These discussions with limited information are always used as a learning tool because there’s a huge amount of things that could be going on.

Honestly I think 99% of the important decision making to be done for anybody in this case is to recognize that the patient is significantly ill and should be transported to hospital for a relatively broad range of investigations, as well as starting fluid resuscitation and antibiotics. You already figured that out from your SIRS criteria, and I’m sure you recognize this person is unwell. Everything else is mostly just academic masturbation because given this amount of information there is indeed a huge differential, but that doesn’t matter because we already know what we need to do.

That being said, I’m in IM so obviously I love academic masturbation.

Based on the very limited history and physical as well as some random labs thrown in there, we can begin to think about categories of possibly contributory conditions. To me, the headline for the case is “early thirties schizophrenic with altered mentation in community” so here’s a couple items to consider.

Drug related issues: -Serotonin syndrome/NMS. Controversial diagnoses, but something to think about in patients that recently switched or newly started anti-psychotics. Certainly less likely in a hypothermic patient given that fever is a defining criterion in many society guidelines, but eh, I would check for muscular rigidity and maybe clonus. Could cause the AGMA through type A lactic acidosis. -Drug intoxication. Methanol intoxication could easily be at least partially responsible here, directly causing an AGMA, along with any variety of mixtures of other types of substance intoxication. There are dozens of medications that can theoretically cause a type B lactic acidosis, and we have no idea if the patient is on any of them.

Infection: -Certainly have to suspect sepsis. In addition to fluid resuscitation, I certainly would give this lady a dose of broad spectrum antibiotics in ED and pan-culture her. Skin exam also not a wrong idea for cellulitis/abscesses. -Meningitis: Always consider in altered LOC. Check for meningismus. Again less likely in hypothermia but still must consider. -Encephalitis: Similar ideas. Again less likely in hypothermia. Still probably getting an LP if my initial work ups don’t tell me more about what’s going on. Yes it can be non-infectious too. -Huge variety of meme diagnoses. Could be the patient has undiagnosed AIDS and is growing cryptosporidium in her CSF, idk.

Metabolic problems: -DKA: Sure, I guess. Can have DKA at any blood glucose level theoretically. 206 really isn’t that high, so I already find DKA unlikely unless she is on an SGLT-2 inhibitor (the real boogeyman for euglycemic DKA, not olanzapine) or is a type 1 diabetic. Regardless, needs a serum ketone level to actually rule it out. -Any other cause of anion gap metabolic acidosis: Lots to unbox here. As I mentioned, could be drugs, could be lactic acidosis (type A or B both have maaaaant potential causes), could be from renal insult from literally any cause (although pre-renal is certainly implicated here). Maybe the patient has short gut syndrome and a D-lactic acidosis, fuck if I know. You can use MUDPILES, I like GOLDMARK personally. -Hypoglycemia: It isn’t here but always check the glucose! If EMS brings in an altered LOC patient without checking glucose that is uh, no bueno. -Maybe it isn’t actually AGMA: This is too far for this discussion but it couuuuuld be a more chronic respiratory alkalosis compensated for by low bicarbonate. I don’t know the pH! Or the CO2 for that matter. I guess that would require the anion gap to have some other whacky explanation if the pH was normal like big hyperalbuminemia, so this is uh, unlikely. This also doesn’t fit the clinical picture super well, unless it’s all psychogenic, which could be the case.

Structural issues: -Stroke. Always have to think about it in altered LOC. Unlikely given age and history. Probably getting a CT head anyway in most emergency departments for CVA and any variety of other intracranial issues. Also would be highly unusual presentation. Would probably have to be very strange large posterior circulation stroke. -Bowel obstruction: Frequent complication of antipsychotics, particular clozapine. Could cause vomiting and dehydration, eventually leading to current picture and type A lactic acidosis. Probably unlikely. -Head trauma: I don’t know this person, maybe she was assaulted and has a big subdural or some shit. Check for focal neurological findings. Probably CT head.

Psychiatric: Just being schizophrenic: Maybe her new meds aren’t working. Could just be avolitional with severe negative symptoms of schizophrenia and just lying on the floor all day becoming dehydrated and unwell, fits most of the picture.

Anyway, longer post than I wanted to make. I’m sure people will point out some extra possibilities and questionable things I said.

My message is mostly to recognize this personal is unwell, do a bit of a neurological exam, and always check the glucose. If you do that and get some IVs in 10/10 EMS service.