Delirium causes

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vishal Khurana, M.B.B.S., M.D. [2]; Pratik Bahekar, MBBS [3]

Overview

Delirium may be caused by severe physical or mental illness, or any process which interferes with the normal metabolism or function of the brain e.g.fever, pain, poison (including toxic drug reactions), brain injury, surgery, traumatic shock, severe lack of food or water or sleep, and even withdrawal symptoms of certain drug and alcohol dependent states, are all known to cause delirium. In addition, there is an interaction between acute and chronic symptoms of brain dysfunction; delirious states are more easily produced in people already suffering with underlying chronic brain dysfunction.

A very common cause of delirium in elderly people is a urinary tract infection, which is easily treatable with antibiotics, reversing the delirium. Delirium, like mental confusion, is a very general and nonspecific symptom of organ dysfunction, where the organ in question is the brain. In addition to many organic causes relating to a structural defect or a metabolic problem in the brain (analogous to hardware problems in a computer), there are also some psychiatric causes, which may also include a component of mental or emotional stress, mental disease, or other "programming" problems (analogous to software problems in a computer).

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Acute liver failure
• Acute Metabolic (acidosis, alkalosis, renal failure, electrolyte imbalances)
• Acute vascular (Stroke, MI, PE, heart failure)
• Adrenal cortex insufficiency
• Acute Altitude sickness
• Brain infection
• Decompression sickness
• Gangrene
• Head injury
• Hyperosmolar non-ketotic diabetic coma
• Hyperthermia
• Hypoglycemia
• Hypothermia
• Hypoxia
• Hypoxemia
• Raised intracranial pressure
• Rickettsiae
• Sepsis
• Toxins/drugs
• Withdrawal

Common Causes of Delirium

A mnemonic for the myriad causes of Delirium: IWATCHDEATH

• Infections (Pneumonia, Urinary Tract Infections)
• Withdrawal (ethanol, opiate)
• Acute Metabolic (acidosis, alkalosis, renal failure, electrolyte imbalances)
• Trauma (acute severe pain)
• Central nervous system pathology (epilepsy, cerebral hemorrhage)
• Hypoxia
• Vitamin Deficiencies (vitamin B12, thiamine)
• Endocriopathies
• Acute vascular (Stroke, MI, PE, heart failure)
• Heavy metals
• Toxins/drugs.

Causes by Organ System

Cardiovascular	Malignant hypertension, Heart failure
Chemical/Poisoning	Withdrawal states from Ethanol, Benzodiazepines, Water hemlock poisoning , Monomethylhydrazine , Toluene, Texas Mescalbean poisoning, Poison hemlock, Organic solvent, Methanol, Marijuana, Lead, Jimson weed, Hyperbaric sickness, Hydrogen sulfide , Heroin, Hallucinogens, Ethylene glycol, Ethanol, Daphne poisoning , Cyanide, Carbon tetrachloride, Carbon monoxide toxicity, Alcohol withdrawal, Thallium Sulfate poisoning, Phencyclidine poisoning, Nickel, Carbonyl poisoning
Dental	No underlying causes
Dermatologic	No underlying causes
Drug Side Effect	Antihistamines, Antipsychotics, Atropine, Cabergoline, Drug overdose, Drug withdrawal, Lithium, Muscle relaxants, Oxcarbazepine, Promethazine, Quinolones, Serotonin syndrome, Valproic acid, Zanamivir
Ear Nose Throat	No underlying causes
Endocrine	Pituitary apoplexy, Phaeochromocytoma, Hypothyroidism, Hypopituitarism, Hypoglycemia, Hyperthyroidism, Hyperosmolar non-ketotic diabetic coma, Hyperglycemia, Hyperthyroidism, Elevated or depressed pituitary function ,Elevated or Depressed adrenal function, Diabetic ketoacidosis, Diabetic hypoglycemia, Cushing syndrome, Adrenal cortex insufficiency
Environmental	Hypothermia, Hyperthermia, Heat stroke, Electric shock, Decompression sickness, Acute Altitude sickness
Gastroenterologic	Elevated or depressed pancreas function, Chronic Liver failure, Acute liver failure
Genetic	No underlying causes
Hematologic	Thrombocytosis, Polycythemia, Leukemic blast cell crisis, Hypereosinophilia
Iatrogenic	Postoperative stress
Infectious Disease	Viral hemorrhagic fever, Vancomycin resistant enterococcal bacteremia, Urinary tract infection, Typhoid fever, Systemic inflammatory response syndrome, Systemic infection, Surgical wound infection, Subdural empyema, Sleeping sickness (West African), Sleeping sickness (East African), Sepsis, Rickettsiae, Rabies , Pyelonephritis, Plague, Neurocysticercosis, Malaria, Intraspinal abscess / granuloma, Intracranial abscess / granuloma, Gangrene, Chest infection, Cerebral malaria, Brain or epidural abscess, Brain infection
Musculoskeletal/Orthopedic	No underlying causes
Neurologic	Venous sinus thrombosis, Raised intracranial pressure, Postictal state, Nonconvulsive status epilepticus, Meningoencephalitis, Meningitis, Intracranial bleeding, Hypertensive encephalopathy, Epileptic seizures, Epidural haemorrhage, Encephalitis, Encephalitis, Cerebrovascular accident, Cerebral oedema, Cerebral infarction, Brain tumor, Brain abscess
Nutritional/Metabolic	Wilson's disease, Wernicke's encephalopathy, Vitamin B12 deficiency, Thiamine (Vitamin B1) deficiency, Niacin deficiencies, Folate deficiency, Acute intermittent porphyria
Obstetric/Gynecologic	No underlying causes
Oncologic	No underlying causes
Ophthalmologic	No underlying causes
Overdose/Toxicity	No underlying causes
Psychiatric	Schizoaffective disorder
Pulmonary	Respiratory failure, Hypoxemia, Hypercarbia
Renal/Electrolyte	Hypophosphatemia, Hypoosmolar states, Hyponatremia, Hypocalcemia, Hyperosmolar states, Hypernatremia, Hypermagnesemia, Hypercalcemia, Hypomagnesemia, Hyperphosphatemia, Chronic renal failure, Acute renal failure
Rheumatology/Immunology/Allergy	Vasculitis
Sexual	No underlying causes
Trauma	Trauma, Skull fracture, Head injury
Urologic	Urinary Track Infection
Miscellaneous	Coproporphyria, Burns

