What is the appropriate full medical workup for a patient presenting with delusions?

Medical Workup for Patients with Delusions

A comprehensive medical workup for patients presenting with delusions should include thorough clinical assessment, targeted laboratory testing, selective neuroimaging, and specialized psychiatric evaluation to distinguish between primary psychiatric disorders and secondary causes of delusions. 1, 2

Initial Clinical Assessment

• Obtain detailed history from the patient and knowledgeable informants, as cognitive status may fluctuate throughout the day 2
• Perform mental status examination to assess appearance, behavior, thought process, thought content (including presence of hallucinations or delusions), mood, affect, insight, and judgment 1
• Evaluate for cardinal features of delirium using validated tools such as the Confusion Assessment Method (CAM) or its variants (CAM-ICU, B-CAM) 1, 2
• Distinguish between primary psychosis (schizophrenia, bipolar disorder, schizoaffective disorder, depression with psychotic features) and secondary causes related to medical conditions 1
• Assess for focal neurological deficits, which may indicate underlying intracranial pathology 1

Laboratory Investigations

• Complete blood count to evaluate for infection or hematologic abnormalities 2, 3
• Comprehensive metabolic panel to assess electrolyte imbalances, renal and liver function 2, 3
• Urinalysis to screen for urinary tract infections (a common precipitating factor for delirium) 1, 2
• Blood glucose measurement to rule out hypo/hyperglycemia 2, 3
• Thyroid function tests to evaluate for thyroid disorders 2
• Medication levels when appropriate (especially for patients on psychotropic medications) 3
• Toxicology screen to assess for substance intoxication or withdrawal 1
• Consider specialized testing based on clinical suspicion (e.g., autoimmune panels, paraneoplastic markers) 1, 4

Imaging Studies

• Brain CT scan should be performed selectively rather than routinely, guided by specific clinical features 1, 2
• Indications for neuroimaging include focal neurological deficits, history of recent head trauma, new-onset seizures, signs of increased intracranial pressure, and unexplained altered mental status despite initial workup 1, 2
• MRI may be preferred when available, though challenges exist with patients who may be combative or unable to follow commands 1
• Consider tailoring MRI examinations for shorter scan times or using motion-reducing sequences for agitated patients 1
• Chest radiography to evaluate for pneumonia or other pulmonary processes that may contribute to delirium 1, 3

Additional Diagnostic Tests

• Electrocardiogram to assess for myocardial ischemia or arrhythmias 1, 2
• Electroencephalography (EEG) when seizure activity is suspected 1
• Lumbar puncture to assess for central nervous system infection when clinically indicated 1

Specialized Psychiatric Evaluation

• Psychiatric consultation is recommended for all patients with delusions 1
• Evaluate for specific types of delusional content: persecutory, somatic, erotomanic, jealous, or grandiose 5
• Assess duration of delusions (diagnosis of delusional disorder requires at least 1 month's duration) 5
• Screen for comorbid mood disorders, which frequently co-occur with delusional disorders 5
• Evaluate for specific delusional syndromes such as delusional infestation (including rare presentations like delusions of fungal infection) 6, 4

Common Pitfalls to Avoid

• Failing to recognize hypoactive delirium, which is commonly missed in clinical settings 2, 3
• Attributing symptoms to dementia without investigating for acute causes 2
• Inadequate screening leading to missed diagnosis in emergency settings 2
• Mistaking delirium for primary psychiatric disorders 3
• Overlooking medical conditions that may present with psychotic symptoms, including endocrine disorders, autoimmune diseases, neoplasms, neurologic disorders, infections, genetic/metabolic disorders, nutritional deficiencies, and drug-related issues 1
• Failing to identify delusions hidden in a person's experience of depression, life history, and personality 7

Management Considerations

• Treatment should target the underlying cause when identified 1
• For primary psychosis, consider pharmacologic management with antipsychotic medications, psychological therapy, and psychosocial interventions 1
• For delirium, implement non-pharmacological approaches including reorientation, maintaining normal sleep-wake cycles, and creating a calm environment 3
• Pharmacological interventions for delirium should be limited to patients with distressing symptoms or safety concerns 3
• Recognize that patients with delusional disorders often lack insight into their condition and may refuse psychiatric treatment 6, 5