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Chiari Malformation in Infants

Experts have estimated that the incidence of Chiari malformation in infants is higher than one per every 1,000 births. Symptoms of Chiari malformation in newborns include headaches, difficulty swallowing, and difficulty breathing. In most cases, the disorder is genetic, but it may be acquired from injury to the spinal cord.

A Chiari malformation (CM) is a condition in which a part of the brain known as the cerebellum is pressed downward through an opening in the base of the skull, which can put pressure on the cerebellum and other brain structures. It can also interfere with the flow of fluid around the brain and spinal cord.

Infants with mild types of CM may exhibit no symptoms, and it is difficult to diagnose CM in newborns. According to U.K. researchers, parents should be alert to signs such as irritability, head banging, and nighttime wakening in infants.

Experts from Children’s Neurosurgical Associates at UCSF Benioff Children’s Hospital Oakland note that a CAT scan may not be useful in diagnosing a type 1 Chiara malformation. Your doctor must order an MRI to determine how much pressure is being put on the baby’s brainstem and spinal cord.

What is a Chiari malformation?

A Chiari malformation involves a part of the brain called the cerebellum, located at the back of the head, near the bottom of the skull. The cerebellum is important in movement coordination.

At the base of the skull is a hole called the foramen magnum. Usually, only the spinal cord passes through this hole. In babies with a Chiari malformation, part of the cerebellum is pressed downward into the foramen magnum.

The pressure on the tissues of the cerebellum can interfere with its function, leading to a variety of symptoms and affecting the flow of cerebrospinal fluid (CSF) within and around the brain and spinal cord.

In some cases, the brainstem may also be affected by a Chiari malformation. The brainstem is a part of the brain that functions to control basic bodily functions, such as breathing, heart rate, and blood pressure. Pressure on the brain stem can affect these basic functions, which can be life-threatening in some cases.

What causes a Chiari malformation?

In most cases, Chiari malformations are congenital, but a few conditions increase the risk for CM in infants. When the mother doesn’t get enough folic acid during pregnancy, this can lead to abnormalities in the baby’s nervous system, including CM.

Some cases of Chiari malformations also arise later in life. A significant loss of cerebrospinal fluid from the brain and spinal cord can lead to a Chiari malformation. This may be the result of an infection, a birth injury, or exposure to a toxin.

Types of Chiari Malformation

Chiari malformations involve the lower back part of the skull and brain, but the specifics can vary between patients. There are four types of CM.

Chiari malformation type 1

Chiari malformation type 1 is the most common and the least severe. In this type of CM, only part of the cerebellum passes through the foramen magnum. CM type 1 is often diagnosed in childhood or even adulthood. Type 1 is the only type of Chiari malformation that can be acquired after birth.

Chiari malformation type 2

In CM type 2, both the brainstem and the cerebellum are partially pressed through the foramen magnum. In most cases, the infant also has myelomeningocele, which is a birth defect in which the back of the skull and spinal canal don’t close properly during fetal development. Type 2 is sometimes called an Arnold-Chiari malformation or a classic Chiari malformation.

Chiari malformation type 3

CM type 3 is more severe. In children with a type 3 Chiari malformation, tissue from the cerebellum and brainstem is partially herniated outside the skull into a sac of skin, a condition known as encephalocele. CM type 3 can be fatal, often due to respiratory failure caused by brainstem compression. Surgery has been reported to improve the outcome for some newborns.

Chiari malformation type 4

Chiari malformation type 4 is severe. In this type, the cerebellum doesn’t fully develop, and parts of it are missing. Parts of the skull and spinal cord may also be visible. This type is generally incompatible with life.

A 2018 study published in the Journal of Clinical Neuroscience found that over half (59 percent) of reported cases of Chiari malformation were type 1, whereas 23 percent were type 2. Types 3 and 4 together represented the remaining 18 percent of cases.

However, this likely represents an undercounting of type 1 cases, since these often produce mild or no symptoms and may therefore not be reported in patient databases.

Does having a Chiari malformation affect life expectancy?

The prognosis for a person with a Chiari malformation depends on the specific type they have. Babies with Chiari malformation type 4 generally do not survive.

Infants with Chiari malformation type 1 usually have a typical life expectancy. It is common for these patients not to have symptoms of their condition. If they do have symptoms, they can often be managed through treatment. Although the symptoms may be bothersome, they generally are not life-threatening.

For babies with type 2 or type 3, the prognosis is variable and generally depends on how severely the brainstem is affected.

Patients with CM type 2 have widely varying outcomes, but with surgery, many can live long lives. Some have severe neurological damage, but others have relatively normal cognitive abilities and can function independently.

The U.K. researchers noted that “there are variations in the outcome and not all cases of CM III will die and severe developmental delay is not a must. Proper operative planning and technique followed by postoperative care and physiotherapy could lead to a reasonable outcome and decreased mortality.”

In their review of 51 Chiari malformation cases, the researchers found that only seven infants with CM type 3 died and the prognosis — the likely course of the condition — ranged from “good development of the children to severe mental and motor retardation.”

Proper surgical care is crucial for infants born with CM type 3 to give them the best chance at a positive outcome.

Symptoms of Chiari Malformation in Newborns

Not all patients with Chiari 1 malformation have symptoms at all. In those who do, symptoms may include:

  • Headache, which is often worse when the pressure in the abdomen increases, for example, by coughing or sneezing
  • Neck pain
  • Problems with fine motor coordination or balance
  • Areas of numbness or muscle weakness
  • Problems with speech or swallowing
  • Scoliosis, a curvature of the spine to the side
  • Sleep apnea, in which the patient stops breathing during sleep

Infants with more severe types of Chiari malformation may also experience breathing problems, gagging or choking frequently, and unusual eye movements.

Treatment for Fetal Chiari Malformations

If your baby doesn’t experience Chiari malformation symptoms, treatment may not be necessary. This is sometimes the case for infants with Type 1 Chiari malformations that are discovered incidentally.

Infants with symptomatic Chiari malformations, surgery is the only way to relieve pressure on the brain. If left untreated, the pressure can have serious consequences — including paralysis.

Surgical procedures may include:

  • Posterior fossa decompression, in which the cerebellum is decompressed by removing small portions of bone from the back of the skull and sometimes the top of the spinal cord. This is a safe procedure that often relieves patients’ symptoms. 
  • Cerebellar tonsillectomy, in which the surgeon removes certain tissues from the cerebellum called the cerebellar tonsils. Removal of these structures doesn’t cause any known neurological problems, and removing them can improve symptoms in some newborns.
  • Closure of a meningomyelocele or encephalocele is indicated in cases of CM type 2 or type 3 to add protection for the delicate brain tissue affected.
  • Shunts are tubes that drain excess cerebrospinal fluid from the head into the chest or abdomen. This is used in cases of hydrocephalus, or the buildup of excess CSF caused by the pressure of the CM blocking the normal flow of this fluid within the nervous system.

If you believe your newborn’s Chiari malformation prognosis is related to your doctor’s failure to provide proper medical management, including frequent physical exams and monitoring of the development of the baby’s backbone, brain, skull, and spinal cord, and to intervene swiftly when surgery is needed, contact Birth Injury Center to talk a lawyer today.

Written by:
Birth Injury Center Team

The Birth Injury Center aims to create informational web content and guides to help women and their families seeking support and guidance for birth injuries caused by medical negligence. All of the content published across The Birth Injury Center website has been thoroughly investigated and approved by medical expert Natalie Speer, RNC-OB, Attorney Ryan Mahoney, and Attorney Rick Meadows.