TOC  |  Neurology

DELIRIUM OR ACUTE CONFUSION

Quick Evaluation: Vital signs; evaluation for head injury or CVA, seizures, meningitis, or sepsis; alcohol or drug/medication history, glucose, oxygen, creatinine, liver function tests.

Until proven otherwise, a sudden change in behavior after age 40 should be considered to be delirium. Delirium is a true medical emergency because many of the causes such as anoxia, hypoglycemia, meningitis, and alcohol withdrawal are potentially lethal and reversible.

Effective management depends on prompt recognition of the condition, diagnosis and treatment of the underlying cause, management of agitation and disruptive behavior, and provision of general supportive care.

All nonessential drugs should be eliminated. Laboratory testing may uncover metabolic problems and fluid or electrolyte disturbances, which should be corrected without delay. Indications for brain imaging depend on the clinical situation. Although brain imaging often uncovers preexisting central nervous system disease, a comprehensive medical evaluation is still needed to identify the precipitating illness, which usually is located outside the nervous system.

A. Toxic or Metabolic causes:

• Drugs /Toxins: Use/abuse of various cerebroactive drugs, as acute atropine intoxication; withdrawal from cerebroactive drugs, as alcohol, barbiturate, tranquilizer, antidepressants,etc.;
• Metabolic: hypoxemia, hypoglycemia, uremia, liver failure, hyponatremia, , etc..
• Fever & infection, especially  in elderly patients.
• Post ictal state, postoperative or in hospital psychosis.

B. Primary cerebral:

• Encephalitis & other multifocal brain disorders, bacterial or TB meningitis, traumatic delirium, CVA, esp. of temporal & parietal area.

C. Underlying brain disease of various etiologies:

• Senility, various structural brain lesions often allows the development of delirium with relatively minor metabolic disturbances..

Confusion

• Infections:  Sepsis (Bacteremia), Meningitis
• Drugs: Anti-cholinergics, Anti-histamines (H1-blockers), Benzodiazepines,
• Narcotics Withdrawal Syndromes: Drug Withdrawal, EtOH Withdrawal
• Vitamin Difficiency: Thiamin Deficiency
• Metabolic Dysfunction: Hepatic Insufficiency, Renal Failure - particularly acute, Endstage Renal Disease
• Endocrine Disorders: Thyrotoxicosis / Hypothyroidism, Adrenal Insufficiency
• Metabolic Derangements: Hypoxia, Hypoglycemia, Electrolyte Abnormalities - especially abnormal sodium and calcium
• Encephalopathy
• Neurodegenerative Disease: Multiple Infarctions, Alzheimer Disease, Parkinson Disease

Encephalopathy

1. Metabolic: Hypoglycemia, Hyponatremia, Hypernatremia, Hypercalcemia, Carbon Dioxide Narcosis, Azotemia, Ketoacidosis, Hyperglycemic Coma (dehydration, hyperglycemia), Hepatic Encephalopathy, Nitrogen Narcosis - scuba diving

2. Toxic Encephalopathies: Alcohol - acute intoxication, withdrawal syndrome, Korsikoff Syndrome, Psychoactive Drugs, Salicylates, Heavy Metals

3. Intracranial lesions: Hemorrhage: subarachnoid, subdural, intracerebral, Cerebral infarction: thromboembolic stroke, Cerebral tumor, Cerebral abscess, Meningitis, Encephalitis, Epilepsy and Post-Ictal State

4. Neuropsychiatric Disease  

References:
Outlines in Clinical Medicine on Physicians' Online 2000
Riordan SM and Williams R. 1997. NEJM. 337(7):473

12182000