Delusional parasitosis following occipito-temporal cerebral infarction

Letters to the Editor

trunk and scalp. Skin biopsy was taken showing abnormal adhesion between keratinocytes.

We admitted the patient to in-patient treatment, discontinued the lithium therapy, and started valproate as a mood stabilizer (750 mg/day, serum level 81 mg/L). Two days later, the skin had visibly improved, and during the following 2 weeks it returned to its usual stable state. Cranial MRI showed no relevant lesions. No abnormalities were found in metabolic parameters or in the neurological examination. The patient’s mood brightened within 3 weeks. Four weeks after discharge, however, she developed a manic episode that made hospitalization for 4 weeks necessary. Since then, we have seen her as an out-patient for 1 year. Her mood has been constantly euthymic, and her skin has showed a stable state.

Discussion A wide range of cutaneous reactions have been described in association with lithium therapy. Lithium can exacerbate psoriasis and acne, as well as seborrheic dermatitis. Maculopapular eruptions, folliculitis, and vaginal ulceration have been reported. The pathomechanism of this side effect of lithium in dermatological diseases with disordered keratinization is most likely due to the inhibition of the adenyl cyclase systems in the epidermis. Subsequently 3⬘,5⬘-AMP levels are lowered, and this leads to an increased epidermal cell proliferation. The blood level of lithium may play a decisive role in the deterioration of the dermatosis. As there is a possible association between bipolar affective disorder and keratosis follicularis, such patients may receive lithium. We are aware of three accounts of patients with keratosis follicularis that flared during lithium therapy [3,10,11]. One report describes the first appearance of Darier’s disease after initiation of lithium therapy [11]. On the other hand, apart from single cases of hypersensitivity syndrome, flush, or deterioration of porphyria cutanea tarda, there were no confirmed serious cutaneous side effects in a study with 1504 new valproate users [12]. These reports and our experience lead us to the recommendation that patients with the comorbidity of unipolar or bipolar affective disorder

and keratosis follicularis should be treated with valproate instead of lithium as a mood stabilizer. uwe ehrt peter brieger University Hospital of Psychiatry and Psychotherapy Martin-Luther-University Halle-Wittenberg Halle/Saale, Germany PII S0163-8343(00)00050-5

References 1. Darier FJ: Psorospermose folliculaire ve´ge´tante. Ann Dermatol Syphilol 10:597–612, 1889 2. White JC: A Case of Keratosis (Ichthyosis) Follicularis. J Cutan Genitourin Dis 2:201–209, 1889 3. Burge SM, Wilkinson JD: Darier–White disease: a review of the clinical features in 163 patients. J Am Acad Dermatol 27:40–50, 1992 4. Getzler NA, Flint A: Keratosis follicularis: a study of one family. Arch Derm 93:545–549, 1966 5. Medansky RS, Woloshin AA: Darier’s disease: an evaluation of its neuro-psychiatric component. Arch Derm 84:482–484, 1961 6. Denicoff KD, Lehman ZA, Rubinow DR, Schmidt PJ, Peck GL: Suicidal ideation in Darier’s disease. J Am Acad Dermatol 22:196–198, 1990 7. Craddock N, McGuffin P, Owen M: Darier’s disease cosegregating with affective disorder. Br J Psychiatry 165:272, 1994 8. Dawson E, Parfitt E, Roberts Q, Daniels J, Lim L, Sham P, Nothen M, Propping P, Lanczik M, Maier W, et al.: Linkage studies of bipolar disorder in the region of the Darier’s disease gene on chromosome 12q23-24.1. Am J Med Genet 60:94–102, 1995 9. Brieger P: Comorbidity in bipolar disorders. In Marneros A, Angst J (eds): Bipolar Disorders. Cambridge: Cambridge University Press (in press). 10. Clark RD Jr, Hammer CJ, Patterson SD: A cutaneous disorder (Darier’s disease) evidently exacerbated by lithium carbonate. Psychosomatics 27:800–801, 1986 11. Milton GP, Peck GL, Fu JJ, DiGiovanna JJ, Nordlund JJ, Thomas JH, Sanders SF: Exacerbation of Darier’s disease by lithium carbonate. J Am Acad Dermatol 23:926–928, 1990 12. Tennis P, Stern RS: Risk of serious cutaneous disorders after initiation of use of phenytoin, carbamazepine, or sodium valproate: a record linkage study. Neurology 49:542–546, 1997

Delusional Parasitosis Following Occipito-Temporal Cerebral Infarction To the Editor Delusional parasitosis is a belief that the skin is infested with worms, insects, or organisms. It could be produced by a variety of organic processes: toxic, metabolic, and by structural disorders. Delusional parasitosis may occur as a monosymptom-

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atic delusional belief or be one of a number of manifestations of paranoid psychosis [1]. Munro [2] considered delusional infestation (parasitosis) as a monosymptomatic hypochrondrial psychosis. Cerebrovascular diseases involving the temporal lobe and subcortical structures have been known to give rise to delusions in general [3–5]. We describe two patients with stroke-related delusional parasitosis involving the left temporo– occipital regions.

