A newborn presents with a midline lumbosacral defect and a protruding sac containing meninges and nerve tissue through a vertebral defect. What is the most likely diagnosis?

1. A

   Meningocele

2. B

   Meningomyelocele

3. C

   Spina bifida occulta

4. D

   Encephalocele

Appeared in: NORCET 9 Mains - 2025

Explanation

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• Meningomyelocele is a type of spina bifida where a sac containing meninges, cerebrospinal fluid (CSF), and portions of the spinal cord or nerve roots protrudes through a vertebral defect.
• The question specifically states the protruding sac contains both 'meninges and nerve tissue,' which is the defining characteristic of meningomyelocele.
• This condition results in neurological deficits below the level of the lesion due to the malformed and exposed spinal cord.
• It is the most common and most severe form of spina bifida cystica (where a sac is present).

Why Other Options Were Wrong

• Option A: A meningocele involves a sac containing only meninges and cerebrospinal fluid (CSF). The spinal cord and nerve tissue are not present in the sac, so neurological function is often preserved.
• Option C: Spina bifida occulta is the mildest form and is 'hidden.' There is a defect in the vertebrae, but no protruding sac is visible on the exterior. The defect is covered by skin and may only be indicated by a dimple, tuft of hair, or birthmark.
• Option D: An encephalocele is a neural tube defect involving a protrusion of brain tissue and meninges through a defect in the skull (cranium), not the vertebral column (spine).

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Differentiation of neural tube defects to guide bedside assessment, documentation, and the next nursing action.
• Immediate nursing care for a newborn with meningomyelocele is critical and focuses on protecting the exposed sac to prevent rupture, infection (meningitis), and further neurological damage.
• Placing the infant in a prone position is a priority intervention to avoid any pressure on the lumbosacral sac.
• Nurses must be vigilant in monitoring for hydrocephalus, a common comorbidity, by measuring head circumference daily and assessing for signs of increased intracranial pressure.

How to Approach the Question

• First, identify the key clinical findings in the question stem: a newborn with a 'midline lumbosacral defect' and a 'protruding sac'.
• Next, focus on the most critical detail: the contents of the sac, which are 'meninges and nerve tissue'.
• Evaluate the options based on their definitions. Recall or look up the differences between the types of neural tube defects.
• Meningocele involves meninges but not nerves.
• Spina bifida occulta has no sac.
• Encephalocele involves the skull, not the spine.

Concept Tested & Keywords

• Concept Tested: Differentiation of neural tube defects
• Stem keywords: newborn, midline lumbosacral defect, protruding sac, meninges, nerve tissue
• Lead-in keywords: most likely diagnosis
• Clinical cues: The presence of 'nerve tissue' in the sac is the definitive clue that distinguishes meningomyelocele from meningocele.

Question ID

QhenQ9sZDWVc5oCIpmTmtq

Copy ID

Reference Book

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 pp. 1368-1370, 1369-1371, 2212-2214