see also: [[Delirium vs psychosis]], [[Hot and bothered]], [[ALS algorithm|Hs and Ts]], [[Coma]] > This is obviously a tremendously broad "symptom" for which I see little value in producing a "general" differential schema, as the cause for confusion in a *particular* patient will need to be tailored to that patient. Therefore, the above sections on [[Delirium vs psychosis|delirium vs psychosis vs dementia]] and evaluation of the [[Hot and bothered]] patient are a bit more useful for those phenotypes. and schema would completely change if presentation was confusion + [[Headache]]. General schema: - consider "special patient" specifics from below - infections -- [[Meningitis]], [[Encephalopathy|Encephalitis]] - metabolic -- [[hypoglycaemia|hypoglycemia]], [[hyponatremia]], [[thyrotoxicosis|thyroid storm]], [[Liver Failure|hepatic encephalopathy]], [[hypercalcaemia|hyper-Ca]] - environmental -- [[Heat-related illness|hyperthermia]] - structural -- [[Subarachnoid haemorrhage|SAH]], [[traumatic brain injury|TBI]], [[Brain Tumours|space-occupying lesion]] - CNS -- [[Seizures|post-ictal]], embolic of some variety - toxicology (not an exhaustive list): - [[Aspirin overdose]] - [[carbon monoxide]] - [[Cholinergic syndrome]] - [[Digoxin toxicity]] - GHB - [[​Lithium Toxicity|lithium]] - [[TCA overdose]] - [[Toxicology#Tox Seizures|Tox seizure → post-ictal]] - **patient specifics** - young woman → ?[[Pre-eclampsia|Eclampsia]], [[thyrotoxicosis]] or [[Hypothyroidism|hypothyroid]]? [[Anorexia]] - immunosuppressed / [[HIV|AIDS]] → consider toxoplasmosis or cryptococcus - [[IVDU issues|IVDU]] → could this be septic emboli from [[Endocarditis]]? - middle-aged adult → ?PRES, [[Liver Failure|hepatic encepalopathy]] - Elderly → infection, sedative drugs, [[Anticholinergic toxicity]], [[​Lithium Toxicity|lithium]], [[Digoxin toxicity]], steroids, beta blockers, chronic [[Hypocalcemia]] - obesity → hypercaponea from OSA **Mnemonic:** AEIOUTIPS -- (although I would never use this as too broad) A - alcohol or drug intox, atypical migraine E - electrolytes, environment (hyper/hypothermia), endocrinopathy, [[Encephalopathy]], [[Seizures|Epilepsy]] I - infection ([[Meningitis]], encephalitis, sepsis) O - [[Tox Resus|overdose]], Oxygen (hypoxia, PE, etc) U - uraemia T - Trauma, tumor I - insulin problem P - poisons, [[schizophrenia|psychosis]] S - stroke, status epilepticus