Welcome to NeuroTalk. This has to be a very difficult time for you. Watching a parent in distress is very painful (I had that experience with my mother years ago too)

One thing that does happen with the elderly is that common drugs that are given to them (some are even OTC now) can cause delirium. And example is Zantac (and other H2 antagonists like Pepcid). When people age, the blood brain barrier starts to let things into the brain which it didn't before when the patient was younger. This situation then leads to unfamiliar side effects.

Many other drugs are capable of causing delirium and behavior changes in the elderly. Here is a link to a discussion we had here in the past:
http://neurotalk.psychcentral.com/sh...light=delirium

Also since then, statins (for lowering cholesterol), have been listed by the FDA as affecting memory and this means that they too are getting into the brain and they could perhaps affect other functions as well.

The elderly also can have a sudden decrease in thyroid functions, when very ill or during trauma/surgery. So the thyroid should be tested ASAP IMO. If the thyroid cannot keep up with the tissue demands during these times, then supplemental hormone can be given.

An ER doctor may or may not know of all the drugs that are difficult for the elderly to handle. So you have to bring this up and ask them to research it.

If your father was given high dose Levaquin or Cipro or Avelox for his pneumonia...this antibiotic goes into the brain of older patients and does mischief there too. So even antibiotics can cause problems, confusion etc in an elderly patient.

Typically, also the elderly can get very low in vitamin B12. A test should be run on your father and the results should be 400pg/ml or higher. Labs still report low values as "normal" so get the numbers. Low B12 is a common cause of dementia-like symptoms in an elderly patient.

I'll look in on this thread daily to see if you have any further questions.