Sunken fontanelle in a infant is sign of which of the following?

UPPSC 2022

Pediatric Nursing

Easy

Appeared in: UPPSC 2022

Explanation

A sunken fontanelle is a direct consequence of fluid loss in the body, which is the hallmark of dehydration.
When an infant is dehydrated, the total body water decreases, which includes the volume of cerebrospinal fluid (CSF) surrounding the brain.
This reduction in fluid volume leads to decreased intracranial pressure.
The fontanelles, being soft and membranous, sink inward in response to this lower pressure, creating a visible depression.

Option A: Down's syndrome is a genetic disorder. While it can be associated with delayed fontanelle closure, a sunken fontanelle is not a characteristic feature of the syndrome itself.
Option B: Turner's syndrome is a chromosomal condition affecting females. Its characteristic signs include short stature and a webbed neck, and it is not associated with the state of the fontanelles.
Option C: Hydrocephalus is the accumulation of excess fluid in the brain, which leads to an increase in intracranial pressure. This causes the fontanelle to become tense and bulge outward, the opposite of a sunken fontanelle.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Assessment of infant hydration status through physical examination as background academic context rather than a clinical decision trigger.
A sunken fontanelle is a significant and often late sign of dehydration in an infant. Nurses must recognize this as a red flag requiring prompt assessment and intervention to prevent progression to hypovolemic shock.
Accurate assessment involves palpating the fontanelle while the infant is calm and held upright, as crying can cause a temporary bulge.
What if? If the fontanelle was tense and bulging instead of sunken, the nurse's primary concern would shift from dehydration to increased intracranial pressure. This would warrant an immediate neurological assessment and reporting to the physician, as it could indicate serious conditions like hydrocephalus or meningitis.

How to Approach the Question

First, identify the key clinical sign presented in the question: 'sunken fontanelle' in an 'infant'.
Next, analyze the meaning of 'sunken'. A sunken appearance implies a loss of volume or pressure underneath.
Evaluate the given options in the context of this understanding.
Option D, Dehydration, directly involves fluid volume loss, which aligns perfectly with the concept of a sunken space.
Option C, Hydrocephalus, involves an accumulation of fluid, which would cause bulging, not sinking.
Options A and B are genetic syndromes. Recall their primary features; a sunken fontanelle is not a defining characteristic of either.

Concept Tested & Keywords

Concept Tested: Assessment of infant hydration status through physical examination.
Stem keywords: sunken fontanelle, infant, sign
Lead-in keywords: which of the following
Clinical cues: The term 'sunken fontanelle' is a critical clinical sign indicating volume depletion.

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 pp. 1357-1359, 1386-1388

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 395-397