Makindo Medical Notes

Encephalocele is a neural tube defect characterized by sac-like protrusions of the brain and meninges through openings in the skull. It requires early diagnosis and, often, surgical intervention to prevent complications.

About

• Definition: Encephalocele is a congenital neural tube defect where brain tissue, cerebrospinal fluid (CSF), and meninges herniate through a skull defect.
• Location: Commonly occurs in the occipital region but can also occur at the front of the skull or near the nose and forehead (nasofrontal).

Aetiology

• Genetic and Environmental Factors: The exact cause is unknown but may involve genetic and environmental factors affecting neural tube closure during development.
• Folic Acid Deficiency: Insufficient folic acid intake during pregnancy is associated with neural tube defects.
• Associated Conditions: Sometimes occurs with other syndromic disorders or chromosomal abnormalities.

Types

• Meningocele: Herniation contains only CSF and meninges, with no brain tissue.
• Encephalocele: Protrusion of brain tissue along with CSF and meninges.
• Hydroencephalocele: Herniation includes CSF, meninges, brain tissue, and part of the ventricular system.

Pathophysiology

• Defect in neural tube closure during early embryonic development, usually in the first 3-4 weeks of gestation.
• Weakening in skull structure allows brain and meningeal herniation, leading to potential compression or dysfunction of neural tissue.

Clinical Features

• Visible Sac-like Protrusion: A noticeable sac on the scalp, often near the occipital region, containing brain tissue or fluid.
• Neurological Symptoms: May include developmental delays, seizures, motor deficits, and hydrocephalus.
• Craniofacial Abnormalities: Midline facial anomalies or skull deformities can occur.

Investigations

• Ultrasound: Prenatal ultrasound can often detect encephaloceles in the second trimester.
• MRI: Provides detailed imaging of the brain tissue involved and the extent of the defect.
• Genetic Testing: May be indicated for syndromic or chromosomal associations.

Management

• Pre-birth Counseling: Discuss prognosis, potential outcomes, and options with parents if detected prenatally.
• Surgical Intervention: Involves reducing the herniated brain tissue and repairing the skull defect. Timing and technique depend on size, location, and presence of symptoms.
• Supportive Care: For developmental delays, hydrocephalus management, physical and occupational therapy, and seizure control if needed.

Prognosis

• Depends on Severity: Prognosis varies significantly, depending on the size and location of the encephalocele, amount of brain tissue involved, and associated conditions.
• Neurological Outcome: Patients with smaller encephaloceles containing only CSF and meninges generally have a better prognosis than those involving brain tissue.