Theory 16/Palliative & Symptom Science
Delirium Is Load Against Reserve
The claim
Delirium occurs when the ratio of neuroinflammatory load to cognitive reserve exceeds a threshold, so the same infection produces delirium in one patient and not another.
01The mechanism
Inflammation disrupts synaptic function, and the brain compensates using reserve capacity. When load exceeds what reserve can absorb, attention and orientation fail.
That makes reserve the modifier, and predicts that reserve proxies should predict delirium at equal illness severity.
02What this is not
Illness-severity models
Those predict delirium from the precipitant. This predicts it from the ratio, which explains discordance at equal severity.
03Predictions
- P1Delirium should track the ratio.
- P2Reserve proxies should predict at equal severity.
04Refutation
Delirium tracking severity at controlled reserve would favour the severity model.