A nurse is discussing antidepressants with a newly licensed nurse. Which of the following clients should the nurse identify as being a candidate for antidepressant therapy?

Rationale:

A. Decreased creatine kinase-MB: CK-MB is a cardiac enzyme that rises within 4–6 hours of myocardial infarction and peaks around 24 hours. A decrease in CK-MB would not indicate acute myocardial injury and is not a diagnostic marker in this case.

B. Decrease in respiratory rate: A lower respiratory rate is not a typical or reliable indicator of myocardial infarction. Clients experiencing an MI are more likely to show signs of dyspnea, anxiety, or increased respiratory effort due to pain or decreased oxygenation.

C. ST segment depression: ST segment depression may indicate myocardial ischemia or a non-ST elevation myocardial infarction (NSTEMI), but it is less specific than biomarkers like troponin. It may also appear in other conditions such as angina or electrolyte imbalances.

D. Increased troponin I: Troponin I is a highly specific and sensitive cardiac biomarker that rises within 3–6 hours of myocardial injury. An elevated troponin I level 6 hours after the onset of chest pain strongly supports the diagnosis of myocardial infarction.

Rationale for Correct Choices:

• Reye's syndrome: The toddler's worsening condition including vomiting, lethargy, and altered consciousness after a viral illness (influenza A) is consistent with Reye’s syndrome, which affects the liver and brain. The progression from mild viral symptoms to neurologic decline without respiratory compromise further supports this diagnosis.
• Aspirin administration: Giving aspirin during a viral illness in children is a well-known precipitant of Reye’s syndrome. The caregivers' report of alternating aspirin with acetaminophen confirms the exposure necessary to trigger the condition in a susceptible child.

Rationale for Incorrect Choices:

• Gastroenteritis: While vomiting is a feature of gastroenteritis, the absence of diarrhea and the presence of neurologic changes like lethargy and poor responsiveness make this unlikely. Additionally, the clear vomiting and lack of fluid intake without prior GI focus suggest another etiology.
• Bronchitis: Bronchitis typically causes a productive cough with wheezing, chest discomfort, and possible fever. This toddler's lungs are clear with a nonproductive cough, and neurologic signs are not typical of bronchitis.
• Acetaminophen administration: Acetaminophen is safe and commonly used to treat fever in toddlers. It is not associated with hepatic encephalopathy or neurologic complications seen in this scenario.
• Oseltamivir administration: Though oseltamivir may cause gastrointestinal side effects like nausea or vomiting, it does not explain the altered mental status and lethargy. It is also unlikely to cause such a significant clinical deterioration on its own.