Delusional parasitosis as presenting symptom of occipital lobe cerebrovascular accident.

Delusional parasitosis manifests as a fixed, false belief that an individual is infested by living organisms. Primary delusional parasitosis is a psychiatric disorder with the delusion as an isolated manifestation, whereas secondary delusional parasitosis is a delusion occurring secondary to a psychiatric disorder, substance use, or medical illness. A 62-year-old woman with no psychiatric history presented to the Emergency Department with two to three months of "whole body itching" and seeing small insects crawling on her skin and in her hair. Exam of her skin and scalp was notable for no appreciable lesions, rashes, excoriations, or insects. Her neurologic exam was notable for full visual fields, and no localizing deficits. A non-contrast head CT demonstrated a nonspecific heterogeneous low-attenuation lesion within the medial right occipital lobe, and a follow up MRI confirmed a right posterior cerebral artery distribution subacute infarction. She was admitted for two days, and ultimately was discharged on aspirin and atorvastatin for secondary prevention. An emergency physician should remain vigilant in his/her assessment of patients with seemingly psychiatric symptoms, in particular elderly patients with no known psychiatric illnesses. Neuroimaging should be amongst studies considered in the evaluation of elderly patients presenting with new onset psychiatric complaints.

Regional gray matter volume and structural network strength in somatic vs. non-somatic delusional disorders.

BACKGROUND: Monothematic delusional disorders are characterized by a single tenacious belief. They provide a great opportunity to study underlying brain structures in the absence of confounding symptoms that accompany delusions in schizophrenia. Delusional beliefs include persecution, jealousy or somatic delusions including infestation. It is unclear whether specific delusional content is associated with distinct neural substrates. METHODS: We used magnetic resonance imaging in patients presenting with somatic vs. non-somatic delusional disorders. Patients with delusional infestation (DI, n=18), and individuals with non-somatic delusional disorders (n=19) were included, together with healthy volunteers (n=20). Uni- and multivariate techniques for structural data analysis were applied to provide a comprehensive characterization of abnormal brain volume at both the regional and neural network level. RESULTS: Patients with DI showed lower gray matter volume in thalamic, striatal (putamen), insular and medial prefrontal brain regions in contrast to non-somatic delusional disorders and healthy controls. Importantly, these differences were consistently detected at regional and network level. Compared to healthy controls, patients with delusional disorders other than DI showed lower gray matter volume in temporal cortical regions. CONCLUSION: The data support the notion that dysfunctional somatosensory and peripersonal networks could mediate somatic delusions in patients with DI in contrast to delusional disorders without somatic content. The data also suggest putative content-specific neural signatures in delusional disorders and in delusion formation per se.

Cortical features of distinct developmental trajectories in patients with delusional infestation.

BACKGROUND: Although there is strong neuroimaging evidence that cortical alterations are a core feature of schizophrenia spectrum disorders, it still remains unclear to what extent such abnormalities occur in monothematic delusional disorders. In individuals with delusional infestation (DI), the delusional belief to be infested with pathogens, previous structural MRI studies have shown prefrontal, temporal, parietal, insular, thalamic and striatal gray matter volume changes. Differential contributions of cortical features of evolutionary and genetic origin (such as cortical thickness, area and folding) which may distinctly contribute to DI pathophysiology are unclear at present. METHODS: In this study, 18 patients with DI and 20 healthy controls (HC) underwent MRI scanning at 1.0T. Using surface-based analyses we calculated cortical thickness, surface area and local gyrification index (LGI). Whole-brain differences between patients and controls were investigated. RESULTS: Surface analyses revealed frontoparietal patterns exhibiting altered cortical thickness, surface area and LGI in DI patients compared to controls. Higher cortical thickness was found in the right medial orbitofrontal cortex (p<0.05, cluster-wise probability [CWP] corrected). Smaller surface area in patients was found in the left inferior temporal gyrus, the precuneus, the pars orbitalis of the right frontal gyrus, and the lingual gyrus (p<0.05, CWP corr.). Lower LGI was found in the left postcentral, bilateral precentral, right middle temporal, inferior parietal, and superior parietal gyri (p<0.01, CWP corr.). CONCLUSION: This study lends further support to the hypothesis that cortical features of distinct evolutionary and genetic origin differently contribute to the pathogenesis of delusional disorders. Regions in which atrophy was observed are part of neural circuits associated with perception, visuospatial control and self-awareness. The data are in line with the notion of a content-specific neural signature of DI.

Functional magnetic resonance imaging in dermatology: The skin, the brain and the invisible.

The skin and brain have a close bi-directional anatomical and functional connection. Historically, the skin-brain axis and the brain-skin axis have been well described. However, brain function in this context has only recently been demystified with the introduction of functional neuroimaging in dermatology. Functional neuroimaging, especially functional magnetic resonance imaging (fMRI), allows indirect visualisation of brain function. This review looks back to the beginnings of functional neuroimaging in dermatology, summarises the currently available dermatology-related fMRI studies and discusses the potential future role of fMRI as a stratifying tool in clinical dermatology and in the development of novel therapies. According to the main body of research made in this field, the focus is placed on experimental itch studies, which described the brain structures involved in itch processing, the regulation of the scratch response, contagious itch and itch suppression.