Weakness and Dizziness 375350.A 58-year-old man presents to the ED complaining of generalized
weakness for the last 2 days. He states that a few days ago he had abdominal
cramps, vomiting, and diarrhea when his whole family got sick after a picnic.
These symptoms resolved a day and a half ago but he has not been eating
well and now feels weak all over. The patient has a history of hypertension
for which he takes hydrochlorothiazide (HCTZ), which was recently increased.
His BP is 144/87 mm Hg, HR is 89 beats per minute, temperature is 98.7°F,
and RR is 12 breaths per minute. The physical examination reveals hypore-
flexia. His electrocardiogram (ECG) is shown below. Which of the following
is the most likely diagnosis?
a. Hypernatremia
b. Hyponatremia
c. Hyperkalemia
d. Hypokalemia
e. Hypercalcemia