In hydroencephaly, most of the brain's front and most important hemispheres are missing or replaced with fluid-filled sacs. It is a rare and severe birth defect affecting brain development. Most babies with hydranencephaly die before or shortly after birth. Hydranencephaly causes severe neurological problems, including blindness, deafness, seizures, and intellectual disability.
The exact cause of hydranencephaly is unknown, but it is believed to be related to a disruption of the blood supply to the developing brain during the first trimester of pregnancy1. Some of the possible causes are:
Infections, such as toxoplasmosis, cytomegalovirus, or syphilis, that can damage the fetal blood vessels or the placenta.
Trauma, such as a maternal injury, a placental abruption, or a cord accident, that can cause bleeding or reduced oxygen to the fetus.
Genetic or chromosomal abnormalities, such as trisomy 13, trisomy 18, or Turner syndrome, that can affect the formation of the brain or the blood vessels.
Environmental toxins, such as mercury, lead, or radiation, that can interfere with the normal development of the brain.
The symptoms of hydranencephaly may vary depending on the extent of the brain damage and the presence of other anomalies. Some of the common symptoms are:
An enlarged head (macrocephaly) due to the accumulation of fluid in the skull.
A sunken appearance of the eyes (enophthalmos) due to the lack of brain tissue behind them.
A small or absent nose (arhinia) or a single nostril (ethmocephaly) due to the malformation of the midline structures of the face.
A cleft lip or palate or other facial defects due to the abnormal development of the facial bones and muscles.
No response to light, sound, touch, or pain due to the absence of the sensory areas of the brain.
Seizures, spasms, or abnormal movements due to the irritation of the remaining brain tissue or the brainstem.
Breathing, feeding, or temperature regulation problems due to the impairment of the autonomic functions of the brainstem.
The diagnosis of hydranencephaly can be made before or after birth, based on the results of various tests and examinations. Some of the tests that may be used to diagnose or confirm hydranencephaly are:
Using ultrasound, which uses sound waves to create images of a fetus inside the womb, hydranencephaly can be detected as early as the 12th week of pregnancy by showing the absence or abnormalities of brain hemispheres.
It uses a strong magnetic field and radio waves to create detailed images of the brain and skull in magnetic resonance imaging (MRI). In cases where ultrasound is inconclusive or unclear, MRI can provide more information about the type and extent of hydranencephaly.
A CT scan, which uses X-rays to create cross-sectional images of the brain and skull, is a type of computer tomography (CT). In addition to detecting the presence or absence of brain hemispheres and fluid-filled sacs, CT scans are less accurate and more invasive than ultrasound and MRI scans.
An examination of the baby's appearance and function after birth can confirm hydranencephaly's presence and severity, as well as identify any associated complications.
There is no cure for hydranencephaly, and the treatment is mainly supportive and palliative. There are several possible treatments for hydranencephaly, depending on the symptoms and complications, as well as the baby's and family's preferences and needs.
A number of drugs are available to help control symptoms, such as seizures, spasms, or pain. However, medications only reduce the frequency and severity of the symptoms, not prevent them from occurring.
It is possible to relieve some of the pressure in the skull by undergoing surgery. A shunt or tube may be placed to drain excess fluid from the brain into the abdomen or the heart, or a part of the skull may be removed to expand the brain. The baby's comfort and quality of life can be improved by surgery, but its brain development and function are not affected.
In order to develop the baby's motor, cognitive, language, or social skills, therapy can include physical, occupational, speech, or behavioral therapy. By getting therapy, the baby can become more independent and self-confident and reach their potential.
The baby and the family can receive emotional, psychological, or practical assistance through counseling, education, or social services. In addition to helping the baby and the family cope with hydranencephaly's challenges and stress, support can assist them in accessing the care and resources they need.
There is no known way to prevent hydranencephaly, as it is a rare and complex condition that occurs before birth. However, some measures that may help reduce the risk or the severity of hydranencephaly are:
Prenatal care and genetic counseling are important, especially if the family has a history of brain disorders such as hydranencephaly. During pregnancy, prenatal care can monitor the fetus's health and development, and genetic counseling can assist in determining hydranencephaly's chances and options.
Avoiding harmful substances or infections during pregnancy, such as alcohol, drugs, mercury, rubella, or toxoplasmosis. It is possible for these substances or infections to interfere with the normal development of the brain and blood vessels, leading to hydranencephaly or other complications.
Taking folic acid supplements before and during pregnancy, as prescribed by your doctor. Folic acid is a vitamin essential to the formation of the neural tube, which forms the brain and spinal cord. Deficit of folic acid can cause neural tube defects, including spina bifida and anencephaly, both of which are sometimes associated with hydranencephaly.
