Mr. H begins to see improvements on Day 7 of taking haloperidol. He no longer brings up infestation but still acknowledges having worms inside him when directly asked. He says the worms cause him less distress than before and he is hopeful to live without discomfort. He also demonstrates an ability to conduct activities of daily living. Because Mr. H is being monitored on an acute inpatient psychiatric basis, he is deemed appropriate for discharge even though his symptoms have not yet fully resolved. After a 19-day hospital stay, Mr. H is discharged on haloperidol 15 mg/d and quetiapine 200 mg/d.
The authors’ observations
Mr. H asked to have his sputum examined. The “specimen sign,” also called “matchbox sign” or “Ziploc bag sign,” in which patients collect what they believe to be infected tissue or organisms in a container, is a well-studied part of DP.5 Such samples should be considered during initial encounters and can be examined for formal evaluation, but cautiously. Overtesting may incur a financial burden or reinforce deleterious beliefs and behaviors.
It can be difficult to identify triggers of DP. Research shows DP may arise from nonorganic and stressful life events, home floods, or contact with people infected with parasites.6,7 Organic causes have also been found, such as patients taking multiple medications for Parkinson disease who developed delusional symptoms.8 Buscarino et al9 reported the case of a woman who started to develop symptoms of delusions and hallucinations after being on high-dose amphetamines for attention-deficit/hyperactivity disorder. Research shows that stopping the suspected medication commonly improves such symptoms.9,10 Although methamphetamine can remain detectable in urine for up to 4 days after use and potentially a few days longer for chronic users due to circulating levels,11 Mr. H’s symptoms continued for weeks after all substances of abuse should have been cleared from his system. This suggests he was experiencing a psychiatric illness and was accurate in distinguishing methamphetamine-induced from psychiatric-induced sensations. Regardless, polysubstance use has been shown to potentially increase the risk and play a role in the onset and progression of delusional illness, as seen in prior cases as well as in this case.9
It has been hypothesized that the pathophysiology of DP is associated with the deterioration of the striatal dopaminergic pathway, leading to an increase in extracellular dopamine levels. The striatum is responsible for most dopamine reuptake in the brain; therefore, certain drugs such as cocaine, methamphetamine, and methylphenidate may precipitate symptoms of DP due to their blockade of presynaptic dopamine reuptake.12 Additionally, conditions that decrease the functioning of striatal dopamine transporters, such as schizophrenia or depression, may be underlying causes of DP.13
Treatment of DP remains a topic of debate. Most current recommendations appear to be based on a small, nonrandomized placebo-controlled trial.14 The first-generation antipsychotic pimozide had been a first-line treatment for DP, but its adverse effect profile, which includes QTc prolongation and extrapyramidal symptoms, led to the exploration of second-generation antipsychotics such as olanzapine and risperidone.15,16 There is a dearth of literature about the use of haloperidol, quetiapine, or a combination of both as treatment options for DP, though the combination of these 2 medications proved effective for Mr. H. Further research is necessary to justify changes to current treatment standards, but this finding highlights a successful symptom reduction achieved with this combination.
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