Delirium/Hallucinations
Differential Overview
Systemic
❑ Drugs/toxins
❑ Sepsis
❑ Hypoglycemia
❑ Hypercalcemia
❑ Hyponatremia
❑ Shock
❑ Delirium tremens
❑ Vitamin B12 deficiency
❑ Hypoxia
❑ Hypercapnia
❑ Thyrotoxicosis
❑ Uremia
❑ Hepatic encephalopathy
❑ Thiamine deficiency
❑ Heat stroke
❑ Hypothermia
❑ Lead intoxication
❑ Carbon monoxide poisoning
Neurologic
❑ Concussion
❑ Hypertensive encephalopathy
❑ Subdural hematoma
❑ Postictal
❑ Transient global amnesia
❑ Meningitis
❑ Right parietal stroke
❑ Encephalitis
❑ Vasculitis
❑ Carcinomatous meningitis
Hallucinations
❑ Drugs
❑ Schizophrenia
❑ Temporal lobe epilepsy
Diagnostic Approach
Delirium is characterized by gross disorientation in the presence of alertness and vigilance, disorders of perception with vivid illusions, and psychomotor and autonomic hyperactivity. It usually develops over a short time and is associated
with fluctuating mental status, decreased attention, disorganized thinking as indicated by rambling, irrelevant, or incoherent speech, and a decreased level of consciousness. The most sensitive findings are variability in level of arousal, impaired short-term memory (e.g., digit span), and disorientation to time. Relatives or friends are helpful sources of information about the tempo and degree of impairment.
Fever, tachycardia, or hypertension should prompt a careful evaluation for a medical cause. Infection is a common cause in the elderly, especially pneumonia or urinary tract infection. Visual hallucinations are organic in origin, due to factors such as drugs, rather than due to schizophrenia.
Confusion Assessment1) Change in mental state (from baseline) that is acute and fluctuates. 2) Difficulty focusing attention or trouble keeping track of what is said. 3) Disorganized thinking (rambling or irrelevant conversation, unpredictable switching between subjects, illogical flow of ideas). 4) Altered level of consciousness (lethargy, stupor, or hyperalert). A positive test requires 1 and 2 positive, and either 3 or 4.
Clinical Findings
Drugs/toxins Delirium may be caused by drugs such as alcohol, opiates, barbiturates, salicylates, ergot, amphetamines, cocaine, or scopolamine. Toxins such as gasoline, glue, ether, liquid paper, or heavy metals can also cause delirium. Hallucinations may be precipitated by alcohol (especially during withdrawal), propranolol, bromocriptine, or cimetidine (in the elderly).
Sepsis Rigors, hypotension, and spiking fever are the major clues in a delirious patient.
Hypoglycemia Suspect this in a known diabetic patient who takes insulin or oral hypoglycemics, or in an alcoholic patient who has marginal glycogen stores. The patient will present with confusion, diaphoresis, tremor, giddiness, and tachycardia. Rapid response to oral or intravenous glucose is
diagnostic.
Hypercalcemia Suspect calcium excess in those patients who have a known cancer. Causes are legion, however, and serum calcium measurement should be considered part of a “metabolic workup.”
Hyponatremia Precipitating factors include polydipsia; use of lithium, diuretics or antipsychotics; or thoracic zoster.
Shock Confusion and restlessness are early and sensitive indicators. Also present are hypotension, tachycardia, and cutaneous vasoconstriction with mottling/livedo.
Delirium tremens During alcohol withdrawal, confusion is followed by autonomic arousal with tachycardia, diaphoresis, and anxiety. This may occur several days into hospitalization, and the altered mental status may make it difficult to then obtain an alcohol history.
Vitamin B12 deficiency Peripheral neuropathy and family history of pernicious anemia are helpful clues.
Hypoxia Delirium occurs with an increased A-a gradient in acute pulmonary embolism or in pulmonary edema. Cyanosis is a helpful clue.
