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Both anosognosia and secondary mania are associated with right hemispheric lesions. These two non-dominant syndromes, however, are rarely described as occurring together. We present a patient with a right thalamic haemorrhage giving rise to profound denial of hemiplegia and elated mood. This case suggests mechanisms for the common production of mania and anosognosia.
A 53 year old, right handed, black man, with a history of alcohol misuse and dependence and untreated hypertension, was brought to the emergency room a few hours after developing an intense headache and left sided numbness and weakness.
On admission he was described as “belligerent,” “agitated,” and “confused.” Blood pressure was 240/160. Neurological examination disclosed left lower facial droop, decreased left corneal and gag reflexes, and left hemiparesis with dense sensory deficits. With increasing obtundation, the patient was transferred to the intensive care unit and intubated. Brain MRI showed a large, right sided, hyperacute thalamic bleed with mass effect and oedema. The patient was extubated 2 days later and 4 days after the stroke he was described as being drowsy and inattentive, but was able to answer questions appropriately. Neurological examination showed contralateral gaze preference, supranuclear vertical gaze palsy, difficulty converging, left sided flaccid hemiparesis, and dense, left sided hemianaesthesia. Deep tendon reflexes were absent on the left and Babinski's reflex was present on the left. In addition, visual extinction and neglect were present.
At the time of onset of right sided weakness the patient insisted that he was “fine,” and an ambulance was called over his objections. After being extubated, the patient acknowledged that he had had a stroke, but, despite his hemiparesis, insisted that he was ready to go home and go back to work. His belief in his ability to walk led to near falls, and he was moved to a room nearer to the nurses' station for closer observation. He told the nurses that someone else's arm was in his bed. On one occasion, holding up his left arm with his right, he told the nurse to, “take it away; it keeps scratching me.” That the left arm “smelled funny” was another reason he wanted the nurses to take it away.
Four weeks after the stroke he first acknowledged that his left arm belonged to him. He spontaneously recalled believing otherwise. By this time he had a moderate hemiplegia and recognised “a little weakness,” but continued to insist that he was well and able to return to work. By the 6th week after stroke the patient more consistently acknowledged that he was weak on the left side of his body. A request for disabled housing “so that I won't be a burden to my family” seemed to indicate an appreciation of his impairment, but this insight was fleeting; within an hour of making such statements the patient might insist that after a week's exercise he would be ready to return to work. His awareness of his hemiplegia fluctuated for 8 weeks after stroke before becoming fixed, but remained shallow after 12 weeks; he no longer planned to return to work and applied for social security disability insurance “because they say I'm disabled.”
The patient's mood was remarkably cheerful and optimistic. A week after the stroke he was noted to praise extravagantly the hospital food, and the nurses found him “talkative.” When he arrived on our ward 11 days after the stroke he was flirtatious with female staff and boasted of having fathered 64 children. His girlfriend was surprised when he kissed her in front of the staff because he had never publicly displayed affection before. He reported excellent energy and expansively invited all of the staff to his home for thanksgiving. Sleep was not disrupted or reduced and he had a good appetite. When beginning to acknowledge his left sided weakness, he remained blissfully unconcerned. He scored 31 points on a mania rating scale,1 which was well in the manic range. The mania resolved gradually over a 10 week period after stroke.
Other than alcoholism, the patient had no history of psychiatric illness and there was no family history of psychiatric illness. The patient had not seen an physician in many years. Visual acuity was found to be reduced to 20/800 in both eyes on the basis of hypertensive retinopathy.
Evaluation 1 month after stroke showed many deficits and a few strengths. Inattention to the left hemispace was marked. By 2 months after stroke he no longer extinguished to double simultaneous stimulation, but, although he could see to the left, was still missing targets in his left visual hemifield. Visual integration, both with and without the requirement of construction, was severely impaired. He was able to correctly recognise and produce facial emotional information. Simple attention was intact, but attentional control (backward span and mental control) was impaired. Visuomotor tracking was slow and he had significant problems with conceptual shifting (both auditory and visual). Language processing difficulties included very poor reading ability, impaired confrontation naming, and impaired performance on a verbal task of fluency and initiation. Auditory comprehension was mildly impaired. Vocabulary scored formally in the borderline impaired range, as did abstract verbal reasoning. On tests of praxis he demonstrated a tendency to use the hand as object. Memory performances were relatively intact. His initial recall of two paragraphs scored formally within the low average range and after a 30 minute delay, he was able to recall most of the information initially encoded, scoring formally within the average range.
Structural brain MRI on admission to the emergency room showed a large right thalamic hemorrhage with mass effect and oedema, with oedema extending into the cerebral peduncle with internal susceptibility consistent with deoxyhaemoglobin. Also present was increased T2 signal bilaterally in frontal areas consistent with ischaemic changes. Brain CT 30 days after stroke showed, in addition to the thalamic lesion, moderate cerebellar atrophy and mild to moderate prominence of the frontal cortical sulci compatible with cerebral atrophy.
Structural MRI performed 44 days after the stroke showed a 2 cm right thalamic haematoma. Functional MRI2 performed the same day demonstrated a 2 cm area of absent cerebral blood volume at the posterior margin of the right thalamus without any evidence of decreased cerebral blood volume within the right parietal, frontal, or temporal cortex.
This is a case of anosognosia of hemiplegia and mania co-occurring in a patient with a large right thalamic haemorrhage. Although anosognosia and mania are not generally thought of as occurring together, when Babinski3 introduced the term anosognosia he used as one of his examples a case in which the patient, though not confused, was “a little overexcited,” and in a later paper he presented a case4 in which there was “a certain agitation, which expresses itself by exaggerated loquacity, a decrease in attention, and a tendency to erotic ideas.” Weinstein and Kahn5 noted that euphoria was common in patients with anosognosia. Moreover, although Cutting6 emphasised that apathy is the mood more usually associated with anosognosia, 10% of his patients with anosognosia were described as having “euphoric mood.”
Right sided thalamic lesions are known to produce both anosognosia and mania, but the relation of each to the pathology is unclear. Only some of the patients with right hemispheric lesions are manic or agnosic. These two syndromes may be related to dysfunction of different neural networks and only occur together when a disease process affects both networks.
Another possibility is that these syndromes are aetiologically related. Could anosognosia be a manifestation of mania? Although it is easy to conceive how elevated mood might facilitate anosognosia of hemiplegia (or other types of anosognosia), it is difficult to explain the presence of denial of ownership and dislike of the left arm (other anosognosic phenomena) on the basis of euphoria. Moreover, Starksteinet al,7 finding that similar frequencies and severities of major and minor depression were present in patients with and without anosognosia, suggest that a particular mood state may not necessarily influence insight.
Several explanations have been proposed to explain the phenomenon of anosognosia.8 9 All the models invoke dysfunction of the cerebral cortex, especially the parietal cortex. It is interesting that in this case functional MRI failed to demonstrate decreased CBV in the parietal lobe.
In summary, we present a case of mania accompanying anosognosia in a patient with a right thalamic haemorrhage. The coexistence of mania and anosognosia may be more common than previously appreciated. The association with anosognosia implies that the mechanisms implicated in the pathogenesis of secondary mania may be similar to those of anosognosia. The absence of evidence of abnormal parietal, temporal, or frontal lobe function by functional MRI in this case is intriguing.
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