally acquired hydranencephaly who survived for 66 and 24 months. We reviewed published reports to ascertain the clinical and laboratory features associated with survival of more than 6 months. This review demonstrates that prolonged survival up to 19 years can occur with hydranencephaly, even without rostral brain regions, with isoelectric electroencephalograms, and with absent-evoked potentials. Finally, the ethical aspects of these findings, as they relate to anencephaly and organ transplantation, are discussed."

These are the kind of posts that really make it seem hydran children are living in a vegetative state. Early on, so much was focused on the fact that Bray was doing the things he was doing completely involuntarily, such emphasis was placed on the fact that sucking, swallowing, crying, breathing, moving were all involuntary actions in a newborn. I was prepared for all of that to stop one day. Instead, as he got older and older, it became more and more obvious that he was doing things with a purpose and he was quite familiar with his surroundings. He is a living, and breathing child who deserves optimistic providers and a chance to live a life outside of his condition...as does every other child regardless of the condition they're titled with.

At WebMD, there is a closer look into the condition which paints a bit of a clearer and more detailed picture, in my opinion:
The word hydranencephaly is a fusion of hydrocephalus and anencephaly, but the condition actually represents a distinct disorder. The condition is characterized by near-total or total absence of the cerebral cortex and basal ganglia. The thalami, pons, cerebral peduncles, and cerebellum are usually present, as may be a small amount of tissue from the occipital, frontal, and temporal lobes. (I myself was shocked upon reading this, because the definition I had been given at my son's diagnosis was that he had a brain-stem and that was all that was in his head...the end?!)
Pathophysiology
Although hydranencephaly is not a well-defined entity, it is considered to be the result of a destructive process or lesion in a previously normal brain. The changes resulting in hydranencephaly can occur at any time from the 11th or 12th week of gestation through the first postnatal year.
Hydranencephaly usually occurs sporadically, although Witters and colleagues reported that a rare, specific form of the disorder, Fowler-type hydranencephaly, appears to have an autosomal recessive inheritance. The most commonly suspected causes of the nongenetic form of hydranencephaly are in utero vascular accidents and infections, such as those caused by Toxoplasma gondii, cytomegalovirus, and herpes simplex, which can cause necrotizing vasculitis and encephalitis. (shocked, once again, to learn that there are more than one type of hydran...varying degrees equal varying results)
Placental abnormalities, diffuse hypoxic-ischemic brain necrosis, the toxic effects of drugs, and thromboplastic material embolized from a deceased co-twin also have been implicated as causative factors.
Frequency
United States
~Hydranencephaly occurs in less than 1 in 10,000 births.
International
~Hydranencephaly occurs in less than 1 in 10,000 births.
Mortality/Morbidity
Hydranencephaly is associated with a markedly reduced life expectancy, with the condition often resulting in stillbirth or a lifespan of less than 1 year. However, there are reports of prolonged survival. With aggressive care, patients can live into their third decade. (Bray's doctors, obviously hadn't heard this...please also note that care doesn't necessarily have to be very aggressive, you just have to be disciplined in doing the research to not let anyone talk you in to giving up to easily)
The variability of survival is probably related to the severity of involvement of brain structures as well as to the aggressiveness of nursing care.
Prolonged survival has not proven to be associated with an improvement in responsiveness or awareness.
Race
No known race predilection exists.
Sex
No known sex predilection exists.
Age
Hydranencephaly is primarily a disease of the fetus; encephaloclastic encephalomalacia can occur in cases of severe perinatal insult.
Anatomy
Hydranencephaly is a loss of the cerebral tissues supplied by the anterior circulation (that is, the internal carotid arteries), with preservation of tissue supplied by the posterior circulation (specifically, the vertebrobasilar system). The portions of the brain supplied by the anterior and posterior circulations can be variable. However, the posterior circulation typically supplies the posterior fossa structures, occipital lobes, and thalami, whereas the anterior circulation supplies the temporal, parietal and frontal lobes. The thalami typically receive their blood supply from posterior circulation perforating vessels, which is why the thalami are preserved in cases of hydranencephaly.
The anterior or posterior circulation may supply the basal ganglia, and feeding vessels may originate from both circulations. In addition, portions of the posterior and medial parietal lobes can have a blood supply from the posterior circulation, although they are usually fed by the middle cerebral artery (MCA) and anterior cerebral artery (ACA), which are anterior branches.
Therefore, hydranencephaly is anatomically characterized by a loss of the cerebral mantle, with variable preservation of small remnants of the occipital and temporal lobes, as well as, at all times, small, basilar portions of the frontal lobes. The thalami and posterior fossa are preserved, as is the brainstem (although it is usually atrophic at histologic evaluation).
Presentation
At birth, children with hydranencephaly may appear healthy, but developmental delay becomes apparent within a few weeks. Common manifestations of the condition include irritability, abnormal muscle tone, seizures, and increasing head size (as a result of hydrocephalus). Swallowing difficulties lead to malnutrition, aspiration, and pneumonia.
Transillumination of the skull has been used to document the large fluid collection in these patients, but its importance and use have decreased because of the availability of cross-sectional imaging.
Preferred Examination
In utero, hydranencephaly is frequently diagnosed with ultrasonography. Magnetic resonance imaging (MRI) is probably the best modality for the overall evaluation of the anomaly and for the documentation of cortical remnants.
Limitations of Techniques
Postnatally, cranial ultrasonography can detect the absence of cerebral tissue, differentiated from alobar holoprosencephaly by the cleaved thalami and the presence of the falx cerebri. Because the brain beneath the fontanelle is clearly visible, absence of any cortical remnant at this level is helpful in the important differentiation of hydranencephaly from severe hydrocephalus. However, if the fontanelle is small or if appropriate high-frequency transducers are not available, it is possible in severe hydrocephalus to overlook a thin rim of cortical mantle.
On computed tomography (CT) scans, cortical tissue below the parietal bony convexity may be overlooked. In these cases, thin sections and overlapped coronal reconstructions may be helpful. In severe hydrocephalus, MRI can reliably depict the remaining cerebral cortical rim.


Okay, alot of that was a bunch of mumbo-jumbo...but there it is! I spent hour after hour looking up pieces of the brain only to discover that what I was reading didn't matter because my son's MRI stated differently than what was expected once I received the printed results. Here's his first MRI results taken the morning after he was born, he's had 3, and I'm sure they won't be the last:

"The head is abnormally enlarged relative to the face. Most of the brain parenchyma is replaced by CSF fluid predominantly in the frontal, temporal and parietal regions with very small thin cortical mantle preserved in the anterior frontal-temporal and posterior parietal regions. The cerebellum is somewhat small in size, but remarkably with normal configuration and signal intensity. The thalami are not fused. THe brainstem is normal in size and signal. Normal falx is visualized. On the GRE sequence, tehre are multiple foci of hemosiderin staining in the biltaeral parasagittal regions likely within the ventricular choroid plexus related to remote homorhage. no definite restricted diffusions is visualized. Findings most consistent with hydranencephaly."

I'd be lying if I told you I understood what all that meant. But I did want to include it, if you're like me just knowing that it comparable to another is settling. I spent a good amount of time trying to understand all of that. Basically, the conclusion I've come up with is that is doesn't matter. He's missing large portions of his brain, and miraculously doing wonderfully despite. He's not the only child to amaze doctors and do the unthinkable. The brain is a huge mystery, I don't care what doctor thinks they're a professional in the neurological field...there's still a lot of unknowns when it comes to the functioning of the neurological system. To prove that explicitly, I discovered the idea of neurological plasticity.