Case 1 A 69-year-old female was seen with a crawling feeling under the scalp and under the skin in the upper trunk and limbs, which she thought was due to insects. Six months earlier, she had suffered a stroke. She would frequently and sometimes continuously scratch or brush her hair with her hand to get rid of them. She had seen a dermatologist and was given a cream with very little relief. By 9 months, she was free of symptoms. There was no past history of mental illness nor a family history. She denied any hallucinations or other delusions of behavioural problems. Inquiry into mood, loss of weight, loss of appetite, sleep, capacity for pleasure, and thoughts about the future did not reveal any symptoms of significant depression. There was no history of substance abuse or heavy drinking. She was on frusemide, potassium supplements, low-dose aspirin, and oral hypoglycemic agents. Examination revealed her to be alert with normal attention span. Her cognition and memory were normal as determined by the Mini-Mental State

Examination. Neurologically, she had minimal weakness of the right arm and leg and a right-sided homonymous hemianopia. There were no sensory impairment. The skin and scalp were normal. She was normotensive with no evidence of cardiac decompensation, and she was in atrial fibrillation. Routine haematological and biochemical tests, including blood sugar, were within normal limits. The electrocardiogram and x-ray of the chest were normal. A carotid doppler showed 80 –90% stenosis of the left internal carotid artery. The computed tomography (CT) scan of the brain showed a left temporo-occipital infarction (Fig. 1).

Case 2 A few weeks following a left cerebro–vascular accident a 65-year-old female gave a history of her skin being “infested with tiny bugs” many years ago, but had been free of symptoms for several years, with a recurrence following the stroke. She reported she had never seen these “bugs,” but knew they were there and that no one believed her, not even the doctors. She had used countless lotions to no avail and continued to use them “just in case” these bugs came back. The itching and scratching were worse at night, and she often scratched hard and occasionally punched herself. The past medical history included migraine-like headaches, chronic multi-disc back problems, and hysterectomy. Following the stroke, she was on warfarin. She is a non-drinker and had not been on recreational drugs. She lived alone. Her first husband walked out

Figure 1. CT scan of brain showing a left temporo– occipital infarction.

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and she had no knowledge of his whereabouts for 8 years when she received divorce papers. She had poor relationship with the second husband, who “walked out on me for another woman,” and split from her third partner. She had two children by the first marriage and a third by the third partner. None of the children now talk to her, and according to one of the daughters she would often try to get the family to look and seek the bugs and buy the lotions. No other family members had seen the “bugs” but complied with her demands. Physical examination revealed no abnormalities in the skin. She had a sensori-motor impairment of the right side with right homonymous hemianopia. The Mini-Mental State Examination scores were normal. There were no overt abnormalities in the other systems, but for atrial fibrillation. The CT scan showed left temporo– occipital infarction (Fig. 2). Doppler scans of the carotid and vertebral arteries were normal. Routine biochemical and haematological tests were within normal limits. She refused any form of treatment. We have briefly presented data from two subjects who showed striking manifestations of delusional parasitosis. Both patients had no history of psychiatric illness nor memory or cognitive impairment. Many of the cases that had been described were due to diffuse disease. Flynn et al. [6] described a 69year-old male with a crawling sensation beneath the skin of the left ear, arm, leg, and the scalp. Neuroimaging revealed lesions in the paraventricular regions bilaterally and in the right splenic area. The symptoms were on the contralateral side. In

our patients, symptoms were bilateral. There is no specifcity as to the region associated with delusions of infestations, but the majority of lesions reported have been in the subcortical structures [6]. In our subjects, they were cortical and subcortical. According to Cummings [1], delusional parasitosis and organic delusions disorders share a common topography of brain lesions involving the subcortical and limbic brain areas and have been associated with lesions in either hemisphere [6] and with lesions at various sites, for instance, the right temporo–parieto– occipital [4], left temporo–parietal [7], right basal ganglia, and with multiple lacunar infarction, and were more closely associated with posterior than anterior lesions of the left hemisphere [6]. Post-stroke psychiatric disorders could be related to structural damage to the neuronal pathways or to abnormalities to some of the brain’s chemical transmitter systems. Interruption of the ascending dopaminergic pathways and transmitter systems are implicated in idiopathic schizophrenia and attention has been drawn to the similarities of delusions in schizophrenia and those of limbic and subcortical disorders [1,7]. According to Cummings [1], delusions could arise from lesions in a variety of locations, and each lesion disrupts limbic– cortical associations in a different way and the abnormal response could interact with intact cortex to give rise to clinically distinguishable delusional syndromes. An explanation as to why delusions are not a uniform feature of similar central nervous system disorders is that there occurrence could be influ-

Figure 2. CT scan of the brain showing a left temporo– occipital infarction.

