Hydranencephaly - Causes, Symptoms, Diagnosis, and Management

What Is Hydranencephaly?

Hydranencephaly is a birth anomaly that affects the central nervous system of the body. In this type of abnormality, certain parts of the brain are missing. Usually, the cerebral hemispheres are affected. In the brain, the cerebrum is divided into two lateral hemispheres, the left and the right side hemispheres. The left side of the hemisphere controls the right side of the body, and the right side of the hemisphere controls the left side. The main function of the cerebral hemisphere is to control speech, thought, emotions, and learning capabilities. Hydranencephaly is a very severe form of bilateral cerebral anomaly.

Hydranencephaly is an abnormality where there are fluid-filled membranous sacs in the brain. These sacs are filled with cerebrospinal fluid (CSF) and remnants of the cortex and white matter. It is the protective layer that cushions the brain and the spinal cord of the body. Hydranencephaly causes deafness, blindness, paralysis, and intellectual defects in children. Moreover, the condition often results in death.

What Are the Etiological Factors Behind Hydranencephaly?

It is suspected that hydranencephaly is a disorder inherited from biological parents. While others believe that it is caused by blockage of the carotid artery in intrauterine life. However, the main cause behind the disorder is still unknown. There are several etiological factors linked to the condition, such as:

• Lack of oxygen to the brain.

• Toxin exposure in the womb.

• Genetic mutation.

• Twin-To-Twin Transfusion Syndrome: During twin pregnancy, if one of the fetuses dies in utero, the embolic material from the deceased twin can be toxic to the other fetus. This causes many life-threatening complications in the fetus.

• A blockage of the carotid artery in the fetus.

• The intrauterine infection causes the death of the brain tissue.

• Mother’s exposure to poisonous substances.

• The fetus is having some circulatory problems.

• A rare syndrome such as fowler syndrome can be another reason for the disorder. It is the syndrome of factor XIII deficiency, and due to this deficiency, intracerebral hemorrhage (hematoma in the brain) can be caused.

• In conditions such as hypoxia (lack of oxygen), maternal exposure to carbon monoxide can cause diffused hypoxic-ischemic brain necrosis.

• If the fetus has a condition such as leukemia (a type of cancer involving white blood cells), it can develop multiple cysts to coalesce inside the brain cavity.

• In conditions such as ischemic shock (a type of stroke caused by a blood vessel clot in the brain), hydranencephaly can occur.

• Intrauterine infections such as toxoplasmosis (a type of infection caused by the Toxoplasma gondii parasite), herpes simplex (viral infection), Epstein-Barr (viral infection), and the respiratory syncytial virus can cause hydranencephaly.

What Are the Signs and Symptoms of Hydranencephaly?

The followings are the signs and symptoms associated with hydranencephaly:

• Seizures.

• Uncontrolled movements of the body.

• Intellectual disability.

• Blindness.

• Deafness.

• Speech impairment.

• Irregular body temperature.

• Developmental defect.

• Breathing problems.

• Digestion problems.

• Larger than normal head size.

• Arms and legs rigidness.

• Increased or decreased muscle tone.

• Twitching of the muscle.

• Poor feeding.

How To Diagnose Hydranencephaly?

Hydranencephaly is a disorder that can be diagnosed at different stages of life. During prenatal ultrasound imaging, the abnormality can be detected. On the other hand, during the postnatal phase, the physical symptoms can reveal the defect. Doctors may go for the following diagnosis for the detection of the disorder:

• Medical History: It reveals the family's medical history and reveals information about the biological parents if anyone in the family had the same disorder. Also, it reveals information about other health-related complications too.

• Physical Characteristics: It shows the symptoms related to this abnormality, such as deafness, speech disability, intellectual disability, or vision-related complications.

• Ultrasound: Prenatal ultrasound during pregnancy can reveal any abnormality related to fetus development. The test creates an image of the fetus in the womb and shows any developmental defect. The test can show if the fetus is missing any cerebral hemisphere during the intrauterine phase.

• Magnetic Resonance Imaging (MRI): If there are any abnormalities revealed during the ultrasound, the doctor may go for an MRI to get more details about the abnormality.

• Computerized Tomography Scan (CT): The test is used to get a 3D image of the soft tissues and bones in the fetal body.

• Angiography: It is the x-ray of the blood vessels with the use of a dye.

• Transillumination: It is the test where the base of the skull is reflected with light to see brain tissue.

• Electroencephalogram: It shows the electrical activity of the brain.

What Are the Complications Associated With Hydranencephaly?

The following are the complications associated with hydranencephaly:

• Cognitive delay.

• Respiratory distress.

• Severe growth failure.

• Irritability.

• Prolonged mechanical ventilation.

• Gastroesophageal distress.

• Developmental delay.

• Deafness.

• Death.

How To Manage Hydranencephaly?

• The prevention of the disorder is complicated and unsure as the prompt diagnosis plays an essential role. However, the pregnant mother can follow a healthy diet and be addiction-free for the health and safety of the baby.

• Moreover, as the chances of pregnancy with this abnormality result in the death of the fetus, some of the parents choose to go with the termination of the pregnancy. Furthermore, if the infant is born without a diagnosed condition, the cure for hydranencephaly is impossible. The treatment options available for the symptoms is the only option.

• Surgical implantation of the shunt or a tube can be used to drain the fluid from the brain, as the extra CSF can build pressure inside the skull. This can cause many neurological symptoms as well.

• Endoscopic choroid plexus coagulation (ECPC) is the treatment used to treat the fast enlargement of the skull in children.

• Supportive therapy, such as physical therapy, is used to improve muscular symptoms.

• Seizures are treated with drug therapy.

• If a child is facing any respiratory distress, tracheostomy or mechanical ventilation is recommended.

Conclusion:

Worldwide, one in 10,000 isolated occurrences of hydranencephaly is seen. It is presumed in these cases that life expectancy is already less. It is a disorder without any definitive treatment options and many physical symptoms. If the disorder is undiagnosed in the prenatal phase, the doctors recommend supportive therapy and surgical therapies for management.