Causes in Alphabetical Order

Acute intermittent porphyria Acute liver failure Acute renal failure Adrenal cortex insufficiency Alcohol withdrawal Acute altitude sickness Antihistamines Antipsychotics Brain abscess Brain infection Brain or epidural abscess Brain tumor Burns Cabergoline Carbon monoxide toxicity Carbon tetrachloride Cardiac failure Cerebral infarction Cerebral malaria Cerebral oedema Cerebrovascular accident Chest infection Chronic Liver failure Chronic renal failure Coproporphyria, hereditary Cushing syndrome Cyanide Daphne poisoning Decompression sickness Diabetic hypoglycemia Diabetic ketoacidosis Drug overdose Drug withdrawal Electric shock Elevated or depressed adrenal function Elevated or depressed pancreas function Elevated or depressed pituitary function Encephalitis Encephalitis Epidural haemorrhage Epileptic seizures Ethanol Ethylene glycol Fat embolism Folate deficiency Gangrene Hallucinogens Head injury Heart failure

Heat stroke Heroin Hperthyroidism Hpherphosphatemia Hydrogen sulfide Hyomagnesemia Hyperbaric sickness Hypercalcemia Hypercarbia Hypereosinophilia Hyperglycemia Hypermagnesia Hypernatremia Hyperosmolar non-ketotic diabetic coma Hyperosmolar states Hypertensive encephalopathy Hyperthermia Hyperthyroid Hypocalcemia Hypoglycemia Hyponatremia hypoosmolar states Hypophosphatemia Hypopituitarism Hypothermia Hypothyroidism Hypoxemia Hypoxia Infections Intracranial abscess / granuloma Intracranial bleeding Intraspinal abscess / granuloma Jimson weed Lead Leukemic blast cell crisis Lithium Liver failure Malaria Malignant hypertension Marijuana Meningitis Meningoencephalitis Methanol Muscle relaxant Neurocysticercosis Niacin deficiencies Nickel poisoning Nonconvulsive status epilepticus Organic solvent

Phaeochromocytoma Phencyclidine Pituitary apoplexy Plague Poison hemlock Polycythemia Porphyria Postictal state Postoperative stress Pyelonephritis Quinolones Rabies Raised intracranial pressure Renal failure, acute Renal failure, chronic Respiratory failure Rickettsiae Schizoaffective disorder Sepsis Serotonin syndrome Skull fracture Sleeping sickness (East African) Sleeping sickness (West African) Subdural empyema Surgical wound infection Systemic infection systemic inflammatory response syndrome Systemic organ failure Texas Mescalbean poisoning Thiamine (Vitamin B1) deficiency Thallium Sulfate poisoning Thrombocytosis Toluene Monomethylhydrazine Trauma Typhoid fever Urinary tract infection Valproic acid Vancomycin resistant enterococcal bacteremia Vasculitis Venous sinus thrombosis Viral hemorrhagic fever Vitamin B12 deficiency Water hemlock poisoning Wernicke's encephalopathy Wilson's disease Zanamivir Withdrawal states e.g. ethanol, benzodiazepines

References