Clinical Case Scenario
A 70-year-old man, known hypertensive managed on telmisartan and thiazide diuretic was brought to the hospital by her family due to confusion and lethargy. For the last week, he had been complaining of low oral intake. He seemed disoriented during inspection, but his hemodynamics were stable. His symptoms started around two days ago and the plasma sodium level was found to be 120 mmol/L. He experienced convulsions at the emergency room after an hour of arriving at ER and was given 3% saline to treat it. Within the following 12 hours, his blood sodium level quickly returned to 136 mmol/L. His neurological condition then worsened. An urgent MRI brain showed the following image as shown in figure 1.
Figure 1: T2 weighted imaging showing hyperintensities in basis pontis (white arrow)
(Case courtesy of Frank Gaillard, Radiopaedia.org, rID: 2598)
Which of the following best describes the pathophysiological process causing the patient's neurological decline?
