Objective:

Present a case report illustrating an example of diagnostic bias leading to delayed diagnosis of neurosyphilis in a patient with history of substance use. Anchoring, confirmation and attribution bias can delay recognition of reversible conditions like neurosyphilis. The lack of response to psychiatric treatment and progressive cognitive decline were key red flags prompting diagnostic reconsideration. Maintaining cognitive flexibility and revisiting the differential diagnosis are critical steps in mitigating bias related diagnostic error.

Background:

Diagnostic bias can obscure reversible causes of neuropsychiatric decline, particularly in patients with a history of substance use. Anchoring and premature attribution and assumptions may lead clinicians to attribute new psychiatric or cognitive symptoms to prior addiction rather than exploring organic etiologies.

Design/Methods:

A 56-year-old man with a history of prior cocaine use was brought from a rehabilitation facility for evaluation of delusional behavior. His family reported several weeks of functional decline and unusual behavior at work. On arrival, he appeared to respond to internal stimuli but had an unremarkable neurological examination. Serial toxicology screens were negative. MRI brain showed nonspecific white matter changes. Lumbar puncture revealed lymphocytic pleocytosis and elevated protein. He was treated empirically with lorazepam for suspected catatonia without benefit, followed by olanzapine 2.5 mg twice daily for persistent psychosis. Cognitive testing revealed significant impairment (MoCA 16/30), prompting further evaluation. CT of the chest, abdomen, and pelvis was unrevealing for malignancy. CSF serology subsequently returned positive for Treponema pallidum by IgG/IgM EIA, RPR, and VDRL, confirming neurosyphilis. The patient completed a 14-day course of IV penicillin with mild cognitive improvement and was discharged home with visiting nursing services.

Results:

NA

Conclusions:

Neurosyphilis remains a treatable cause of neuropsychiatric decline that can present as primary psychiatric illness. Clinicians must maintain diagnostic openness, particularly in patients with stigmatizing histories, and avoid anchoring in order to prevent irreversible cognitive deterioration.