Medical Workup for Hallucinations

Initial Assessment

The American College of Radiology recommends a comprehensive neurological and psychiatric evaluation to rule out secondary causes of hallucinations, with appropriate neuroimaging (preferably MRI) to exclude intracranial processes requiring intervention 1
Assessing for insight, whether the patient recognizes hallucinations aren't real, can help narrow the differential diagnosis, and preserved insight suggests conditions like Charles Bonnet Syndrome, according to the American Academy of Ophthalmology 2
Evaluating for accompanying symptoms such as altered mental status, delirium, or other psychotic symptoms is crucial, as recommended by the American College of Radiology 1
Screening for risk factors, including medication use (especially anticholinergics, steroids, dopaminergic agents), is important, as suggested by the National Comprehensive Cancer Network 4

Primary psychiatric disorders (schizophrenia, bipolar disorder, schizoaffective disorder, depression with psychotic features) should be considered, according to the American College of Radiology 1
Secondary causes, such as neurological disorders (Parkinson's disease, dementia with Lewy bodies, epilepsy, peduncular hallucinosis), should be evaluated, as recommended by the American Academy of Neurology, although the specific citation is from Praxis Medical Insights 3
Charles Bonnet Syndrome (visual hallucinations with preserved insight and vision loss) is a potential diagnosis, according to the American Academy of Ophthalmology 2
Delirium (often due to infection, metabolic disturbances, or medication effects) should be assessed, as suggested by the National Comprehensive Cancer Network 4

A complete blood count (CBC) to assess for infection is recommended by the American College of Radiology 1
A comprehensive metabolic panel to evaluate for electrolyte disturbances, renal or hepatic dysfunction is suggested by the American College of Radiology 1
A toxicology screen for substance use is recommended by the American College of Radiology 1
Urinalysis to rule out urinary tract infection (common cause of delirium) is suggested by the American College of Radiology 1

Brain MRI is preferred over CT to better visualize structural abnormalities, according to the American College of Radiology 1

An electroencephalogram (EEG) if seizure activity is suspected is recommended by the American College of Radiology 1
A lumbar puncture if central nervous system infection is suspected is suggested by the American College of Radiology 1
A formal ophthalmologic examination if Charles Bonnet Syndrome is suspected is recommended by the American Academy of Ophthalmology 2
The Confusion Assessment Method (CAM) or other validated tools to assess for delirium is suggested by the American College of Radiology 1

Hallucinations with preserved insight may indicate Charles Bonnet Syndrome, especially in patients with vision impairment, according to the American Academy of Ophthalmology 2
For patients with Parkinson's disease, regular monitoring using appropriate scales like the Neuropsychiatric Inventory (NPI) is recommended by the International Parkinson and Movement Disorder Society, although the specific citation is from Praxis Medical Insights 5

Overlooking medication side effects as potential causes, particularly in older adults, is a common pitfall, according to the National Comprehensive Cancer Network 4
Neglecting to assess for delirium, which is often underdiagnosed, especially the hypoactive subtype, is a common mistake, as suggested by the National Comprehensive Cancer Network 4