A 42-year-old woman is brought to the emergency department by her husband due to sudden-onset, severe weakness in her legs that rapidly progressed over the last 12 hours. She is now unable to stand or bear weight. She also reports feeling intensely "short of breath." Her medical history is significant for a 5-year history of primary Sjögren syndrome, for which she takes artificial tears and cevimeline. Vital signs are temperature (), pulse 105/min, blood pressure 115/75 mm Hg, and respirations 26/min. Oxygen saturation is 98% on room air.
Physical examination reveals a tachypneic woman taking deep, rapid breaths. Lungs are clear to auscultation bilaterally. Neurologic examination shows 1/5 motor strength in the bilateral lower extremities and 3/5 in the upper extremities. Deep tendon reflexes are absent globally. Sensation is intact.
Laboratory results are as follows:
| Laboratory Parameter | Result | Reference Range |
|---|---|---|
| Serum chemistry | ||
| Sodium | 139 mEq/L | 136–145 mEq/L |
| Potassium | 1.7 mEq/L | 3.5–5.0 mEq/L |
| Chloride | 114 mEq/L | 98–106 mEq/L |
| Bicarbonate | 12 mEq/L | 22–28 mEq/L |
| Arterial blood gas (room air) | ||
| pH | 7.25 | 7.35–7.45 |
| 26 mm Hg | 35–45 mm Hg | |
| 98 mm Hg | 80–100 mm Hg | |
| Urinalysis | ||
| pH | 7.0 | 4.5–8.0 |
| Leukocyte esterase | Positive | Negative |
| Nitrites | Positive | Negative |
| Thyroid function tests | ||
| TSH | 0.3 U/mL | 0.4–4.0 U/mL |
| Free | 1.1 ng/dL | 0.9–1.7 ng/dL |
Which of the following is the most appropriate next step in the management of this patient?
- Intravenous potassium chloride administrationAnswer
- BEndotracheal intubation and mechanical ventilation
- CIntravenous piperacillin-tazobactam administration
- DOral levothyroxine administration
- EIntravenous furosemide and continuous positive airway pressure