neurologic disorders
Delirium
Etiology of Delirium
Themost common causesof delirium are the following: Drugs, particularly anticholinergics, psychoactive drugs or medications, and opioids Dehydration Infection Many other conditions can cause delirium (see table). In about 10 to 20% of patients, no cause is identified. include brain disorders (eg, Dementia , Precipitating factorsinclude use of drugs (particularly≥3 new medications), infection, dehydration, shock, hypoxia, anemia, immobility, undernutrition, use of bladder catheters (whether urinary retention is present or not), hospitalization, pain, sleep deprivation, and emotional stress. Unrecognized liver or kidney failure may cause medication toxicity and delirium by impairing the metabolism and reducing the clearance of a previously well-tolerated medication. Delirium can be a common presenting symptom in older patients with a viral disease. For example, coronavirus disease 2019 (COVID-19) can often cause delirium without other typical symptoms or signs of COVID-19. Delirium is more likely to result in poor hospital outcomes (eg, need for ICU care) and death in patients with COVID-19 ( Etiology reference ). Recent exposure to anesthesia also increases risk, especially if exposure is prolonged and if anticholinergics are given during surgery. After surgery, pain and the use of opioid analgesics can also contribute to delirium. Decreased sensory stimuli at night may trigger delirium in at-risk patients. For older patients in an ICU, risk of delirium (ICU psychosis) is particularly high. Status epilepticus is an underrecognized cause of altered mental status in ICU patients that should be considered. 1.Kennedy M, Helfand BKI, Gou RY, et al: Delirium in older patients with COVID-19 presenting to the emergency department.JAMA Netw Open3 (11):e2029540, 2020. doi:10.1001/jamanetworkopen.2020.29540 