Correct Answer: B

Rationale: Autonomy is the ethical principle that respects an individual's right to make their own decisions about their medical treatment, even if it goes against medical advice or the preferences of others. In this case, the 70-year-old patient has voluntarily decided not to have the pacemaker inserted despite the physician's recommendation. The fact that the patient's decision is respected by the family reflects the importance of honoring the patient's autonomy and right to make decisions about their own healthcare.

Correct Answer: B

Rationale: Entamoeba histolytica is a parasitic protist known to cause amoebiasis, a gastrointestinal infection that can lead to symptoms such as foul-smelling diarrhea containing cysts. Upon microscopic examination of the feces, the presence of Entamoeba histolytica cysts is a key diagnostic feature. This parasite can be transmitted through contaminated food or water, and individuals infected with Entamoeba histolytica may experience abdominal pain, bloody diarrhea, and weight loss. Proper diagnosis and treatment are essential to manage this infection and prevent complications.

Correct Answer: A

Rationale: The patient is most likely experiencing Type 1 diabetes mellitus based on the presentation of polyuria, polydipsia, polyphagia, hyperglycemia, and glycosuria. Type 1 diabetes is characterized by autoimmune destruction of the beta cells in the pancreas, leading to absolute insulin deficiency. This results in high blood sugar levels (hyperglycemia) and glucose spilling into the urine (glycosuria). Patients with Type 1 diabetes often present with the classic symptoms of polyuria (increased urination), polydipsia (increased thirst), and polyphagia (increased hunger) due to the body's inability to utilize glucose for energy effectively. Management of Type 1 diabetes typically involves lifelong insulin therapy to maintain blood sugar levels within a target range.

Correct Answer: B

Rationale: Elevating the head of the bed to improve respiratory mechanics is the most appropriate intervention for managing paroxysmal nocturnal dyspnea in a patient with end-stage heart failure. By keeping the head of the bed elevated, gravity helps reduce the pooling of fluid in the lungs, making it easier for the patient to breathe and reducing dyspnea. This strategy can help improve oxygenation and decrease the sensation of breathlessness, providing relief for the patient. Administering diuretic medications (Option A) can also be beneficial to reduce fluid overload, although positioning remains a key intervention. Encouraging the patient to sleep in a reclined position (Option C) can help alleviate symptoms, but specifically elevating the head of the bed is a more targeted approach. Referring the patient to a sleep specialist (Option D) may not be necessary at this time, as the primary concern is managing the acute symptom of paroxysmal nocturnal dyspnea

Correct Answer: A

Rationale: The described presentation of a painless, slowly enlarging mass in the right neck just above the clavicle, along with the cytology findings of clusters of polygonal cells with clear cytoplasm and centrally located nuclei, is classic for parathyroid adenoma. Parathyroid adenomas are benign tumors arising from one of the parathyroid glands, which are typically located in the neck region close to the thyroid gland. The clear cytoplasm and centrally located nuclei of the cells are characteristic histological features of parathyroid adenomas. This condition can often lead to hyperparathyroidism, characterized by increased levels of parathyroid hormone (PTH) and hypercalcemia. Treatment involves surgical removal of the adenoma.