Delirium - definition, common causes, physical examination

Definition:

Delirium is defined by the acute onset of fluctuating cognitive impairment and a disturbance of consciousness. Cognition includes memory, language, orientation, judgement, conducting interpersonal relationships, performing actions (praxis), and problem solving. Delirium is thus marked by short-term confusion and changes in cognition. There is also rapid improvement in most cases when the causative factor is identified and eliminated.

Abnormalities of mood, perception, and behavior are common psychiatric symptoms. Tremor, asterixis, nystagmus, incoordination, and urinary incontinence are common neurological symptoms.

Common causes of delirium:

1) Central nervous system disorder	Seizure (postictal, nonconvulsive status, status) Migraine Head trauma, brain tumor, subarachnoid hemorrhage, subdural, epidural hematoma, abscess, intracerebral hemorrhage, cerebellar hemorrhage, nonhemorrhagic stroke, transient ischemia
2) Metabolic disorder	Electrolyte abnormalities Diabetes, hypoglycemia, hyperglycemia, or insulin resistance
3) Systemic illness	Infection (e.g., sepsis, malaria, erysipelas, viral, plague, Lyme disease, syphilis, or abscess) Trauma Change in fluid status (dehydration or volume overload) Nutritional deficiency Burns Uncontrolled pain Heat stroke High altitude (usually >5,000 m)
4) Medications	Pain medications (e.g., postoperative meperidine or morphine) Antibiotics, antivirals, and antifungals Steroids Anesthesia Cardiac medications Antihypertensives Antineoplastic agents Anticholinergic agents Neuroleptic malignant syndrome Serotonin syndrome
5) Over-the-counter preparations	Herbals, teas, and nutritional supplements
6) Botanicals	Jimsonweed, oleander, foxglove, hemlock, dieffenbachia, and Amanita phalloides
7) Cardiac	Cardiac failure, arrhythmia, myocardial infarction, cardiac assist device, cardiac surgery
8) Pulmonary	Chronic obstructive pulmonary disease, hypoxia, SIADH, acid base disturbance
9) Endocrine	Adrenal crisis or adrenal failure, thyroid abnormality, parathyroid abnormality
10) Hematological	Anemia, leukemia, blood dyscrasia, stem cell transplant
11) Renal	Renal failure, uremia, SIADH
12) Hepatic	Hepatitis, cirrhosis, hepatic failure
13) Neoplasm	Neoplasm (primary brain, metastases, paraneoplastic syndrome)
14) Drugs of abuse	Intoxication and withdrawal
15) Toxins	Intoxication and withdrawal Heavy metals and aluminum

Physical examination of a delirious patient:

Parameter	Finding	Clinical Implication
1. Pulse	Bradycardia	Hypothyroidism Stokes-Adams syndrome Increased intracranial pressure
	Tachycardia	Hyperthyroidism Infection Heart failure
2. Temperature	Fever	Sepsis Thyroid storm Vasculitis
3. Blood pressure	Hypotension	Shock Hypothyroidism Addison's disease
	Hypertension	Encephalopathy Intracranial mass
4. Respiration	Tachypnea	Diabetes Pneumonia Cardiac failure Fever Acidosis (metabolic)
	Shallow	Alcohol or other substance intoxication
5. Carotid vessels	Bruits or decreased pulse	Transient cerebral ischemia
6. Scalp and face	Evidence of trauma
7. Neck	Evidence of nuchal rigidity	Meningitis Subarachnoid hemorrhage
8. Eyes	Papilledema	Tumor Hypertensive encephalopathy
	Pupillary dilatation	Anxiety Autonomic overactivity (e.g., delirium tremens)
9. Mouth	Tongue or cheek lacerations	Evidence of generalized tonic-clonic seizures
10. Thyroid	Enlarged	Hyperthyroidism
11. Heart	Arrhythmia	Inadequate cardiac output, possibility of emboli
	Cardiomegaly	Heart failure Hypertensive disease
12. Lungs	Congestion	Primary pulmonary failure Pulmonary edema Pneumonia
13. Breath	Alcohol
	Ketones	Diabetes
14. Liver	Enlargement	Cirrhosis Liver failure
15. Nervous system
a. Reflexes	Asymmetry with Babinski's signs	Mass lesion Cerebrovascular disease Preexisting dementia
	Snout	Frontal mass Bilateral posterior cerebral artery occlusion
b. Abducent nerve (sixth cranial nerve)	Weakness in lateral gaze	Increased intracranial pressure
c. Limb strength	Asymmetrical	Mass lesion Cerebrovascular disease
d. Autonomic	Hyperactivity	Anxiety Delirium