A patient experiences residual effects following an acute attack of Ménière's disease and receives a new prescription for an antihistamine. Which assessment finding indicates that the medication is effective?

Choice A reason: Redness and edema noted at the incision site are signs of inflammation, which are normal in the early stages of wound healing. The nurse should monitor the site for signs of infection, such as purulent drainage, increased pain, or fever.

Choice B reason: Apical heart rate of 100 to 110 beats/minute is a sign of tachycardia, which may be caused by pain, anxiety, dehydration, or blood loss. The nurse should assess the client's vital signs, fluid status, and hemoglobin level, and administer pain medication as prescribed.

Choice C reason: High-pitched sound heard upon inspiration is a sign of stridor, which is a life-threatening emergency that indicates airway obstruction. The nurse should call for help, administer oxygen, and prepare for intubation or tracheostomy.

Choice D reason: Pain rating of 8 on a scale of 0 to 10 is a sign of severe pain, which may impair the client's recovery and increase the risk of complications. The nurse should administer pain medication as prescribed and use non-pharmacological methods to relieve pain, such as positioning, distraction, or relaxation techniques.

Choice A reason: Fasting blood sugar of 200 mg/dL (11.1 mmol/L) indicates hyperglycemia, which is a high level of glucose in the blood. It can be caused by diabetes mellitus, stress, infection, or medication. Hyperglycemia can cause symptoms such as thirst, hunger, frequent urination, fatigue, and blurred vision. However, it does not affect the safety or accuracy of MRI with contrast.

Choice B reason: Glycosylated hemoglobin A1c of 8% indicates poor glycemic control over the past three months. It can be caused by diabetes mellitus, chronic kidney disease, or hemoglobinopathy. Glycosylated hemoglobin A1c reflects the average blood glucose level over the lifespan of red blood cells, which is about 120 days. However, it does not affect the safety or accuracy of MRI with contrast.

Choice C reason: Blood urea nitrogen of 22 mg/dL (7.9 mmol/L) indicates mild azotemia, which is a high level of nitrogenous waste products in the blood. It can be caused by dehydration, high protein intake, gastrointestinal bleeding, or kidney impairment. Azotemia can cause symptoms such as nausea, vomiting, confusion, and lethargy. However, it does not affect the safety or accuracy of MRI with contrast.

Choice D reason: Serum creatinine of 1.9 mg/dL (169 umol/L) indicates moderate renal insufficiency, which is a reduced ability of the kidneys to filter and excrete waste products and fluids from the body. It can be caused by diabetes mellitus, hypertension, glomerulonephritis, or nephrotoxic drugs. Renal insufficiency can cause symptoms such as edema, anemia, electrolyte imbalance, and acidosis. It can also increase the risk of contrast-induced nephropathy, which is a sudden deterioration of kidney function after exposure to contrast media used for imaging studies such as MRI. Contrast-induced nephropathy can lead to acute kidney injury, dialysis requirement, or even death. Therefore, serum creatinine should be reported to the healthcare provider before MRI with contrast to assess the risk and benefit of the procedure and to take preventive measures such as hydration, medication adjustment, or alternative imaging modalities.