A Disoriented, Nauseated Car-Wreck Victim

Robert M. Centor, MD; Karen L. Samples


February 13, 2006

Most medical students and residents find acid-base and electrolyte cases difficult to decipher, and this area is difficult to master by reading textbooks alone. I run a monthly conference to discuss these problems with students and housestaff, and I find that discussing patient data in depth leads to improved understanding.

For that reason, we are starting this new case series of interesting acid-base and electrolyte problems. We will present a new problem each month and give you 2 weeks to work on it before revealing the solution. We encourage questions; in fact, if the explanations are not clear, please ask for further explanation. We want you to understand these problems and become an expert over time. A link will be provided to discuss each case.

Initially, we will derive cases from our patient archives at the University of Alabama School of Medicine. However, eventually we will need more cases to discuss. If you have an interesting acid-base or electrolyte abnormality, we invite you to submit it for consideration. We are especially looking for problems involving Na, K, Ca, Mg, or phosphate. I will determine whether they complement our previous discussions. If we accept your submission, I will work with you to achieve publication on this site as soon as feasible.

A 42-year-old white man comes to the ER after a motor vehicle accident in which he was ejected from his car into a lake. He is confused and only remembers trying to swim. The emergency medical technician (EMT) reports nausea, vomiting, and agitation.


VS: T 98, BP 169/78, RR 24, SaO 2, 100% RA

GEN: Thin, barrel-chested man in acute distress. He is flushed, diaphoretic, and tachypneic, demonstrating Kussmaul respirations and accessory muscle use. Breath has a sweet odor.

HEENT: Pupils equal, round, and reactive. Extraocular muscles intact. Anicteric.

CV: Regular rate and rhythm, no murmurs, rubs, or gallops.

PULM: Clear to auscultation bilaterally.

ABD: Scaphoid. Soft. Good bowel sounds. 4-cm laceration across right midclavicular line.

EXT: Bruise on right shin.

Labs are as follows:

  • Electrolyte panel: sodium 140, potassium 4.6, chloride 102, bicarbonate 5, BUN 7, creatinine 1.2, glucose 118

  • ABG: pH 7.06; pO2 130; pCO2 8; calculated HCO3 2

His trauma evaluation and x-rays are entirely unremarkable.

Define the acid-base disorder and develop a differential diagnosis.

What additional tests would you order?

Feel free to discuss this case with other medical students, including those visiting the Medscape discussion board here. You may also pose questions for me there, and I will try to address them as soon as possible.

Watch for the solution in 2 weeks on the Medscape Med Students site.


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