|Year : 2015 | Volume
| Issue : 1 | Page : 64-66
Organic delusional disorder in a case suggesting Huntington's disease
Manu Sharma, Girish Kumar, AT Safeekh, P John Mathai
Department of Psychiatry, Father Muller Medical College, Mangalore, Karnataka, India
|Date of Web Publication||8-Dec-2014|
Department of Psychiatry, Father Muller Medical College, Kankanady, Mangalore - 575 002, Karnataka
Source of Support: None, Conflict of Interest: None
Huntington's Disease (HD) is an autosomal dominant progressive degenerative disorder of the basal ganglia characterized by motor, cognitive, and psychiatric manifestations, with an estimated prevalence of 1.75 per 100,000. It can present any time between infancy and senescence. Mood disorders, obsessive compulsive symptoms, psychosis, delirium, sexual disorders, and 'frontal' syndromes, have been reported in patients with HD. Delusions are seen in only about 5-12%. Indian data on HD has been largely through case reports. Given this background, we present an uncommon case with clinical features suggestive of HD and organic delusional disorder. This case report presents the psychiatric and neurological features of a 39-year-old male, who presented with abnormal choreiform movements since eight years, followed by a delusion of infidelity, and a family history suggestive of HD. Differential diagnosis and laboratory results, including neuroimaging and treatment, are presented. Delusions are the common manifestation of psychosis in patients with brain disorders, occurring more often than a formal thought disorder. Lesions of the temporal lobes or caudate nuclei and bilateral brain involvement are common in disorders manifesting psychosis. However, reasons for the infrequent occurrence of delusions in HD, in comparison to other neurodegenerative disorders, are unknown.
Keywords: Basal ganglia, Huntington′s disease, organic delusional disorder
|How to cite this article:|
Sharma M, Kumar G, Safeekh A T, Mathai P J. Organic delusional disorder in a case suggesting Huntington's disease. Muller J Med Sci Res 2015;6:64-6
|How to cite this URL:|
Sharma M, Kumar G, Safeekh A T, Mathai P J. Organic delusional disorder in a case suggesting Huntington's disease. Muller J Med Sci Res [serial online] 2015 [cited 2019 Jun 20];6:64-6. Available from: http://www.mjmsr.net/text.asp?2015/6/1/64/146468
| Introduction|| |
Huntington's disease (HD) is an autosomal dominant progressive degenerative disorder of the basal ganglia characterized by motor, cognitive, and psychiatric manifestations, with an estimated prevalence of 1.75 per 100,000. Indian data on HD has been largely through case reports.  Mood disorders, obsessive compulsive symptoms, psychosis, delirium, sexual disorders, and 'frontal' syndromes have been reported in patients with HD. Delusions are seen in only about 5-12% of the patients.  Given this background, we present an uncommon case with clinical features suggestive of HD and organic delusional disorder.
| Case Report|| |
A 39-year-old, premorbidly well, male manual laborer, with class eight education, who was a resident of a nuclear family in a rural area, with history of abnormal involuntary movements of neck and limbs, irritability, and abusiveness since eight years, followed by suspiciousness toward his wife's fidelity since seven years, was brought by his wife. The symptoms were of a gradual onset, with a progressive course. These abnormal movements were aggravated during outbursts of anger, and disturbances in mood, but were absent during sleep. There was no weakness in any of the limbs, but he was unable to perform regular household activities properly and had to change his job from being a truck driver to a manual laborer. There was no history of chest pain, breathlessness, substance use, prescription medication use or exposure to toxins. He had an unremarkable past or personal history. Family history revealed similar abnormal movements in his father, who had died around the age of 60 years.
On mental state examination, he was conscious and alert with normal psychomotor activity. No abnormality with speech or language was found. He had an appropriate irritable affect with increased reactivity and range. A secondary, non-bizarre, persistent delusion of infidelity was elicited. On cognitive function testing, his attention was aroused, but was not sustained. He was oriented, but with impaired recent memory. General intelligence was average and demonstrated a semi-abstract level of thinking on proverb and similarity testing.
