To recap
50 something man admitted to our service after being found unresponsive. He is well known to our hospital, is homeless, an alcoholic and has a seizure disorder.
In the ER he is found to have bilateral lower lobe pneumonia, and an alcohol level of 426. He becomes hypotensive, requires intubation and pressors.
The resident presents these laboratory tests:
| Na | 138 | Cl | 109 | BUN | 15 | glu | 151 |
| K | 3.9 | CO2 | 15 | creat | 1.0 |
On 50 % oxygen:
| pH | 7.29 |
| pCO2 | 33 |
| pO2 | 86 |
| HCO3 | 16 |
Over 24 hours we were able to extubate the patient and discontinue the pressors. He became alert, but without any memory of his admission.
I had speculated about his acid base status on presentation. I needed more information. His albumin was 4. Previous electrolyte panels were normal (no previous RTA). The patient had had no diarrhea, but some vomiting.
Day 2 he had these numbers:
| Na | 138 | Cl | 106 | BUN | 12 | glu | 99 |
| K | 4.0 | CO2 | 24 | creat | 0.7 |
On 6 liters oxygen:
| pH | 7.43 |
| pCO2 | 40 |
| pO2 | 112 |
| HCO3 | 27 |
CXR was consistent with aspiration pneumonia – no ARDS. Given this information:
1. What was his likely acid-base disorder?
2. Speculate on an etiology.
{ 2 comments… read them below or add one }
The rapid resolution of the metabolic acidosis suggests severe sepsis is less likely than one one of two things -alcoholic ketoacidosis (what were ketone values) or if lactate was significantly elevated on admission but has rapidly returned to normal, a seizure right before presentation.
Based on the history if the ketones were negative I would say it was either rapid resolution of sepsis or, more likely, a seizure before the blood gas. If the ketones were positive I would say alcoholic ketoacidosis. Glucose, lots of vitamins , good diet, antibiotics and alcohol counseling.
That’s my guess.
Why do I feel that we’ve overlooked something significant?
Dr. C, thanks for trying to clue us in (not sure if it helped, though). I’m sure the answer lies in explaining the original underlying nonanion gap acidosis. You’ve ruled out RTA and diarrhea, the acid resolution r/o fistulas, he doesn’t have a reason to take an aldo antagonist or CA inh.
I believe alcoholic ketoacidosis can give you a mixed AG and nongap acidosis. It should also resolve fairly quickly with treatment. Is this alcoholic ketoacidosis? If not — I’m stumped and ready to learn.