# A 6-month-old infant is brought to the emergency department by parents who report the child has been having severe coughing episodes for the past week. Which assessment finding would be most characteristic of pertussis (whooping cough) in this infant?

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## 문제

A 6-month-old infant is brought to the emergency department by parents who report the child has been having severe coughing episodes for the past week. Which assessment finding would be most characteristic of pertussis (whooping cough) in this infant?

## 보기

1. High fever with chills and rigors
2. Barking cough with stridor on inspiration
3. Productive cough with purulent sputum
4. Paroxysmal coughing followed by inspiratory whoop and vomiting **✔ 정답**

**정답: 4**

## 해설

Pertussis is characterized by paroxysmal coughing followed by an inspiratory whoop and vomiting, especially in infants. Other options represent symptoms of other respiratory conditions like croup or bacterial pneumonia.

## 심화 해설

Understanding Intussusception

Intussusception is a serious pediatric abdominal emergency where one segment of the intestine telescopes into an adjacent distal segment [1]. This process leads to compression of the mesenteric vessels, causing bowel wall edema, venous congestion, and if not promptly treated, can progress to arterial obstruction, bowel ischemia, and necrosis [1]. The classic clinical presentation in an infant includes sudden, severe, colicky abdominal pain that causes the child to draw up their legs and cry inconsolably, often alternating with periods of lethargy.

Analysis of Assessment Findings

The most characteristic assessment finding for intussusception is the passage of currant jelly-like stools, which are a mixture of blood and mucus [1,3]. This finding is a hallmark sign resulting from the ischemic bowel mucosa sloughing off and mixing with intestinal secretions. While this is a classic and highly specific sign, it is often a later finding and its absence does not rule out the condition [1].

Let's examine why the other options are less characteristic for this specific condition:

- Projectile vomiting immediately after feeding is more classically associated with hypertrophic pyloric stenosis, a condition typically presenting in infants 2-8 weeks old, not at 6 months. In intussusception, vomiting is a common symptom, but it is usually non-bilious initially and may become bilious as the obstruction progresses, rather than being specifically projectile and immediately postprandial [3].

- An olive-shaped mass in the epigastric area is the pathognomonic finding for hypertrophic pyloric stenosis, not intussusception. In intussusception, a palpable abdominal mass is often described as a "sausage-shaped" mass, typically located in the right upper quadrant, reflecting the telescoped segment of bowel [1].

- High-pitched bowel sounds throughout the abdomen are a general sign of a mechanical bowel obstruction and are not specific to intussusception. While they may be present, they do not carry the same diagnostic specificity as the currant jelly stool. The bowel sounds in intussusception can vary, and the abdomen may be distended with a palpable mass [1].

Clinical Reasoning and Diagnostic Confirmation

When an infant presents with the triad of colicky abdominal pain, a palpable abdominal mass, and currant jelly stools, the clinical suspicion for intussusception is extremely high. The definitive diagnosis is typically made with abdominal ultrasound, which will reveal a characteristic "target sign" or "pseudo-kidney sign" on transverse and longitudinal views, respectively, representing the layers of the telescoped bowel [3]. Prompt recognition is critical because the first-line treatment is often non-operative hydrostatic or pneumatic enema reduction, which has a higher success rate when performed early in the disease course [2,4]. Delays in diagnosis increase the risk of enema reduction failure and the need for surgical intervention due to complications like bowel ischemia or perforation [2,4].References (research sources)

- [1]High risk and low incidence diseases: Pediatric intussusception.Research articleLong B, Easter J, Koyfman A. (2025) · DOI: 10.1016/j.ajem.2025.02.020

- [3]A rare case of intusscusception in a 6-month-old baby.Research articleFiagbedzi E, Arkorful J, Appiah E, Otumi N, Ofori I, Gorleku PN. (2024) · DOI: 10.1016/j.radcr.2024.06.080

## 임상 시나리오

Clinical Guide: Assessing for Pertussis in Infants

**Clinical Pearl:** The classic triad of pertussis—paroxysmal coughing, inspiratory whoop, and post-tussive vomiting—may not be present in infants younger than 6 months. In this age group, apnea and cyanosis are often the primary presenting signs, making a high index of suspicion critical.

Stages of Pertussis

- **Catarrhal Phase (1-2 weeks):** Highly contagious stage with nonspecific symptoms (rhinorrhea, low-grade fever, mild cough). Often indistinguishable from a common cold.

- **Paroxysmal Phase (1-6 weeks):** Characterized by the hallmark fits of rapid, uncontrollable coughing. The inspiratory whoop occurs as the patient gasps for air. Infants may exhibit gagging, gasping, or a frightened look instead of a classic whoop.

- **Convalescent Phase (weeks to months):** Gradual resolution of coughing paroxysms, though intermittent episodes can recur with subsequent respiratory infections.

Key Nursing Assessment

- **Observe the Cough:** Watch for a complete coughing episode. Note the pattern: a series of rapid coughs on one breath followed by a sudden, forceful inspiration.

- **Monitor for Complications:** Assess for apnea, cyanosis, and signs of increased intracranial pressure (bulging fontanelles) from severe coughing. Pneumonia is a common secondary complication.

- **Feeding and Hydration:** Evaluate for post-tussive vomiting and poor feeding, which can lead to dehydration and failure to thrive.

Infection Control & Management

- **Isolation:** Implement droplet precautions immediately. The patient is highly contagious during the catarrhal and early paroxysmal phases.

- **Diagnosis:** Nasopharyngeal swab for PCR or culture is the gold standard. Leukocytosis with lymphocytosis is a classic but nonspecific lab finding.

- **Treatment:** Macrolide antibiotics (e.g., azithromycin) are the first-line treatment to reduce infectivity. Administer early in the catarrhal phase for best effect; during the paroxysmal phase, treatment limits spread but may not alter symptom duration. Supportive care includes oxygen, gentle suctioning, and small, frequent feedings.

## 핵심 개념

- **Paroxysmal cough** — Severe, rapid, and uncontrollable fits of coughing that occur in bursts, characteristic of the paroxysmal phase of pertussis.
- **Inspiratory whoop** — A high-pitched sound produced when a patient struggles to inhale against a temporarily narrowed glottis after a severe coughing fit.
- **Post-tussive vomiting** — Vomiting that occurs immediately following a severe coughing episode, a common finding in pertussis due to the force of the paroxysms.
- **Catarrhal phase** — The initial stage of pertussis lasting 1-2 weeks, characterized by nonspecific symptoms mimicking a viral upper respiratory infection such as low-grade fever and mild cough.
- **Bordetella pertussis** — A gram-negative coccobacillus bacterium that causes pertussis by attaching to cilia in the respiratory epithelium and producing toxins.

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