More Information About Grace's Diagnosis
What is Hydranencephaly?
Hydranencephaly is a rare condition in which the brain's cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid. An infant with hydranencephaly may appear normal at birth. The infant's head size and spontaneous reflexes such as sucking, swallowing, crying, and moving the arms and legs may all seem normal. However, after a few weeks the infant usually becomes irritable and has increased muscle tone. After a few months of life, seizures and hydrocephalus (excessive accumulation of cerebrospinal fluid in the brain) may develop. Other symptoms may include visual impairment, lack of growth, deafness, blindness, spastic quadriparesis (paralysis), and intellectual deficits. Hydranencephaly is considered to be an extreme form of porencephaly (a rare disorder characterized by a cyst or cavity in the cerebral hemispheres) and may be caused by vascular infections or traumatic disorders after the 12th week of pregnancy. Diagnosis may be delayed for several months because early behavior appears to be relatively normal. Some infants may have additional abnormalities at birth including seizures, myoclonus (spasm or twitching of a muscle or group of muscles), and respiratory problems.
What are some of the complications of Hydranencephaly?
Hydrocephalus – Hydrocephalus is often one of the first difficulties faced by the child. Some children have mild hydrocephalus but live their entire life without a shunt and some never do develop an increase in intracranial pressure from fluid.
Irritability – A child with Hydranencephaly is often very irritable in the first year. A build up of fluid is one of the first things to check if a child is irritable.
ncreased Muscle Tone – Children with Hydranencephaly may have increased tone in their bodies (spasticity). Physical and Occupational therapy can be very helpful in preventing problems from increased tone.
Seizures – Seizures are fairly common in children with Hydranencephaly (approx. 75% of children experience them). The type and severity of the seizures vary from child to child. Most of the seizures are fairly short and mild but some children do have longer more severe seizures. There are many different seizure medications children take. Often a child needs more than one medication at a time and they frequently need to have their medications changed. A problem both in diagnosing a child who has Hydranencephaly with seizures and in treating them is that EEGs, and medications are geared towards those who are having cortical seizures. Most children with Hydranencephaly have no cortex and have brain stem seizures.
Feeding – Children with Hydranencephaly may have trouble sucking and swallowing. Many families are told that their child will lose these abilities within a few weeks of birth when the "higher" cortical areas of the brain normally kick in, if this happens, the child would require tube feeding to survive.
Vision/Hearing –In one study, 92% of the children can hear. Some children may not understand what they hear but do respond to sounds and familiar words. 60% of the children are thought to see at least some of the time, many children have what is called Cortical Visual Impairment. This means that there is nothing wrong with their eyes, but that their brains aren’t able to tell them what they are seeing. This sort of vision can come and go so that children see some things and not others or will see one day and not the next.
Other Conditions Children with Hydranencephaly may have – Asthma/Reactive Airways disease (RAD); Diabetes Insipidus (a high sodium level and excessive urine output); Gastro esophageal Reflux (food comes up which causes vomiting or excessive acid production); Constipation; Some children also develop obstructed or difficult breathing and need to have a Bipap, ventilator, or tracheostomy.
Is there any treatment?
There is no definitive treatment for hydranencephaly. Treatment is symptomatic and supportive. Hydrocephalus may be treated with a shunt (a surgically implanted tube that diverts fluid from one pathway to another).
What is the prognosis?
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.