Hypercapnia Carbon dioxide retention from alveolar hypoventilation occurs subacutely in a patient who has chronic obstructive pulmonary disease, especially during an episode of acute bronchoconstriction.
Thyrotoxicosis Fine tremor, silky skin, tachycardia, heat intolerance, lid lag, and exophthalmos are all clues, variably present.
Uremia Delirium may rarely be a presenting sign of uremia, and it is accompanied by peripheral and periorbital edema.
Hepatic encephalopathy There is usually a prominent history of alcoholism. Concurrent findings of metabolic encephalopathy, such as asterixis or myoclonus, are present. Findings of chronic liver disease include spider angiomata, ascites, hemorrhoids, and distended superficial abdominal veins.
Thiamine deficiency Wernicke encephalopathy should be suspected in a delirious patient with alcoholism or malnutrition. Concurrent findings include horizontal nystagmus, ophthalmoplegia, and ataxia.
Heat stroke Outdoor exposure, especially with exercise, and a high core temperature with a paucity of sweating are found.
Hypothermia Environmental cold exposure, low core temperature, and intense vasoconstriction are found.
Lead intoxication Symptoms include fatigue, depression, confusion, episodic vague abdominal pain, and peripheral neuropathy. A gray lead line may appear on the gums.
Carbon monoxide poisoning Suspect this with exposure to engine exhaust or a kerosene space heater in a patient with a severe headache and flushed face.
Concussion Confusion immediately follows head trauma (or appears in a situation suggestive of head trauma).
Hypertensive encephalopathy The blood pressure will be markedly elevated. There will usually be retinal hemorrhages and exudates reflective of intracranial vasculopathy as well as papilledema.
Subdural hematoma A history of head trauma or a recent fall in an elderly patient is the common scenario. A lucid interval is a classic sign of extradural middle meningeal hematoma. These patients may also be intoxicated, which makes diagnosis more difficult. Suspect this when there is temporal trauma, gradual onset of contralateral hemiparesis, and a dilated reactive pupil. A plantar extensor (Babinski) reflex is consistent with a contralateral hematoma.
Postictal If the seizure was not witnessed, clues such as tongue biting or incontinence are often present.
Transient global amnesia Sudden, complete, anterograde loss of memory and learning develops in the presence of strong emotion or physical exertion.
Meningitis Fever, prominent headache, photophobia, and neck stiffness/
rigidity make a lumbar puncture mandatory.
Right parietal stroke Symptoms result from impaired attention found in a nondominant hemispheric stroke. It should be suspected when atrial fibrillation is present.
Encephalitis Fever and confusion are prominent. Temporal lobe symptoms such as hallucinations are often manifest, especially with herpes simplex encephalitis.
Vasculitis It usually occurs in the context of active systemic connective tissue disease (fever, arthralgias, serositis).
Carcinomatous meningitis It is recognized by multiple cranial nerve palsies in a patient with a known primary cancer.
Schizophrenia Auditory hallucinations, especially with a paranoid quality, are a common manifestation.
Temporal lobe epilepsy Complex illusions with altered consciousness, automatisms, and déjà vu or jamais vu phenomena occur.
Pictures
Book Source Details
- Book Title: Field Guide to Bedside Diagnosis
- Author(s): David S. Smith
- Year of Publication: 2007
- Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Delusions
Read excerpts from these other book chapters related to Delusions:
Medical Books Excerpts
- DELUSIONS
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- DELUSIONS
- "Differential Diagnosis in Primary Care" (2007)
- [ read ]
- DELUSIONS
- "Differential Diagnosis in Primary Care" (2007)
- [ read ]
Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2008 Williams & Wilkins.
More About Causes of Delusions
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More About This Book:
Title: Field Guide to Bedside Diagnosis
Authors: David S. Smith
Publisher: Lippincott Williams & Wilkins
Copyright: 2007
ISBN: 0-78178-165-5
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» Next page: Delusional disorders (Handbook of Diseases)
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