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enced by several factors, namely genetic constitution, age of onset, early life experiences, personality characteristics, exact location and extent of lesion— among others [1]. The duration of symptoms of delusional parasitosis could range from 2 months to 20 years with an average of 2 years with a recent exacerbation in long-standing cases [2] and are well-illustrated in our patients. Treatment is usually unsatisfactory and many drugs have been tried, most often without success. Antidepressants and neuroleptics have been suggested as treatment of choice with varying degrees of benefit [6], and pimozide is said to produce striking responses [8]. It is possible that the symptoms that are observed are more complex and most unlikely to be due to disruption of a single neurotransmission system [9]. Case 1 in our study did not have any treatment and Case 2 refused treatment. Although not usually associated with any other psychiatric illness, the patient with delusional parasitosis could manifest instability, eccentricity, or a social pre-morbid personality [2]. Munro [2] drew attention to the high frequency of divorces, separations, and non-marriage separations and habitual problems of sustaining relationships as in Case 2 in our study. A pathogenic relationship between the delusional parasitosis and the temporo– occipital lobes is invoked. It is hypothesised that delusional parasitosis could arise from strategically placed lesions causing damage to the anatomical pathways, vascular compromise or to biochemical changes involving the neurotransmitter systems. n. nagaratnam l. o’neile Department of Medicine Aged Care Services and Rehabilitation Blacktown-Mt Druitt Health Blacktown, NSW, 2148, Australia PII S0163-8343(00)00064-5

References 1. Cummings JL: Organic delusions: phenomenology, anatomical correlations and review. Br J Psychiatry 14:184–197, 1985 2. Munro A: Monosymptomatic hypochondriacal psychosis. Can Psychiatr Assoc J 23:497–500, 1978 3. Levine DN, Finklestein S: Delayed psychosis after right temperoparietal stroke or trauma related to epilepsy. Neurology 32:267–273, 1982 4. Peroutka SJ, Sohmer BH, Kumer AJ, et al: Hallucina-

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tions and delusions following a right temperoparietal occipital infarction. John Hopkins Med J 151:181–185, 1982 Nagaratnam N, Pathmanathan N: Behavioural and psychiatric aspects of silent cerebral infarction. Br J Clin Pract 51:160–163, 1997 Flynn FG, Cummings JL, Scheibel J, et al: Monosymptomatic delusions of parasitosis associated with ischaemic cerebrovascular disease. J Geriatr Psychiat Neurol 2:134–138, 1989 Cummings JL, Miller B, Hill MA, et al: Neuropsychiatric aspects of multi-infarct dementia and dementia of the Alzheimer type. Arch Neurol 44:389–393, 1987 Renvoize EB, Kent J, Klar HM: Delusional infestation in dementia. A case report. Br J Psychiatry 150:403– 405, 1987 Anderson G, Vestergaart K: Letter. Stroke 22:2296, 1994

The Usefulness of Single Photon Emission Computed Tomography in Charles Bonnet Syndrome: A Case with Occipital Lobe Involvement To the Editor Charles Bonnet syndrome (CBS) is characterized by vivid, complex and recurrent visual hallucinations in psychologically normal people, and is often associated with eye pathology [1,2]. It has been debated whether CBS is caused by sensory deprivation due to eye pathology or by certain brain damage [1,3]. Static neuroimaging techniques such as computed tomography (CT) or magnetic resonance imaging (MRI) have been used repeatedly to address this issue, whereas a functional neuroimaging technique, single photon emission computed tomography (SPECT), has been used only in a few cases [4 – 6]. We therefore performed SPECT in a patient with CBS and detected an occipital lesion. The etiological significance of this lesion and the role of functional neuroimaging in CBS cases are discussed.

Case Report A 73-year-old right-handed woman without prior personal or family neuropsychiatric history was referred to our clinic for evaluation of her mental state. At age 32, she was diagnosed as having an inherited retinal disease, retinitis pigmentosa. Her vision had gradually deteriorated, necessitating full assistance from her husband in her daily activities. By age 70, she was only able to perceive the movement of raised fingers but not to count them. She had a