A patient presents with chest pain, dyspnea, and a friction rub heard on auscultation. An electrocardiogram (ECG) shows diffuse ST-segment elevation. Which cardiovascular disorder is most likely responsible for these symptoms?

Correct Answer: D

Rationale: The clinical presentation of chest pain, dyspnea, and a friction rub heard on auscultation is suggestive of pericarditis. The diffuse ST-segment elevation seen on the electrocardiogram (ECG) is a classic finding in pericarditis, known as the "universal sign." In contrast, stable angina typically presents with chest pain on exertion that is relieved by rest or nitroglycerin, while unstable angina presents with chest pain at rest or with minimal exertion. Acute myocardial infarction would typically present with ST-segment elevation in specific leads correlating with the area of myocardial ischemia/infarction. However, in the context of diffuse ST-segment elevation and symptoms suggestive of inflammation (friction rub), the most likely diagnosis is pericarditis.

Correct Answer: C

Rationale: The presentation described is consistent with fungal keratitis. Fungal keratitis typically presents with a yellowish-white spot on the cornea, surrounded by a ring of inflammation. The filamentous opacities seen on slit-lamp examination are characteristic of fungal hyphae extending from the corneal lesion. This condition is often associated with risk factors such as trauma with vegetable matter, contact lens wear, or topical corticosteroid use. Prompt diagnosis and treatment with antifungal medications are essential to prevent complications and preserve vision.

Correct Answer: A

Rationale: Natural killer (NK) cells play a vital role in the innate immune response by identifying and eliminating virus-infected cells, as well as tumor cells, without the need for prior exposure or activation. NK cells are able to detect abnormal cells by recognizing changes in the cell surface molecules, such as downregulation of MHC class I molecules. Once activated, NK cells release cytotoxic granules containing perforin and granzyme, leading to the destruction of the target cell. This direct killing mechanism is crucial for controlling viral infections and preventing the development of tumors. NK cells do not produce antibodies (option B), present antigens to T cells (option C), or release cytokines to recruit other immune cells (option D) as their primary function in the immune response.

Correct Answer: B

Rationale: Patient's uterine contractions lasting 70 seconds and occurring every 90 seconds signify hyperstimulation, which can be a serious complication associated with oxytocin administration. This may result in decreased uterine perfusion, fetal distress, and other adverse effects. The first action should be to discontinue the oxytocin infusion to prevent further complications and allow the uterus to relax. Observations and assessment should continue to monitor the patient's condition and response after discontinuing the infusion. Giving an emergency bolus of oxytocin or increasing the IV infusion rate would exacerbate the hyperstimulation, and turning the client to her left side and breathing deeply would not address the underlying issue of oxytocin-induced hyperstimulation.

Correct Answer: C

Rationale: An amniotic fluid embolism is a rare and life-threatening complication during labor and delivery. It occurs when amniotic fluid or fetal cells enter the maternal circulation, triggering a rapid immune response that can lead to cardiovascular collapse and respiratory failure. The priority nursing intervention for a woman in active labor diagnosed with an amniotic fluid embolism is to initiate cardiopulmonary resuscitation (CPR) to support her vital functions and circulation. Providing immediate CPR can help sustain her until further medical interventions can be implemented. Administering oxygen and preparing for a cesarean section may be necessary but should occur after CPR is initiated to stabilize the woman's condition. Inserting an indwelling urinary catheter is not the priority in this emergency situation, as maintaining adequate cardiac and respiratory function takes precedence.