His general physical examination was non-contributory and normotensive. His cardiovascular system, abdomen, and respiratory system were essentially normal. On central nervous system examination he had normal power in all four limbs. The deep tendon reflexes in all four limbs were normal and the plantar reflex was normal bilaterally as well. The sensory and cerebellar systems were normal and the bladder and bowel were intact. However, he could not fix his gaze at one point for more than 30 seconds, with repetitive blinking movements, and was not able to protrude his tongue out for more than 30 seconds. Oculomotor examination revealed slowing of the saccades. Abnormal choreiform movements were noted in the upper and lower limb extremities, along with neck and proximal upper limb dystonia. His Mini Mental State Examination Score was 17/30.
Hematological and biochemical investigations including peripheral blood smear, thyroid profile, and rheumatoid factor were within normal limits. Slit lamp examination was negative for Kayser-Fleischer (KF) rings. Magnetic resonance imaging (MRI) of the brain [Figure 1] and [Figure 2] showed prominence of the lateral ventricles, flattening of the wall of the frontal horn, and the bicaudate distance between the ventricles was also increased, suggestive of atrophy of the caudate nucleus.
|Figure 1: MRI of the brain of the patient showing atrophy of the bilateral caudate nuclei|
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|Figure 2: MRI of the brain of the patient showing bilateral caudate nucleus atrophy|
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Considering the history, clinical examination, MRI findings, and family history of the patient, a diagnosis of organic delusional disorder; Huntington's disease, was made. Due to financial constraints, the patient's family members declined genetic testing for confirmation of clinical diagnosis. He was discharged on Olanzapine 20 mg HS, Lorazepam 2 mg HS, Tetrabenazine 25 mg TID, and Vitamin E 400 mg BD. The patient did not return for follow up.
| Discussion|| |
Huntington's disease (HD), a progressive disorder characterized by dementia and chorea inherited as an autosomal dominant disorder, displays a striking variability in the clinical manifestations and the age at which the first symptoms appear. It usually begins in mid-life, between ages 21 and 50, with an average age of onset of 40 years. Chorea and cognitive impairment slowly worsen for 15 to 20 years and death commonly results from intercurrent infection at an average age of 54 years.
Huntington's disease is a member of the growing family of neurodegenerative disorders associated with trinucleotide repeat expansion. The cytosine-adenosine-guanidine (CAG) triplet expansion in exon 1 encodes an enlarged polyglutamine tract in the Huntington protein. The precise pathophysiological mechanisms of HD are poorly understood, but research in transgenic animal models of the disorder is providing an insight into the causative factors and potential treatments. 
Neuropsychiatric symptoms are common in HD and are considered to be its presenting manifestation. Research characterizing these symptoms in HD is variable, however, it is encumbered by limitations within and across the studies.  Gaining a better understanding of the neuropsychiatric symptoms is essential, as these symptoms have implications for disease management, prognosis, and quality of life for patients and caregivers. Neuropsychiatric symptoms are prevalent in HD and are relatively independent of the cognitive and motor aspects of the disease.
The Huntington's Disease presents a unique opportunity to investigate the development and evolution of psychopathological disorders. The presence of abnormal movements and a positive family history in this case provides 'external' validating factors. Delusions are the common manifestations of psychosis in patients with brain disorders, occurring more often than a formal thought disorder. Lesions of the temporal lobes or caudate nuclei and bilateral brain involvement are common in disorders manifesting psychosis.  The 'basal ganglia-thalamocortical' and 'corticostriatal-thalamocortical' loops connect the limbically related cortical regions with the mesolimbic-mesostriatal dopamine system. By directing research focus on these loops, we can view the neural network that may produce delusional thinking when its restitutive function fails. Given the importance of the hippocampus in the memory system of the medial temporal lobe, as the recipient of emotional valencing from the amygdala, and as a key 'loop' structure for cognitive functional integrity, the former may be a nodal area in the development of 'rational' as opposed to 'delusional' thinking. 
| Conclusion|| |
The reasons for the infrequent occurrence of delusions in HD in comparison to other neurodegenerative disorders are unknown. The hypothesized link between the neuropsychiatric symptoms of HD and the frontal-striatal circuitry need exploration.
| References|| |
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[Figure 1], [Figure 2]