Which of the following conditions refers to a brain development disorder where the brain surface appears smooth due to a lack of normal folds?

1. A

   Anencephaly

2. B

   Lissencephaly

3. C

   Plagiocephaly

4. D

   Brachycephaly

Appeared in: Bihar NHM CHO-2025

Explanation

• Lissencephaly, which literally means 'smooth brain,' is a rare brain malformation caused by defective neuronal migration during the 12th to 24th weeks of gestation.
• This defect results in the absence of the normal gyri (folds) and sulci (grooves) of the cerebral cortex, a condition known as agyria.
• The brain surface appears smooth, which is the key characteristic described in the question.
• It is associated with severe neurodevelopmental problems, including seizures, profound intellectual disability, and motor impairments.

Why Other Options Were Wrong

• Option A: Anencephaly is a neural tube defect characterized by the absence of a major portion of the brain and skull, not just the absence of folds on the surface.
• Option C: Plagiocephaly refers to the asymmetrical flattening of the skull shape. It is a cranial deformity and does not involve the underlying brain structure or the presence of gyri.
• Option D: Brachycephaly refers to a condition where the head is disproportionately wide and flat in the back. Like plagiocephaly, it is a deformity of the skull, not the brain's cortical surface.

Related Visual

• Visual 1: Comparative Illustration - A side-by-side image showing a normal brain with complex gyri and sulci next to a lissencephalic brain with a smooth surface to highlight the stark difference.
• Visual 2: Diagram - Illustrations of plagiocephaly and brachycephaly to show that these are skull shape abnormalities, distinct from the brain's surface texture.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Congenital Neurological Disorders as background academic context rather than a clinical decision trigger.
• Nursing care for an infant with lissencephaly is complex and focuses on managing symptoms, such as controlling seizures with anticonvulsant medications, ensuring adequate nutrition (often requiring feeding tubes), and managing respiratory issues.
• Families require extensive emotional support and genetic counseling, as many cases of lissencephaly are linked to genetic mutations. Understanding the genetic basis can help in counseling for future pregnancies.
• What if the question described a flattened head on one side from an infant sleeping in the same position? The answer would be Plagiocephaly, a positional deformity managed with repositioning techniques and sometimes helmet therapy, which has a much better prognosis than lissencephaly.

How to Approach the Question

• First, identify the key phrase in the question: 'brain surface appears smooth due to a lack of normal folds'.
• Break down the term 'Lissencephaly': 'Lissen-' (from Greek 'lissos', meaning smooth) and '-cephaly' (referring to the head/brain). This linguistic clue directly points to 'smooth brain'.
• Recall or look up the definitions of the other options. Anencephaly involves the absence of the brain, while plagiocephaly and brachycephaly are skull shape issues.
• Differentiate between disorders of brain formation (Lissencephaly, Anencephaly) and disorders of skull shape (Plagiocephaly, Brachycephaly).
• Select the option that precisely matches the description of a smooth brain surface.

Concept Tested & Keywords

• Concept Tested: Congenital Neurological Disorders
• Stem keywords: brain development disorder, brain surface, smooth, lack of normal folds
• Lead-in keywords: Which of the following
• Negative lead-in flag: false

Question ID

QYgTc67YfL2NwXb7HbVg48

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