Encephalopathy in a nutshell

Although not the definitive, all encompassing, reasons for encephalopathy/delirium/altered mental status, this short list certainly covers many of the most prevalent causes.

Etiology	Physical Exam	Bedside Diagnostic Tests	History	STAT Diagnostic Tests
"Bugs" Infection	Temperature SpO2 Meningeal signs Lines (vascular, GI, GU)		Headache Aspiration Productive cough Vomiting / Diarrhea Urinary changes	CXR UA and urine c/s Blood c/s Sputum c/s C. difficile toxin
"Drugs" Side effects of and withdrawal from drugs		Naloxone trial	MAR (narcotics, corticosteroids, CNS agents) Review home medications Alcohol/substance abuse
"Lytes" Electrolyte abnormalities particularly hypo- and hyperosmolar states		I-STAT	Ins/Outs	BMP Serum osmolarity
"Plights" Inadequate pain control	Pain scale Abdominal examination	Bladder scan
"Beating" Cardiac arrhythmia and ischemia	Heart rate Blood pressure Jugular venous pulsation Heart murmurs and additional sounds	Telemetry I-STAT Troponin		EKG Cardiac markers BNP
"Bleeding" Acute blood loss	Scleral pallor Rectal exam	Fecal occult blood test I-STAT (ABG also has an H&H)	Recent surgery Anticoagulation	CBC
"Gases" Hypoxemia or hypercarbia Acidosis or alkalosis	Respiratory rate SpO2	ABG	History of hypercarbia Previous ABG
"Glucose" Hypo- and hyperglycemia		Accu-check I-STAT	Diabetes mellitus Insulin or oral antihyperglycemic medications
"Gourd" Intracranial pathology (i.e. stroke, mass effect, traumatic brain injury) Seizure	Neurological examination		Documentation of seizure-like activity without formal history of seizure Trauma History of dementia or seizure	CT head without contrast