Contributed by Daniel D. Rhoads, MD and Octavia M. Peck Palmer, PhD
A 66-year-old female with metastatic colon cancer presents to the emergency department with the complaint of weakness, which was so bad that she had to be carried to the car before being driven to the ED. She underwent debulking surgery one month prior to presentation and has since followed up for problems including fecal impaction and diarrhea. She has poor oral intake and is losing weight. She reports compliance with her bowel regimen of docusate sodium, senna, polyethylene glycol, and milk of magnesia. Initial laboratory findings are listed in the table.
ED evaluation concluded that the patient had an acute kidney injury that was likely due to volume depletion. Intravenous fluid resuscitation was commenced, and the patient was admitted.
Which electrolyte abnormality may best help to explain the patient's weakness, and what predisposing factors put this patient at risk for the development of this abnormal finding?