# Situation: A 45-year-old man with hypertrophic cardiomyopathy (HCM) is admitted to the coronary care unit after fainting at home. Echocardiography shows a thickened septum with left ventricular outflow tract obstruction. He has vomited repeatedly for 2 days. Before discharge, the nurse advises that his children and siblings be screened for the condition. What is the reason for this advice?

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> subject: Nursing Practice V — Care of Clients with Maladaptive Patterns of Behavior; Care of Clients with Life-Threatening Conditions, Acute Multi-Organ Problems, High Acuity and Emergency Situations

## 문제

Situation: A 45-year-old man with hypertrophic cardiomyopathy (HCM) is admitted to the coronary care unit after fainting at home. Echocardiography shows a thickened septum with left ventricular outflow tract obstruction. He has vomited repeatedly for 2 days.

Before discharge, the nurse advises that his children and siblings be screened for the condition. What is the reason for this advice?

## 보기

1. It results from a viral infection spread within households
2. It follows untreated high blood pressure that runs in families
3. It develops from a high-salt diet that families share
4. It is usually caused by an inherited genetic variant **✔ 정답**

**정답: 4**

## 해설

Hypertrophic cardiomyopathy is usually genetic, so first-degree relatives are screened, commonly with an electrocardiogram, echocardiography, and sometimes genetic testing, to find the condition before a first event.

## 심화 해설

Why screen the family?

Hypertrophic cardiomyopathy (HCM) is not caused by a shared infection, diet, or untreated hypertension. In most cases, it is a heritable myocardial disease caused by pathogenic variants in genes that encode cardiac sarcomere proteins, and it is typically transmitted as an autosomal dominant trait [3]. This means a first-degree relative—such as a child or sibling—has a substantial chance of carrying the same variant even when that relative currently has no symptoms. The purpose of family screening is to identify the condition before a first clinical event such as syncope, arrhythmia, or sudden cardiac death occurs [1].

Key point! The patient’s repeated vomiting and fainting are clinical manifestations of HCM, but they do not make the disease contagious. The reason relatives are screened is genetic transmission, not household exposure.

What does screening actually involve?

For first-degree relatives, evaluation generally includes electrocardiography, echocardiography, and in selected cases genetic testing. Echocardiography is central because it can detect asymmetric septal hypertrophy and left ventricular outflow tract obstruction even before a person reports symptoms. In children, clinical screening is usually recommended from around 10 years of age, although earlier evaluation may be considered when there is a strong family history or concerning symptoms [1][3]. Serial follow-up is important because HCM shows age-related penetrance: a relative with a normal echocardiogram in childhood can still develop measurable disease later [1].

Watch out! A single normal echocardiogram does not rule out HCM in a young relative. The disease can emerge over time, which is why repeated clinical screening is recommended rather than a one-time test [1][3].

How this connects to the answer choices

The incorrect options all point to environmental or acquired causes. Viral infection within a household does not explain the sarcomere gene variants found in HCM. Untreated hypertension can cause concentric left ventricular hypertrophy, but that is a different phenotype from the asymmetric septal hypertrophy and outflow tract obstruction seen in this patient. A shared high-salt diet influences blood pressure and volume status, not the genetic architecture of the myocardium. The correct rationale is that HCM is usually caused by an inherited genetic variant, and screening relatives is a form of cascade screening intended to detect affected individuals early [3].

| Distractor | Why it is incorrect |
| --- | --- |
| Viral infection spread within households | HCM is a genetic sarcomere disease, not an infectious process [3] |
| Untreated high blood pressure that runs in families | Hypertension causes concentric hypertrophy, not the asymmetric septal hypertrophy with outflow obstruction typical of HCM |
| High-salt diet that families share | Dietary sodium does not produce pathogenic sarcomere gene variants or autosomal dominant inheritance [3] |
| Inherited genetic variant | Correct: most HCM is caused by autosomal dominant variants in sarcomere genes, so first-degree relatives are screened [1][3] |

Key point! Family screening in HCM is not only about confirming a diagnosis. It is a preventive strategy: identifying affected relatives before syncope, heart failure, or sudden death becomes their first presentation. This is why the nurse’s discharge teaching includes advising that children and siblings be evaluated.References (research sources)

- [1]Yield of Clinical Screening for Hypertrophic Cardiomyopathy in Child First-Degree Relatives.Research articleNorrish G, Jager J, Field E, Quinn E, Fell H, Lord E (2019) · DOI: 10.1161/CIRCULATIONAHA.118.038846

- [3]Clinical and Genetic Screening for Hypertrophic Cardiomyopathy in Paediatric Relatives: Changing Paradigms in Clinical Practice.Research articleLawley CM, Kaski JP (2023) · DOI: 10.3390/jcm12082788

## 임상 시나리오

Family Screening in Hypertrophic CardiomyopathyWhy first-degree relatives need evaluation
Hypertrophic cardiomyopathy (HCM) is usually caused by an inherited genetic variant in cardiac sarcomere protein genes, transmitted as an autosomal dominant trait. A first-degree relative has a substantial chance of carrying the same variant even without symptoms.

The purpose of family screening is to identify HCM before a first clinical event such as syncope, arrhythmia, or sudden cardiac death. Screening typically includes electrocardiography, echocardiography, and sometimes genetic testing.

Echocardiography is central because it can detect asymmetric septal hypertrophy and left ventricular outflow tract obstruction before symptoms appear. Clinical screening in children is usually recommended from around 10 years of age, with earlier evaluation if there is a strong family history or concerning symptoms.

CautionHCM shows age-related penetrance, so a normal screening result in a young relative does not rule out future disease. Serial follow-up is essential, and symptoms such as recurrent vomiting or fainting in the proband do not make the condition contagious—transmission is genetic, not household-based.

## 핵심 개념

- **Hypertrophic cardiomyopathy (HCM)** — A genetic myocardial disease characterized by asymmetric septal hypertrophy and left ventricular outflow tract obstruction.
- **Autosomal dominant** — A pattern of inheritance where one copy of a pathogenic gene variant is sufficient to cause the condition.
- **First-degree relative** — A parent, sibling, or child who shares approximately 50% of an individual's genes.
- **Left ventricular outflow tract obstruction** — Narrowing of the path through which blood exits the left ventricle, often caused by septal hypertrophy in HCM.
- **Sarcomere** — The basic contractile unit of cardiac muscle; HCM is often caused by variants in genes encoding sarcomere proteins.

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